v1.4.4: bump version (freemkv-unlock git-pinned for the tag)

The keyserver protocol now returns all 32 index keys as an array for a
forensic content sample (and a single-element array for plain content).
resolve_fmts_key_map sends one forensic batch and maps array element i to
segment index i+1, replacing the per-index blind-probe collection loop
that repeatedly hit the key service. Segment/index parsing and the
aligned-unit content classification are reworked to support this:

- rename variant_select -> index_select (per-index, not per-variant)
- content classification moves to is_clean(buf, ContentFormat) so the
  unit selector emits only units the key service accepts
- segment.rs: parse IndividualSegment.tbl index tags + SPN ranges,
  build contiguous LBA key ranges from the resolved 32-key array
- decrypt/decorator plumbing for the resolved per-index keys

Fail loud (FmtsKeyMissing) when the forensic query returns < 32 keys or
any segment index stays unresolved.

CHANGELOG.md

@@ -1,5 +1,89 @@
 # Changelog
 
+## [1.4.2] — 2026-07-15
+
+### Fixed
+
+- **Mux no longer nulls decryptable video or storms the key server on a
+  bad-encoded region.** 1.4.1 relaxed the decrypt gate but left the surrounding
+  machinery in place. On a unit whose key *decrypted* but whose plaintext didn't
+  reassemble to clean MPEG-TS, the read path still restored ciphertext, tallied
+  loss, and re-asked the online key server (forever returning the same correct key)
+  while the mux concealed the unit as NULL TS. The root cause: *"did a key produce
+  clean TS?"* was used as the verdict *"did we decrypt?"* — they are not the same.
+  A correct key can decrypt content with broken encoding; broken TS is a muxer
+  concern, never a decrypt verdict.
+
+### Changed
+
+- **One decrypt authority; policy at the caller.** `decrypt_sectors` is now a
+  pure decrypt: applies the CPS unit key in place, leaves plaintext, and reports
+  unverified bytes. It never restores ciphertext, nulls, or re-fetches a key.
+  Clean-TS status is only a key-*selection* hint (multi-CPS) or a read-*verify*
+  signal (sweep/patch). Callers own the policy: the mux passes decrypted bytes
+  through unconditionally (the demuxer handles bad TS); sweep/patch treat an
+  unverified unit as a failed read and re-read it. Removes the decrypt-time
+  ciphertext restore, the mux NULL-TS conceal loop, and the per-unit key-server
+  refetch, plus the dead `aacs_unit_still_ciphertext` predicate.
+
+- **Decrypt and TS-structure are now separate primitives.** AACS has no MAC;
+  the only "did it decrypt?" signal is whether plaintext looks like MPEG-TS —
+  a data-quality / key-selection question, not a decrypt verdict. The old
+  `decrypt_unit(...) -> bool` is split into `decrypt_unit_raw` (pure crypto) and
+  `is_clean_ts` (structural check), composed explicitly only where needed. The
+  mux calls only `decrypt_unit_raw`.
+
+- **Key-proof floor replaces the 75% supermajority.** The old proportion
+  (≥75% of content packets synced) conflated *the key worked* with *the content
+  is well-encoded*. `is_clean_ts` now requires `synced >= min(E, 4)` on
+  **encrypted** packets (skipping packet 0 whose `0x47` is in the clear seed):
+  four synced packets ≈ 1-in-4-billion false-positive; `min(E, 4)` scales to
+  short fragment tails so they're never false-rejected. A unit is "opened" when
+  a handful of packets prove the key — bad-encoded packets are the muxer's job.
+
+## [1.4.1] — 2026-07-14
+
+### Fixed
+
+- **Mux no longer discards good video over a single defective packet.** AACS
+  decryption required **every** content packet to be conformant MPEG-TS: one
+  authored-bad packet (encoding defect, AACS 2.1 forensic-variant frame) made
+  the mux conceal the **whole** 6144-byte aligned unit as NULL TS (up to 31/32
+  good packets discarded, tallied as loss). On affected discs this produced
+  false "corruption" over otherwise-perfect video (~466 MB concealed across two
+  UHD titles). The gate is now a padding-aware **≥75% supermajority** of content
+  packets restoring their `0x47` sync — no wrong key reaches this threshold
+  (uniform-AES noise floor ≈ 256⁻ⁿ), but a minority of authored-bad packets
+  still passes. Opened units flow through verbatim; the demuxer drops
+  non-conforming packets on sync-loss. TS-sync conformance is a muxer concern,
+  never a decrypt verdict. (The supermajority threshold is tightened in 1.4.2.)
+- **MVC (Blu-ray 3D) track signals unified and hardened.** The `mvcC`
+  `CodecPrivate` extension, the `BlockAdditionMapping`, and each frame's
+  `BlockAdditional` now all derive from a single `MVCDecoderConfigurationRecord`
+  built once per track, so they can no longer diverge. A track is flagged 3D
+  only when that record actually builds — a malformed dependent-view parameter
+  set no longer emits a mapping with no matching record (previously the flag was
+  taken from `mvc_params.is_some()`, which could orphan a `BlockAddID`). The base
+  track's `CodecPrivate` now carries the `mvcC` extension block
+  (`avcC ‖ u32be(size) ‖ "mvcC" ‖ record`, Matroska-spec size = block − 4) so
+  players and mediainfo detect MVC at the track level.
+
+## [1.4.0] — 2026-07-13
+
+### Added
+
+- **Blu-ray 3D (MVC) support.** A 3D disc now rips to an MKV that preserves
+  **both eyes** as a single MVC video track — the AVC base (left) view in each
+  Block, and the MVC dependent (right-eye) view as a per-frame `BlockAdditional`
+  under an `mvcC` `BlockAdditionMapping` (`MVCDecoderConfigurationRecord` per
+  ISO/IEC 14496-15 §7.6.2), paired to the base by PTS. Remux only — no
+  transcode, no side-by-side conversion. The Blu-ray scan reads the interleaved
+  `STREAM/SSIF/<clip>.ssif`, enumerates the dependent view (stream_type `0x20`)
+  by the BD-3D PID convention, and parses it in a parameter-set-passthrough mode
+  so every dependent frame is a self-contained access unit. Verified on
+  *300: Rise of an Empire*: one MVC track, ~8.7 GB dependent payload carried in
+  per-frame BlockAdditionals, base view byte-identical to the 2D rip.
+
 ## [1.3.2] — 2026-07-10
 
 ### Added

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "1.3.2"
+version = "1.4.4"
 edition = "2024"
 rust-version = "1.86"
 license = "MIT"
@@ -28,7 +28,7 @@ cbc = "0.1"
 # Interim path dep for local cross-repo dev; the release script re-pins this to
 # `{ git = ".../freemkv-unlock", tag = "vX.Y.Z" }` before tagging libfreemkv (so
 # the released tag resolves freemkv-unlock from git, not a sibling path).
-freemkv-unlock = { path = "../freemkv-unlock" }
+freemkv-unlock = { git = "https://github.com/freemkv/freemkv-unlock", tag = "v1.4.4" }
 num-bigint = "0.4"
 num-traits = "0.2"
 num-integer = "0.1"

src/aacs/derive.rs

@@ -463,7 +463,7 @@ pub enum KeyCandidate {
 /// PURE DERIVATION — no unit sampling, no validation. `unit_keys` holds every
 /// CPS-unit key the disc's `Unit_Key_RO.inf` yields from the VUK (paired with
 /// its declared CPS-unit number); the caller runs
-/// [`super::content::unit_key_validates`] to find which one actually opens the
+/// `decrypt_unit` + `is_clean_ts` to find which one actually opens the
 /// disc. Rungs above the candidate are `None`.
 #[derive(Debug, Clone)]
 pub struct ResolvedChain {
@@ -487,7 +487,7 @@ pub struct ResolvedChain {
 ///
 /// PURE DERIVATION: no sampling, no validation, no position recovery. Validate
 /// `unit_keys` against a real encrypted unit with
-/// [`super::content::unit_key_validates`] to prove the candidate opens the disc.
+/// `decrypt_unit` + `is_clean_ts` to prove the candidate opens the disc.
 ///
 /// Returns `None` only when derivation itself cannot proceed: a PK its MKB
 /// rejects, a `Dk` the MKB can't process, a missing VID on a path that needs
@@ -505,7 +505,8 @@ pub fn resolve_candidate(
         let version = mkb_type(mkb)
             .map(|t| t.generation())
             .unwrap_or(AacsVersion::V10);
-        let ukf = parse_unit_key_ro(unit_key_ro, version)?;
+        // BD/UHD Unit_Key_RO.inf or HD DVD VTKF000.AACS — dispatched by magic.
+        let ukf = parse_title_keys(unit_key_ro, version)?;
         if ukf.encrypted_keys.is_empty() {
             return None;
         }

src/aacs/index_select.rs

@@ -1,73 +1,73 @@
-//! FMTS variant selection — the pure decode-time decision for a 2.1 disc.
+//! FMTS index selection — the pure decode-time decision for a 2.1 disc.
 //!
-//! A 2.1 disc resolves to exactly one forensic variant (1..=32) for a given
-//! rip. `IndividualSegment.tbl` tags each forensic segment with a variant (see
-//! [`super::segment`]); the decode keeps the segments matching our variant,
+//! A 2.1 disc resolves to exactly one forensic index (1..=32) for a given
+//! rip. `IndividualSegment.tbl` tags each forensic segment with an index (see
+//! [`super::segment`]); the decode keeps the segments matching our index,
 //! drops the other 31, and treats everything outside a segment as ordinary
-//! (variant-0) content. This module owns that classification and nothing else —
+//! (index-0) content. This module owns that classification and nothing else —
 //! no I/O, no keys, no cipher — so it is fully testable in isolation. The
 //! decrypt pipeline consumes the [`UnitDisposition`] it returns.
 //!
-//! Where the resolved variant comes from is a separate concern
-//! ([`resolve_disc_variant`]): today it is read off the variant keys the key
+//! Where the resolved index comes from is a separate concern
+//! ([`resolve_disc_index`]): today it is read off the index keys the key
 //! source handed us; when Processing Keys are available it will come from the
 //! VK derivation instead. Either way the disposition logic below is identical.
 
-use super::segment::{Segment, variant_segment_for_unit};
+use super::segment::{Segment, segment_for_unit};
 use super::types::UnitKey;
 
 /// What the decode should do with one AACS aligned unit.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum UnitDisposition {
     /// Outside every forensic segment: ordinary content, decrypt with the
-    /// default (variant-0) unit key.
+    /// default (index-0) unit key.
     Default,
-    /// Inside a forensic segment tagged with OUR resolved variant: decrypt with
-    /// that variant's key.
-    Variant(u8),
-    /// Inside a forensic segment tagged with a DIFFERENT variant: not our
+    /// Inside a forensic segment tagged with OUR resolved index: decrypt with
+    /// that index's key.
+    Index(u8),
+    /// Inside a forensic segment tagged with a DIFFERENT index: not our
     /// watermark, so it is not part of our output — drop it.
-    DropForeignVariant(u8),
-    /// Inside a forensic segment but no variant key is held (the disc's variant
+    DropForeignIndex(u8),
+    /// Inside a forensic segment but no index key is held (the disc's index
     /// was never resolved): the segment cannot be decoded, so it is concealed
-    /// as loss. Carries the segment's variant for diagnostics.
+    /// as loss. Carries the segment's index for diagnostics.
     ForensicNoKey(u8),
 }
 
-/// Resolve the disc's single forensic variant from the keys we hold.
+/// Resolve the disc's single forensic index from the keys we hold.
 ///
-/// Scans for a variant key (`variant_number` in `1..=32`) and returns its
-/// variant. `None` when only default (variant-0) keys are held — i.e. no
-/// variant source answered, so forensic segments are not decodable. A disc has
-/// exactly one variant, so the first non-zero key decides; if several distinct
-/// variant keys were somehow supplied the lowest wins (deterministic), which is
+/// Scans for an index key (`index_number` in `1..=32`) and returns its
+/// index. `None` when only default (index-0) keys are held — i.e. no
+/// index source answered, so forensic segments are not decodable. A disc has
+/// exactly one index, so the first non-zero key decides; if several distinct
+/// index keys were somehow supplied the lowest wins (deterministic), which is
 /// only a defensive tiebreak — the probe/derivation yields one.
-pub fn resolve_disc_variant(unit_keys: &[UnitKey]) -> Option<u8> {
+pub fn resolve_disc_index(unit_keys: &[UnitKey]) -> Option<u8> {
     unit_keys
         .iter()
-        .map(|k| k.variant_number)
+        .map(|k| k.index_number)
         .filter(|&v| v != 0)
         .min()
 }
 
 /// Classify the AACS aligned unit at `unit_offset` (clip-relative bytes) given
-/// the forensic segment map and the disc's resolved variant (`None` if no
-/// variant key is held).
+/// the forensic segment map and the disc's resolved index (`None` if no
+/// index key is held).
 pub fn unit_disposition(
     unit_offset: u64,
     segments: &[Segment],
-    disc_variant: Option<u8>,
+    disc_index: Option<u8>,
 ) -> UnitDisposition {
-    match variant_segment_for_unit(segments, unit_offset) {
+    match segment_for_unit(segments, unit_offset) {
         // Not in any forensic segment → ordinary content.
         None => UnitDisposition::Default,
-        // In a forensic segment → decide by whether it is our variant.
+        // In a forensic segment → decide by whether it is our index.
         Some(seg) => {
-            let seg_variant = seg.variant as u8;
-            match disc_variant {
-                Some(v) if v == seg_variant => UnitDisposition::Variant(v),
-                Some(_) => UnitDisposition::DropForeignVariant(seg_variant),
-                None => UnitDisposition::ForensicNoKey(seg_variant),
+            let seg_index = seg.index as u8;
+            match disc_index {
+                Some(v) if v == seg_index => UnitDisposition::Index(v),
+                Some(_) => UnitDisposition::DropForeignIndex(seg_index),
+                None => UnitDisposition::ForensicNoKey(seg_index),
             }
         }
     }
@@ -79,7 +79,7 @@ mod tests {
     use crate::aacs::content::ALIGNED_UNIT_LEN;
     use crate::aacs::segment::{SOURCE_PACKET_LEN, parse_individual_segments};
 
-    /// Build a one-record segment table (variant, start_spn, end_spn).
+    /// Build a one-record segment table (index, start_spn, end_spn).
     fn tbl(recs: &[(u16, u32, u32)]) -> Vec<Segment> {
         let mut v = Vec::new();
         v.extend_from_slice(&0x0100_0000u32.to_be_bytes());
@@ -95,23 +95,23 @@ mod tests {
         parse_individual_segments(&v).expect("parse")
     }
 
-    fn uk(idx: u32, variant: u8) -> UnitKey {
-        if variant == 0 {
+    fn uk(idx: u32, index: u8) -> UnitKey {
+        if index == 0 {
             UnitKey::new(idx, [0u8; 16])
         } else {
-            UnitKey::variant(idx, [variant; 16], variant)
+            UnitKey::forensic(idx, [index; 16], index)
         }
     }
 
     #[test]
-    fn resolve_picks_the_single_variant_key() {
-        // Default keys only → no variant resolved.
-        assert_eq!(resolve_disc_variant(&[uk(0, 0)]), None);
-        assert_eq!(resolve_disc_variant(&[]), None);
-        // One variant key among defaults → that variant.
-        assert_eq!(resolve_disc_variant(&[uk(0, 0), uk(1, 7)]), Some(7));
-        // Defensive: lowest of several distinct variants (deterministic).
-        assert_eq!(resolve_disc_variant(&[uk(0, 9), uk(1, 3)]), Some(3));
+    fn resolve_picks_the_single_index_key() {
+        // Default keys only → no index resolved.
+        assert_eq!(resolve_disc_index(&[uk(0, 0)]), None);
+        assert_eq!(resolve_disc_index(&[]), None);
+        // One index key among defaults → that index.
+        assert_eq!(resolve_disc_index(&[uk(0, 0), uk(1, 7)]), Some(7));
+        // Defensive: lowest of several distinct indexes (deterministic).
+        assert_eq!(resolve_disc_index(&[uk(0, 9), uk(1, 3)]), Some(3));
     }
 
     #[test]
@@ -130,29 +130,29 @@ mod tests {
     }
 
     #[test]
-    fn unit_in_our_variant_decrypts() {
+    fn unit_in_our_index_decrypts() {
         let segs = tbl(&[(7, 100, 200)]);
         let off = 120u64 * SOURCE_PACKET_LEN;
         assert_eq!(
             unit_disposition(off, &segs, Some(7)),
-            UnitDisposition::Variant(7)
+            UnitDisposition::Index(7)
         );
     }
 
     #[test]
-    fn unit_in_foreign_variant_drops() {
-        // Segment tagged variant 7, but our disc variant is 3 → drop it.
+    fn unit_in_foreign_index_drops() {
+        // Segment tagged index 7, but our disc index is 3 → drop it.
         let segs = tbl(&[(7, 100, 200)]);
         let off = 120u64 * SOURCE_PACKET_LEN;
         assert_eq!(
             unit_disposition(off, &segs, Some(3)),
-            UnitDisposition::DropForeignVariant(7)
+            UnitDisposition::DropForeignIndex(7)
         );
     }
 
     #[test]
     fn forensic_unit_with_no_key_is_concealed() {
-        // A forensic segment but we never resolved a variant → conceal as loss.
+        // A forensic segment but we never resolved an index → conceal as loss.
         let segs = tbl(&[(7, 100, 200)]);
         let off = 120u64 * SOURCE_PACKET_LEN;
         assert_eq!(
@@ -164,7 +164,7 @@ mod tests {
     #[test]
     fn straddling_unit_still_classified_as_its_segment() {
         // A unit whose 32-packet span only tails into the segment still routes
-        // to the segment (matches variant_segment_for_unit's span test).
+        // to the segment (matches segment_for_unit's span test).
         let segs = tbl(&[(5, 100, 200)]);
         let unit_packets = (ALIGNED_UNIT_LEN as u64 / SOURCE_PACKET_LEN) as u32; // 32
         // Start so the unit covers [80, 80+31] = [80, 111]: overlaps at 100.
@@ -172,7 +172,7 @@ mod tests {
         assert!(80 + unit_packets - 1 >= 100, "sanity: unit tails into seg");
         assert_eq!(
             unit_disposition(off, &segs, Some(5)),
-            UnitDisposition::Variant(5)
+            UnitDisposition::Index(5)
         );
     }
 }

src/aacs/inf.rs

@@ -161,6 +161,87 @@ pub fn parse_unit_key_ro(data: &[u8], version: AacsVersion) -> Option<UnitKeyFil
     })
 }
 
+/// HD DVD Video Title Key File (`VTKF000.AACS`) magic — "DVD HD Video TKF".
+pub const VTKF_MAGIC: &[u8; 12] = b"DVD_HD_V_TKF";
+/// Fixed header length before the first title-key entry.
+const VTKF_HEADER_LEN: usize = 0x80;
+/// Each title-key entry: BE32 flag + 16-byte encrypted key + 12-byte 0xFF pad.
+const VTKF_ENTRY_LEN: usize = 0x20;
+
+/// Parse an HD DVD `VTKF000.AACS` into the SAME [`UnitKeyFile`] a BD/UHD
+/// `Unit_Key_RO.inf` yields — so the shared AACS crypto (`derive_unit_keys` →
+/// `decrypt_unit_key(vuk, …)`) unwraps HD DVD title keys with no change. Only
+/// the on-disc CONTAINER differs between BD and HD DVD; the title-key unwrap is
+/// the identical AES-128 VUK step (`Kt = AES-128D(Kvu, Kte)`).
+///
+/// Layout (grounded in real discs — Shaun of the Dead, Anchorman, Harry Potter):
+/// ```text
+///   [0x00..0x0C] magic "DVD_HD_V_TKF"
+///   [0x0C..0x10] BE32 total file length
+///   [0x10..0x1C] associated playlist name ("VPLST000.XPL")
+///   [0x1C..0x80] reserved (zero)
+///   [0x80..]     32-byte entries: BE32 flag | 16-byte ENCRYPTED title key | 12-byte 0xFF pad
+///                flag bit 31 (0x8000_0000) set = present; a cleared flag ends the table
+///   [tail]       16-byte signature/MAC (never a key — the cleared-flag stop guards it)
+/// ```
+/// Entries number 1..=N as CPS units, matching `Unit_Key_RO`'s 1-based CPS
+/// numbering, so a title's CPS unit indexes this list identically. The
+/// title→CPS mapping itself is playlist-driven (`VPLST000.XPL`) and owned by the
+/// HD DVD enumerator, so `title_cps_unit` is left empty here.
+pub fn parse_vtkf(data: &[u8]) -> Option<UnitKeyFile> {
+    if data.len() < VTKF_HEADER_LEN || &data[..12] != VTKF_MAGIC {
+        return None;
+    }
+    // SHA1 of the WHOLE file — the KEYDB lookup key. BackupHDDVD-family key
+    // databases index an HD DVD disc by SHA1(VTKF000.AACS), the same role the
+    // BD disc_hash plays for `Unit_Key_RO.inf`.
+    let hash = disc_hash(data);
+
+    let mut encrypted_keys = Vec::new();
+    let mut pos = VTKF_HEADER_LEN;
+    let mut cps: u32 = 1;
+    while pos + VTKF_ENTRY_LEN <= data.len() {
+        let flag = u32::from_be_bytes([data[pos], data[pos + 1], data[pos + 2], data[pos + 3]]);
+        // A cleared present-bit terminates the key table. The file's trailing
+        // 16-byte signature then follows and must NOT be read as a key.
+        if flag & 0x8000_0000 == 0 {
+            break;
+        }
+        let mut key = [0u8; 16];
+        key.copy_from_slice(&data[pos + 4..pos + 20]);
+        encrypted_keys.push((cps, key));
+        cps += 1;
+        pos += VTKF_ENTRY_LEN;
+    }
+    if encrypted_keys.is_empty() {
+        return None;
+    }
+
+    Some(UnitKeyFile {
+        disc_hash: hash,
+        app_type: 0,     // HD DVD VTKF carries no BD-ROM app_type
+        num_bdmv_dir: 0, // BD-only concept
+        use_skb_mkb: false,
+        version: AacsVersion::V10, // HD DVD is always AACS 1.0
+        encrypted_keys,
+        title_cps_unit: Vec::new(),
+    })
+}
+
+/// Parse a disc's title-key file, dispatching on the self-describing magic:
+/// an HD DVD `VTKF000.AACS` (`DVD_HD_V_TKF`) → [`parse_vtkf`]; anything else is a
+/// BD/UHD `Unit_Key_RO.inf` → [`parse_unit_key_ro`]. Both return the same
+/// [`UnitKeyFile`], so every downstream AACS derivation stays container-agnostic
+/// — the single seam where BD-vs-HD-DVD key layout is resolved (mirrors the key
+/// service, which classifies HD DVD by the very same magic).
+pub fn parse_title_keys(data: &[u8], version: AacsVersion) -> Option<UnitKeyFile> {
+    if data.len() >= 12 && &data[..12] == VTKF_MAGIC {
+        parse_vtkf(data)
+    } else {
+        parse_unit_key_ro(data, version)
+    }
+}
+
 /// MKB disc structure format code.
 const MKB_DISC_STRUCTURE_FORMAT: u8 = 0x83;
 
@@ -283,3 +364,94 @@ pub fn parse_content_cert(data: &[u8]) -> Option<ContentCert> {
         version,
     })
 }
+
+#[cfg(test)]
+mod vtkf_tests {
+    use super::*;
+
+    /// Build a synthetic `VTKF000.AACS` matching the real on-disc layout
+    /// (Shaun of the Dead / Anchorman): magic, BE32 size, playlist name,
+    /// reserved to 0x80, then 32-byte present-flagged entries, a cleared-flag
+    /// terminator, and a 16-byte trailer.
+    fn synth_vtkf(keys: &[[u8; 16]]) -> Vec<u8> {
+        let mut v = Vec::new();
+        v.extend_from_slice(VTKF_MAGIC); // 0x00
+        v.extend_from_slice(&0u32.to_be_bytes()); // 0x0C size (patched below)
+        v.extend_from_slice(b"VPLST000.XPL"); // 0x10
+        v.resize(0x80, 0); // reserve to first entry
+        for k in keys {
+            v.extend_from_slice(&0x8000_0000u32.to_be_bytes()); // present flag
+            v.extend_from_slice(k); // 16-byte encrypted title key
+            v.extend_from_slice(&[0xFFu8; 12]); // 0xFF pad → 32-byte entry
+        }
+        // Cleared-flag terminator entry (must NOT be read as a key).
+        v.extend_from_slice(&[0u8; VTKF_ENTRY_LEN]);
+        // 16-byte trailing signature (must NOT be read as a key).
+        v.extend_from_slice(&[0xABu8; 16]);
+        let len = v.len() as u32;
+        v[0x0C..0x10].copy_from_slice(&len.to_be_bytes());
+        v
+    }
+
+    #[test]
+    fn parse_vtkf_extracts_present_entries_and_stops_at_terminator() {
+        let k1 = [0x11u8; 16];
+        let k2 = [0x22u8; 16];
+        let k3 = [0x33u8; 16];
+        let data = synth_vtkf(&[k1, k2, k3]);
+
+        let ukf = parse_vtkf(&data).expect("valid VTKF must parse");
+        // Exactly the three present entries — the cleared-flag terminator and
+        // the 16-byte trailer are NOT mistaken for keys.
+        assert_eq!(ukf.encrypted_keys.len(), 3, "must stop at the cleared flag");
+        assert_eq!(ukf.encrypted_keys[0], (1, k1), "CPS units number 1..=N");
+        assert_eq!(ukf.encrypted_keys[1], (2, k2));
+        assert_eq!(ukf.encrypted_keys[2], (3, k3));
+        assert_eq!(ukf.version, AacsVersion::V10, "HD DVD is AACS 1.0");
+        // disc_hash is SHA1 of the whole file (the KEYDB lookup key).
+        assert_eq!(ukf.disc_hash, disc_hash(&data));
+    }
+
+    #[test]
+    fn parse_vtkf_rejects_non_magic() {
+        let mut data = synth_vtkf(&[[0x11u8; 16]]);
+        data[0] = b'X'; // corrupt magic
+        assert!(
+            parse_vtkf(&data).is_none(),
+            "non-VTKF magic must be rejected"
+        );
+        assert!(
+            parse_vtkf(&[0u8; 4]).is_none(),
+            "too short must be rejected"
+        );
+    }
+
+    #[test]
+    fn parse_title_keys_dispatches_by_magic() {
+        // VTKF magic → parse_vtkf.
+        let data = synth_vtkf(&[[0x44u8; 16], [0x55u8; 16]]);
+        let ukf = parse_title_keys(&data, AacsVersion::V10).expect("VTKF dispatch");
+        assert_eq!(ukf.encrypted_keys.len(), 2);
+
+        // Non-VTKF → parse_unit_key_ro (a 2-byte buffer is not a valid inf, so
+        // this proves it ROUTED to the BD parser rather than parse_vtkf).
+        assert!(
+            parse_title_keys(&[0x00, 0x00], AacsVersion::V10).is_none(),
+            "non-magic input must route to parse_unit_key_ro"
+        );
+    }
+
+    /// The whole point of the seam: a parsed VTKF feeds the SHARED VUK→title-key
+    /// crypto (`decrypt_unit_key`) exactly like a BD `Unit_Key_RO.inf` would —
+    /// no HD-DVD-specific crypto path.
+    #[test]
+    fn vtkf_encrypted_keys_feed_shared_vuk_unwrap() {
+        let enc = [0x9Au8; 16];
+        let data = synth_vtkf(&[enc]);
+        let ukf = parse_vtkf(&data).unwrap();
+        let vuk = [0x5Cu8; 16];
+        let derived = super::super::derive::decrypt_unit_key(&vuk, &ukf.encrypted_keys[0].1);
+        // Same as applying the shared unwrap directly to the stored enc key.
+        assert_eq!(derived, super::super::derive::decrypt_unit_key(&vuk, &enc));
+    }
+}

src/aacs/mod.rs

@@ -29,6 +29,7 @@ pub mod content;
 pub mod crypto;
 pub mod derive;
 pub mod host_certs;
+pub mod index_select;
 pub mod inf;
 pub mod mkb;
 pub mod provider;
@@ -38,12 +39,19 @@ pub mod segment_key;
 pub mod trace;
 pub mod types;
 pub mod variant;
-pub mod variant_select;
 
-/// On-disc UDF paths to the AACS key-input files (with their fallbacks).
-/// Centralised so every reader (`resolve_vid_only`, `read_aacs_inputs`,
-/// `read_mkb_content`, `read_aacs_version`) walks the exact same files — adding
-/// or changing a fallback in one place can then never silently diverge the
+/// On-disc UDF paths to the AACS key-input files.
+///
+/// BD and UHD keep their key material under `/AACS/…`; HD DVD keeps the
+/// equivalents under `/ANY!/…` with different names (`VTKF000.AACS` is the
+/// title-key file — magic `DVD_HD_V_TKF`; `MKBROM.AACS` is the MKB). The
+/// container difference is expressed here purely as DATA: each ROLE
+/// ([`UNIT_KEY_RO_PATHS`], [`MKB_PATHS`], [`CONTENT_CERT_PATHS`]) is an ordered
+/// candidate list, and every reader walks it with [`read_first`] taking the
+/// first that reads. No reader ever branches on disc type — a BD/UHD disc has
+/// the `/AACS/` files so those win; an HD DVD has neither, so it falls through
+/// to the `/ANY!/` entry. Centralised so `resolve_vid_only`, `read_aacs_inputs`,
+/// `read_mkb_content`, and `read_aacs_version` can never silently diverge the
 /// disc_hash / MKB / VID that another reader feeds a key service.
 pub const PATH_UNIT_KEY_RO: &str = "/AACS/Unit_Key_RO.inf";
 pub const PATH_UNIT_KEY_RO_DUPLICATE: &str = "/AACS/DUPLICATE/Unit_Key_RO.inf";
@@ -51,6 +59,46 @@ pub const PATH_MKB_RO: &str = "/AACS/MKB_RO.inf";
 pub const PATH_MKB_RW: &str = "/AACS/MKB_RW.inf";
 pub const PATH_CONTENT_CERT: &str = "/AACS/Content000.cer";
 pub const PATH_CONTENT_CERT_ALT: &str = "/AACS/Content001.cer";
+/// HD DVD title-key file (`/ANY!/`), forwarded as `inf_b64`; the key service
+/// recognises it by its `DVD_HD_V_TKF` magic.
+pub const PATH_VTKF_HDDVD: &str = "/ANY!/VTKF000.AACS";
+/// HD DVD Media Key Block (`/ANY!/`), forwarded as `mkb_b64`.
+pub const PATH_MKBROM_HDDVD: &str = "/ANY!/MKBROM.AACS";
+/// HD DVD content certificate (`/ANY!/`); byte 0 gives the AACS major (0x00 → V10).
+pub const PATH_CONTENT_CERT_HDDVD: &str = "/ANY!/CONTENT_CERT.AACS";
+
+/// Title-key / `Unit_Key_RO.inf` role, in resolution order (BD/UHD, then HD DVD).
+pub const UNIT_KEY_RO_PATHS: &[&str] = &[
+    PATH_UNIT_KEY_RO,
+    PATH_UNIT_KEY_RO_DUPLICATE,
+    PATH_VTKF_HDDVD,
+];
+/// MKB role, in resolution order (BD/UHD RO then RW, then HD DVD).
+pub const MKB_PATHS: &[&str] = &[PATH_MKB_RO, PATH_MKB_RW, PATH_MKBROM_HDDVD];
+/// Content-certificate role, in resolution order (BD/UHD, then HD DVD).
+pub const CONTENT_CERT_PATHS: &[&str] = &[
+    PATH_CONTENT_CERT,
+    PATH_CONTENT_CERT_ALT,
+    PATH_CONTENT_CERT_HDDVD,
+];
+
+/// Walk an AACS role's candidate paths and return the first that reads.
+///
+/// `read` performs the actual per-path read (full file or bounded prefix), so
+/// callers share the same first-present walk regardless of read style. Returns
+/// [`Error::AacsNoKeys`] if no candidate is present. This is the single place
+/// the `/AACS/` (BD/UHD) vs `/ANY!/` (HD DVD) layout difference is resolved.
+pub(crate) fn read_first<F>(candidates: &[&str], mut read: F) -> crate::error::Result<Vec<u8>>
+where
+    F: FnMut(&str) -> crate::error::Result<Vec<u8>>,
+{
+    for path in candidates {
+        if let Ok(buf) = read(path) {
+            return Ok(buf);
+        }
+    }
+    Err(crate::error::Error::AacsNoKeys)
+}
 
 // The module structure IS the public API — consumers import from the owning
 // module directly (e.g. `aacs::content::decrypt_unit`, `aacs::mkb::MkbType`,
@@ -61,7 +109,7 @@ pub const PATH_CONTENT_CERT_ALT: &str = "/AACS/Content001.cer";
 // content-decrypt entry points that downstream key-source crates import through
 // the `aacs::` path. These are the stable, load-bearing names; keeping them here
 // lets those crates track the module refactor without a lockstep re-pin.
-pub use content::{ALIGNED_UNIT_LEN, decrypt_unit_try_keys};
+pub use content::ALIGNED_UNIT_LEN;
 pub use derive::derive_vuk;
 pub use types::{DeviceKey, HostCert, MediaKey, ProcessingKey, UnitKey, Vid, Vuk};
 
@@ -71,7 +119,7 @@ mod tests {
     //! Touching one representative item per module keeps these as a
     //! compile-time contract that the module paths stay stable.
 
-    use super::content::{ALIGNED_UNIT_LEN, ts_sync_destroyed};
+    use super::content::ALIGNED_UNIT_LEN;
     use super::inf::{disc_hash, disc_hash_hex};
     use super::mkb::{AacsVersion, mkb_content_len, walk_mkb};
     use super::variant::is_variant_mkb;
@@ -99,7 +147,10 @@ mod tests {
     fn public_helpers_are_callable_by_module_path() {
         // Touch a representative function from each module so a dropped/renamed
         // item fails to compile. Smoke calls, not behavioural assertions.
-        let _ = ts_sync_destroyed(&[0u8; ALIGNED_UNIT_LEN]);
+        let _ = !crate::aacs::content::is_clean(
+            &[0u8; ALIGNED_UNIT_LEN],
+            crate::disc::ContentFormat::BdTs,
+        );
         let _ = mkb_content_len(&[]);
         let _ = is_variant_mkb(&walk_mkb(&[]));
         let _ = disc_hash_hex(&disc_hash(b"x"));

src/aacs/resolve.rs

@@ -156,7 +156,7 @@ pub fn resolve_keys_v2(ctx: &ResolveContext<'_>) -> Option<ResolvedKeys> {
 /// equivalent of path 2 — there's no host-side PK derivation against a
 /// Variant MKB.)
 pub fn resolve_keys_v21(ctx: &ResolveContext<'_>) -> Option<ResolvedKeys> {
-    let uk_file = parse_unit_key_ro(ctx.unit_key_ro, AacsVersion::V20)?;
+    let uk_file = parse_title_keys(ctx.unit_key_ro, AacsVersion::V20)?;
     let hash_hex = disc_hash_hex(&uk_file.disc_hash);
     let bus_encryption = ctx
         .content_cert
@@ -280,8 +280,9 @@ fn resolve_keys_classical(ctx: &ResolveContext<'_>, version: AacsVersion) -> Opt
         .map(|cc| cc.bus_encryption)
         .unwrap_or(false);
 
-    // Parse Unit_Key_RO.inf at the version-appropriate stride.
-    let uk_file = parse_unit_key_ro(ctx.unit_key_ro, version)?;
+    // Parse the disc's title-key file (BD/UHD Unit_Key_RO.inf at the
+    // version-appropriate stride, or HD DVD VTKF000.AACS) → common UnitKeyFile.
+    let uk_file = parse_title_keys(ctx.unit_key_ro, version)?;
 
     let hash_hex = disc_hash_hex(&uk_file.disc_hash);
     let has_vid = *ctx.volume_id != [0u8; 16];

src/aacs/segment.rs

@@ -1,40 +1,49 @@
 //! AACS 2.1 FMTS forensic segment map — `AACS/IndividualSegment.tbl`.
 //!
-//! An FMTS main feature interleaves N "variant" segments — the sequence-key /
-//! forensic-watermark mechanism. The same frames are authored as several
-//! slightly different variants; each variant is encrypted under its own SEGMENT
-//! key (from `SegmentKeyNNNNN.tbl`), NOT the CPS Unit Key. A player with the
-//! right device keys can decrypt exactly one variant per segment, and which one
-//! silently identifies the player (traitor tracing). Decrypting a variant
-//! segment with the Unit Key yields garbage — broken HEVC reference frames
-//! (empirically: `Could not find ref with POC …` on a plain unit-key rip).
+//! An FMTS main feature interleaves short forensic **segments** — the sequence-key
+//! / forensic-watermark mechanism. Each segment carries an **index** (1..32): a
+//! tag in `IndividualSegment.tbl` that selects which of the 32 forensic **index
+//! keys** decrypts that segment's units, in place of the ordinary CPS Unit Key.
 //!
-//! This table says WHERE the variant segments live so a decoder can decrypt
-//! them with segment keys and select one coherent variant instead of muxing
+//! Terminology (see the project AACS reference): the **index** here is NOT the
+//! AACS 2.1 *Media Key Variant* — that is the 65536-value device selector in the
+//! MKB that decides *which set* of index keys a device receives, a layer this
+//! module does not deal with. All the index keys belong to one variant, whose
+//! number is unknown and irrelevant to the segment map. Decrypting a segment with
+//! the Unit Key yields garbage — broken HEVC reference frames (empirically:
+//! `Could not find ref with POC …` on a plain unit-key rip).
+//!
+//! This table says WHERE the segments live and which index each carries, so a
+//! decoder can decrypt them with the matching index key instead of muxing
 //! unit-key garbage.
 //!
 //! Format (validated against a retail AACS 2.1 disc):
 //! ```text
 //!   header (8 bytes):  u32 type | u16 count | u16 record_size (= 16)
 //!   record[count] (16 bytes each):
-//!     u32 marker (= 0x01000000) | u16 variant | u16 flag (= 1)
+//!     u32 marker (= 0x01000000) | u16 index | u16 flag (= 1)
 //!     u32 start_spn | u32 end_spn        (source-packet numbers, inclusive)
 //! ```
-//! `variant` is the 1..32 forensic-variant tag, NOT a sequential segment id:
-//! measured on a retail 2.1 disc (Zombieland) it cycles 1,2,…,32,1,2,… across
-//! records in file order — 24 full cycles of 32 plus a final partial cycle of
-//! 24 = 792 records. Source-packet numbers are the 192-byte BDAV packet index:
-//! byte offset = `spn * 192`. Each segment is ~2560 packets (~480 KB), spread
-//! across the entire 54 GB feature (one roughly every 67 MB).
+//! `index` is the 1..32 forensic index tag, NOT a sequential segment id: measured
+//! on a retail 2.1 disc (Zombieland) it cycles 1,2,…,32,1,2,… across records in
+//! file order — 24 full cycles of 32 plus a final partial cycle of 24 = 792
+//! records. Source-packet numbers are the 192-byte BDAV packet index: byte offset
+//! = `spn * 192`. Each segment is ~2560 packets (~480 KB) = 80 aligned units,
+//! spread across the entire 54 GB feature (one roughly every 67 MB). Inside a
+//! segment the 80 units interleave in two stride-2 halves: applying the segment's
+//! index key decrypts ~40 of them to clean TS and garbles the other ~40 (a second
+//! interleaved half, unidentified), which the demux then drops — leaving one
+//! coherent stream. Confirmed by decoding a retail disc with a full set of 32
+//! index keys.
 
 /// Fixed size of one `IndividualSegment.tbl` record.
 pub const SEGMENT_RECORD_LEN: usize = 16;
 /// Bytes per BDAV source packet (188-byte TS + 4-byte arrival-time header).
 pub const SOURCE_PACKET_LEN: u64 = 192;
 
-/// Whether a 2.1 (FMTS) disc may rip WITHOUT segment (variant) keys.
+/// Whether a 2.1 (FMTS) disc may rip WITHOUT the forensic index keys.
 ///
-/// `true` (today): the forensic variant segments are skipped as expected loss
+/// `true` (today): the forensic segments are skipped as expected loss
 /// and the bulk of the title decodes with the unit key, so a 2.1 disc rips
 /// mostly-complete. A unit key (VUK) is still required, exactly as for any AACS
 /// disc. `false`: the absence of a segment-key source is a hard, UPFRONT failure
@@ -45,17 +54,17 @@ pub const SOURCE_PACKET_LEN: u64 = 192;
 /// refused. Hardcoded on purpose — not a user setting.
 ///
 /// [`Error::FmtsKeyMissing`]: crate::error::Error::FmtsKeyMissing
-pub const BYPASS_FMTS_KEY: bool = true;
+pub const BYPASS_FMTS_KEY: bool = false;
 
-/// One forensic variant segment: the inclusive source-packet range it occupies
-/// in the FMTS clip.
+/// One forensic segment: the inclusive source-packet range it occupies in the
+/// FMTS clip.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Segment {
-    /// Forensic variant tag, 1..=32 (field@4 of the record). Cycles across the
-    /// table rather than counting up — it selects WHICH variant this range is,
-    /// which is what a variant-keyed decode routes on. (`0` is not used here;
-    /// the default/non-forensic content carries no segment record at all.)
-    pub variant: u16,
+    /// Forensic index tag, 1..=32 (field@4 of the record). Cycles across the
+    /// table rather than counting up — it selects WHICH of the 32 index keys
+    /// decrypts this range. (`0` is not used here; the default/non-forensic
+    /// content carries no segment record at all.)
+    pub index: u16,
     /// First source packet of the segment (inclusive).
     pub start_spn: u32,
     /// Last source packet of the segment (inclusive).
@@ -109,8 +118,8 @@ pub fn lba_byte_offset(lba: u32) -> u64 {
 /// unit's clip-relative byte offset.
 ///
 /// This is the routing decision behind a 2.1 decrypt-miss: a unit that
-/// overlaps a forensic segment must be opened with that segment's **variant
-/// key** (from `SegmentKeyNNNNN.tbl`), not the CPS Unit Key. Opening it with
+/// overlaps a forensic segment must be opened with that segment's **index key**
+/// (selected by the segment's `index`), not the CPS Unit Key. Opening it with
 /// the Unit Key is exactly what yields the broken-reference-frame garbage a
 /// plain unit-key rip produces. A unit outside every segment is ordinary
 /// content and a miss on it is a Unit-Key miss, so this returns `None` and the
@@ -118,16 +127,16 @@ pub fn lba_byte_offset(lba: u32) -> u64 {
 ///
 /// The unit is tested as a packet *span* (`[off/192, (off+6144-1)/192]`) so a
 /// unit that only partly overlaps a segment edge is still classified as
-/// variant; on the observed disc segments are unit-aligned, but the span test
+/// forensic; on the observed disc segments are unit-aligned, but the span test
 /// does not rely on that.
-pub fn variant_segment_for_unit(segments: &[Segment], unit_offset: u64) -> Option<&Segment> {
+pub fn segment_for_unit(segments: &[Segment], unit_offset: u64) -> Option<&Segment> {
     let unit_len = crate::aacs::content::ALIGNED_UNIT_LEN as u64;
     let first = (unit_offset / SOURCE_PACKET_LEN) as u32;
     let last = ((unit_offset + unit_len - 1) / SOURCE_PACKET_LEN) as u32;
     segments.iter().find(|s| s.overlaps_spn(first, last))
 }
 
-/// Parse `IndividualSegment.tbl` into its forensic variant segments, in table
+/// Parse `IndividualSegment.tbl` into its forensic segments, in table
 /// order. Returns `None` when the header is malformed, the record size is not
 /// [`SEGMENT_RECORD_LEN`], or the declared record count overruns the buffer —
 /// so a truncated / foreign table degrades to "no segment map" rather than
@@ -147,12 +156,12 @@ pub fn parse_individual_segments(tbl: &[u8]) -> Option<Vec<Segment>> {
     let mut segments = Vec::with_capacity(count);
     for i in 0..count {
         let o = 8 + i * record_size;
-        // o+4..o+8 = variant (u16, 1..32) + flag (u16); o+8..o+16 = start/end SPN.
-        let variant = u16::from_be_bytes([tbl[o + 4], tbl[o + 5]]);
+        // o+4..o+8 = index (u16, 1..32) + flag (u16); o+8..o+16 = start/end SPN.
+        let index = u16::from_be_bytes([tbl[o + 4], tbl[o + 5]]);
         let start_spn = u32::from_be_bytes([tbl[o + 8], tbl[o + 9], tbl[o + 10], tbl[o + 11]]);
         let end_spn = u32::from_be_bytes([tbl[o + 12], tbl[o + 13], tbl[o + 14], tbl[o + 15]]);
         segments.push(Segment {
-            variant,
+            index,
             start_spn,
             end_spn,
         });
@@ -160,12 +169,74 @@ pub fn parse_individual_segments(tbl: &[u8]) -> Option<Vec<Segment>> {
     Some(segments)
 }
 
+/// Map a clip-relative byte offset to the absolute LBA that holds it, by walking
+/// the title's extents (the `.fmts` clip's sectors in file order). Segment
+/// offsets in [`Segment`] are clip-relative source-packet numbers, so this is how
+/// a segment's `spn` range becomes disc LBAs. `None` if the offset is past the
+/// clip.
+pub fn clip_byte_to_lba(extents: &[crate::disc::Extent], clip_byte: u64) -> Option<u32> {
+    let mut cum = 0u64;
+    for e in extents {
+        let len = e.sector_count as u64 * crate::consts::SECTOR_BYTES as u64;
+        if clip_byte < cum + len {
+            let sector_in_ext = ((clip_byte - cum) / crate::consts::SECTOR_BYTES as u64) as u32;
+            return Some(e.start_lba.saturating_add(sector_in_ext));
+        }
+        cum += len;
+    }
+    None
+}
+
+/// Build the `[start_lba, end_lba) → key_idx` ranges for an FMTS forensic key map.
+///
+/// Each forensic segment's clip-relative source-packet span becomes an absolute
+/// LBA range tagged with the key its `index` selects (via `index_to_key_idx`,
+/// e.g. `|i| i as usize` when the pool is `[base, idx1, idx2, …]`). Applying that
+/// one key across the whole segment decodes the ~40 units of its interleave half
+/// to clean TS and garbles the other ~40 (the second interleaved half), which the
+/// demux then drops — yielding one coherent stream. Ranges outside every segment
+/// are left for the map's default (the ordinary Unit Key). A segment that straddles
+/// a UDF extent boundary is emitted as one range per whole-sector slice it covers.
+///
+/// The result feeds [`AacsKeyMap::from_ranges`](crate::decrypt::AacsKeyMap::from_ranges)
+/// with the Unit-Key index as the default — the same structure the CPS map uses,
+/// only finer-grained.
+pub fn fmts_key_ranges(
+    segments: &[Segment],
+    extents: &[crate::disc::Extent],
+    index_to_key_idx: &dyn Fn(u16) -> usize,
+) -> Vec<(u32, u32, usize)> {
+    let mut ranges = Vec::new();
+    for s in segments {
+        let start_byte = s.start_spn as u64 * SOURCE_PACKET_LEN;
+        let end_byte = (s.end_spn as u64 + 1) * SOURCE_PACKET_LEN; // exclusive
+        // A segment is unit-aligned and contiguous in clip bytes; map its first
+        // and last sector to LBAs. Segments are ~480 KB and extents are GB-sized,
+        // so a segment almost never crosses an extent boundary — but if the two
+        // ends land in different extents (non-contiguous LBAs), skip rather than
+        // emit a wrong span; the units there fall to the Unit Key (garble+drop),
+        // never a mis-decrypt.
+        let (Some(a), Some(b)) = (
+            clip_byte_to_lba(extents, start_byte),
+            clip_byte_to_lba(extents, end_byte - 1),
+        ) else {
+            continue;
+        };
+        if b >= a
+            && (b - a) as u64 == (end_byte - 1 - start_byte) / crate::consts::SECTOR_BYTES as u64
+        {
+            ranges.push((a, b + 1, index_to_key_idx(s.index)));
+        }
+    }
+    ranges
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     /// Build a table with the real on-disc layout: 8-byte header + N 16-byte
-    /// records. `recs` are `(variant, start_spn, end_spn)`.
+    /// records. `recs` are `(index, start_spn, end_spn)`.
     fn build_tbl(recs: &[(u16, u32, u32)]) -> Vec<u8> {
         let mut v = Vec::new();
         v.extend_from_slice(&0x0100_0000u32.to_be_bytes()); // type
@@ -181,11 +252,75 @@ mod tests {
         v
     }
 
+    #[test]
+    fn fmts_key_ranges_maps_segments_to_lba_by_index() {
+        use crate::disc::Extent;
+        // One big clip extent starting at LBA 1000. Clip byte B lives at
+        // LBA 1000 + B/2048.
+        let extents = vec![Extent {
+            start_lba: 1000,
+            sector_count: 1_000_000,
+        }];
+        // Two segments, indexes 5 and 7 (spn ranges as on a real disc).
+        let segs = vec![
+            Segment {
+                index: 5,
+                start_spn: 100,
+                end_spn: 199,
+            },
+            Segment {
+                index: 7,
+                start_spn: 10_000,
+                end_spn: 10_099,
+            },
+        ];
+        // Pool layout [base, idx1, idx2, …] → index N uses key slot N.
+        let ranges = fmts_key_ranges(&segs, &extents, &|v| v as usize);
+        assert_eq!(ranges.len(), 2, "one LBA range per segment");
+        // Segment 0: spn 100..=199 → clip bytes [19200, 38400) → sectors 9..=18
+        // → LBA 1009..1019, key index 5.
+        assert_eq!(ranges[0], (1009, 1019, 5));
+        // Segment 1: spn 10000..=10099 → bytes [1_920_000, 1_939_200) →
+        // sectors 937..=946 → LBA 1937..1947, key index 7.
+        assert_eq!(ranges[1], (1937, 1947, 7));
+
+        // The ranges drive an AacsKeyMap with the Unit Key (index 0) as default.
+        let map = crate::decrypt::AacsKeyMap::from_ranges(ranges, 0);
+        assert_eq!(map.key_idx_for(500), 0, "outside any segment → Unit Key");
+        assert_eq!(map.key_idx_for(1012), 5, "inside index-5 segment → key 5");
+        assert_eq!(map.key_idx_for(1940), 7, "inside index-7 segment → key 7");
+        assert_eq!(
+            map.key_idx_for(1019),
+            0,
+            "segment end is exclusive → Unit Key"
+        );
+    }
+
+    #[test]
+    fn clip_byte_to_lba_walks_extents() {
+        use crate::disc::Extent;
+        let extents = vec![
+            Extent {
+                start_lba: 100,
+                sector_count: 10,
+            }, // clip bytes [0, 20480)
+            Extent {
+                start_lba: 500,
+                sector_count: 10,
+            }, // clip bytes [20480, 40960)
+        ];
+        assert_eq!(clip_byte_to_lba(&extents, 0), Some(100));
+        assert_eq!(clip_byte_to_lba(&extents, 2048), Some(101));
+        assert_eq!(clip_byte_to_lba(&extents, 20480), Some(500)); // second extent
+        assert_eq!(clip_byte_to_lba(&extents, 22528), Some(501));
+        assert_eq!(clip_byte_to_lba(&extents, 40960), None); // past the clip
+    }
+
     #[test]
     fn parses_real_disc_layout() {
         // First three records observed on retail 2.1 (Zombieland): the variant
         // field counts 1,2,3,… (it wraps at 32 further into the table — see
-        // `variant_field_cycles_one_to_thirty_two`), segments are 2560 packets.
+        // `index_field_cycles_one_to_thirty_two`), segments are 2560 packets.
         let tbl = build_tbl(&[
             (1, 343680, 346239),
             (2, 695616, 698175),
@@ -193,9 +328,9 @@ mod tests {
         ]);
         let segs = parse_individual_segments(&tbl).expect("parse");
         assert_eq!(segs.len(), 3);
-        assert_eq!(segs[0].variant, 1);
-        assert_eq!(segs[1].variant, 2);
-        assert_eq!(segs[2].variant, 3);
+        assert_eq!(segs[0].index, 1);
+        assert_eq!(segs[1].index, 2);
+        assert_eq!(segs[2].index, 3);
         assert_eq!(segs[0].start_spn, 343680);
         assert_eq!(segs[0].end_spn, 346239);
         assert_eq!(segs[0].packet_count(), 2560);
@@ -234,18 +369,18 @@ mod tests {
     }
 
     #[test]
-    fn unit_inside_segment_routes_to_variant() {
+    fn unit_inside_segment_routes_to_index() {
         // A real first-record segment: packets [343680, 346239].
         let segs = parse_individual_segments(&build_tbl(&[(1, 343680, 346239)])).unwrap();
         // A unit sitting squarely inside: start at packet 344000 → byte 344000*192.
         let off = 344000u64 * SOURCE_PACKET_LEN;
-        let hit = variant_segment_for_unit(&segs, off).expect("inside the segment");
-        assert_eq!(hit.variant, 1);
+        let hit = segment_for_unit(&segs, off).expect("inside the segment");
+        assert_eq!(hit.index, 1);
     }
 
     #[test]
-    fn variant_field_cycles_one_to_thirty_two() {
-        // Reality on Zombieland: field@4 is the variant, cycling 1..=32 in file
+    fn index_field_cycles_one_to_thirty_two() {
+        // Reality on Zombieland: field@4 is the index, cycling 1..=32 in file
         // order (NOT a sequential segment id). Reproduce one-and-a-bit cycles.
         let mut recs = Vec::new();
         let mut spn = 1000u32;
@@ -258,9 +393,9 @@ mod tests {
         }
         let segs = parse_individual_segments(&build_tbl(&recs)).unwrap();
         assert_eq!(segs.len(), 64);
-        assert_eq!(segs[31].variant, 32); // end of first cycle
-        assert_eq!(segs[32].variant, 1); // wraps, does not become 33
-        assert!(segs.iter().all(|s| (1..=32).contains(&s.variant)));
+        assert_eq!(segs[31].index, 32); // end of first cycle
+        assert_eq!(segs[32].index, 1); // wraps, does not become 33
+        assert!(segs.iter().all(|s| (1..=32).contains(&s.index)));
     }
 
     #[test]
@@ -268,29 +403,29 @@ mod tests {
         let segs = parse_individual_segments(&build_tbl(&[(1, 343680, 346239)])).unwrap();
         // A unit well before the segment is ordinary content → None (unit-key path).
         let off = 1000u64 * SOURCE_PACKET_LEN;
-        assert!(variant_segment_for_unit(&segs, off).is_none());
+        assert!(segment_for_unit(&segs, off).is_none());
     }
 
     #[test]
-    fn unit_straddling_a_segment_edge_counts_as_variant() {
+    fn unit_straddling_a_segment_edge_counts_as_forensic() {
         // Segment starts at packet 100. A unit that ENDS just inside it (its 32
-        // packets straddle the boundary) must still route to the variant key,
-        // because part of its ciphertext is variant-encrypted.
+        // packets straddle the boundary) must still route to the index key,
+        // because part of its ciphertext is forensic-encrypted.
         let segs = parse_individual_segments(&build_tbl(&[(7, 100, 200)])).unwrap();
         // Unit covering packets [80, 111]: overlaps [100,200] at the tail.
         let off = 80u64 * SOURCE_PACKET_LEN;
-        let hit = variant_segment_for_unit(&segs, off).expect("straddles the start edge");
-        assert_eq!(hit.variant, 7);
+        let hit = segment_for_unit(&segs, off).expect("straddles the start edge");
+        assert_eq!(hit.index, 7);
         // A unit ending exactly at packet 99 (offset s.t. last = 99) does NOT overlap.
         let before = 68u64 * SOURCE_PACKET_LEN; // [68, 99]
-        assert!(variant_segment_for_unit(&segs, before).is_none());
+        assert!(segment_for_unit(&segs, before).is_none());
     }
 
     #[test]
-    fn no_segments_never_routes_to_variant() {
+    fn no_segments_never_routes_to_index() {
         // The 1.0 / 2.0 case: no forensic map, so every miss is a unit-key miss.
-        assert!(variant_segment_for_unit(&[], lba_byte_offset(0)).is_none());
-        assert!(variant_segment_for_unit(&[], lba_byte_offset(9_999_999)).is_none());
+        assert!(segment_for_unit(&[], lba_byte_offset(0)).is_none());
+        assert!(segment_for_unit(&[], lba_byte_offset(9_999_999)).is_none());
     }
 
     #[test]

src/aacs/types.rs

@@ -57,41 +57,40 @@ pub struct ProcessingKey(pub [u8; 16]);
 pub struct UnitKey {
     pub idx: u32,
     pub key: [u8; 16],
-    /// AACS 2.1 (FMTS) forensic-variant tag.
+    /// AACS 2.1 (FMTS) forensic **index** tag (see [`crate::aacs::segment`]).
     ///
     /// `0` = ordinary (non-forensic) content — the value for every 1.0 / 2.0
-    /// key and for the bulk of a 2.1 title. `1..=32` = a variant key that
-    /// decrypts the forensic segments tagged with that same variant in
-    /// `IndividualSegment.tbl`. A disc resolves to exactly one variant, so at
-    /// most one non-zero value is ever in play for a given rip; the decode
-    /// selects the segments matching it and drops the other variants.
-    pub variant_number: u8,
+    /// key and for the bulk of a 2.1 title. `1..=32` = a forensic index key that
+    /// decrypts the `IndividualSegment.tbl` segments tagged with that same index.
+    /// This is the per-segment index (1..32), NOT the AACS 2.1 Media Key Variant
+    /// (the 65536-value device selector), which is a separate MKB-layer concern.
+    pub index_number: u8,
 }
 
 impl UnitKey {
-    /// An ordinary (non-forensic) unit key: `variant_number == 0`. The value
+    /// An ordinary (non-forensic) unit key: `index_number == 0`. The value
     /// for every AACS 1.0 / 2.0 key and the bulk of a 2.1 title.
     pub const fn new(idx: u32, key: [u8; 16]) -> Self {
         Self {
             idx,
             key,
-            variant_number: 0,
+            index_number: 0,
         }
     }
 
-    /// A forensic-variant key: `variant_number` in `1..=32`, decrypting the
-    /// `IndividualSegment.tbl` segments tagged with that variant.
-    pub const fn variant(idx: u32, key: [u8; 16], variant_number: u8) -> Self {
+    /// A forensic index key: `index_number` in `1..=32`, decrypting the
+    /// `IndividualSegment.tbl` segments tagged with that index.
+    pub const fn forensic(idx: u32, key: [u8; 16], index_number: u8) -> Self {
         Self {
             idx,
             key,
-            variant_number,
+            index_number,
         }
     }
 
-    /// Whether this key decrypts ordinary (non-forensic) content.
-    pub const fn is_default_variant(&self) -> bool {
-        self.variant_number == 0
+    /// Whether this key decrypts ordinary (non-forensic) content (index 0).
+    pub const fn is_default_index(&self) -> bool {
+        self.index_number == 0
     }
 }
 

src/decrypt.rs

@@ -150,10 +150,15 @@ pub fn decrypt_threads() -> usize {
 pub enum DecryptKeys {
     /// No encryption on this disc.
     None,
-    /// AACS (Blu-ray / UHD). Unit keys + optional read data key.
+    /// AACS (Blu-ray / UHD / HD-DVD). Unit keys + optional read data key. The
+    /// `format` is the disc's content container (BD/UHD/FMTS = Transport Stream,
+    /// HD-DVD `.evo` = Program Stream); it travels with the keys because both are
+    /// resolved once per disc, and the key SELECTOR (`is_clean`) needs it to prove
+    /// a key structurally against the right container.
     Aacs {
         unit_keys: Vec<(u32, [u8; 16])>,
         read_data_key: Option<[u8; 16]>,
+        format: crate::disc::ContentFormat,
     },
     /// CSS (DVD). Title key for sector descrambling.
     Css { title_key: [u8; 5] },
@@ -166,6 +171,183 @@ impl DecryptKeys {
     }
 }
 
+/// Proactive AACS key-selection map: which held unit key decrypts each LBA of a
+/// title's encrypted content, decided ONCE before mux from the disc's CPS-unit
+/// (and, later, FMTS segment) structure — never by trial-decrypt-and-check per
+/// unit at mux time.
+///
+/// This is the pivot that ends the mux "key-server storm": the old path decrypts
+/// a unit, checks whether the plaintext looks like clean MPEG-TS, and — because
+/// authored-bad content never reaches that bar — concludes "wrong key, fetch a
+/// fresh one" and re-asks the key service for units it already holds the correct
+/// key for. There is NO per-unit byte pattern that separates "correctly decrypted
+/// but authored-bad" from "still encrypted", so that check is unanswerable. The
+/// map removes the question: we resolve one key per CPS unit / segment up front
+/// (see `resolve_mux_key_map`), record which LBA ranges each covers, and at mux
+/// time simply "decrypt this LBA with key K" and trust it — bad TS is the muxer's
+/// concern, exactly as for a physically-read clear disc.
+///
+/// Ranges are `[start_lba, end_lba)` → index into the `Aacs { unit_keys }` pool,
+/// sorted and disjoint. `default_idx` covers any LBA no range claims — the
+/// single-CPS case is just an empty range list with `default_idx = 0`, so the
+/// common disc pays zero lookup cost and needs no structural walk.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct AacsKeyMap {
+    ranges: Vec<(u32, u32, usize)>,
+    default_idx: usize,
+}
+
+impl AacsKeyMap {
+    /// The whole title is one CPS unit → one key (`idx`) everywhere. This is the
+    /// overwhelmingly common disc (incl. every single-CPS UHD); no LBA walk.
+    pub fn single(idx: usize) -> Self {
+        Self {
+            ranges: Vec::new(),
+            default_idx: idx,
+        }
+    }
+
+    /// Build from explicit `[start_lba, end_lba) → key_idx` ranges (multi-CPS /
+    /// FMTS). Ranges are sorted; `default_idx` answers any uncovered LBA.
+    pub fn from_ranges(mut ranges: Vec<(u32, u32, usize)>, default_idx: usize) -> Self {
+        ranges.sort_by_key(|&(start, _, _)| start);
+        Self {
+            ranges,
+            default_idx,
+        }
+    }
+
+    /// The unit-key index to decrypt the aligned unit at `lba` with. O(log n) —
+    /// the last range whose start is `<= lba` and whose end is `> lba`, else the
+    /// default. Cheap enough to call per aligned unit on the mux hot path.
+    pub fn key_idx_for(&self, lba: u32) -> usize {
+        if self.ranges.is_empty() {
+            return self.default_idx;
+        }
+        match self
+            .ranges
+            .binary_search_by(|&(start, _, _)| start.cmp(&lba))
+        {
+            Ok(i) => self.ranges[i].2,
+            Err(0) => self.default_idx,
+            Err(i) => {
+                let (start, end, idx) = self.ranges[i - 1];
+                if lba >= start && lba < end {
+                    idx
+                } else {
+                    self.default_idx
+                }
+            }
+        }
+    }
+
+    /// The `[start_lba, end_lba) → key_idx` ranges (sorted, disjoint). Empty for a
+    /// single-CPS map (everything uses [`default_idx`](Self::default_idx)).
+    pub fn ranges(&self) -> &[(u32, u32, usize)] {
+        &self.ranges
+    }
+
+    /// The key index for any LBA no explicit range claims (the single-CPS key).
+    pub fn default_idx(&self) -> usize {
+        self.default_idx
+    }
+
+    /// The distinct key indices this map can select — the CPS units / segments a
+    /// title actually reaches. Used by the resolver to know which keys to secure
+    /// up front.
+    pub fn key_indices(&self) -> Vec<usize> {
+        let mut v: Vec<usize> = self.ranges.iter().map(|&(_, _, i)| i).collect();
+        v.push(self.default_idx);
+        v.sort_unstable();
+        v.dedup();
+        v
+    }
+}
+
+/// Decrypt a buffer of sectors in-place using a resolved [`AacsKeyMap`] — the
+/// mux's TRUSTED decrypt. `base_lba` is the absolute LBA of `buf`'s first sector;
+/// each aligned unit (3 sectors) is decrypted with the key the map assigns to its
+/// LBA. There is NO key trial and NO `is_clean` verdict: the map already decided
+/// the key from disc structure, so we apply it and move on — a unit that decrypts
+/// to authored-bad TS passes through for the muxer to drop, never re-fetched.
+///
+/// Only [`DecryptKeys::Aacs`] uses a map (CSS self-cracks per region inside
+/// [`decrypt_sectors`]; `None` is clear) — other variants are a no-op here so the
+/// decorator can dispatch uniformly. A map index outside the held pool is a
+/// fail-loud [`Error::DecryptFailed`]: the resolver's job is to guarantee every
+/// selectable index is present, so a gap here is a resolver bug, not silent loss.
+pub fn decrypt_sectors_mapped(
+    buf: &mut [u8],
+    keys: &DecryptKeys,
+    base_lba: u32,
+    map: &AacsKeyMap,
+) -> Result<(), crate::error::Error> {
+    let (unit_keys, rdk, format) = match keys {
+        DecryptKeys::Aacs {
+            unit_keys,
+            read_data_key,
+            format,
+        } => (unit_keys, *read_data_key, *format),
+        // Clear / CSS: the mapped path is AACS-only. Leave the buffer untouched;
+        // CSS descrambles via `decrypt_sectors` and `None` is already clear.
+        _ => return Ok(()),
+    };
+
+    let unit_len = aacs::content::ALIGNED_UNIT_LEN;
+    let unit_sectors = (unit_len / 2048) as u32;
+
+    // Validate every selectable index up front (fail loud) so the per-unit hot
+    // loop can index without bounds churn and a resolver gap never silently
+    // passes ciphertext through as "decrypted".
+    for idx in map.key_indices() {
+        if unit_keys.get(idx).is_none() {
+            return Err(crate::error::Error::DecryptFailed);
+        }
+    }
+
+    let decrypt_one = |idx_in_buf: usize, chunk: &mut [u8]| {
+        if chunk.len() != unit_len {
+            return; // trailing partial unit: clear tail on disc, leave as-is
+        }
+        // Gate on the authoritative encrypted flag ONLY (the CPI bits in the clear
+        // seed) — no `is_clean`. A clear unit (flag unset) is left untouched; an
+        // encrypted unit is decrypted with its MAPPED key and trusted.
+        if !aacs::content::aacs_unit_encrypted(chunk, format) {
+            return;
+        }
+        let unit_lba = base_lba.saturating_add((idx_in_buf as u32) * unit_sectors);
+        let key_idx = map.key_idx_for(unit_lba);
+        // Bounds already proven above; index directly.
+        let key = &unit_keys[key_idx].1;
+        if let Some(ref rdk_key) = rdk {
+            aacs::content::decrypt_bus(chunk, rdk_key);
+        }
+        aacs::content::decrypt_unit(chunk, key);
+    };
+
+    let nthreads = decrypt_threads();
+    let nunits = buf.len() / unit_len;
+    if nthreads <= 1 || nunits < PARALLEL_MIN_UNITS {
+        for (i, chunk) in buf.chunks_mut(unit_len).enumerate() {
+            decrypt_one(i, chunk);
+        }
+    } else {
+        match decrypt_pool() {
+            Some(pool) => pool.install(|| {
+                buf.par_chunks_mut(unit_len)
+                    .enumerate()
+                    .for_each(|(i, chunk)| decrypt_one(i, chunk));
+            }),
+            None => {
+                for (i, chunk) in buf.chunks_mut(unit_len).enumerate() {
+                    decrypt_one(i, chunk);
+                }
+            }
+        }
+    }
+    Ok(())
+}
+
 /// Decrypt a buffer of sectors in-place.
 ///
 /// For AACS: processes in 6144-byte aligned units (3 sectors).
@@ -180,14 +362,16 @@ impl DecryptKeys {
 /// Returns `Err` if decryption was expected but keys are missing or invalid.
 /// Never produces silently corrupted output.
 ///
-/// On success returns the number of bytes belonging to scrambled AACS units
-/// that **no available key could decrypt** — those units are restored to their
-/// original encrypted bytes (so a clear nav-file is never corrupted), but for
-/// genuine encrypted content this is silent data loss the downstream TS
-/// assembler will drop without a sync. The decrypt-on-read decorator folds this
-/// count into the mux loss accounting so a partial key failure can't be reported
-/// as a perfect rip. `0` for `None` / `Css` and for any AACS buffer where every
-/// scrambled unit decrypted.
+/// Pure decrypt: every encrypted unit has a key APPLIED in place and the
+/// plaintext is left as-is — this function applies NO policy (it never restores
+/// ciphertext, nulls, or re-fetches). On success it returns the number of bytes
+/// belonging to units a key was applied to but that did NOT reassemble to clean
+/// MPEG-TS ("unverified"). "Did a key open it to clean TS?" is a key-SELECTION /
+/// read-VERIFY signal, NOT a "did we decrypt?" verdict — a correct key can
+/// decrypt content whose encoding is broken. The caller decides what an
+/// unverified unit means: the mux passes the bytes to the muxer; the sweep/patch
+/// verify path recovers a key and retries, or fails the read. `0` for `None` /
+/// `Css` and for any AACS buffer where every unit reached clean TS.
 pub fn decrypt_sectors(
     buf: &mut [u8],
     keys: &mut DecryptKeys,
@@ -204,7 +388,8 @@ pub fn decrypt_sectors(
 /// no TS sync, which would otherwise be mistaken for ciphertext). `base_lba` is
 /// the absolute LBA of `buf`'s first sector; aligned units are 3 sectors.
 ///
-/// `content_ranges` is sorted, merged, disjoint `[start_lba, end_lba)`.
+/// `content_ranges` is sorted, merged, disjoint `(start_lba, sector_count)`
+/// tuples (each covering `[start_lba, start_lba + sector_count)`).
 pub fn decrypt_sectors_in_content(
     buf: &mut [u8],
     keys: &mut DecryptKeys,
@@ -240,6 +425,7 @@ fn decrypt_sectors_impl(
         DecryptKeys::Aacs {
             unit_keys,
             read_data_key,
+            format,
         } => {
             // Validate that unit_key_idx is in-range before doing anything else.
             // This preserves the existing contract: an out-of-range explicit index
@@ -248,8 +434,13 @@ fn decrypt_sectors_impl(
                 return Err(crate::error::Error::DecryptFailed);
             }
 
-            // Strip CPS-unit IDs — the decrypt primitives only want the raw key bytes.
-            let raw_keys: Vec<[u8; 16]> = unit_keys.iter().map(|(_, k)| *k).collect();
+            // Container of this disc's content — the key SELECTOR (`is_clean`)
+            // checks the decrypted plaintext against the right structure (TS vs PS).
+            let format = *format;
+            // Index `unit_keys` directly for the raw key bytes (the `.1` of each
+            // `(cps_id, key)`); no per-call `Vec` of stripped keys — the decrypt
+            // closures only ever need `len()` / `[idx].1`, so collecting one would
+            // just be a heap alloc/free on every batch of the mux hot path.
             let rdk: Option<[u8; 16]> = *read_data_key;
             let unit_len = aacs::content::ALIGNED_UNIT_LEN;
             // AACS decrypts whole 6144-byte aligned units. The live mux path
@@ -272,7 +463,7 @@ fn decrypt_sectors_impl(
             //     silent corruption. We fail loud (Error::DecryptFailed), matching
             //     the highway path's Error::ExtentNotUnitAligned policy.
             //
-            // Detection: ts_sync_destroyed() short-circuits to false for any
+            // Detection: !crate::aacs::content::is_clean(, crate::disc::ContentFormat::BdTs) short-circuits to false for any
             // buffer shorter than a full unit, so it cannot judge a partial. We
             // instead apply the same TS-sync-intactness test it uses internally
             // (ts_sync_count vs ts_packet_total) directly to the available
@@ -293,10 +484,14 @@ fn decrypt_sectors_impl(
                     Some((base, ranges)) => lba_in_ranges(base.saturating_add(nfull * 3), ranges),
                     None => true,
                 };
-                if partial_in_content {
+                // TS-only: a scrambled trailing PARTIAL unit (< a full 6144-byte
+                // unit) can't be unit-decrypted, so fail loud. Validity is the SAME
+                // `is_clean` proof floor used everywhere — a clear TS tail passes it,
+                // a scrambled one fails. PS (`.evo`) partials lack the TS structure,
+                // so this stays TS-only (HD-DVD partial-scramble is not yet wired).
+                if partial_in_content && format == crate::disc::ContentFormat::BdTs {
                     let partial = &buf[buf.len() - partial_len..];
-                    let packets = aacs::content::ts_packet_total(partial);
-                    if packets > 0 && aacs::content::ts_sync_count(partial) <= packets / 2 {
+                    if !aacs::content::is_clean(partial, format) {
                         return Err(crate::error::Error::DecryptFailed);
                     }
                 }
@@ -320,27 +515,34 @@ fn decrypt_sectors_impl(
             // accounting so a partial key failure isn't reported as a clean rip.
             let dropped_bytes = AtomicUsize::new(0);
 
-            // Per-unit decrypt closure. For a scrambled full aligned unit:
+            // Per-unit PURE decrypt closure. For a scrambled full aligned unit:
             //   1. Try the cached key index first (avoids scanning all keys on the
             //      common case where a disc run uses one CPS unit throughout).
             //   2. On miss, try every key in order (multi-CPS-unit discs).
-            //   3. Accept the first key whose output passes the TS-sync verify.
-            //   4. Only restore-to-original if NO key validates (non-m2ts unit or
-            //      genuine decrypt failure). See test
-            //      `nav_file_unit_survives_decrypt_attempt`.
+            //   3. Select the first key whose output passes the TS-sync verify.
+            //   4. If NONE yields clean TS, keep the applied-key plaintext anyway
+            //      (a key WAS applied — bad TS is the caller's/muxer's concern) and
+            //      tally the unit as unverified. Never restore ciphertext / null.
+            //      Nav protection is the caller's content gate, not a restore here.
             //
             // If a read_data_key is present (AACS 2.0 bus encryption), bus-decrypt
             // must happen first — it's a shared layer on top that is key-independent
             // across all CPS units on the disc.
             let decrypt_one = |chunk: &mut [u8]| {
-                if chunk.len() != unit_len || !aacs::content::aacs_unit_needs_decrypt(chunk) {
+                // Gate on `aacs_unit_needs_decrypt` (encrypted-flag set AND structure
+                // not yet restored): the flag alone isn't enough because it lives in
+                // the plaintext header and survives decryption, so an already-decrypted
+                // unit would be decrypted a SECOND time (scrambling it) on any re-run of
+                // this pass. The structure-restored half makes it idempotent. This is
+                // ALSO the sole gate protecting the now-pure `decrypt_unit` from
+                // decrypting a clear unit.
+                if chunk.len() != unit_len || !aacs::content::aacs_unit_needs_decrypt(chunk, format)
+                {
                     return;
                 }
-                // Save original bytes so we can restore if no key validates.
-                let original: Vec<u8> = chunk.to_vec();
 
-                // Build a bus-decrypted copy to try unit keys against, or work
-                // in-place when there is no bus layer.
+                // Bus-decrypt (AACS 2.0) in place first — a shared layer under every
+                // CPS unit key. Whatever we do below operates on the bus-clear bytes.
                 if let Some(ref rdk_key) = rdk {
                     aacs::content::decrypt_bus(chunk, rdk_key);
                 }
@@ -349,29 +551,68 @@ fn decrypt_sectors_impl(
                 // back to the full list skipping the hint.
                 let hint = last_key_idx.load(Ordering::Relaxed);
                 let try_order =
-                    std::iter::once(hint).chain((0..raw_keys.len()).filter(move |&i| i != hint));
+                    std::iter::once(hint).chain((0..unit_keys.len()).filter(move |&i| i != hint));
 
+                // Compose the two SEGREGATED primitives explicitly. `decrypt_unit`
+                // is the decrypt (apply the key, leave the plaintext). `is_clean`
+                // is a SEPARATE structural question used here ONLY as a multi-CPS-unit
+                // key SELECTOR — the first key whose output is clean for the disc's
+                // container (`format`: TS or PS) is the match. "Did a key produce
+                // clean structure?" is NOT "did we decrypt?": a correct key can
+                // decrypt content whose encoding is broken (a muxer concern). When
+                // NO key yields clean structure we STILL decrypted (the cached-hint
+                // key is applied): keep those bytes and report the unit UNVERIFIED.
+                // This function applies no policy; the caller decides what unverified
+                // means (mux passes it to the muxer; sweep/patch recover or fail).
+
+                // Single-key fast path (the vast majority of titles): with no
+                // alternate key to fall back on there is nothing to try/rollback,
+                // so decrypt in place — no per-unit scratch alloc or copy-back.
+                // Clean → cache the hint; unclean → keep the applied bytes and
+                // tally unverified, exactly as the loop below would with one key.
+                if unit_keys.len() == 1 {
+                    aacs::content::decrypt_unit(chunk, &unit_keys[0].1);
+                    if aacs::content::is_clean(chunk, format) {
+                        last_key_idx.store(0, Ordering::Relaxed);
+                    } else {
+                        dropped_bytes.fetch_add(chunk.len(), Ordering::Relaxed);
+                    }
+                    return;
+                }
+
+                // Trial each key against a STACK scratch (unit_len is always
+                // ALIGNED_UNIT_LEN and the guard above proved chunk.len() == unit_len)
+                // so a failing attempt doesn't clobber the bus-decrypted base in
+                // `chunk` that the next key retries on — with no per-key heap Vec.
+                // `chunk` is NOT mutated in this loop, so on total miss we simply
+                // re-apply the first key in place (decrypt_unit is pure), which
+                // reproduces the first attempt without stashing its bytes.
+                let mut scratch = [0u8; aacs::content::ALIGNED_UNIT_LEN];
+                let scratch = &mut scratch[..chunk.len()];
+                let mut first_idx: Option<usize> = None;
                 for idx in try_order {
-                    if let Some(key) = raw_keys.get(idx) {
-                        // Work on a per-key copy so a failing attempt doesn't
-                        // clobber the bus-decrypted base we'll retry on.
-                        let mut attempt: Vec<u8> = chunk.to_vec();
-                        if aacs::content::decrypt_unit(&mut attempt, key) {
-                            chunk.copy_from_slice(&attempt);
+                    if let Some((_, key)) = unit_keys.get(idx) {
+                        scratch.copy_from_slice(chunk);
+                        aacs::content::decrypt_unit(scratch, key);
+                        if aacs::content::is_clean(scratch, format) {
+                            chunk.copy_from_slice(scratch);
                             last_key_idx.store(idx, Ordering::Relaxed);
                             return;
                         }
+                        if first_idx.is_none() {
+                            first_idx = Some(idx);
+                        }
                     }
                 }
 
-                // No key validated — restore the original encrypted bytes and
-                // tally the loss. The unit is flagged encrypted (we only reach
-                // here past the CPI gate) but no key applied: genuine encrypted
-                // content with a missing/wrong sub-key. We always tally; the mux
-                // read path treats
-                // the count as loss (its extents are real content), while
-                // metadata-probe callers that don't install a loss sink ignore it.
-                chunk.copy_from_slice(&original);
+                // No key yielded clean structure. Keep the first-tried key's
+                // plaintext (the pool is non-empty past the guard, so `first_idx` is
+                // always `Some`) and tally the unit as unverified. Never restore
+                // ciphertext; that is a caller concern, threaded through the recovery
+                // ciphertext, not this seam.
+                if let Some(idx) = first_idx {
+                    aacs::content::decrypt_unit(chunk, &unit_keys[idx].1);
+                }
                 dropped_bytes.fetch_add(chunk.len(), Ordering::Relaxed);
             };
 
@@ -408,11 +649,14 @@ fn decrypt_sectors_impl(
                 // back to the serial path rather than panic.
                 match decrypt_pool() {
                     Some(pool) => {
-                        let chunks: Vec<&mut [u8]> = buf.chunks_mut(unit_len).collect();
+                        // `par_chunks_mut` iterates the units in place — no
+                        // intermediate `Vec<&mut [u8]>` allocation per batch.
                         pool.install(|| {
-                            chunks.into_par_iter().enumerate().for_each(|(idx, chunk)| {
-                                process(idx, chunk);
-                            });
+                            buf.par_chunks_mut(unit_len)
+                                .enumerate()
+                                .for_each(|(idx, chunk)| {
+                                    process(idx, chunk);
+                                });
                         });
                     }
                     None => {
@@ -442,13 +686,15 @@ fn decrypt_sectors_impl(
 mod tests {
     use super::*;
 
-    /// Regression for the 0.18.1 nav-file scramble bug. A non-m2ts unit (here
-    /// an MPLS file: starts "MPLS", carries no TS syncs) reads as scrambled
-    /// under `ts_sync_destroyed`, gets AES-decrypted with the unit key, fails
-    /// the TS-sync verification, and must be restored to its original bytes —
-    /// not left scrambled.
+    /// Regression for the 0.18.1 nav-file scramble bug, modern form. A non-m2ts
+    /// unit (here an MPLS file: starts "MPLS", whose byte-0 'M'=0x4D coincidentally
+    /// sets the CPI bits, so it reads as encrypted) must never be scrambled by a
+    /// decrypt attempt. The decrypter applies NO policy and no longer restores — so
+    /// nav protection is the CALLER's content gate: a real read (sweep/patch) is
+    /// content-gated, and every whole-disc caller passes the encrypted-content
+    /// extents so nav LBAs are skipped entirely and left untouched.
     #[test]
-    fn nav_file_unit_survives_decrypt_attempt() {
+    fn nav_file_unit_survives_when_gated_out_of_content() {
         let mut unit = vec![0u8; aacs::content::ALIGNED_UNIT_LEN];
         unit[0] = b'M';
         unit[1] = b'P';
@@ -462,11 +708,14 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
-        decrypt_sectors(&mut unit, &mut keys, 0).unwrap();
+        // The unit sits at LBA 0..3; the content extents are elsewhere (100..110),
+        // so this nav unit is OUTSIDE content and the gate skips it untouched.
+        decrypt_sectors_in_content(&mut unit, &mut keys, 0, 0, &[(100, 10)]).unwrap();
         assert_eq!(
             unit, snapshot,
-            "non-m2ts unit must be restored after failed decrypt"
+            "a nav unit outside the content extents must be left untouched by the gate"
         );
     }
 
@@ -531,6 +780,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let original = scrambled_region(aacs::content::ALIGNED_UNIT_LEN);
 
@@ -564,6 +814,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = scrambled_region(2 * aacs::content::ALIGNED_UNIT_LEN);
         // unit0 @ LBA 0 (clear/skip), unit1 @ LBA 3 (content). Content = [(3,3)].
@@ -582,6 +833,7 @@ mod tests {
         let mut keys_g = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut keys_u = keys_g.clone();
         let original = scrambled_region(aacs::content::ALIGNED_UNIT_LEN);
@@ -632,6 +884,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let original = scrambled_region(aacs::content::ALIGNED_UNIT_LEN);
         let mut buf = original.clone();
@@ -650,6 +903,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let original = clear_ts_region(aacs::content::ALIGNED_UNIT_LEN);
         let mut buf = original.clone();
@@ -768,6 +1022,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let u = aacs::content::ALIGNED_UNIT_LEN;
         let mut buf = vec![0u8; 3 * u];
@@ -785,6 +1040,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = scrambled_region(2 * aacs::content::ALIGNED_UNIT_LEN);
         // unit0 @ LBA0 content, unit1 @ LBA3 out. Content = [(0,3)].
@@ -804,6 +1060,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         // One full clear unit + a scrambled single-sector partial, all OUTSIDE
         // content → the partial must be tolerated (Ok), not DecryptFailed.
@@ -826,6 +1083,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         // One full scrambled unit + a 2048-byte (single-sector) CLEAR tail.
         let unit = scrambled_region(aacs::content::ALIGNED_UNIT_LEN);
@@ -851,6 +1109,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         // One full unit + a 4096-byte (two-sector) SCRAMBLED tail.
         let unit = clear_ts_region(aacs::content::ALIGNED_UNIT_LEN);
@@ -873,6 +1132,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf: Vec<u8> = Vec::new();
         assert!(decrypt_sectors(&mut buf, &mut keys, 0).is_ok());
@@ -886,6 +1146,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = clear_ts_region(aacs::content::ALIGNED_UNIT_LEN * 2);
         let snapshot = buf.clone();
@@ -927,6 +1188,7 @@ mod tests {
             DecryptKeys::Aacs {
                 unit_keys: vec![(0, [0; 16])],
                 read_data_key: None,
+                format: crate::disc::ContentFormat::BdTs,
             }
             .is_encrypted()
         );
@@ -1141,6 +1403,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, [0xAB; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = clear_ts_region(aacs::content::ALIGNED_UNIT_LEN);
         let err = decrypt_sectors(&mut buf, &mut keys, 5)
@@ -1161,6 +1424,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = clear_ts_region(aacs::content::ALIGNED_UNIT_LEN);
         let err = decrypt_sectors(&mut buf, &mut keys, 0).expect_err("empty unit_keys must error");
@@ -1235,13 +1499,14 @@ mod tests {
         let mut unit = clear_ts_unit();
         aacs_encrypt_unit_for_test(&mut unit, &key1);
         assert!(
-            aacs::content::ts_sync_destroyed(&unit),
+            !crate::aacs::content::is_clean(&unit, crate::disc::ContentFormat::BdTs),
             "encrypted unit must look scrambled before decrypt"
         );
 
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, key0), (1, key1)], // two CPS units
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
 
         // Call with the default hint (idx 0) — the fix must fall back to key1.
@@ -1249,7 +1514,7 @@ mod tests {
         decrypt_sectors(&mut buf, &mut keys, 0).expect("multi-CPS decrypt must succeed");
 
         assert!(
-            !aacs::content::ts_sync_destroyed(&buf),
+            crate::aacs::content::is_clean(&buf, crate::disc::ContentFormat::BdTs),
             "unit encrypted under key1 must be fully decrypted (TS syncs restored)"
         );
         // Every sync position must carry 0x47.
@@ -1276,11 +1541,12 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, key)],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = unit;
         decrypt_sectors(&mut buf, &mut keys, 0).expect("single-key disc must decrypt");
         assert!(
-            !aacs::content::ts_sync_destroyed(&buf),
+            crate::aacs::content::is_clean(&buf, crate::disc::ContentFormat::BdTs),
             "single-key disc: TS syncs must be restored"
         );
         assert_eq!(
@@ -1290,21 +1556,18 @@ mod tests {
         );
     }
 
-    /// Regression for the silent partial-decrypt-loss defect: a scrambled AACS
-    /// unit that NO supplied key can decrypt is restored to its original
-    /// ciphertext (so a clear nav-file is never corrupted) AND `decrypt_sectors`
-    /// returns the unit's byte length as the dropped count. Before the fix this
-    /// returned `()` and the still-encrypted bytes flowed downstream to be
-    /// silently dropped by the TS assembler with zero loss accounting — a rip
-    /// missing real content reported `lost_video_secs=0` and passed the abort
-    /// gate even under `abort_on_lost_secs=0`.
+    /// A unit no supplied key opens to clean TS is still DECRYPTED in place (the
+    /// key is applied — decryption ran; a broken result is bad data, not a decrypt
+    /// failure) and NEVER restored to ciphertext. `decrypt_sectors` still returns
+    /// the unit's byte length as the UNVERIFIED count — the read-verify signal the
+    /// sweep/patch caller consumes (the mux ignores it and passes the bytes to the
+    /// muxer). This is the single decrypt authority applying no policy.
     ///
-    /// Grounding: the `dropped_bytes.fetch_add(chunk.len(), …)` on the
-    /// no-key-validated restore path; the function returns that tally.
-    /// Mutation: drop the `fetch_add` (or return a constant 0) → dropped == 0,
-    /// this fails.
+    /// Grounding: `dropped_bytes.fetch_add(chunk.len(), …)` in `decrypt_one`, and
+    /// the removal of the `copy_from_slice(&original)` restore.
+    /// Mutation: re-add the restore → `buf == ciphertext`, this fails.
     #[test]
-    fn aacs_undecryptable_unit_reports_dropped_bytes() {
+    fn aacs_undecryptable_unit_is_decrypted_not_restored() {
         let real_key = [0x33u8; 16];
         let wrong_key = [0x44u8; 16]; // not the encrypting key
 
@@ -1313,26 +1576,27 @@ mod tests {
         aacs_encrypt_unit_for_test(&mut unit, &real_key);
         let ciphertext = unit.clone();
         assert!(
-            aacs::content::ts_sync_destroyed(&unit),
+            !crate::aacs::content::is_clean(&unit, crate::disc::ContentFormat::BdTs),
             "encrypted unit must look scrambled going in"
         );
 
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, wrong_key)],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = unit;
-        let dropped = decrypt_sectors(&mut buf, &mut keys, 0)
-            .expect("undecryptable unit is not a hard error");
+        let unverified =
+            decrypt_sectors(&mut buf, &mut keys, 0).expect("applying a key is never a hard error");
 
         assert_eq!(
-            dropped,
+            unverified,
             aacs::content::ALIGNED_UNIT_LEN,
-            "the whole scrambled unit must be reported as dropped when no key validates"
+            "a unit that did not reach clean TS is reported unverified"
         );
-        assert_eq!(
+        assert_ne!(
             buf, ciphertext,
-            "an undecryptable unit must be restored to its original ciphertext, not garbled"
+            "the unit must be DECRYPTED in place (key applied), never restored to ciphertext"
         );
     }
 
@@ -1363,22 +1627,26 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, key)],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let dropped = decrypt_sectors(&mut buf, &mut keys, 0).expect("partial decrypt is Ok");
 
         assert_eq!(
             dropped,
             aacs::content::ALIGNED_UNIT_LEN,
-            "exactly one unit's worth of bytes must be reported dropped"
+            "exactly one unit's worth of bytes must be reported unverified"
         );
         assert!(
-            !aacs::content::ts_sync_destroyed(&buf[..aacs::content::ALIGNED_UNIT_LEN]),
+            crate::aacs::content::is_clean(
+                &buf[..aacs::content::ALIGNED_UNIT_LEN],
+                crate::disc::ContentFormat::BdTs
+            ),
             "the decryptable unit must come out clear"
         );
-        assert_eq!(
+        assert_ne!(
             &buf[aacs::content::ALIGNED_UNIT_LEN..],
             &unit_b_ciphertext[..],
-            "the undecryptable unit must be restored to ciphertext"
+            "the unverified unit is DECRYPTED in place (key applied), never restored to ciphertext"
         );
     }
 
@@ -1392,6 +1660,7 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![(0, key)],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = unit;
         let dropped = decrypt_sectors(&mut buf, &mut keys, 0).expect("clean decrypt");

src/disc/encrypt.rs

@@ -311,15 +311,11 @@ impl Disc {
     ) -> Result<AacsState> {
         use crate::aacs;
 
-        let uk_ro_data = udf_fs
-            .read_file(reader, crate::aacs::PATH_UNIT_KEY_RO)
-            .or_else(|_| udf_fs.read_file(reader, crate::aacs::PATH_UNIT_KEY_RO_DUPLICATE))
-            .map_err(|_| Error::AacsNoKeys)?;
+        let uk_ro_data =
+            aacs::read_first(aacs::UNIT_KEY_RO_PATHS, |p| udf_fs.read_file(reader, p))?;
         let dh = aacs::inf::disc_hash(&uk_ro_data);
 
-        let cc = udf_fs
-            .read_file(reader, crate::aacs::PATH_CONTENT_CERT)
-            .or_else(|_| udf_fs.read_file(reader, crate::aacs::PATH_CONTENT_CERT_ALT))
+        let cc = aacs::read_first(aacs::CONTENT_CERT_PATHS, |p| udf_fs.read_file(reader, p))
             .ok()
             .as_deref()
             .and_then(aacs::inf::parse_content_cert);

src/disc/extract.rs

@@ -288,63 +288,6 @@ impl Disc {
     }
 }
 
-/// True for the AACS-encrypted stream files (`.m2ts`, `.ssif`). Every other UDF
-/// file is clear (nav / playlists / filesystem) and needs no decrypt verify.
-fn is_aacs_clip(name: &str) -> bool {
-    let lower = name.to_ascii_lowercase();
-    lower.ends_with(".m2ts") || lower.ends_with(".ssif")
-}
-
-/// Enumerate the disc's AACS clip (`.m2ts`/`.ssif`) files as
-/// [`crate::disc::verify::ClipLayout`]s for the post-read verify gate: each
-/// clip's declared size plus its absolute disc extents in FILE order. Reads the
-/// UDF tree through `reader`.
-///
-/// FAIL-SAFE: any enumeration error (bad UDF read, name collision, …) yields an
-/// EMPTY list — the verify gate then covers nothing and the sweep behaves as
-/// today. Enumeration must never break a rip, so the error is logged, not
-/// propagated.
-pub(crate) fn clip_layouts(reader: &mut dyn SectorSource) -> Vec<crate::disc::verify::ClipLayout> {
-    let result = (|| -> Result<Vec<crate::disc::verify::ClipLayout>> {
-        let fs = udf::read_filesystem(reader)?;
-        let mut planned: Vec<PlannedFile> = Vec::new();
-        let mut dirs: Vec<PathBuf> = Vec::new();
-        let mut seen_hosts: std::collections::HashMap<PathBuf, String> =
-            std::collections::HashMap::new();
-        plan_tree(
-            reader,
-            &fs,
-            &fs.root,
-            Path::new(""),
-            "",
-            true,
-            &mut planned,
-            &mut dirs,
-            &mut seen_hosts,
-        )?;
-        Ok(planned
-            .into_iter()
-            .filter(|pf| pf.inline.is_none() && is_aacs_clip(&pf.disc_name))
-            .map(|pf| crate::disc::verify::ClipLayout {
-                size: pf.size,
-                extents: pf.extents,
-                // Every AACS clip we enumerate today is BD-TS (`.m2ts`/`.ssif`).
-                // HD-DVD `.evo` (program stream) maps to `ContainerKind::Ps` here
-                // once `is_aacs_clip` recognises it — the one-line HD-DVD hook.
-                container: crate::disc::verify::ContainerKind::Ts,
-            })
-            .collect())
-    })();
-    result.unwrap_or_else(|e| {
-        tracing::warn!(
-            target: "freemkv::verify",
-            error = %e,
-            "clip enumeration failed; post-read verify disabled for this pass"
-        );
-        Vec::new()
-    })
-}
-
 /// A borrowing `SectorSource` wrapper. Lets the decrypting decorator "own" an
 /// inner source for its lifetime while the caller keeps the underlying
 /// `&mut dyn SectorSource` (the decorator is a `DecryptingSectorSource<S>`

src/disc/mod.rs

@@ -10,7 +10,7 @@
 
 mod bluray;
 mod dvd;
-pub mod dvd_audio_probe;
+pub(crate) mod dvd_audio_probe;
 mod encrypt;
 mod extract;
 mod hddvd;
@@ -19,7 +19,6 @@ mod patch;
 pub mod read_error;
 mod section_recover;
 mod sweep;
-pub mod verify;
 
 use crate::drive::{Drive, extract_scsi_context};
 use crate::error::{Error, Result};
@@ -85,7 +84,8 @@ pub struct Disc {
 pub enum ContentFormat {
     /// Blu-ray BD Transport Stream (192-byte packets)
     BdTs,
-    /// DVD MPEG-2 Program Stream (VOB)
+    /// MPEG-2 Program Stream — DVD (`.vob`) and HD-DVD (`.evo`). For AACS content
+    /// this selects the PS-aware encrypted-flag / structural checks.
     MpegPs,
 }
 
@@ -1623,12 +1623,11 @@ impl Disc {
         // detection needs the read, the read needs auth, auth needs detection.
         // The handshake is itself the detector: on a non-CSS (unencrypted) DVD
         // the disc-key read fails, `resolve` returns None, and the disc is left
-        // in the clear. This block is DVD-only (MPEG-PS); BD/UHD (MPEG-TS) goes
-        // through the AACS handshake above and never reaches here.
-        if disc.css.is_none()
-            && disc.content_format == ContentFormat::MpegPs
-            && !disc.titles.is_empty()
-        {
+        // in the clear. This block is DVD-only: gate on `DiscFormat::Dvd`, NOT
+        // `content_format == MpegPs` — HD-DVD `.evo` is ALSO MPEG-PS but is AACS,
+        // not CSS, so it must never enter the CSS/REPORT-KEY handshake (it goes
+        // through the AACS path above). BD/UHD are MPEG-TS and never reach here.
+        if disc.css.is_none() && disc.format == DiscFormat::Dvd && !disc.titles.is_empty() {
             // CSS title keys are per-VTS, and ONLY the scrambled movie content
             // carries a non-zero key. Menu / VMG / logo cells (often the
             // low-LBA first extent) return a ZERO title key over REPORT KEY —
@@ -1744,10 +1743,13 @@ impl Disc {
         // pre-decrypted one. A pre-decrypted image has its scramble flags clear,
         // so `crack_key` finds no crackable sector and the disc stays in the
         // clear. AACS images go through KEYDB VUK lookup, not here.
-        if disc.css.is_none()
-            && disc.content_format == ContentFormat::MpegPs
-            && !disc.titles.is_empty()
-        {
+        //
+        // Gate on `DiscFormat::Dvd`, NOT `content_format == MpegPs`: HD-DVD
+        // `.evo` images are ALSO MPEG-PS but are AACS, not CSS — they must not
+        // enter the CSS crack path. A CSS DVD's IFO (which defines the titles
+        // this branch reads) is unscrambled, so `detect_format` reliably sets
+        // `Dvd` from the SD-resolution titles even on a still-scrambled image.
+        if disc.css.is_none() && disc.format == DiscFormat::Dvd && !disc.titles.is_empty() {
             let main_extents = match disc
                 .titles
                 .iter()
@@ -1799,10 +1801,9 @@ impl Disc {
         reader: &mut dyn SectorSource,
         udf_fs: &udf::UdfFs,
     ) -> Result<(Vec<u8>, Vec<u8>, u8)> {
-        let inf = udf_fs
-            .read_file(reader, crate::aacs::PATH_UNIT_KEY_RO)
-            .or_else(|_| udf_fs.read_file(reader, crate::aacs::PATH_UNIT_KEY_RO_DUPLICATE))
-            .map_err(|_| Error::AacsNoKeys)?;
+        let inf = crate::aacs::read_first(crate::aacs::UNIT_KEY_RO_PATHS, |p| {
+            udf_fs.read_file(reader, p)
+        })?;
         let mkb = Self::read_mkb_content(reader, udf_fs)?;
         let version = Self::read_aacs_version(reader, udf_fs);
         Ok((inf, mkb, version))
@@ -1820,12 +1821,12 @@ impl Disc {
     /// mis-strided title keys (silent wrong unit keys), so a missing cert must
     /// not quietly pick the V10 stride for a UHD disc.
     fn read_aacs_version(reader: &mut dyn SectorSource, udf_fs: &udf::UdfFs) -> u8 {
-        match udf_fs
-            .read_file(reader, crate::aacs::PATH_CONTENT_CERT)
-            .or_else(|_| udf_fs.read_file(reader, crate::aacs::PATH_CONTENT_CERT_ALT))
-            .ok()
-            .as_deref()
-            .and_then(crate::aacs::inf::parse_content_cert)
+        match crate::aacs::read_first(crate::aacs::CONTENT_CERT_PATHS, |p| {
+            udf_fs.read_file(reader, p)
+        })
+        .ok()
+        .as_deref()
+        .and_then(crate::aacs::inf::parse_content_cert)
         {
             Some(c) => c.version.major(),
             None => {
@@ -1856,10 +1857,9 @@ impl Disc {
         const MAX_BYTES: usize = 64 * 1024 * 1024;
         let mut want = START_BYTES;
         loop {
-            let buf = udf_fs
-                .read_file_prefix(reader, crate::aacs::PATH_MKB_RO, want)
-                .or_else(|_| udf_fs.read_file_prefix(reader, crate::aacs::PATH_MKB_RW, want))
-                .map_err(|_| Error::AacsNoKeys)?;
+            let buf = crate::aacs::read_first(crate::aacs::MKB_PATHS, |p| {
+                udf_fs.read_file_prefix(reader, p, want)
+            })?;
             let n = crate::aacs::mkb::mkb_content_len(&buf);
             // `n` strictly inside `buf` => the record walk reached the padding
             // boundary (full content captured). `buf` shorter than `want` =>
@@ -2297,12 +2297,15 @@ fn aligned_unit_keys_validate(
     unit_keys: &[(u32, [u8; 16])],
     read_data_key: Option<&[u8; 16]>,
     samples: &[Vec<u8>],
+    format: ContentFormat,
 ) -> bool {
-    use crate::aacs::content::{ALIGNED_UNIT_LEN, aacs_unit_needs_decrypt, decrypt_unit_full};
+    use crate::aacs::content::{
+        ALIGNED_UNIT_LEN, aacs_unit_needs_decrypt, decrypt_bus, decrypt_unit, is_clean,
+    };
     let scrambled: Vec<&[u8]> = samples
         .iter()
         .map(|s| s.as_slice())
-        .filter(|s| aacs_unit_needs_decrypt(s))
+        .filter(|s| aacs_unit_needs_decrypt(s, format))
         .collect();
     if scrambled.is_empty() {
         return true; // nothing to disprove against — accept
@@ -2324,7 +2327,13 @@ fn aligned_unit_keys_validate(
             hb.tick_cpu(tried, total);
             tried += 1;
             probe.copy_from_slice(&sample[..ALIGNED_UNIT_LEN]);
-            if decrypt_unit_full(&mut probe, k, read_data_key) {
+            // bus layer (AACS 2.0) first, then the CPS unit key, then the structural
+            // proof — the composed form of the old `decrypt_unit_full`.
+            if let Some(rdk) = read_data_key {
+                decrypt_bus(&mut probe, rdk);
+            }
+            decrypt_unit(&mut probe, k);
+            if is_clean(&probe, format) {
                 covered = true;
                 break;
             }
@@ -2351,6 +2360,7 @@ impl Disc {
             crate::decrypt::DecryptKeys::Aacs {
                 unit_keys: aacs.unit_keys.clone(),
                 read_data_key: aacs.read_data_key,
+                format: self.content_format,
             }
         } else if let Some(ref css) = self.css {
             crate::decrypt::DecryptKeys::Css {
@@ -2645,28 +2655,6 @@ impl Disc {
         self.ensure_decryptable_keys(raw, keys)
     }
 
-    /// Upfront FMTS (AACS 2.1) key gate, parallel to
-    /// [`ensure_title_decryptable`](Self::ensure_title_decryptable). A 2.1 disc
-    /// carries forensic variant segments that need segment (variant) keys the
-    /// unit-key path cannot provide. When
-    /// [`BYPASS_FMTS_KEY`](crate::aacs::segment::BYPASS_FMTS_KEY) is `false`,
-    /// their absence is a hard upfront failure ([`Error::FmtsKeyMissing`]) — the
-    /// same policy as a missing unit key, so a forensic-holed rip is refused, not
-    /// produced. When `true` (the default today) the segments are skipped as
-    /// expected loss and this passes. `raw` mode and non-FMTS discs always pass.
-    pub fn ensure_forensic_segments_decryptable(&self, raw: bool) -> Result<()> {
-        if raw || crate::aacs::segment::BYPASS_FMTS_KEY {
-            return Ok(());
-        }
-        // A 2.1 (FMTS) disc carries forensic variant segments with no segment-key
-        // source (none exists yet), so its variant segments cannot be opened.
-        // Refuse upfront rather than emit a forensic-holed rip.
-        if self.format == DiscFormat::Fmts {
-            return Err(Error::FmtsKeyMissing);
-        }
-        Ok(())
-    }
-
     /// Inject pre-resolved AACS unit keys into a scanned disc — the deferred-mux
     /// / resume path. The keys come from the mapfile's `# freemkv-uk:` header
     /// (persisted at sweep time when the disc was keyed), so the mux decrypts
@@ -2840,7 +2828,12 @@ impl Disc {
         // de-scramble it. With no samples (or only clear ones) there is nothing
         // to disprove against, so the key is accepted as-is — keeping the
         // sample-less paths (resume / mapfile cache) byte-for-byte unchanged.
-        if !aligned_unit_keys_validate(&candidate_unit_keys, read_data_key.as_ref(), samples) {
+        if !aligned_unit_keys_validate(
+            &candidate_unit_keys,
+            read_data_key.as_ref(),
+            samples,
+            self.content_format,
+        ) {
             return Err(crate::error::Error::AacsKeyRejected);
         }
 
@@ -3073,10 +3066,6 @@ impl Disc {
             progress: opts.progress,
             halt: opts.halt.clone(),
             key_fetch: opts.key_fetch.clone(),
-            // Disc::copy's internal patch grinds each range fully (it's a
-            // single-call recovery); the breadth-first fast-capture ordering is
-            // an autorip multi-pass concern.
-            fast_capture: false,
         };
         let pr = self.patch(reader, path, &patch_opts)?;
         tracing::info!(
@@ -3131,27 +3120,15 @@ impl Disc {
         // A decrypting sweep (`opts.decrypt`, e.g. `disc:// → iso://` without
         // `--raw`) decrypts each unit IN PLACE → the ISO holds plaintext.
         //
-        // A NON-decrypting MULTIPASS sweep (`!opts.decrypt && skip_on_error`, the
-        // autorip / `--multipass` path) writes the ISO as CIPHERTEXT, but we
-        // still resolve the keys and VERIFY each unit on a scratch copy: a unit
-        // that won't decrypt fails the read (`DECRYPT_VERIFY_READ`) exactly like
-        // a SCSI error, and flows into the SAME read-error recovery (skip /
-        // NonTrimmed / patch). This is the one spot that makes "a read succeeded"
-        // mean "read AND decrypts" — everything downstream is unchanged. With no
-        // usable AACS keys (no keydb) it degrades to a plain pass-through.
-        //
-        // A plain `--raw` single-pass (no `skip_on_error`) stays a pass-through:
-        // the user asked for the raw image, untouched and unchecked.
-        // The sweep COPIES ciphertext (multipass / `--raw`) or decrypts IN PLACE
-        // (`opts.decrypt`, the rare disc→decrypted-ISO). It deliberately does NOT
-        // decrypt-VERIFY: a whole-disc sweep reads disc-absolute, but AACS aligned
-        // units are anchored to each clip's FILE start and clips can be non-6144-
-        // aligned OR fragmented across UDF extents — so a disc-absolute verify
-        // mis-aligns the unit grid and false-fails good clips (it skipped the
-        // ~990 MB orphan-CPS clip on Dunkirk). Verification moved to the
-        // clip-anchored [`Disc::verify_clips`] pass that runs AFTER the sweep,
-        // reading each clip file-order-anchored from the ISO. The read here stays
-        // a fail-safe copy; alignment is never assumed.
+        // Every other sweep (`!opts.decrypt`: the autorip / `--multipass` path and
+        // plain `--raw`) writes the ISO as CIPHERTEXT verbatim — keys = `None`, a
+        // pure pass-through. Bad sectors are found by PHYSICAL read success (a SCSI
+        // read error → skip / NonTrimmed → patch re-read), NOT by decrypt structure.
+        // (The old decrypt-VERIFY read gate — which mis-aligned the disc-absolute
+        // unit grid against clip-file-anchored AACS units and false-failed good
+        // clips like Dunkirk's orphan-CPS clip — was removed. There is no scratch
+        // verify and no post-sweep clip-anchored pass; decryptability is proven at
+        // mux time, not at capture time.)
         let keys = if opts.decrypt {
             self.decrypt_keys()
         } else {
@@ -3177,22 +3154,6 @@ impl Disc {
         };
         let reader = &mut reader;
 
-        // Post-read verify gate (universal `read -> verify -> sign-off`). Built
-        // ONLY for the ciphertext sweep (`!opts.decrypt`, the multipass rip
-        // path) so `observe` always sees on-disc ciphertext and never
-        // double-decrypts already-plaintext bytes. `UnitVerifier::new` is itself
-        // fail-safe: it returns `None` (verify disabled, behavior unchanged) for
-        // a non-AACS disc, no keys, the kill-switch off, or an empty clip
-        // enumeration. We resolve the REAL AACS keys here even though the sweep
-        // copies ciphertext, and reuse the application's key-fetch seam.
-        let mut verifier = if opts.decrypt {
-            None
-        } else {
-            let verify_keys = self.decrypt_keys();
-            let layouts = extract::clip_layouts(&mut *reader);
-            crate::disc::verify::UnitVerifier::new(&layouts, &verify_keys, opts.key_fetch.clone())
-        };
-
         // Mapfile: load if resuming, else wipe + recreate.
         let mapfile_path = self.mapfile_for(path);
         // covers_disc reconciliation. A resume against a mapfile whose total
@@ -3483,18 +3444,6 @@ impl Disc {
                         // The consumer thread sees decrypted bytes; the
                         // pre-0.18 inline decrypt_sectors call lived here.
 
-                        // Post-read verify: observe the just-read ciphertext
-                        // BEFORE it is moved into the channel, collecting the
-                        // clip units this batch completes that are confidently
-                        // undecryptable. Sent as `MarkBad` AFTER the `Good`
-                        // below so the FIFO pipe records `Finished` first and the
-                        // downgrade to `NonTrimmed` last. No-op when the gate is
-                        // disabled (`verifier` is `None`).
-                        let verify_bad = verifier
-                            .as_mut()
-                            .map(|v| v.observe(block_lba, &buf[..block_bytes as usize]))
-                            .unwrap_or_default();
-
                         // Move the batch into the channel via fresh
                         // owned Vec. The producer's `buf` is reused
                         // for the next read.
@@ -3503,26 +3452,6 @@ impl Disc {
                             producer_err = Some(consumer_gone());
                             break 'outer;
                         }
-                        // Downgrade any unit that failed verify (decrypt-fail ==
-                        // bad read). decrypt-fail is NOT physical damage, so it
-                        // deliberately does not touch the damage-jump window.
-                        let mut send_failed = false;
-                        for (bad_lba, bad_cnt) in verify_bad {
-                            if pipe
-                                .send(WorkItem::MarkBad {
-                                    pos: bad_lba as u64 * 2048,
-                                    len: bad_cnt as u64 * 2048,
-                                })
-                                .is_err()
-                            {
-                                producer_err = Some(consumer_gone());
-                                send_failed = true;
-                                break;
-                            }
-                        }
-                        if send_failed {
-                            break 'outer;
-                        }
                         bytes_done = bytes_done.saturating_add(block_bytes);
                         pos += block_bytes;
                     }
@@ -4009,18 +3938,6 @@ pub struct PatchOptions<'a> {
     /// On-decrypt-miss key fetch (see [`CopyOptions::key_fetch`]). Lets Pass N
     /// recover an orphan CPS unit's key when re-reading its bad range.
     pub key_fetch: Option<crate::sector::KeyFetch>,
-    /// Fast-capture pass: read each bad range ONCE at the full batch and leave
-    /// every failed block `NonTrimmed` for a later pass — WITHOUT bisecting,
-    /// re-reading, or grinding it here. This lets a first retry pass grab the
-    /// readable blocks (the sweep's good skip-ahead overshoot) of EVERY range
-    /// quickly, before any single range's slow per-sector recovery — so
-    /// recovered data surfaces across the whole disc first instead of grinding
-    /// section 1 to exhaustion before even touching section 2. A later pass
-    /// (`fast_capture = false`) does the granular bisect/retry on what's left.
-    /// No data is dropped: a failed block stays `NonTrimmed` until a granular
-    /// pass recovers it or finally gives up. A transport fault (bridge crash)
-    /// still aborts — it isn't a recoverable bad sector.
-    pub fast_capture: bool,
 }
 
 /// Result returned by [`Disc::patch`].
@@ -4867,6 +4784,7 @@ mod tests {
             crate::decrypt::DecryptKeys::Aacs {
                 unit_keys,
                 read_data_key,
+                ..
             } => {
                 assert_eq!(unit_keys, uk, "injected UK must be the decrypt key");
                 assert_eq!(read_data_key, None, "ISO mux needs no bus key");
@@ -5386,14 +5304,15 @@ mod tests {
 
     #[test]
     fn unit_key_validation_gates_on_real_ciphertext() {
-        use crate::aacs::content::{ALIGNED_UNIT_LEN, ts_sync_destroyed};
+        use crate::aacs::content::ALIGNED_UNIT_LEN;
 
         // No samples -> nothing to disprove against -> accept (sample-less paths
         // like resume / mapfile must be unaffected).
         assert!(super::aligned_unit_keys_validate(
             &[(0, [0x11u8; 16])],
             None,
-            &[]
+            &[],
+            ContentFormat::BdTs
         ));
 
         // A clear unit (TS syncs intact) is not scrambled -> proves nothing ->
@@ -5404,18 +5323,22 @@ mod tests {
             clear[off] = 0x47;
             off += 192;
         }
-        assert!(!ts_sync_destroyed(&clear));
+        assert!(crate::aacs::content::is_clean(
+            &clear,
+            crate::disc::ContentFormat::BdTs
+        ));
         assert!(super::aligned_unit_keys_validate(
             &[(0, [0x11u8; 16])],
             None,
-            &[clear.clone()]
+            &[clear.clone()],
+            ContentFormat::BdTs
         ));
 
         // A genuinely scrambled unit the RIGHT key restores to clear TS.
         let uk = [0x5au8; 16];
         let enc = encrypt_unit_for_test(&clear, &uk);
         assert!(
-            ts_sync_destroyed(&enc),
+            !crate::aacs::content::is_clean(&enc, crate::disc::ContentFormat::BdTs),
             "encrypted unit must read scrambled"
         );
 
@@ -5423,16 +5346,23 @@ mod tests {
         assert!(super::aligned_unit_keys_validate(
             &[(7, uk)],
             None,
-            &[enc.clone()]
+            &[enc.clone()],
+            ContentFormat::BdTs
         ));
         // Wrong key -> cannot de-scramble a scrambled sample -> reject.
         assert!(!super::aligned_unit_keys_validate(
             &[(7, [0x00u8; 16])],
             None,
-            &[enc.clone()]
+            &[enc.clone()],
+            ContentFormat::BdTs
         ));
         // Empty key set against a scrambled sample -> reject.
-        assert!(!super::aligned_unit_keys_validate(&[], None, &[enc]));
+        assert!(!super::aligned_unit_keys_validate(
+            &[],
+            None,
+            &[enc],
+            ContentFormat::BdTs
+        ));
     }
 
     #[test]
@@ -5444,7 +5374,7 @@ mod tests {
         // CPS-unit-1 sectors then passed through as raw encrypted bytes into the
         // ISO/MKV with no error surfaced. The gate must now reject a key set
         // that leaves any scrambled sample uncovered.
-        use crate::aacs::content::{ALIGNED_UNIT_LEN, ts_sync_destroyed};
+        use crate::aacs::content::ALIGNED_UNIT_LEN;
 
         let mut clear = vec![0u8; ALIGNED_UNIT_LEN];
         let mut off = 4;
@@ -5457,8 +5387,14 @@ mod tests {
         let uk1 = [0x22u8; 16];
         let sample0 = encrypt_unit_for_test(&clear, &uk0); // CPS unit 0 body
         let sample1 = encrypt_unit_for_test(&clear, &uk1); // CPS unit 1 body
-        assert!(ts_sync_destroyed(&sample0));
-        assert!(ts_sync_destroyed(&sample1));
+        assert!(!crate::aacs::content::is_clean(
+            &sample0,
+            crate::disc::ContentFormat::BdTs
+        ));
+        assert!(!crate::aacs::content::is_clean(
+            &sample1,
+            crate::disc::ContentFormat::BdTs
+        ));
 
         let samples = vec![sample0.clone(), sample1.clone()];
 
@@ -5467,21 +5403,24 @@ mod tests {
         assert!(!super::aligned_unit_keys_validate(
             &[(0, uk0)],
             None,
-            &samples
+            &samples,
+            ContentFormat::BdTs
         ));
 
         // Complete key set (both CPS units) -> accept.
         assert!(super::aligned_unit_keys_validate(
             &[(0, uk0), (1, uk1)],
             None,
-            &samples
+            &samples,
+            ContentFormat::BdTs
         ));
 
         // Order-independent: covering key present anywhere in the set is fine.
         assert!(super::aligned_unit_keys_validate(
             &[(1, uk1), (0, uk0)],
             None,
-            &samples
+            &samples,
+            ContentFormat::BdTs
         ));
     }
 

src/disc/patch.rs

@@ -405,9 +405,15 @@ pub(super) fn compute_initial_state(
         bad_ranges.reverse();
     }
     let work_total: u64 = bad_ranges.iter().map(|(_, sz)| *sz).sum();
+    // Fail SAFE when metadata is indeterminate: assume a regular file so a
+    // real `sync_all` failure is surfaced, not swallowed. `/dev/null` and pipes
+    // report success-with-non-file here (so they still correctly map to
+    // `false`); only a genuine metadata error (e.g. transient NFS ESTALE) hits
+    // the default, and for a data-integrity guard "surface the error" is the
+    // right side to err on.
     let is_regular = std::fs::metadata(path)
         .map(|m| m.file_type().is_file())
-        .unwrap_or(false);
+        .unwrap_or(true);
     Ok((
         map,
         initial_stats,
@@ -1247,7 +1253,24 @@ impl Disc {
     pub fn bytes_bad_in_title(&self, mapfile_path: &std::path::Path, title: &DiscTitle) -> u64 {
         let map = match mapfile::Mapfile::load(mapfile_path) {
             Ok(m) => m,
-            Err(_) => return 0,
+            // A MISSING mapfile is legitimate (no damage was ever tracked — e.g. a
+            // clean single-pass rip): 0 bad bytes is correct. Any OTHER load error
+            // (corrupt / unreadable mapfile) means we CANNOT know the damage — and
+            // a returned 0 reads to the caller as "clean." Logging alone is not
+            // fail-safe: the RETURN VALUE drives the loss/abort accounting, not the
+            // log. So fail safe by reporting the ENTIRE title as bad (its full
+            // in-extent byte count) — a corrupt damage record must surface as
+            // maximal loss, never as a clean rip.
+            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return 0,
+            Err(e) => {
+                tracing::warn!(
+                    target: "freemkv::disc",
+                    path = %mapfile_path.display(),
+                    error = %e,
+                    "bytes_bad_in_title: mapfile load failed; reporting whole title bad (fail-safe: cannot confirm clean)"
+                );
+                return bytes_bad_in_title(title, &[(0, u64::MAX)]);
+            }
         };
         let bad_ranges = map.ranges_with(&[
             mapfile::SectorStatus::NonTrimmed,
@@ -1299,33 +1322,13 @@ impl Disc {
         let bytes_good_before = initial_stats.bytes_good;
         let bytes_good_start = bytes_good_before;
 
-        // Post-read verify gate for the patch pass (ciphertext multipass only,
-        // `!opts.decrypt`). Built here from the raw reader's UDF enumeration;
-        // reused AFTER the recovery loop (`reverify_iso`) to re-check the units
-        // this pass touched by reading them WHOLE back from the patched ISO —
-        // patch re-reads only the bad sectors of a unit, so per-unit verify
-        // can't run live. Fail-safe `None` when disabled / non-AACS / no keys.
-        let mut verifier = if opts.decrypt {
-            None
-        } else {
-            let verify_keys = self.decrypt_keys();
-            let layouts = crate::disc::extract::clip_layouts(&mut *reader);
-            crate::disc::verify::UnitVerifier::new(&layouts, &verify_keys, opts.key_fetch.clone())
-        };
         // Decrypt-aware read — symmetric with `Disc::sweep`. A decrypting patch
-        // (`opts.decrypt`) decrypts in place (plaintext ISO). A NON-decrypting
-        // patch (the multipass / `--raw --multipass` path) resolves the keys and
-        // VERIFIES each unit on a scratch copy: a re-read that STILL won't decrypt
-        // fails the read (`DECRYPT_VERIFY_READ`) and stays NonTrimmed, so the
-        // retry loop keeps re-reading it "until it decrypts or retries exhaust"
-        // exactly as for a SCSI read error — and a unit that DOES decrypt on a
-        // fresh read (the drive returned different bytes) is recovered for free.
-        // With no usable AACS keys this degrades to a plain pass-through.
-        // Symmetric with `Disc::sweep`: the patch COPIES ciphertext (multipass /
-        // `--raw`) or decrypts IN PLACE (`opts.decrypt`). It does NOT decrypt-
-        // VERIFY — the disc-absolute read can't anchor to a clip's file-relative
-        // unit grid (see `Disc::sweep` + `Disc::verify_clips`). Re-reads recover
-        // bad sectors; the clip-anchored verify pass re-checks them afterward.
+        // (`opts.decrypt`) decrypts in place (plaintext ISO); a NON-decrypting
+        // patch (the multipass / `--raw --multipass` path) copies ciphertext
+        // verbatim (keys = `None` → pass-through). Bad sectors are found by
+        // PHYSICAL read success, not by decrypt structure: a re-read that returns
+        // good bytes recovers the range; a read that errors leaves it NonTrimmed
+        // for the next pass. (The old decrypt-VERIFY read gate was removed.)
         let keys = if opts.decrypt {
             self.decrypt_keys()
         } else {
@@ -1435,64 +1438,7 @@ impl Disc {
         // sink's summary. `close` failing on a regular-file sync_all is
         // surfaced here as `Error::IoError`, matching pre-split
         // behaviour.
-        let mut summary = pipe.finish()?;
-
-        // Scoped post-read re-verify (decrypt-fail == bad read). The consumer
-        // has flushed the ISO + mapfile; re-read each clip unit this pass touched
-        // WHOLE from the patched ISO and downgrade any that still won't decrypt
-        // to NonTrimmed, so the orchestrator's end-of-recovery promotion
-        // terminalizes it. Reuses the same verifier as the sweep. Fail-safe:
-        // disabled gate / unreadable ISO / load failure all leave the pass as-is.
-        if let Some(mut v) = verifier.take() {
-            if let Ok(mut m) = mapfile::Mapfile::load(&mapfile_path) {
-                // Only units whose every backing sector was actually READ
-                // (Finished) may be re-verified — we can't verify what wasn't read
-                // (a non-Finished sector is zero-filled because the read failed),
-                // and must not waste a key lookup on a known-bad block.
-                let finished = m.ranges_with(&[mapfile::SectorStatus::Finished]);
-                let is_finished = |lba: u32| -> bool {
-                    let p = lba as u64 * 2048;
-                    finished.iter().any(|&(s, sz)| p >= s && p < s + sz)
-                };
-                if let Ok(mut iso) = crate::io::file_sector_source::FileSectorSource::open(path) {
-                    let bad = v.reverify_iso(&mut iso, &bad_ranges, &is_finished);
-                    if !bad.is_empty() {
-                        let n: usize = bad.len();
-                        for (lba, cnt) in bad {
-                            if let Err(e) = m.record(
-                                lba as u64 * 2048,
-                                cnt as u64 * 2048,
-                                mapfile::SectorStatus::NonTrimmed,
-                            ) {
-                                tracing::warn!(
-                                    lba,
-                                    "reverify downgrade: mapfile record failed ({e}) — unit may stay mismarked as good"
-                                );
-                            }
-                        }
-                        if let Err(e) = m.flush() {
-                            tracing::warn!(
-                                "reverify downgrade: mapfile flush failed ({e}) — downgrade not persisted; a resume could mismark it good"
-                            );
-                        }
-                        // The re-verify ran AFTER `pipe.finish()` snapshotted
-                        // `summary.stats`, so those stats still count the just-
-                        // downgraded units as good. Refresh from the mapfile so
-                        // `build_outcome` reports the true post-downgrade picture
-                        // (bytes_good ↓, bytes_pending ↑) — otherwise the caller
-                        // over-reports recovery and can call an imperfect rip
-                        // "complete".
-                        summary.stats = m.stats();
-                        tracing::info!(
-                            target: "freemkv::verify",
-                            phase = "patch.reverify",
-                            downgraded_ranges = n,
-                            "post-read re-verify downgraded undecryptable units to NonTrimmed"
-                        );
-                    }
-                }
-            }
-        }
+        let summary = pipe.finish()?;
 
         let outcome = build_outcome(
             &state,

src/disc/sweep.rs

@@ -66,14 +66,6 @@ pub(super) enum WorkItem {
     /// tell them apart without parsing a flag.
     GapFill { pos: u64, len: u64 },
 
-    /// Post-read verify downgrade. The producer's `UnitVerifier` found that the
-    /// just-`Finished` clip unit at `[pos, pos+len)` is confidently undecryptable
-    /// (a silent bad read). The consumer re-records the range as `NonTrimmed` so
-    /// the patch pass re-reads it — the ISO bytes (ciphertext) already written by
-    /// the preceding `Good` are left in place for the patch to overwrite. FIFO
-    /// pipe ordering guarantees this arrives AFTER the `Good` that wrote them.
-    MarkBad { pos: u64, len: u64 },
-
     /// Producer wants the latest mapfile stats for the progress
     /// callback. Consumer responds on `prog_tx` with a fresh
     /// [`ProgressSnapshot`]. Best-effort: if the producer hasn't
@@ -182,12 +174,6 @@ impl Sink<WorkItem> for SweepSink {
                 }
                 self.map.record(pos, len, SectorStatus::NonTrimmed)?;
             }
-            WorkItem::MarkBad { pos, len } => {
-                // Verify downgrade: the ISO bytes are already written by the
-                // preceding Good; only the mapfile status changes so patch
-                // re-reads this range. No file write.
-                self.map.record(pos, len, SectorStatus::NonTrimmed)?;
-            }
             WorkItem::StatsRequest => {
                 let stats = self.map.stats();
                 // DAMAGE only — NOT NonTried. NonTried is the unread remainder

src/io/file_sector_source/mod.rs

@@ -78,8 +78,8 @@ use crate::consts::{SECTOR_BYTES, SECTOR_BYTES_U64};
 /// read side. Mirrors `WRITEBACK_CHUNK_BYTES` so the read-side page
 /// cache stays bounded the same way the write side does.
 ///
-/// 32 MiB is the empirically tuned value on the rip1 test bed (single
-/// 7200rpm HDD via SATA): smaller windows (8 / 16 MiB) shorten the
+/// 32 MiB is the empirically tuned value on a 7200rpm HDD via SATA:
+/// smaller windows (8 / 16 MiB) shorten the
 /// kernel-readahead overlap and slow the producer; larger windows
 /// (64 / 128 MiB) let the page cache pin enough of the ISO to
 /// pressure concurrent writes. Override via `FREEMKV_READ_DROP_CHUNK_MIB`.

src/keysource.rs

@@ -23,6 +23,64 @@ use crate::aacs::types::{UnitKey, Vid};
 use crate::disc::Key;
 use crate::error::Error;
 
+/// Minimum encrypted-content unit samples a single online key request must carry.
+///
+/// The key service identifies a key by which of the submitted units it decrypts,
+/// so too few samples — especially on FMTS, where a segment interleaves several
+/// variants at the unit level — can return a key that matches an incidental unit
+/// rather than the one asked about (a false positive). This many distinct units
+/// make the request unambiguous.
+///
+/// Canonical here (the base crate) so BOTH consumers agree on one value: the
+/// online source in `freemkv-keysources` (which refuses to send an under-sampled
+/// request) re-exports it, and libfreemkv's own FMTS forensic query
+/// ([`crate::mux`]) sizes its per-segment batch by it. Layering forbids the
+/// reverse import (keysources depends on libfreemkv, not vice versa), so the
+/// value lives at the lower layer both share.
+pub const MIN_SAMPLE_UNITS: usize = 8;
+
+/// A set of encrypted content-unit samples PROVEN to carry at least
+/// [`MIN_SAMPLE_UNITS`] units — the online `/decode` request's proof-of-ownership.
+///
+/// "Parse, don't validate": the only constructor, [`DecodeSampleSet::new`], returns
+/// `None` for an under-sized slice, so an online key request simply *cannot be built*
+/// from too few samples. The runtime `len() < MIN_SAMPLE_UNITS` check that used to
+/// live at the request site (and was silently forgotten by an under-sampling caller,
+/// reading as "key service down") becomes a compile-time obligation: a request builder
+/// that takes `&DecodeSampleSet` can never receive an unchecked `Vec`.
+///
+/// The *count* enforced here is a runtime property of the disc (how many encrypted
+/// units it yields); the *requested* count is a caller-side compile-time constant that
+/// callers pin to `MIN_SAMPLE_UNITS` (see e.g. autorip's `SAMPLE_UNITS`). Together the
+/// two make under-sampling unrepresentable at the request boundary.
+#[derive(Debug, Clone)]
+pub struct DecodeSampleSet(Vec<Vec<u8>>);
+
+impl DecodeSampleSet {
+    /// Wrap `units` iff it carries at least [`MIN_SAMPLE_UNITS`] samples; `None`
+    /// otherwise (the caller then skips the online source rather than sending an
+    /// ambiguous request). This is the sole way to obtain a `DecodeSampleSet`.
+    pub fn new(units: Vec<Vec<u8>>) -> Option<Self> {
+        (units.len() >= MIN_SAMPLE_UNITS).then_some(Self(units))
+    }
+
+    /// The proven-sufficient samples. Guaranteed `>= MIN_SAMPLE_UNITS` in length.
+    pub fn units(&self) -> &[Vec<u8>] {
+        &self.0
+    }
+
+    /// Number of samples — always `>= MIN_SAMPLE_UNITS`.
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    /// Always `false` (a `DecodeSampleSet` never holds fewer than `MIN_SAMPLE_UNITS`);
+    /// provided so the type satisfies the usual `len`/`is_empty` pairing.
+    pub fn is_empty(&self) -> bool {
+        false
+    }
+}
+
 /// The public AACS inputs a key source needs to look a disc up. Captured at
 /// scan; contains no secrets — only the disc identity and the on-disc AACS
 /// structures a source or key server may key on.
@@ -318,7 +376,28 @@ pub fn key_fetch(
     inputs: DiscInputs,
     make_sources: std::sync::Arc<dyn Fn() -> Vec<Box<dyn KeySource>> + Send + Sync>,
 ) -> crate::sector::KeyFetch {
+    // Memoize by the fingerprint of the sample batch. The resolved keys are
+    // disc-level (the same clip's index / CPS keys are identical for every title
+    // that references it), and this one closure is shared across every title's mux
+    // — so the first title resolves a given batch over the network and every later
+    // title (or repeated batch) is answered from the cache with no request. Empty
+    // replies are cached too: a key the service does not have for a batch will not
+    // appear on a re-ask, so re-hitting the network buys nothing.
+    let cache: std::sync::Arc<std::sync::Mutex<std::collections::HashMap<u64, Vec<[u8; 16]>>>> =
+        std::sync::Arc::new(std::sync::Mutex::new(std::collections::HashMap::new()));
     std::sync::Arc::new(move |samples: &[Vec<u8>]| -> Vec<[u8; 16]> {
+        let fp = {
+            use std::hash::{Hash, Hasher};
+            let mut h = std::collections::hash_map::DefaultHasher::new();
+            samples.len().hash(&mut h);
+            for s in samples {
+                s.hash(&mut h);
+            }
+            h.finish()
+        };
+        if let Some(hit) = cache.lock().unwrap_or_else(|e| e.into_inner()).get(&fp) {
+            return hit.clone();
+        }
         let sources = make_sources();
         let mut di = inputs.clone();
         di.samples = samples.to_vec();
@@ -327,10 +406,15 @@ pub fn key_fetch(
         // derives unit keys from `enc_title_keys`, which a V10 disc parses at the
         // 48-byte stride — hardcoding the V20 stride here corrupted them.
         let ctx = DiscInputsCtx::new(&di);
-        fetch_unit_keys(&sources, &ctx)
+        let keys: Vec<[u8; 16]> = fetch_unit_keys(&sources, &ctx)
             .into_iter()
             .map(|u| u.key)
-            .collect()
+            .collect();
+        cache
+            .lock()
+            .unwrap_or_else(|e| e.into_inner())
+            .insert(fp, keys.clone());
+        keys
     })
 }
 
@@ -407,7 +491,7 @@ pub fn read_encrypted_units(
                     break;
                 }
                 let u = &buf[o..o + ALIGNED_UNIT_LEN];
-                if aacs_unit_encrypted(u) {
+                if aacs_unit_encrypted(u, title.content_format) {
                     out.push(u.to_vec());
                     if out.len() >= n {
                         return out;
@@ -425,6 +509,46 @@ mod tests {
     use crate::aacs::types::UnitKey;
     use std::sync::{Arc, Mutex};
 
+    fn units(n: usize) -> Vec<Vec<u8>> {
+        (0..n).map(|i| vec![i as u8; 4]).collect()
+    }
+
+    // ── DecodeSampleSet: the online request can't be built under-sized ─────────
+
+    /// Fewer than MIN_SAMPLE_UNITS → no set. Mutation: accepting a short slice
+    /// resurrects the exact autorip bug (a 4-sample request silently skipped /
+    /// read as "service down").
+    #[test]
+    fn decode_sample_set_rejects_under_min() {
+        for n in 0..MIN_SAMPLE_UNITS {
+            assert!(
+                DecodeSampleSet::new(units(n)).is_none(),
+                "{n} samples (< {MIN_SAMPLE_UNITS}) must not build a DecodeSampleSet"
+            );
+        }
+    }
+
+    /// Exactly the minimum, and above it, construct — and expose all samples.
+    #[test]
+    fn decode_sample_set_accepts_min_and_above() {
+        let exact = DecodeSampleSet::new(units(MIN_SAMPLE_UNITS)).expect("min builds");
+        assert_eq!(exact.len(), MIN_SAMPLE_UNITS);
+        assert_eq!(exact.units().len(), MIN_SAMPLE_UNITS);
+        assert!(!exact.is_empty());
+
+        let more = DecodeSampleSet::new(units(MIN_SAMPLE_UNITS + 5)).expect("above min builds");
+        assert_eq!(more.len(), MIN_SAMPLE_UNITS + 5);
+    }
+
+    /// The wrapped units round-trip byte-for-byte (the request carries exactly what
+    /// was gathered — no reordering/truncation).
+    #[test]
+    fn decode_sample_set_preserves_units() {
+        let raw = units(MIN_SAMPLE_UNITS);
+        let set = DecodeSampleSet::new(raw.clone()).unwrap();
+        assert_eq!(set.units(), raw.as_slice());
+    }
+
     // ── KeySource default-method behaviour ────────────────────────────────────
 
     /// KeySource::host_certs() defaults to empty regardless of the MKB argument.
@@ -717,7 +841,7 @@ mod tests {
         );
         for s in &samples {
             assert!(
-                aacs_unit_encrypted(s),
+                aacs_unit_encrypted(s, crate::disc::ContentFormat::BdTs),
                 "every sample is a CPI-flagged encrypted unit (byte0 & 0xC0 != 0)"
             );
         }
@@ -800,7 +924,7 @@ mod tests {
         );
         for s in &samples {
             assert!(
-                aacs_unit_encrypted(s),
+                aacs_unit_encrypted(s, crate::disc::ContentFormat::BdTs),
                 "only CPI-flagged units are selected"
             );
             assert_eq!(

src/lib.rs

@@ -187,7 +187,10 @@ pub use identity::DriveId;
 // don't touch `DecryptKeys` directly — `DiscStream::new(reader, title, keys, …)`
 // accepts whatever `Disc::decrypt_keys()` returned. `decrypt_sectors()` is
 // for callers that operate on raw sector buffers (e.g. ISO patching).
-pub use decrypt::{DecryptKeys, decrypt_sectors, decrypt_threads, set_decrypt_threads};
+pub use decrypt::{
+    AacsKeyMap, DecryptKeys, decrypt_sectors, decrypt_sectors_mapped, decrypt_threads,
+    set_decrypt_threads,
+};
 
 // ─── Disc structure ─────────────────────────────────────────────────────────
 //
@@ -248,6 +251,7 @@ pub use mux::{InputOptions, StreamUrl, input, output, parse_url};
 // single decrypt-on-read decorator (AACS / CSS / none) — wrap any
 // `SectorSource` to get plaintext sectors out.
 pub use mux::build_iso_pipeline;
+pub use mux::resolve_mux_key_map;
 pub use scsi::{DriveInfo, ScsiSense, ScsiTransport, drive_has_disc, list_drives};
 pub use sector::{
     DecryptingSectorSource, FileSectorSink, FileSectorSource, KeyFetch, PrefetchedSectorSource,

src/mux/demux_sink.rs

@@ -241,11 +241,23 @@ impl EsWriter for AnnexBWriter {
 /// Delegates to the canonical hvcC/avcC → Annex-B converters in
 /// [`crate::mux::hevc`] — the single source of truth across all muxers.
 fn annexb_param_sets(codec: Codec, record: &[u8]) -> Vec<u8> {
-    match codec {
-        Codec::Hevc => hvcc_to_annex_b(record).unwrap_or_default(),
-        Codec::H264 => avcc_to_annex_b(record).unwrap_or_default(),
-        _ => Vec::new(),
-    }
+    let converted = match codec {
+        Codec::Hevc => hvcc_to_annex_b(record),
+        Codec::H264 => avcc_to_annex_b(record),
+        _ => return Vec::new(),
+    };
+    converted.unwrap_or_else(|| {
+        // A malformed hvcC/avcC record yields no parameter sets. Returning empty
+        // means keyframes ship WITHOUT in-band SPS/PPS — playable from the first
+        // keyframe but broken for seek-to-arbitrary-point and hardware decoders.
+        // Surface it rather than silently degrading the output.
+        tracing::warn!(
+            target: "mux",
+            ?codec,
+            "codec-private (hvcC/avcC) parse failed; keyframes will lack in-band SPS/PPS"
+        );
+        Vec::new()
+    })
 }
 
 /// PGS `.sup` writer: rebuilds the HDMV segment framing the parser stripped.

src/mux/demux_thread.rs

@@ -7,7 +7,7 @@
 //! With [`crate::sector::PrefetchedSectorSource`] alone, read+decrypt
 //! already runs on a producer thread; the *consumer* (main) thread
 //! still serialises `ts_demuxer.feed` (M2TS parsing) with the codec
-//! parsers. Profiling on the rip1 testbed showed feed at ~37 % and
+//! parsers. Profiling showed feed at ~37 % and
 //! codec parse at ~44 % of consumer wall time — i.e. feed is heavy
 //! enough that pipelining it with parse pays for itself.
 //!

src/mux/disc.rs

@@ -108,11 +108,6 @@ pub struct DiscStream {
     /// inline `decrypt::decrypt_sectors` step. `DecryptKeys::None`
     /// (raw / unencrypted disc) makes the decorator a pass-through.
     reader: DecryptingSectorSource<Box<dyn SectorSource>>,
-    /// Shared decrypt-loss counter, cloned once at construction from
-    /// `reader.decrypt_loss()`. `lost_bytes()` loads it directly so the
-    /// per-frame hot path performs no per-call `Arc::clone` (matching the
-    /// `PipelinedPesStream` pattern).
-    decrypt_loss: std::sync::Arc<std::sync::atomic::AtomicU64>,
     title: DiscTitle,
     /// Mirror of the keys handed in at construction. The decorator
     /// owns the cryptographic state; this field is kept for
@@ -237,12 +232,12 @@ impl DiscStream {
 
         // CSS/unencrypted content needs a decrypting wrapper to yield plaintext
         // VOB bytes before the AC-3 sub-stream probe can read real `acmod`s.
-        // MUX path: tolerate decrypt loss — conceal an undecryptable unit (NULL TS
-        // fill) + tally + log rather than abort the stream (P3). DiscStream is a
-        // decode/mux stream (live-drive single-pass / direct), never the
-        // ciphertext-preserving sweep, so concealment is always correct here.
-        let mut reader =
-            DecryptingSectorSource::new(reader, decrypt_keys.clone()).tolerate_decrypt_loss();
+        // MUX path (read > decrypt > mux): decrypt every unit in place and pass the
+        // bytes to the muxer; a unit that decrypts to broken TS is the muxer's
+        // concern, never conceal / re-fetch / count as loss (fail loud only on a
+        // genuine can't-decrypt). DiscStream is a decode/mux stream (live-drive
+        // single-pass / direct), never the ciphertext-preserving sweep.
+        let mut reader = DecryptingSectorSource::new(reader, decrypt_keys.clone());
 
         // Wrong-substream fix (Silence-of-the-Lambs): re-route the title's
         // declared AC-3 audio onto the physically-correct `0x8x` sub-streams by
@@ -293,9 +288,6 @@ impl DiscStream {
         // the decorator is a pass-through). Reset the unit base the probe read
         // advanced so the first fill_extents read starts cleanly.
         reader.set_unit_base(0);
-        // Clone the shared loss counter once here so `lost_bytes()` never
-        // clones an Arc per frame on the mux hot path.
-        let decrypt_loss = reader.decrypt_loss();
 
         // B1 resync gates: one per stream, video flagged so the gate only
         // drop-to-keyframes video (audio/subtitle always admit). Computed before
@@ -311,7 +303,6 @@ impl DiscStream {
 
         Self {
             reader,
-            decrypt_loss,
             title,
             decrypt_keys,
             unit_align,
@@ -1003,14 +994,12 @@ impl crate::pes::Stream for DiscStream {
     }
 
     fn lost_bytes(&self) -> u64 {
-        // Read-error zero-fill loss (counted in fill_extents) PLUS decrypt-time
-        // loss — bytes of scrambled AACS units the decorator could not decrypt
-        // and passed through still encrypted (the TS assembler silently drops
-        // them). Both are real missing content the abort gate must see; without
-        // the decrypt term a partial key failure reports lost_bytes=0 and a rip
-        // missing segments passes even under abort_on_lost_secs=0.
+        // Read-error zero-fill loss (counted in fill_extents) — real missing
+        // content the abort gate must see. There is no decrypt-loss term: the
+        // decrypt path passes bad-encoded/undecryptable units through (a broken-TS
+        // unit is the muxer's concern, and a missing key is indistinguishable from
+        // bad authoring here), so only physical read loss is reported.
         self.lost_bytes
-            .saturating_add(self.decrypt_loss.load(std::sync::atomic::Ordering::Relaxed))
     }
 }
 
@@ -1489,6 +1478,7 @@ mod tests {
         let keys = crate::decrypt::DecryptKeys::Aacs {
             unit_keys: vec![(0, [0u8; 16])],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut stream = DiscStream::new(Box::new(reader), title, keys, 8, ContentFormat::BdTs);
         stream.skip_errors = true;

src/mux/mkv.rs

@@ -121,6 +121,29 @@ fn mvc_decoder_config_record(subset_sps: &[u8], pps: &[u8]) -> Option<Vec<u8>> {
     Some(record)
 }
 
+/// Build the `CodecPrivate` for an MVC (Blu-ray 3D) base track: the base view's
+/// `AVCDecoderConfigurationRecord` (`avcc`) followed by an `mvcC` extension
+/// block, per the Matroska Codec Specifications §4.3.9:
+///
+/// ```text
+/// avcC ‖ u32be(extension_block_size − 4) ‖ "mvcC" ‖ MVCDecoderConfigurationRecord
+/// ```
+///
+/// The size field is the extension block length **excluding the 4-byte size
+/// field itself** — i.e. `4 ("mvcC") + record.len()`. This is the track-level
+/// MVC signal that decoders and mediainfo read (the per-frame `BlockAdditional`
+/// under the `mvcC` BlockAdditionMapping carries the dependent view's data). A
+/// plain (2D) track never calls this — it writes its `avcc` verbatim.
+fn mvc_codec_private(avcc: &[u8], record: &[u8]) -> Vec<u8> {
+    let ext_size = (4 + record.len()) as u32; // "mvcC" (4) + record; = block size − 4
+    let mut out = Vec::with_capacity(avcc.len() + 8 + record.len());
+    out.extend_from_slice(avcc);
+    out.extend_from_slice(&ext_size.to_be_bytes());
+    out.extend_from_slice(b"mvcC");
+    out.extend_from_slice(record);
+    out
+}
+
 /// Resolve a video stream's CICP colour code points — `(matrix, transfer,
 /// primaries, range)`, ITU-T H.273 — using a single precedence so EVERY sink
 /// (the MKV muxer here AND the FVI sidecar in `videomap.rs`) agrees and can
@@ -762,23 +785,35 @@ fn block_ts(is_video: bool, prev: Option<i64>, pts_ticks: i64) -> i64 {
 
 /// Encode a Matroska track number as an EBML VINT into a stack buffer,
 /// returning the buffer and the used length. Track numbers are small (1-based,
-/// a handful of tracks), so 1 byte covers `< 0x80` and 2 bytes covers the rest;
-/// no heap allocation, called once per block on the mux hot path.
+/// a handful of tracks), so 1 byte covers `< 0x80`, 2 bytes covers `< 0x4000`,
+/// and 3 bytes covers `< 0x20_0000`; no heap allocation, called once per block
+/// on the mux hot path.
 ///
-/// The 2-byte form holds 14 payload bits (max 0x3FFF). The `debug_assert`
-/// guards the 0x4000 bound: at or above it, `(track_num >> 8)` is >= 0x40 and
-/// OR-ing the 0x40 length marker would clobber it, corrupting the track
-/// number. Not reachable today (track numbers are `i+1` over a few streams),
-/// so this documents the bound rather than handling 3-byte VINTs.
-fn track_vint(track_num: usize) -> ([u8; 2], usize) {
+/// Each width uses a marker bit that must NOT collide with the payload's top
+/// byte: the 1-byte marker is 0x80 (7 payload bits), the 2-byte marker 0x40
+/// (14 payload bits), the 3-byte marker 0x20 (21 payload bits). Handling all
+/// three in RELEASE (not just `debug_assert`) means an out-of-2-byte-range
+/// track number can never silently clobber the marker bit and corrupt the
+/// block. Real discs never approach even the 2-byte range; the 21-bit ceiling
+/// is an absurd upper bound kept as a `debug_assert`.
+fn track_vint(track_num: usize) -> ([u8; 3], usize) {
     if track_num < 0x80 {
-        ([(track_num as u8) | 0x80, 0], 1)
+        ([(track_num as u8) | 0x80, 0, 0], 1)
+    } else if track_num < 0x4000 {
+        ([0x40 | ((track_num >> 8) as u8), track_num as u8, 0], 2)
     } else {
         debug_assert!(
-            track_num < 0x4000,
-            "track number {track_num} exceeds the 14-bit 2-byte EBML VINT range"
+            track_num < 0x20_0000,
+            "track number {track_num} exceeds the 21-bit 3-byte EBML VINT range"
         );
-        ([0x40 | ((track_num >> 8) as u8), track_num as u8], 2)
+        (
+            [
+                0x20 | ((track_num >> 16) as u8),
+                (track_num >> 8) as u8,
+                track_num as u8,
+            ],
+            3,
+        )
     }
 }
 
@@ -882,9 +917,23 @@ impl<W: Write + Seek> MkvMuxer<W> {
         let mut track_uids: Vec<u64> = Vec::with_capacity(tracks.len());
         let mut ac3_channel_fixups: std::collections::HashMap<usize, Ac3ChannelFixup> =
             std::collections::HashMap::new();
+        // Per track: whether it emitted a conforming `mvcC` BlockAdditionMapping.
+        // Filled below from the SAME built record that drives the CodecPrivate
+        // mvcC extension, so the three MVC signals never diverge.
+        let mut track_has_mvc_mapping: Vec<bool> = Vec::with_capacity(tracks.len());
         for (i, track) in tracks.iter().enumerate() {
             let track_uid = (i + 1) as u64 | 0x100_0000;
             track_uids.push(track_uid);
+            // Build the MVC (Blu-ray 3D) MVCDecoderConfigurationRecord ONCE per
+            // track from the dependent view's subset-SPS/PPS. `None` for every
+            // non-3D track (and if the params are malformed) — the single source
+            // of truth for the CodecPrivate mvcC extension, the
+            // BlockAdditionMapping, and whether BlockAdditionals are conforming.
+            let mvc_record = track
+                .mvc_params
+                .as_ref()
+                .and_then(|(sps, pps)| mvc_decoder_config_record(sps, pps));
+            track_has_mvc_mapping.push(mvc_record.is_some());
             let entry_pos = ebml::start_master(&mut writer, ebml::TRACK_ENTRY)?;
             ebml::write_uint(&mut writer, ebml::TRACK_NUMBER, (i + 1) as u64)?;
             ebml::write_uint(&mut writer, ebml::TRACK_UID, track_uid)?;
@@ -904,7 +953,20 @@ impl<W: Write + Seek> MkvMuxer<W> {
             }
 
             if let Some(ref cp) = track.codec_private {
-                ebml::write_binary(&mut writer, ebml::CODEC_PRIVATE, cp)?;
+                match mvc_record.as_ref() {
+                    // MVC (Blu-ray 3D) base track: CodecPrivate = base-view avcC
+                    // followed by the `mvcC` extension block. This is the
+                    // track-level signal decoders/mediainfo read to recognise the
+                    // stereoscopic MVC track (the per-frame dependent view rides
+                    // in BlockAdditional under the mapping below).
+                    Some(record) => {
+                        let cp_mvc = mvc_codec_private(cp, record);
+                        ebml::write_binary(&mut writer, ebml::CODEC_PRIVATE, &cp_mvc)?;
+                    }
+                    // Non-MVC (2D/UHD/audio/…): write the codec_private verbatim —
+                    // the unchanged path, byte-identical to a 2D mux.
+                    None => ebml::write_binary(&mut writer, ebml::CODEC_PRIVATE, cp)?,
+                }
             }
             // Pre-0.13 a deferred codecPrivate path existed for video tracks
             // (placeholder reserve + later seek-back fill via
@@ -1004,8 +1066,8 @@ impl<W: Write + Seek> MkvMuxer<W> {
             // Video) carries the mvcC MVCDecoderConfigurationRecord so players /
             // mediainfo recognise the dependent (right-eye) view that rides as a
             // per-frame BlockAdditional under this mapping (BlockAddIDValue = 2).
-            if let Some((subset_sps, pps)) = track.mvc_params.as_ref() {
-                if let Some(record) = mvc_decoder_config_record(subset_sps, pps) {
+            match mvc_record.as_ref() {
+                Some(record) => {
                     let map_pos = ebml::start_master(&mut writer, ebml::BLOCK_ADDITION_MAPPING)?;
                     ebml::write_uint(
                         &mut writer,
@@ -1013,18 +1075,25 @@ impl<W: Write + Seek> MkvMuxer<W> {
                         BLOCK_ADD_ID_VALUE_MVC,
                     )?;
                     ebml::write_uint(&mut writer, ebml::BLOCK_ADD_ID_TYPE, BLOCK_ADD_ID_TYPE_MVCC)?;
-                    ebml::write_binary(&mut writer, ebml::BLOCK_ADD_ID_EXTRA_DATA, &record)?;
+                    ebml::write_binary(&mut writer, ebml::BLOCK_ADD_ID_EXTRA_DATA, record)?;
                     ebml::end_master(&mut writer, map_pos)?;
-                } else {
+                }
+                // `mvc_params` present but the record failed to build (malformed
+                // parameter sets): no mapping, and `track_has_mvc_mapping` above
+                // is already `false`, so BlockAdditionals are dropped — the file
+                // stays conforming rather than carrying an orphaned BlockAddID.
+                None if track.mvc_params.is_some() => {
+                    let (s, p) = track.mvc_params.as_ref().unwrap();
                     tracing::warn!(
                         target: "mux",
                         "MVC track: could not build MVCDecoderConfigurationRecord from the \
                          dependent view's parameter sets (subset_sps={} B, pps={} B); \
                          emitting no mvcC mapping — the 3D pairing will not be signalled.",
-                        subset_sps.len(),
-                        pps.len(),
+                        s.len(),
+                        p.len(),
                     );
                 }
+                None => {}
             }
 
             // Dolby Vision signaling — BlockAdditionMapping is a child of the
@@ -1117,7 +1186,7 @@ impl<W: Write + Seek> MkvMuxer<W> {
             primary_video_track: tracks
                 .iter()
                 .position(|t| t.track_type == ebml::TRACK_TYPE_VIDEO),
-            track_has_mvc_mapping: tracks.iter().map(|t| t.mvc_params.is_some()).collect(),
+            track_has_mvc_mapping,
             continuity: TimelineContinuity::new(),
             cues: Vec::new(),
             frame_count: 0,
@@ -3450,7 +3519,7 @@ mod tests {
     }
 
     #[test]
-    fn track_vint_encodes_one_and_two_byte_forms() {
+    fn track_vint_encodes_one_two_and_three_byte_forms() {
         // 1-byte form for track numbers < 0x80, high bit set.
         let (b, n) = track_vint(1);
         assert_eq!(&b[..n], &[0x81]);
@@ -3461,6 +3530,12 @@ mod tests {
         assert_eq!(&b[..n], &[0x40, 0x80]);
         let (b, n) = track_vint(0x3FFF);
         assert_eq!(&b[..n], &[0x7F, 0xFF]);
+        // 3-byte form at/above 0x4000, 0x20 length marker in the top byte —
+        // handled in RELEASE (no silent marker-bit clobber), not just debug.
+        let (b, n) = track_vint(0x4000);
+        assert_eq!(&b[..n], &[0x20, 0x40, 0x00]);
+        let (b, n) = track_vint(0x1F_FFFF);
+        assert_eq!(&b[..n], &[0x3F, 0xFF, 0xFF]);
     }
 
     // ============================================================
@@ -4600,6 +4675,60 @@ mod tests {
         assert!(find_id(&data, ebml::BLOCK_ADDITION_MAPPING).is_none());
     }
 
+    #[test]
+    fn mvc_codec_private_appends_mvcc_extension_block() {
+        // avcC ‖ u32be(4 + record.len()) ‖ "mvcC" ‖ record (Matroska Codec Spec §4.3.9).
+        let avcc = vec![0x01, 0x64, 0x00, 0x33, 0xFF, 0xE1, 0xAA];
+        let record = vec![0x01, 0x80, 0x00, 0x33, 0xBF, 0x01, 0xCC]; // 7 bytes
+        let out = mvc_codec_private(&avcc, &record);
+        assert_eq!(&out[..avcc.len()], &avcc[..], "avcC preserved verbatim");
+        // size field = 4 ("mvcC") + 7 (record) = 11 = extension block size minus 4.
+        assert_eq!(&out[avcc.len()..avcc.len() + 4], &11u32.to_be_bytes());
+        assert_eq!(&out[avcc.len() + 4..avcc.len() + 8], b"mvcC");
+        assert_eq!(
+            &out[avcc.len() + 8..],
+            &record[..],
+            "record after the mvcC fourcc"
+        );
+    }
+
+    #[test]
+    fn mvc_track_codec_private_carries_avcc_plus_mvcc() {
+        // An MVC base track's CodecPrivate must be the base avcC followed by the
+        // mvcC extension — the track-level signal mediainfo/decoders read.
+        let avcc = vec![
+            0x01, 0x64, 0x00, 0x33, 0xFF, 0xE1, 0x00, 0x05, 0x67, 0x64, 0x00, 0x33, 0x99,
+        ];
+        let subset_sps = vec![0x6F, 0x80, 0x00, 0x33, 0x11, 0x22];
+        let pps = vec![0x68, 0xEE, 0x3C];
+        let mut v = make_video_track();
+        v.codec_private = Some(avcc.clone());
+        v.mvc_params = Some((subset_sps.clone(), pps.clone()));
+        let data = MkvMuxer::new(Cursor::new(Vec::new()), &[v], None, 0.0, &[])
+            .unwrap()
+            .writer
+            .into_inner();
+        let record = mvc_decoder_config_record(&subset_sps, &pps).unwrap();
+        let expected = mvc_codec_private(&avcc, &record);
+        assert!(
+            data.windows(expected.len())
+                .any(|w| w == expected.as_slice()),
+            "emitted CodecPrivate must be avcC + mvcC extension"
+        );
+
+        // A non-MVC (2D) track writes its avcC VERBATIM — no mvcC appended.
+        let mut v2 = make_video_track();
+        v2.codec_private = Some(avcc.clone());
+        let d2 = MkvMuxer::new(Cursor::new(Vec::new()), &[v2], None, 0.0, &[])
+            .unwrap()
+            .writer
+            .into_inner();
+        assert!(
+            !d2.windows(4).any(|w| w == b"mvcC"),
+            "2D track CodecPrivate must not carry an mvcC extension"
+        );
+    }
+
     // ---- CodecPrivate emission (avcC / hvcC / VC-1 / MPEG-2) -------------
     //
     // `MkvTrack::video` always builds with `codec_private: None`; the PES mux

src/mux/mkvstream.rs

@@ -1016,7 +1016,11 @@ fn parse_track(
                     arem = arem.saturating_sub(ahlen as u64 + as_);
                     match aid {
                         ebml::SAMPLING_FREQUENCY => sr = ebml::read_float_val(r, as_ as usize)?,
-                        ebml::CHANNELS => ch = read_uint_bounded(r, as_)? as u8,
+                        // Clamp instead of `as u8`: a foreign/corrupt MKV with a
+                        // CHANNELS value that is a multiple of 256 would truncate to
+                        // 0 (an invalid channel count) on a bare cast. Saturate to
+                        // u8::MAX so an absurd count degrades to "many", never to 0.
+                        ebml::CHANNELS => ch = read_uint_bounded(r, as_)?.min(u8::MAX as u64) as u8,
                         _ => {
                             skip_bytes(r, as_)?;
                         }

src/mux/mod.rs

@@ -117,6 +117,7 @@ pub use network::NetworkStream;
 pub use null::NullStream;
 pub use pipelined_stream::PipelinedPesStream;
 pub use resolve::build_iso_pipeline;
+pub use resolve::resolve_mux_key_map;
 pub use resolve::{InputOptions, StreamUrl, input, output, parse_url};
 pub use stdio::StdioStream;
 

src/mux/pipelined_stream.rs

@@ -56,14 +56,6 @@ pub struct PipelinedPesStream {
     /// `std::env::var_os` takes a process-wide lock, so the per-batch /
     /// per-poll reads it replaces were needless hot-path overhead.
     skip_parse: bool,
-    /// Cumulative bytes of scrambled AACS units the producer's decrypt step
-    /// could not decrypt — silent decrypt loss the demux drops without a sync.
-    /// Shared with the producer thread's [`DecryptingSectorSource`]
-    /// (`crate::sector::DecryptingSectorSource::decrypt_loss`). Surfaced through
-    /// [`Stream::lost_bytes`] so the file-backed mux abort gate sees a partial
-    /// decrypt failure instead of reporting a perfect rip. `None` for pipelines
-    /// with no AACS decrypt step (e.g. the M2TS byte-stream path).
-    decrypt_loss: Option<std::sync::Arc<std::sync::atomic::AtomicU64>>,
     /// Count of dropped DVD navigation packets (private_stream_2, 0xBF). These
     /// are expected on every disc; instead of a per-packet WARN they're tallied
     /// and summarised once at EOF.
@@ -134,7 +126,6 @@ impl PipelinedPesStream {
             pending_frames: std::collections::VecDeque::new(),
             eof: false,
             skip_parse: std::env::var_os("FREEMKV_SKIP_PARSE").is_some(),
-            decrypt_loss: None,
             dropped_nav_packets: 0,
             resync,
             is_video,
@@ -142,20 +133,6 @@ impl PipelinedPesStream {
         }
     }
 
-    /// Attach the producer's decrypt-loss counter so [`Stream::lost_bytes`]
-    /// reports bytes of scrambled AACS units that could not be decrypted (and
-    /// were therefore silently dropped downstream). Obtained from the
-    /// producer's `DecryptingSectorSource::decrypt_loss()` before it is moved
-    /// into the prefetch thread. The M2TS / no-decrypt pipelines leave this
-    /// unset.
-    pub(crate) fn with_decrypt_loss(
-        mut self,
-        loss: std::sync::Arc<std::sync::atomic::AtomicU64>,
-    ) -> Self {
-        self.decrypt_loss = Some(loss);
-        self
-    }
-
     /// Pull one batch of `PesPacket`s from the demux thread, run
     /// codec parse on each, enqueue resulting `PesFrame`s on
     /// `pending_frames`. Returns Ok(true) on success, Ok(false) on
@@ -464,17 +441,9 @@ impl Stream for PipelinedPesStream {
             .and_then(|(_, parser)| parser.codec_private())
     }
 
-    fn lost_bytes(&self) -> u64 {
-        // The file-backed highway has no read-error zero-fill term (resolve
-        // tracks read loss separately), but the producer's decrypt step can
-        // pass scrambled units through undecrypted — silent loss the demux
-        // drops. Surface that so the mux abort gate sees a partial AACS/CSS
-        // decrypt failure rather than reporting a perfect rip.
-        self.decrypt_loss
-            .as_ref()
-            .map(|c| c.load(std::sync::atomic::Ordering::Relaxed))
-            .unwrap_or(0)
-    }
+    // `lost_bytes` uses the trait default (0): the file-backed highway has no
+    // read-error zero-fill term (resolve/mapfile tracks physical read loss
+    // separately) and the decrypt path no longer reports a decrypt-loss term.
 }
 
 #[cfg(test)]

src/mux/resolve.rs

@@ -358,12 +358,11 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
             // case must NOT raise a false E7023.
             disc.ensure_title_decryptable(opts.raw, &keys, title_is_clear)
                 .map_err(|e| -> io::Error { e.into() })?;
-            // Upfront FMTS gate, parallel to the unit-key gate above. With
-            // BYPASS_FMTS_KEY this is a no-op and a 2.1 disc's forensic units are
-            // concealed as ordinary decrypt loss below; without it, a 2.1 disc
-            // lacking segment keys fails here rather than emitting a holed mux.
-            disc.ensure_forensic_segments_decryptable(opts.raw)
-                .map_err(|e| -> io::Error { e.into() })?;
+            // FMTS (AACS 2.1) forensic segments are sourced + fail-loud-checked
+            // downstream by `resolve_mux_key_map`/`resolve_fmts_key_map`, which hold
+            // the key-fetch closure and can actually attempt resolution. (An older
+            // upfront blanket-reject gate lived here; it predated the resolver and
+            // rejected every 2.1 disc before a source could be tried.)
             // Correct TrueHD channel counts (MPLS understates 7.1/Atmos as 5.1)
             // by probing the first DECRYPTED access units of the chosen title.
             // A fresh reader avoids disturbing the mux reader below. Skipped in
@@ -391,11 +390,11 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
             let title = disc.titles[idx].clone();
             let format = disc.content_format;
             // ISO file: 8192-sector batch (16 MiB at 2048 B/sector) —
-            // sequential read from fast storage, no bad sectors. Measured
-            // optimum on the rip1 testbed; bumping to 16384 sectors (32 MiB)
-            // regressed (more cache pressure, longer per-batch latency starves
-            // the consumer between iterations). Physical drives keep smaller
-            // batches for adaptive error handling.
+            // sequential read from fast storage, no bad sectors. Empirically
+            // optimal; bumping to 16384 sectors (32 MiB) regressed (more cache
+            // pressure, longer per-batch latency starves the consumer between
+            // iterations). Physical drives keep smaller batches for adaptive
+            // error handling.
             const ISO_MUX_BATCH_SECTORS: u16 = 8192;
 
             // Pass `DecryptKeys::None` to the decrypt decorator when
@@ -600,6 +599,350 @@ fn build_demux_state(title: &DiscTitle, format: ContentFormat) -> DemuxState {
     (parsers, pid_to_track, ts, ps)
 }
 
+/// Resolve the proactive [`AacsKeyMap`](crate::decrypt::AacsKeyMap) for a title
+/// before muxing. It decides which held unit key decrypts each of the title's
+/// LBA ranges and secures any key the pool is missing through the app's
+/// configured source (`fetch`) up front, never reactively per unit at mux time.
+///
+/// This is what ends the key-server storm. The old mux decrypted a unit, checked
+/// whether the plaintext looked like clean MPEG-TS, and — because authored-bad
+/// content never reaches that bar — re-asked the key service for a key it already
+/// held. There is no per-unit byte pattern that separates "correctly decrypted
+/// but authored-bad" from "still encrypted", so that check is unanswerable. Here
+/// we answer the answerable question instead: which CPS unit does each LBA range
+/// belong to, decided by the disc's key structure (validated once against real
+/// ciphertext samples, where the `is_clean` proof IS sound). The mux then just
+/// decrypts each unit with its mapped key and trusts it.
+///
+/// Single-CPS (the overwhelming majority, incl. every single-key UHD) is the
+/// trivial map: one key everywhere, no sampling. Multi-CPS assigns each extent to
+/// the key that opens a real sample from it; a bad-content extent no sample can
+/// classify inherits its predecessor's key (contiguity). FMTS segment mapping
+/// layers onto the same structure.
+/// FMTS (AACS 2.1) branch of [`resolve_mux_key_map`]. Returns `Some(map)` when the
+/// disc carries `IndividualSegment.tbl` AND a key source is configured; `None`
+/// otherwise (not FMTS, or no source — the caller's base-Unit-Key path then
+/// applies, and the forensic units garble and are dropped by the demux).
+///
+/// The forensic segments each carry an **index** tag (1..32) selecting one of 32
+/// **index keys** the base Unit Key cannot open (see [`crate::aacs::segment`]).
+/// This resolves those keys up front from the configured source — sending, per
+/// index, a batch of same-index units the service maps to that index's key — adds
+/// them to the pool, and builds a per-segment LBA→key map. Applying a segment's
+/// key over its whole range decodes the ~40 units of that index's interleave half
+/// to clean TS and garbles the other ~40 (the alternate half), which the demux
+/// then drops, yielding one coherent stream. The base Unit Key covers everything
+/// outside a segment.
+fn resolve_fmts_key_map(
+    reader: &mut dyn SectorSource,
+    title: &DiscTitle,
+    keys: &mut crate::decrypt::DecryptKeys,
+    fetch: Option<&crate::sector::KeyFetch>,
+    _format: ContentFormat,
+) -> io::Result<Option<crate::decrypt::AacsKeyMap>> {
+    use crate::aacs::content::ALIGNED_UNIT_LEN;
+    use crate::aacs::segment::{clip_byte_to_lba, parse_individual_segments};
+
+    // Off by default: while `BYPASS_FMTS_KEY` is set, forensic decode is disabled —
+    // no segment table read, no key-service traffic — and the caller's base-Unit-Key
+    // path applies (the forensic units garble and the demux drops them, the shipped
+    // behaviour). Flip `BYPASS_FMTS_KEY` to false to activate forensic decode once
+    // the index-key resolution is validated end to end.
+    if crate::aacs::segment::BYPASS_FMTS_KEY {
+        return Ok(None);
+    }
+
+    // Load the segment map; absent → not an FMTS disc.
+    let Ok(udf) = crate::udf::read_filesystem(reader) else {
+        return Ok(None);
+    };
+    let Ok(tbl) = udf.read_file(reader, "/AACS/IndividualSegment.tbl") else {
+        return Ok(None);
+    };
+    let Some(segments) = parse_individual_segments(&tbl) else {
+        return Ok(None);
+    };
+    if segments.is_empty() {
+        return Ok(None);
+    }
+    // This IS an FMTS disc, so the forensic index keys are REQUIRED — exactly like
+    // a Unit Key. Without a configured key source we cannot obtain them, so we
+    // cannot produce a complete rip: fail loud rather than silently drop the
+    // forensic segments. (The caller may still choose `--raw`, which never reaches
+    // this path.)
+    let Some(fetch) = fetch else {
+        return Err(crate::error::Error::FmtsKeyMissing.into());
+    };
+    tracing::info!(target: "freemkv::keysource", segments = segments.len(), extents = title.extents.len(), "fmts: begin index-key resolution");
+
+    // Read aligned unit `index` of `seg`: clip byte `start_spn*192 + index*6144`.
+    let read_unit =
+        |reader: &mut dyn SectorSource, seg: &crate::aacs::segment::Segment, index: usize| {
+            let clip_byte = seg.start_spn as u64 * 192 + index as u64 * ALIGNED_UNIT_LEN as u64;
+            let lba = clip_byte_to_lba(&title.extents, clip_byte)?;
+            let mut c = vec![0u8; ALIGNED_UNIT_LEN];
+            reader.read_sectors(lba, 3, &mut c, false).ok()?;
+            Some(c)
+        };
+    // ── ONE forensic query. The key service returns ALL forensic index keys for the
+    //    disc in a single response, ORDERED by index (array element i = index i+1).
+    //    So send one clean single-variant batch (a segment's even-phase units) and
+    //    read the whole set back — no per-index probing, no phase measurement, no
+    //    decrypt-and-check: the array position IS the index. The first readable
+    //    segment whose batch yields the full set wins; a short (e.g. 1-key,
+    //    base-UK-shaped) response means that batch wasn't forensic (a wrong
+    //    feature-title mapping), so try the next segment.
+    //
+    //    ANCHOR RULE: the query MUST sample an INDEX-1 segment. The key service only
+    //    returns the full set for the canonical anchor sample (a unit that decrypts
+    //    under the index-1 key); a batch from any other forensic index is rejected
+    //    (a base-UK-shaped miss). The `index == 1` filter guarantees every batch we
+    //    send is an anchor — and the forensic tag cycles 1..32 in file order, so
+    //    ~1-in-32 segments qualify (~25 across the feature), leaving ample read-fault
+    //    fallback within the `MAX_ANCHOR_ATTEMPTS` budget. ─────────────────────────
+    const N_INDEX: usize = 32;
+    // Each forensic batch carries the server's minimum-samples count (the same
+    // disambiguation floor the online source enforces), drawn as even-phase units
+    // to land one clean variant half.
+    const BATCH_UNITS: usize = crate::keysource::MIN_SAMPLE_UNITS;
+    // Read-fault fallback budget: how many INDEX-1 (anchor) segments to attempt
+    // before giving up. Only matters when the leading anchor segments are
+    // unreadable; each attempt is one server round-trip, so it is bounded.
+    const MAX_ANCHOR_ATTEMPTS: usize = 16;
+    let mut index_keys: Vec<[u8; 16]> = Vec::new();
+    for seg in segments
+        .iter()
+        .filter(|s| s.index == 1)
+        .take(MAX_ANCHOR_ATTEMPTS)
+    {
+        let mut batch: Vec<Vec<u8>> = Vec::new();
+        for p in 0..BATCH_UNITS {
+            if let Some(c) = read_unit(reader, seg, p * 2) {
+                batch.push(c);
+            }
+        }
+        if batch.len() < BATCH_UNITS {
+            continue; // read fault / short tail
+        }
+        let fresh = fetch(&batch);
+        if fresh.len() >= N_INDEX {
+            index_keys = fresh;
+            break;
+        }
+    }
+    tracing::info!(target: "freemkv::keysource", held = index_keys.len(), need = N_INDEX, "fmts: collection done");
+    // The full set is required. Anything short holes the rip — fail loud like a
+    // missing Unit Key rather than emit forensic-holed output.
+    if index_keys.len() < N_INDEX {
+        return Err(crate::error::Error::FmtsKeyMissing.into());
+    }
+
+    // Map array position → forensic index (element i = index i+1); add each key to
+    // the pool and remember its slot by tag. `base_idx` is the Unit Key (slot 0).
+    let base_idx = 0usize;
+    let mut tag_slot: std::collections::HashMap<u16, usize> = std::collections::HashMap::new();
+    if let crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } = keys {
+        for (i, k) in index_keys.iter().take(N_INDEX).enumerate() {
+            let tag = (i + 1) as u16;
+            let slot = match unit_keys.iter().position(|(_, h)| h == k) {
+                Some(s) => s,
+                None => {
+                    let s = unit_keys.len();
+                    // CPS-unit id is cosmetic for the mapped decrypt (it indexes by
+                    // slot); use a high, distinct number for the forensic keys.
+                    unit_keys.push((1000 + s as u32, *k));
+                    s
+                }
+            };
+            tag_slot.insert(tag, slot);
+        }
+    }
+
+    // ── Build the per-segment LBA ranges directly from the tag. Each segment is
+    //    decoded from its TAG half: the map routes the segment's whole span to its
+    //    tag's key; the tag key opens the tag half wherever it interleaves, and the
+    //    un-served version-B half — decrypted with that (for it, wrong) key —
+    //    garbles and the demux drops it, leaving one clean variant per span. No
+    //    re-read and no phase needed here: byte-5 `seg.index` selects the key. A
+    //    segment whose tag is somehow absent (cannot happen with all 32 held) or
+    //    that straddles an extent boundary is left unmapped and tallied. ─────────
+    let mut ranges: Vec<(u32, u32, usize)> = Vec::with_capacity(segments.len());
+    let mut unresolved = 0usize;
+    for seg in &segments {
+        let Some(&slot) = tag_slot.get(&seg.index) else {
+            unresolved += 1;
+            continue;
+        };
+        let start_byte = seg.start_spn as u64 * 192;
+        let end_byte = (seg.end_spn as u64 + 1) * 192;
+        let (Some(a), Some(b)) = (
+            clip_byte_to_lba(&title.extents, start_byte),
+            clip_byte_to_lba(&title.extents, end_byte - 1),
+        ) else {
+            unresolved += 1;
+            continue;
+        };
+        // Only emit a contiguous within-extent range (segments are ~480 KB; a rare
+        // extent-straddle is left unresolved rather than given a wrong span).
+        if b >= a && (b - a) as u64 == (end_byte - 1 - start_byte) / 2048 {
+            ranges.push((a, b + 1, slot));
+        } else {
+            unresolved += 1;
+        }
+    }
+    // Every forensic segment must map to an index key. Any that did not is a hole
+    // in the rip — with the full 32-key set in hand this should never happen, so
+    // treat it as a hard failure (a read fault or an unexpected on-disc layout)
+    // rather than silently emitting a segment the base Unit Key only garbles.
+    if unresolved != 0 {
+        return Err(crate::error::Error::FmtsKeyMissing.into());
+    }
+
+    Ok(Some(crate::decrypt::AacsKeyMap::from_ranges(
+        ranges, base_idx,
+    )))
+}
+
+pub fn resolve_mux_key_map(
+    reader: &mut dyn SectorSource,
+    title: &DiscTitle,
+    keys: &mut crate::decrypt::DecryptKeys,
+    fetch: Option<&crate::sector::KeyFetch>,
+    format: ContentFormat,
+) -> io::Result<crate::decrypt::AacsKeyMap> {
+    use crate::aacs::content::{
+        ALIGNED_UNIT_LEN, ALIGNED_UNIT_SECTORS, aacs_unit_encrypted, decrypt_unit, is_clean,
+    };
+
+    let pool_len = match keys {
+        crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } => unit_keys.len(),
+        // CSS / clear: no AACS map (the decorator's map path is AACS-only).
+        _ => return Ok(crate::decrypt::AacsKeyMap::single(0)),
+    };
+
+    // Secure the disc's key up front from the configured source when the pool is
+    // empty (a genuine "no key yet" — e.g. keydb miss, online-only disc).
+    if pool_len == 0 {
+        if let Some(f) = fetch {
+            let samples = crate::keysource::read_encrypted_units(reader, title, 8);
+            if !samples.is_empty() {
+                let fresh = f(&samples);
+                if let crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } = keys {
+                    for k in fresh {
+                        if !unit_keys.iter().any(|(_, h)| *h == k) {
+                            let i = unit_keys.len() as u32;
+                            unit_keys.push((i, k));
+                        }
+                    }
+                }
+            }
+        }
+        // If the pool is STILL empty, this AACS-encrypted title needs a Unit Key we
+        // could not obtain from any source. That is the same situation as any known
+        // key we don't hold — fail loud at resolve time rather than deferring an
+        // opaque decrypt error (or, worse, emitting ciphertext) at mux time.
+        let empty = matches!(
+            keys,
+            crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } if unit_keys.is_empty()
+        );
+        if empty {
+            return Err(crate::error::Error::DecryptFailed.into());
+        }
+        return Ok(crate::decrypt::AacsKeyMap::single(0));
+    }
+    // FMTS (AACS 2.1): if the disc carries `IndividualSegment.tbl`, the forensic
+    // segments need per-index keys the base Unit Key can't open. Resolve them up
+    // front from the configured source and build a per-segment map. Returns `None`
+    // when the disc is not FMTS, or no key source is configured (then the base UK
+    // path below applies and the forensic units garble → demux drops them).
+    if let Some(map) = resolve_fmts_key_map(reader, title, keys, fetch, format)? {
+        return Ok(map);
+    }
+    if pool_len == 1 {
+        // One CPS unit → one key everywhere. No structural walk, no sampling.
+        return Ok(crate::decrypt::AacsKeyMap::single(0));
+    }
+
+    // Multi-CPS: read a spread of real encrypted units from each extent and pick
+    // the held key that opens one (the `is_clean` proof is sound HERE — samples
+    // are guaranteed real content, not the authored-bad units that trip the mux).
+    let sample_units = |reader: &mut dyn SectorSource, start: u32, sectors: u32| -> Vec<Vec<u8>> {
+        let total_units = sectors / ALIGNED_UNIT_SECTORS;
+        let mut out = Vec::new();
+        if total_units == 0 {
+            return out;
+        }
+        const PROBES: u32 = 8;
+        for p in 1..=PROBES {
+            let unit = ((total_units as u64 * p as u64) / (PROBES as u64 + 1)) as u32;
+            if unit >= total_units {
+                continue;
+            }
+            let lba = start.saturating_add(unit.saturating_mul(ALIGNED_UNIT_SECTORS));
+            let mut buf = vec![0u8; ALIGNED_UNIT_LEN];
+            if reader
+                .read_sectors(lba, ALIGNED_UNIT_SECTORS as u16, &mut buf, false)
+                .is_ok()
+                && aacs_unit_encrypted(&buf, format)
+            {
+                out.push(buf);
+            }
+        }
+        out
+    };
+    let pick = |samples: &[Vec<u8>], pool: &[(u32, [u8; 16])]| -> Option<usize> {
+        for (i, (_, k)) in pool.iter().enumerate() {
+            if samples.iter().any(|s| {
+                let mut u = s.clone();
+                decrypt_unit(&mut u, k);
+                is_clean(&u, format)
+            }) {
+                return Some(i);
+            }
+        }
+        None
+    };
+
+    let mut ranges: Vec<(u32, u32, usize)> = Vec::with_capacity(title.extents.len());
+    let mut last_idx = 0usize;
+    for ext in &title.extents {
+        let samples = sample_units(reader, ext.start_lba, ext.sector_count);
+        // Snapshot the current pool for the pure `pick` closure.
+        let pool: Vec<(u32, [u8; 16])> = match keys {
+            crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } => unit_keys.clone(),
+            _ => Vec::new(),
+        };
+        let mut idx = pick(&samples, &pool);
+        if idx.is_none() {
+            if let Some(f) = fetch {
+                if !samples.is_empty() {
+                    let fresh = f(&samples);
+                    if let crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } = keys {
+                        for k in fresh {
+                            if !unit_keys.iter().any(|(_, h)| *h == k) {
+                                let i = unit_keys.len() as u32;
+                                unit_keys.push((i, k));
+                            }
+                        }
+                        idx = pick(&samples, unit_keys);
+                    }
+                }
+            }
+        }
+        // A bad-content extent no sample can classify inherits its predecessor's
+        // key (CPS boundaries are contiguous, so the neighbour is almost always
+        // right); this never storms and never mis-fails a decryptable disc.
+        let idx = idx.unwrap_or(last_idx);
+        last_idx = idx;
+        ranges.push((
+            ext.start_lba,
+            ext.start_lba.saturating_add(ext.sector_count),
+            idx,
+        ));
+    }
+    Ok(crate::decrypt::AacsKeyMap::from_ranges(ranges, 0))
+}
+
 /// Assemble the ISO mux pipeline (read+decrypt → demux → parse) for
 /// a `FileSectorSource`-backed reader. Returns the resulting
 /// `PipelinedPesStream`.
@@ -618,17 +961,16 @@ fn build_demux_state(title: &DiscTitle, format: ContentFormat) -> DemuxState {
 /// - `halt`: cooperative cancel token (not a timeout); when cancelled the
 ///   pipeline stops at the next boundary. `None` disables cancellation.
 /// - `event_fn`: optional progress/event callback invoked by the prefetcher.
-/// - `fetch`: optional fresh-key-on-failure callback (see
-///   [`crate::sector::KeyFetch`]). When a unit no held key decrypts, the
-///   decrypt decorator hands that ciphertext to `fetch` and adds any key it
-///   returns. `None` keeps the prior behaviour (the unit is counted as loss).
+/// - `fetch`: optional key source used UP FRONT by [`resolve_mux_key_map`] to
+///   secure any CPS-unit key the pool is missing. Not a per-unit mux-time
+///   callback: the map decides the key for every LBA before the read loop starts.
 // Eight reader/title/keys/tuning/callback params is inherent to the mux entry
 // point; grouping them into a struct would only move the same fields around.
 #[allow(clippy::too_many_arguments)]
 pub fn build_iso_pipeline<S: SectorSource + Send + 'static>(
-    reader: S,
+    mut reader: S,
     title: DiscTitle,
-    keys: crate::decrypt::DecryptKeys,
+    mut keys: crate::decrypt::DecryptKeys,
     batch_sectors: u16,
     format: ContentFormat,
     halt: Option<crate::halt::Halt>,
@@ -645,27 +987,30 @@ pub fn build_iso_pipeline<S: SectorSource + Send + 'static>(
         crate::decrypt::DecryptKeys::Aacs { .. } => 3,
         _ => 1,
     };
-    // MUX path: tolerate decrypt loss. An undecryptable content unit is concealed
-    // (NULL TS fill) + tallied + logged, never an abort — decrypt-verify is a RIP
-    // gate, not a mux gate (P3). The rip's own read paths keep their fail-loud
-    // decorator; only this mux pipeline opts in.
+    // MUX path: read > decrypt > mux. Resolve the proactive AACS key map UP FRONT
+    // — one key per CPS unit / segment, secured from the configured source and
+    // recorded against the LBA ranges it covers. The mux then decrypts each unit
+    // with its KNOWN key and trusts it: no per-unit `is_clean` verdict, no reactive
+    // key-fetch, no key-server storm. A unit that decrypts to broken TS is the
+    // muxer's problem, exactly as before. AACS-only; CSS self-cracks per region.
+    let key_map =
+        match &keys {
+            crate::decrypt::DecryptKeys::Aacs { .. } => Some(std::sync::Arc::new(
+                resolve_mux_key_map(&mut reader, &title, &mut keys, fetch.as_ref(), format)?,
+            )),
+            _ => None,
+        };
     let mut decrypting =
-        crate::sector::DecryptingSectorSource::new(Box::new(reader) as Box<dyn SectorSource>, keys)
-            .tolerate_decrypt_loss();
-    // Install the fresh-key-on-failure callback (if any) so a unit no held key
-    // decrypts is re-tried via the application's key source before being counted
-    // as loss. An AACS 2.1 forensic-segment unit that no key opens is just an
-    // undecryptable unit like any other: concealed and counted as decrypt loss —
-    // a loss is a loss, no FMTS special casing.
-    if let Some(cb) = fetch {
-        decrypting = decrypting.with_key_fetch(cb);
+        crate::sector::DecryptingSectorSource::new(Box::new(reader) as Box<dyn SectorSource>, keys);
+    if let Some(map) = key_map {
+        decrypting = decrypting.with_key_map(map);
     }
-    // Grab the loss counters before the decorator is moved into the producer
-    // thread. It tracks bytes of scrambled AACS units no key could decrypt —
-    // silent loss the demux drops; the consuming stream surfaces it through
-    // `lost_bytes()` so the mux abort gate sees a partial decrypt failure rather
-    // than a clean rip. Forensic (2.1) undecryptable units land here too.
-    let decrypt_loss = decrypting.decrypt_loss();
+    // Loss-counter handle. The mux does NOT tally decrypt-quality misses: a
+    // broken-TS unit is the muxer's concern, and a missing key is an up-front
+    // resolve failure — indistinguishable from bad authoring at this seam, so
+    // counting it would false-abort a bad-encoded-but-decryptable disc. A genuine
+    // can't-decrypt surfaces as `Err`; `lost_bytes()` reflects physical read loss
+    // only (there is no decrypt-loss term to fold in).
 
     // Wrong-substream fix (Silence-of-the-Lambs): before the prefetcher takes
     // the reader, probe the feature head through the (plaintext) decrypting
@@ -691,10 +1036,13 @@ pub fn build_iso_pipeline<S: SectorSource + Send + 'static>(
     let (demux_thread, demux_rx) =
         super::demux_thread::DemuxThread::spawn_zero_copy(rx, recycle_tx, shell, halt, ts, ps)
             .map_err(|e| -> io::Error { e.into() })?;
-    Ok(
-        PipelinedPesStream::new(demux_thread, demux_rx, title, parsers, pid_to_track)
-            .with_decrypt_loss(decrypt_loss),
-    )
+    Ok(PipelinedPesStream::new(
+        demux_thread,
+        demux_rx,
+        title,
+        parsers,
+        pid_to_track,
+    ))
 }
 
 /// Assemble the M2TS file mux pipeline (read → demux → parse) for a

src/mux/ts.rs

@@ -12,9 +12,11 @@ use crate::consts::TS_PACKET_BYTES;
 
 /// TS sync byte.
 const SYNC_BYTE: u8 = 0x47;
-/// MPEG-TS null-packet PID (0x1FFF). Carries no elementary stream; the P3
-/// concealment fill emits null packets on this PID, tagged with an
-/// adaptation-field discontinuity_indicator to signal a concealed gap.
+/// MPEG-TS null-packet PID (0x1FFF). Carries no elementary stream. The demuxer
+/// still recognises a `0x1FFF` packet with an adaptation-field
+/// discontinuity_indicator as a concealed-gap loss signal, but the in-tree WRITER
+/// that emitted these (the removed NULL-TS concealment fill) is gone — the mux no
+/// longer conceals; only externally-authored markers reach this path now.
 const NULL_PID: u16 = 0x1FFF;
 
 /// A reassembled PES packet with timestamp info.
@@ -34,8 +36,10 @@ pub struct PesPacket {
     pub source: Option<crate::pes::SourcePos>,
     /// True when one or more packets for this stream were lost before this PES —
     /// a continuity break (CC gap or adaptation-field discontinuity_indicator) on
-    /// a tracked PID, or the CC-independent concealment marker the mux emits when
-    /// it replaces an undecryptable unit with NULL-TS packets (P3/A2). This PES is
+    /// a tracked PID, or a CC-independent NULL-TS concealment marker (P3/B1). NOTE:
+    /// the mux no longer emits such markers (the concealment writer was removed);
+    /// this now flags only real discontinuities and externally-authored markers.
+    /// This PES is
     /// the FIRST whose data is entirely after the gap: a mid-frame loss drops the
     /// truncated partial and flags the next complete PES; a loss landing on a PES
     /// boundary flags the PES STARTING after it (never the one just flushed). So
@@ -200,7 +204,7 @@ impl PesAssembler {
 /// BD Transport Stream demuxer.
 pub struct TsDemuxer {
     assemblers: Vec<PesAssembler>,
-    pid_index: Vec<i16>, // PID → index into assemblers, -1 = not tracked
+    pid_index: Vec<i32>, // PID → index into assemblers, -1 = not tracked
     remainder: Vec<u8>,  // leftover bytes from previous feed() call
     /// Absolute source byte offset of the NEXT byte to be fed — the running
     /// base that turns an in-buffer packet offset into a source position.
@@ -224,20 +228,17 @@ impl TsDemuxer {
     /// limits. Empty `pids` yields max_pid 0; the floor still produces a
     /// valid (wholly-unused) table.
     pub fn new(pids: &[u16]) -> Self {
-        // The PID→assembler index is stored as i16 (-1 = untracked), so a
-        // 32768th+ tracked PID would truncate to a negative value and be
-        // silently treated as untracked. Callers pass a handful of PIDs
-        // (BD-TS has at most ~8192), so this is a programmer-error guard.
-        debug_assert!(
-            pids.len() <= i16::MAX as usize,
-            "TsDemuxer: too many PIDs for an i16 index table"
-        );
+        // The PID→assembler index is stored as i32 (-1 = untracked). PIDs are
+        // u16 (≤ 65535) and the assembler index `i` is bounded by the number of
+        // distinct PIDs (≤ 65536), both far below i32::MAX, so `i as i32` can
+        // never truncate to a negative value and be mis-read as untracked —
+        // unlike an i16 table, this is safe in RELEASE, not just under debug.
         let max_pid = pids.iter().copied().max().unwrap_or(0) as usize;
         let table_size = (max_pid + 1).max(8192);
-        let mut pid_index = vec![-1i16; table_size];
+        let mut pid_index = vec![-1i32; table_size];
         let mut assemblers = Vec::with_capacity(pids.len());
         for (i, &pid) in pids.iter().enumerate() {
-            pid_index[pid as usize] = i as i16;
+            pid_index[pid as usize] = i as i32;
             assemblers.push(PesAssembler::new(pid));
         }
         Self {
@@ -368,10 +369,13 @@ impl TsDemuxer {
         let pusi = ts[1] & 0x40 != 0; // Payload Unit Start Indicator
         let adaptation = (ts[3] >> 4) & 0x03;
 
-        // P3/B1 CONCEALMENT MARKER. The decrypt layer fills an undecryptable
-        // aligned unit with NULL-TS packets (PID 0x1FFF) that carry an
-        // adaptation-field discontinuity_indicator (see `aacs::content::fill_null_ts_unit`).
-        // This is the authoritative loss signal — unlike a tracked PID's 4-bit
+        // P3/B1 CONCEALMENT MARKER: a NULL-TS packet (PID 0x1FFF) carrying an
+        // adaptation-field discontinuity_indicator. NOTE: the in-tree writer that
+        // laid these down on an undecryptable unit was removed with the pure-decrypt
+        // passthrough change (the mux no longer conceals), so this recognition now
+        // only fires on externally-authored markers — a candidate for removal with
+        // the rest of the retired concealment path.
+        // As a loss signal it is CC-INDEPENDENT — unlike a tracked PID's 4-bit
         // continuity_counter it is CC-INDEPENDENT, so it survives a loss that is
         // an exact multiple of 16 packets and a loss at the very start of a PID
         // (no prior CC to diff against). The decrypt layer cannot know which
@@ -1057,7 +1061,7 @@ mod tests {
 
     /// One 192-byte BD source packet that is a B1 concealment marker: a PID-0x1FFF
     /// null packet carrying the adaptation-field discontinuity_indicator (the byte
-    /// shape `fill_null_ts_unit` writes for every packet of a concealed unit).
+    /// shape of a concealed-unit packet).
     fn null_marker_packet() -> Vec<u8> {
         let mut pkt = vec![0u8; BD_SOURCE_PACKET_BYTES];
         pkt[4] = SYNC_BYTE; // 0x47

src/sector/mod.rs

@@ -129,6 +129,10 @@ impl SectorSource for Box<dyn SectorSource> {
     fn set_speed(&mut self, kbs: u16) {
         (**self).set_speed(kbs)
     }
+
+    fn set_unit_base(&mut self, lba: u32) {
+        (**self).set_unit_base(lba)
+    }
 }
 
 impl SectorSource for &mut (dyn SectorSource + '_) {
@@ -160,6 +164,10 @@ impl SectorSource for &mut (dyn SectorSource + '_) {
     fn set_speed(&mut self, kbs: u16) {
         (**self).set_speed(kbs)
     }
+
+    fn set_unit_base(&mut self, lba: u32) {
+        (**self).set_unit_base(lba)
+    }
 }
 
 /// Write 2048-byte sectors to a disc image or composed sink.
@@ -181,7 +189,7 @@ pub trait SectorSink: Send {
 }
 
 pub use crate::io::file_sector_source::FileSectorSource;
-pub use decrypting::{DECRYPT_VERIFY_READ, DecryptingSectorSource, KeyFetch};
+pub use decrypting::{DecryptingSectorSource, KeyFetch};
 pub use file::FileSectorSink;
 pub use prefetched::PrefetchedSectorSource;
 
@@ -198,23 +206,33 @@ mod tests {
         capacity: u32,
         reads: Arc<Mutex<Vec<(u32, u16, bool)>>>,
         speeds: Arc<Mutex<Vec<u16>>>,
+        unit_bases: Arc<Mutex<Vec<u32>>>,
     }
 
-    /// A `Spy` under test plus the handles recording its reads and speed sets.
-    type SpyHarness = (Spy, Arc<Mutex<Vec<(u32, u16, bool)>>>, Arc<Mutex<Vec<u16>>>);
+    /// A `Spy` under test plus the handles recording its reads, speed sets,
+    /// and unit-base sets.
+    type SpyHarness = (
+        Spy,
+        Arc<Mutex<Vec<(u32, u16, bool)>>>,
+        Arc<Mutex<Vec<u16>>>,
+        Arc<Mutex<Vec<u32>>>,
+    );
 
     impl Spy {
         fn new(capacity: u32) -> SpyHarness {
             let reads = Arc::new(Mutex::new(Vec::new()));
             let speeds = Arc::new(Mutex::new(Vec::new()));
+            let unit_bases = Arc::new(Mutex::new(Vec::new()));
             (
                 Self {
                     capacity,
                     reads: reads.clone(),
                     speeds: speeds.clone(),
+                    unit_bases: unit_bases.clone(),
                 },
                 reads,
                 speeds,
+                unit_bases,
             )
         }
     }
@@ -238,6 +256,16 @@ mod tests {
         fn set_speed(&mut self, kbs: u16) {
             self.speeds.lock().unwrap().push(kbs);
         }
+        fn set_unit_base(&mut self, lba: u32) {
+            self.unit_bases.lock().unwrap().push(lba);
+        }
+    }
+
+    /// Call `set_unit_base` through a generic `S: SectorSource` bound — this is
+    /// the path that actually exercises the `Box<dyn>` / `&mut dyn` FORWARDING
+    /// impls (a direct call on a `dyn` value dispatches via the vtable instead).
+    fn set_unit_base_generic<S: SectorSource>(mut s: S, base: u32) {
+        s.set_unit_base(base);
     }
 
     /// The default `capacity_sectors` is 0 (unknown). Grounding: trait
@@ -286,7 +314,7 @@ mod tests {
     /// Box<dyn SectorSource>` forwarding bodies.
     #[test]
     fn boxed_dyn_forwards_all_methods() {
-        let (spy, reads, speeds) = Spy::new(777);
+        let (spy, reads, speeds, unit_bases) = Spy::new(777);
         let mut boxed: Box<dyn SectorSource> = Box::new(spy);
 
         assert_eq!(boxed.capacity_sectors(), 777, "capacity must forward");
@@ -308,24 +336,46 @@ mod tests {
             vec![5400],
             "set_speed must forward"
         );
+
+        // set_unit_base through the generic bound exercises the forwarding impl
+        // (a direct `boxed.set_unit_base()` would vtable-dispatch instead). A
+        // missing forwarding body would silently no-op and record nothing.
+        set_unit_base_generic(boxed, 64);
+        assert_eq!(
+            *unit_bases.lock().unwrap(),
+            vec![64],
+            "set_unit_base must forward through Box<dyn>"
+        );
     }
 
-    /// `&mut dyn SectorSource` must likewise forward all three methods.
+    /// `&mut dyn SectorSource` must likewise forward every method.
     /// Grounding: `impl SectorSource for &mut (dyn SectorSource + '_)`.
     #[test]
     fn mut_ref_dyn_forwards_all_methods() {
-        let (mut spy, reads, speeds) = Spy::new(123);
-        let r: &mut dyn SectorSource = &mut spy;
+        let (mut spy, reads, speeds, unit_bases) = Spy::new(123);
 
-        assert_eq!(r.capacity_sectors(), 123);
+        {
+            let r: &mut dyn SectorSource = &mut spy;
+            assert_eq!(r.capacity_sectors(), 123);
 
-        let mut buf = vec![0u8; 2 * 2048];
-        let n = r.read_sectors(7, 2, &mut buf, false).unwrap();
-        assert_eq!(n, 2 * 2048);
+            let mut buf = vec![0u8; 2 * 2048];
+            let n = r.read_sectors(7, 2, &mut buf, false).unwrap();
+            assert_eq!(n, 2 * 2048);
 
-        r.set_speed(8800);
+            r.set_speed(8800);
+        }
+
+        // Pass `&mut dyn` as a generic S so the forwarding impl's set_unit_base
+        // is the one under test, not the vtable path.
+        let r2: &mut dyn SectorSource = &mut spy;
+        set_unit_base_generic(r2, 128);
 
         assert_eq!(*reads.lock().unwrap(), vec![(7, 2, false)]);
         assert_eq!(*speeds.lock().unwrap(), vec![8800]);
+        assert_eq!(
+            *unit_bases.lock().unwrap(),
+            vec![128],
+            "set_unit_base must forward through &mut dyn"
+        );
     }
 }

src/sector/prefetched.rs

@@ -252,11 +252,14 @@ impl PrefetchedSectorSource {
                         };
                         if bytes <= buf.capacity() {
                             // Re-expose `bytes` without zero-filling pages that
-                            // `read_sectors` is about to overwrite. The enclosing
-                            // capacity guard makes the `set_len` provably sound even
-                            // if a recycled buffer ever comes back smaller than the
-                            // `vec![0u8; batch_bytes]` it was born with.
-                            debug_assert!(bytes <= buf.capacity(), "set_len exceeds capacity");
+                            // `read_sectors` is about to overwrite. Sound because the
+                            // enclosing `bytes <= capacity` guard bounds the length,
+                            // and every byte below `capacity` is physically
+                            // initialised: buffers are born `vec![0u8; batch_bytes]`
+                            // and only ever grown via `resize(_, 0)`, so a recycled
+                            // buffer that came back shorter (consumer `truncate`)
+                            // still has initialised backing storage under `set_len`,
+                            // which `read_sectors` then overwrites before any read.
                             unsafe { buf.set_len(bytes) };
                         } else {
                             buf.resize(bytes, 0);

src/sector/recovery.rs

@@ -103,25 +103,30 @@ pub struct RecoverCtx {
     pub prev_dropped: usize,
 }
 
-/// A recovery: given a read's still-scrambled `buf` and the **generic**
-/// [`DecryptKeys`], make units decrypt (crack or fetch a key into `keys`) and/or
-/// classify the loss (see [`MissOutcome`]). The type names NO encryption scheme
-/// — the installed recovery decides what to do with the generic keys, so any
-/// scheme (an AACS key-fetch, a future CSS re-crack) is just a different
-/// [`Recover`] the input stream installs. `FnMut` so per-recovery
-/// state (the AACS dedup set / call budget) lives in the closure's captures with
-/// no lock; `Send` so it can ride the mux highway's producer thread.
-pub type Recover = Box<dyn FnMut(&mut [u8], &mut DecryptKeys, &RecoverCtx) -> MissOutcome + Send>;
+/// A recovery: given a read's post-decrypt `target` (pure decrypt leaves the
+/// applied-key plaintext), the matching on-disc `ciphertext`, and the **generic**
+/// [`DecryptKeys`], make units decrypt (fetch a key into `keys` and retry) and/or
+/// classify the loss (see [`MissOutcome`]). Decryption itself lives in ONE place
+/// (`decrypt_sectors`); a recovery only supplies the missing KEY and re-runs it.
+/// `ciphertext` is separate from `target` because a pure decrypt overwrites the
+/// target with plaintext — the key server still needs the original on-disc bytes,
+/// and the retry re-decrypts from them. The type names NO encryption scheme; any
+/// scheme is just a different [`Recover`] the input stream installs. `FnMut` so
+/// per-recovery state (dedup set / call budget) lives in the closure's captures;
+/// `Send` so it can ride the mux highway's producer thread.
+pub type Recover =
+    Box<dyn FnMut(&mut [u8], &[u8], &mut DecryptKeys, &RecoverCtx) -> MissOutcome + Send>;
 
-/// The AACS key-fetch step used by [`key_fetch`]: gather the
-/// still-scrambled units, ask `fetch` for keys, add any new ones to the pool and
-/// re-decrypt. `dry` / `calls` are the caller-owned dedup set and call budget.
-/// Returns the post-retry dropped-byte count.
+/// The AACS key-fetch step used by [`key_fetch`]: gather the units the pool did
+/// NOT open, ask `fetch` for keys, add any new ones to the pool and re-decrypt.
+/// `dry` / `calls` are the caller-owned dedup set and call budget. Returns the
+/// post-retry unverified-byte count.
 fn aacs_fetch_step(
     dry: &mut HashSet<u64>,
     calls: &mut usize,
     fetch: &KeyFetch,
-    buf: &mut [u8],
+    target: &mut [u8],
+    ciphertext: &[u8],
     keys: &mut DecryptKeys,
     ctx: &RecoverCtx,
 ) -> usize {
@@ -130,14 +135,25 @@ fn aacs_fetch_step(
         return prev_dropped;
     }
     let unit_len = crate::aacs::content::ALIGNED_UNIT_LEN;
-    // Gather up to MAX_FETCH_SAMPLES still-scrambled aligned units — the exact
-    // on-disc ciphertext no held key could open. A trailing partial unit
+    // Container of this disc's content — travels with the keys; drives the
+    // encrypted-flag / structure check below (TS vs PS).
+    let format = match &*keys {
+        DecryptKeys::Aacs { format, .. } => *format,
+        _ => crate::disc::ContentFormat::BdTs,
+    };
+    // Gather up to MAX_FETCH_SAMPLES units the current pool did NOT open. Detect
+    // them on the post-decrypt TARGET (a failed unit stays TS-destroyed; an opened
+    // one is now clean TS and is skipped), but SAMPLE the matching on-disc
+    // `ciphertext` — the exact bytes the key server needs. A trailing partial unit
     // (chunks_exact remainder) can't be a whole scrambled unit, so skipping it is
     // correct.
     let mut samples: Vec<Vec<u8>> = Vec::new();
-    for chunk in buf.chunks_exact(unit_len) {
-        if crate::aacs::content::aacs_unit_needs_decrypt(chunk) {
-            samples.push(chunk.to_vec());
+    for (t, c) in target
+        .chunks_exact(unit_len)
+        .zip(ciphertext.chunks_exact(unit_len))
+    {
+        if crate::aacs::content::aacs_unit_needs_decrypt(t, format) {
+            samples.push(c.to_vec());
             if samples.len() >= MAX_FETCH_SAMPLES {
                 break;
             }
@@ -172,10 +188,13 @@ fn aacs_fetch_step(
         dry.extend(fps);
         return prev_dropped;
     }
-    // Retry now that the pool has grown; a unit that still won't decrypt is
-    // genuine loss. A retry error must not mask the original count.
+    // Retry now that the pool has grown. Reset the target to the on-disc
+    // ciphertext first (a pure decrypt already overwrote it with the failed
+    // plaintext), then re-run the ONE decrypt. A unit that still won't reach clean
+    // TS stays unverified; a retry error must not mask the original count.
+    target.copy_from_slice(ciphertext);
     redecrypt(
-        buf,
+        target,
         keys,
         ctx.unit_key_idx,
         ctx.lba,
@@ -187,7 +206,7 @@ fn aacs_fetch_step(
 /// No recovery: a miss is loss. Equivalent to installing nothing — provided so a
 /// caller that wants an explicit "give up" recovery has one.
 pub fn none() -> Recover {
-    Box::new(|_buf, _keys, ctx| MissOutcome::loss(ctx.prev_dropped))
+    Box::new(|_target, _ciphertext, _keys, ctx| MissOutcome::loss(ctx.prev_dropped))
 }
 
 /// AACS key-fetch recovery (BD / UHD): on a miss, ask the application's key
@@ -195,9 +214,9 @@ pub fn none() -> Recover {
 pub fn key_fetch(fetch: KeyFetch) -> Recover {
     let mut dry: HashSet<u64> = HashSet::new();
     let mut calls: usize = 0;
-    Box::new(move |buf, keys, ctx| {
+    Box::new(move |target, ciphertext, keys, ctx| {
         MissOutcome::loss(aacs_fetch_step(
-            &mut dry, &mut calls, &fetch, buf, keys, ctx,
+            &mut dry, &mut calls, &fetch, target, ciphertext, keys, ctx,
         ))
     })
 }
@@ -243,8 +262,10 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
-        let out = r(&mut buf, &mut keys, &ctx(0, 6144));
+        let cipher = buf.clone();
+        let out = r(&mut buf, &cipher, &mut keys, &ctx(0, 6144));
         assert_eq!(out.dropped, 6144);
     }
 
@@ -265,8 +286,10 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
-        r(&mut buf, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
+        let cipher = buf.clone();
+        r(&mut buf, &cipher, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
         assert_eq!(calls.load(Ordering::SeqCst), 1, "fetch called once");
         let DecryptKeys::Aacs { unit_keys, .. } = &keys else {
             unreachable!()
@@ -289,11 +312,14 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         let mut buf = scrambled_unit(0x44);
-        r(&mut buf, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
+        let cipher = buf.clone();
+        r(&mut buf, &cipher, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
         let mut buf2 = scrambled_unit(0x44); // identical ciphertext
-        r(&mut buf2, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
+        let cipher2 = buf2.clone();
+        r(&mut buf2, &cipher2, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
         assert_eq!(
             calls.load(Ordering::SeqCst),
             1,
@@ -313,13 +339,15 @@ mod tests {
         let mut keys = DecryptKeys::Aacs {
             unit_keys: vec![],
             read_data_key: None,
+            format: crate::disc::ContentFormat::BdTs,
         };
         // Distinct ciphertext each time so the dry-set never short-circuits; only
         // the internal call budget should stop the fetch. The closure self-limits,
         // so the decorator can call it unconditionally.
         for i in 0..(MAX_FETCH_CALLS as u8 + 5) {
             let mut buf = scrambled_unit(i);
-            r(&mut buf, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
+            let cipher = buf.clone();
+            r(&mut buf, &cipher, &mut keys, &ctx(0, ALIGNED_UNIT_LEN));
         }
         assert_eq!(
             calls.load(Ordering::SeqCst),

src/udf.rs

@@ -1790,6 +1790,57 @@ mod tests {
         assert!(inf[2048..].iter().all(|&b| b == 0xBB));
     }
 
+    #[test]
+    fn read_aacs_inputs_falls_through_to_hddvd_any_dir() {
+        // HD DVD keeps its AACS material under /ANY!/ (VTKF000.AACS title-key
+        // file + MKBROM.AACS), NOT /AACS/Unit_Key_RO.inf + /AACS/MKB_RO.inf. The
+        // role-based candidate lists must fall through to the /ANY!/ files with
+        // NO disc-type branch, so the online keyserver POST carries the HD DVD
+        // title-key file (magic "DVD_HD_V_TKF") as inf_b64 + MKBROM as mkb_b64 —
+        // the server then classifies the disc as HD DVD by that magic.
+        let any = DirEntry {
+            name: "ANY!".to_string(),
+            is_dir: true,
+            meta_lba: 0,
+            size: 0,
+            entries: vec![
+                file_entry("VTKF000.AACS", 5, 2048),
+                file_entry("MKBROM.AACS", 7, 2048),
+            ],
+        };
+        let root = DirEntry {
+            name: String::new(),
+            is_dir: true,
+            meta_lba: 0,
+            size: 0,
+            entries: vec![any], // deliberately NO /AACS/ dir
+        };
+        let mut reader = MapReader::new();
+        // VTKF000.AACS: one extent whose content opens with the HD DVD magic.
+        let mut vtkf = [0u8; 2048];
+        vtkf[..12].copy_from_slice(b"DVD_HD_V_TKF");
+        reader.put(5, build_efe_long(2048, &[(0, 2048, 10)]));
+        reader.put(10, vtkf);
+        // MKBROM.AACS: one extent with a type-0x10 AACS-1.0 (HD DVD) version record.
+        let mut mkb = [0u8; 2048];
+        mkb[..12].copy_from_slice(&[
+            0x10, 0x00, 0x00, 0x0C, 0x00, 0x04, 0x10, 0x03, 0x00, 0x00, 0x00, 0x03,
+        ]);
+        reader.put(7, build_efe_long(2048, &[(0, 2048, 50)]));
+        reader.put(50, mkb);
+
+        let fs = fs_with(0, 0, root);
+        let (inf, _mkb, _version) =
+            crate::disc::Disc::read_aacs_inputs_from_reader(&mut reader, &fs)
+                .expect("read_aacs_inputs must source the HD DVD /ANY!/ files");
+        assert_eq!(
+            &inf[..12],
+            b"DVD_HD_V_TKF",
+            "inf must be the HD DVD VTKF (its magic), sourced from /ANY!/ via the \
+             candidate fall-through — not /AACS/Unit_Key_RO.inf"
+        );
+    }
+
     #[test]
     fn merge_ranges_saturates_near_u32_max() {
         // Adjacent ranges near u32::MAX must not panic (debug) or wrap.

tests/crypto_tests.rs

@@ -131,16 +131,15 @@ fn aacs_decrypt_unit_roundtrip() {
     }
 
     // Verify it looks encrypted (body TS syncs scrambled)
-    assert!(aacs::content::ts_sync_destroyed(&plain));
+    assert!(!aacs::content::is_clean(
+        &plain,
+        libfreemkv::disc::ContentFormat::BdTs
+    ));
 
     // Now decrypt
-    let result = aacs::content::decrypt_unit(&mut plain, &unit_key);
+    aacs::content::decrypt_unit(&mut plain, &unit_key);
     assert!(
-        result,
-        "decrypt_unit should return true on valid encrypted unit"
-    );
-    assert!(
-        !aacs::content::ts_sync_destroyed(&plain),
+        aacs::content::is_clean(&plain, libfreemkv::disc::ContentFormat::BdTs),
         "decrypted unit should read as clear (TS syncs restored)"
     );
 
@@ -258,9 +257,9 @@ fn aacs_vuk_derivation_roundtrip() {
     assert_eq!(vuk, vuk2, "derive_vuk not deterministic");
 }
 
-/// Test: aacs_ts_sync_destroyed detects scrambled units via the raw TS syncs.
+/// Test: `is_clean` distinguishes clean vs scrambled units via the TS proof floor.
 #[test]
-fn aacs_ts_sync_destroyed_detection() {
+fn aacs_is_clean_detection() {
     // A clear unit: TS sync (0x47) intact at every 192-byte packet → not
     // scrambled. (Flag bits play no role.)
     let mut clear = vec![0u8; aacs::content::ALIGNED_UNIT_LEN];
@@ -270,7 +269,7 @@ fn aacs_ts_sync_destroyed_detection() {
         off += 192;
     }
     assert!(
-        !aacs::content::ts_sync_destroyed(&clear),
+        aacs::content::is_clean(&clear, libfreemkv::disc::ContentFormat::BdTs),
         "clear unit (syncs intact) must not be scrambled"
     );
 
@@ -279,32 +278,35 @@ fn aacs_ts_sync_destroyed_detection() {
     flagged[0] = 0xC0; // copy-control bits
     flagged[7] = 0xC0; // TSC bits
     assert!(
-        !aacs::content::ts_sync_destroyed(&flagged),
+        aacs::content::is_clean(&flagged, libfreemkv::disc::ContentFormat::BdTs),
         "flag bits must not be read as encryption"
     );
 
     // A scrambled body (syncs destroyed) → scrambled.
     let scrambled = vec![0x99u8; aacs::content::ALIGNED_UNIT_LEN];
     assert!(
-        aacs::content::ts_sync_destroyed(&scrambled),
+        !aacs::content::is_clean(&scrambled, libfreemkv::disc::ContentFormat::BdTs),
         "unit with no intact TS syncs must read as scrambled"
     );
 
     // Too short
     let short = vec![0xFFu8; 100];
     assert!(
-        !aacs::content::ts_sync_destroyed(&short),
+        aacs::content::is_clean(&short, libfreemkv::disc::ContentFormat::BdTs),
         "short buffer should not be detected"
     );
 }
 
-/// Test: aacs_decrypt_unit_unencrypted_passthrough
+/// Test: aacs_clear_unit_reports_not_encrypted
 ///
-/// A clear unit (TS syncs intact) should pass through decrypt_unit unchanged.
+/// `decrypt_unit` is now PURE (applies the key unconditionally). The "leave a
+/// clear unit untouched" policy lives at the caller's gate `aacs_unit_encrypted`:
+/// a CPI-clear unit reports not-encrypted, so the caller never hands it to
+/// decrypt_unit.
 #[test]
-fn aacs_decrypt_unit_unencrypted_passthrough() {
+fn aacs_clear_unit_reports_not_encrypted() {
     let mut unit = vec![0x42u8; aacs::content::ALIGNED_UNIT_LEN];
-    // Intact TS syncs every 192 bytes → not scrambled → passthrough.
+    // Intact TS syncs every 192 bytes → not scrambled.
     let mut off = 4;
     while off < aacs::content::ALIGNED_UNIT_LEN {
         unit[off] = 0x47;
@@ -312,13 +314,15 @@ fn aacs_decrypt_unit_unencrypted_passthrough() {
     }
     // CPI bits (byte 0) CLEAR → the authoritative gate reads this as plaintext.
     unit[0] &= 0x3F;
-    let original = unit.clone();
-    let key = [0xAA; 16];
 
-    assert!(!aacs::content::ts_sync_destroyed(&unit));
-    let result = aacs::content::decrypt_unit(&mut unit, &key);
-    assert!(result, "clear unit should return true");
-    assert_eq!(unit, original, "clear unit should be unchanged");
+    assert!(aacs::content::is_clean(
+        &unit,
+        libfreemkv::disc::ContentFormat::BdTs
+    ));
+    assert!(
+        !aacs::content::aacs_unit_encrypted(&unit, libfreemkv::disc::ContentFormat::BdTs),
+        "CPI-clear unit reports not-encrypted; the caller never decrypts it"
+    );
 }
 
 // ── AACS cross-validation with independent AES implementation ──────────────
@@ -413,11 +417,7 @@ fn aacs_cross_validation_encrypt_then_decrypt() {
     );
 
     // -- Decrypt with the library --
-    let ok = aacs::content::decrypt_unit(&mut plaintext, &unit_key);
-    assert!(
-        ok,
-        "decrypt_unit returned false (TS sync verification failed)"
-    );
+    aacs::content::decrypt_unit(&mut plaintext, &unit_key);
 
     // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(
@@ -458,44 +458,14 @@ fn aacs_cross_validation_alternate_key() {
         &mut plaintext[16..aacs::content::ALIGNED_UNIT_LEN],
     );
 
-    assert!(aacs::content::decrypt_unit(&mut plaintext, &unit_key));
+    aacs::content::decrypt_unit(&mut plaintext, &unit_key);
 
     // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(&plaintext[..], &expected[..]);
 }
 
-/// Verify that `decrypt_bus` correctly reverses AES-CBC encryption applied
-/// per-sector to bytes 16..2048 (bus encryption layer).
-#[test]
-fn aacs_bus_decrypt_cross_validation() {
-    let read_data_key: [u8; 16] = [
-        0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF,
-        0x00,
-    ];
-
-    let mut plaintext = vec![0u8; aacs::content::ALIGNED_UNIT_LEN];
-    #[allow(clippy::needless_range_loop)]
-    for i in 0..aacs::content::ALIGNED_UNIT_LEN {
-        plaintext[i] = ((i * 3 + 17) & 0xFF) as u8;
-    }
-    let expected = plaintext.clone();
-
-    // Encrypt per-sector: AES-CBC encrypt bytes 16..2048 of each 2048-byte sector
-    for sector_start in (0..aacs::content::ALIGNED_UNIT_LEN).step_by(2048) {
-        ref_aes_cbc_encrypt(
-            &read_data_key,
-            &CROSS_AACS_IV,
-            &mut plaintext[sector_start + 16..sector_start + 2048],
-        );
-    }
-    assert_ne!(&plaintext[16..32], &expected[16..32]);
-
-    aacs::content::decrypt_bus(&mut plaintext, &read_data_key);
-    assert_eq!(
-        plaintext, expected,
-        "bus decrypt did not recover original plaintext"
-    );
-}
+// (`decrypt_bus` is a crate-internal layer — its cross-validation lives in-crate
+// in `aacs::content`'s unit tests, not here.)
 
 // ── CSS roundtrip test vectors ─────────────────────────────────────────────
 
@@ -663,6 +633,28 @@ fn css_stevenson_attack_validates_cracked_key() {
              This is expected: synthetic sectors lack the TAB1 output encoding \
              present in real CSS-encrypted DVD sectors."
         );
+        // Never let this test pass vacuously: when the attack can't converge on
+        // synthetic data, still assert always-true properties of the CSS keystream
+        // so a real regression is caught on every run — descramble_sector is
+        // DETERMINISTIC (same key/seed/data → same output) and NON-TRIVIAL (it
+        // actually transforms the payload, not a silent no-op).
+        for (key, seed) in candidates {
+            let mut base = vec![0x00u8; 2048];
+            base[0x14] = 0x30;
+            base[0x54..0x59].copy_from_slice(seed);
+            base[0x80..0x8A]
+                .copy_from_slice(&[0x00, 0x00, 0x01, 0xE0, 0x00, 0x00, 0x80, 0x80, 0x05, 0x21]);
+            let mut a = base.clone();
+            let mut b = base.clone();
+            css::lfsr::descramble_sector(key, &mut a);
+            css::lfsr::descramble_sector(key, &mut b);
+            assert_eq!(a, b, "descramble must be deterministic for key={key:02X?}");
+            assert_ne!(
+                &a[0x80..2048],
+                &base[0x80..2048],
+                "descramble must transform the payload for key={key:02X?}"
+            );
+        }
     }
 }
 
@@ -707,6 +699,20 @@ fn css_recover_title_key_with_exact_plaintext() {
              The LFSR0 recovery phase may not converge for this combination.",
             title_key, seed
         );
+        // Never pass vacuously: when LFSR0 recovery can't converge on this
+        // synthetic sector, still assert always-true properties of the cipher so
+        // a real regression is caught on every run — descramble_sector is
+        // DETERMINISTIC and NON-TRIVIAL (actually transforms the payload).
+        let mut a = original.clone();
+        let mut b = original.clone();
+        css::lfsr::descramble_sector(&title_key, &mut a);
+        css::lfsr::descramble_sector(&title_key, &mut b);
+        assert_eq!(a, b, "descramble must be deterministic");
+        assert_ne!(
+            &a[0x80..2048],
+            &original[0x80..2048],
+            "descramble must transform the payload"
+        );
     }
 }
 

tests/pass_n_patch_fix.rs

@@ -27,21 +27,39 @@ fn decrypt_sectors_with_aacs_keys_works() {
 
     let unit_key: [u8; 16] = [0xAAu8; 16];
 
-    // Encrypt the unit using AACS algorithm
-    aacs::content::decrypt_unit(&mut unit, &unit_key); // decrypt_unit is idempotent on already-encrypted data
+    // Apply the key to the pattern to produce ciphertext-shaped bytes for the
+    // call below. (decrypt_unit is now PURE — it applies the key unconditionally,
+    // so it is NOT idempotent; never call it twice on the same unit.)
+    aacs::content::decrypt_unit(&mut unit, &unit_key);
+    // (byte 0 keeps its CPI bits set from above, so `decrypt_sectors` recognises
+    // this as encrypted content and actually applies the key.)
 
-    // Now we have encrypted data - create DecryptKeys with actual keys
-    let mut keys = DecryptKeys::Aacs {
+    let mut aacs_keys = DecryptKeys::Aacs {
         unit_keys: vec![(0u32, unit_key)],
         read_data_key: None,
+        format: libfreemkv::disc::ContentFormat::BdTs,
     };
+    let mut none_keys = DecryptKeys::None;
 
-    // decrypt_sectors should handle this without error
-    let result = libfreemkv::decrypt::decrypt_sectors(&mut unit, &mut keys, 0);
+    // The regression this guards is passing `DecryptKeys::None` where AACS keys
+    // were meant. Prove the two DIVERGE: AACS applies the key (bytes change), None
+    // leaves the unit byte-for-byte untouched. is_ok alone can't catch that —
+    // both variants return Ok.
+    let mut with_aacs = unit.clone();
+    let mut with_none = unit.clone();
+    libfreemkv::decrypt::decrypt_sectors(&mut with_aacs, &mut aacs_keys, 0)
+        .expect("AACS decrypt must not error");
+    libfreemkv::decrypt::decrypt_sectors(&mut with_none, &mut none_keys, 0)
+        .expect("None decrypt must not error");
 
-    assert!(
-        result.is_ok(),
-        "decrypt_sectors with AACS keys should not error"
+    assert_ne!(
+        with_aacs, unit,
+        "AACS keys must actually transform the unit"
+    );
+    assert_eq!(with_none, unit, "None keys must leave the unit untouched");
+    assert_ne!(
+        with_aacs, with_none,
+        "AACS decrypt must differ from the None no-op (the None-vs-Aacs regression)"
     );
 }
 
@@ -90,16 +108,25 @@ fn aacs_encryption_flag_detection() {
         off += 192;
     }
     // Encryption is the scrambled body (TS syncs destroyed), NOT a flag bit.
-    assert!(!aacs::content::ts_sync_destroyed(&unit));
+    assert!(aacs::content::is_clean(
+        &unit,
+        libfreemkv::disc::ContentFormat::BdTs
+    ));
 
     // Flag bits on a synced unit do not make it look encrypted.
     unit[0] = 0xC0;
     unit[7] = 0xC0;
-    assert!(!aacs::content::ts_sync_destroyed(&unit));
+    assert!(aacs::content::is_clean(
+        &unit,
+        libfreemkv::disc::ContentFormat::BdTs
+    ));
 
     // Scrambled body (syncs gone) → encrypted.
     let scrambled = vec![0x99u8; aacs::content::ALIGNED_UNIT_LEN];
-    assert!(aacs::content::ts_sync_destroyed(&scrambled));
+    assert!(!aacs::content::is_clean(
+        &scrambled,
+        libfreemkv::disc::ContentFormat::BdTs
+    ));
 }
 
 /// Test: DecryptKeys::is_encrypted() correctly identifies encrypted state.
@@ -111,6 +138,7 @@ fn decrypt_keys_is_encrypted_variants() {
     let aacs = DecryptKeys::Aacs {
         unit_keys: vec![],
         read_data_key: None,
+        format: libfreemkv::disc::ContentFormat::BdTs,
     };
     assert!(aacs.is_encrypted());
 

tests/pass_n_size_aware_skip.rs

@@ -275,7 +275,6 @@ fn patch_block_sectors_zero_does_not_busy_spin() {
         progress: None,
         halt: Some(halt.clone()),
         key_fetch: None,
-        fast_capture: false,
     };
 
     let outcome = disc.patch(&mut reader, &iso_path, &opts);

tests/passn_handler_ab.rs

@@ -232,8 +232,6 @@ struct Golden {
     bytes_unreadable: u64,
     /// `bytes_pending` (NonTrimmed) at end.
     bytes_pending: u64,
-    /// Did the pass exit via wedge-detection?
-    wedged_exit: bool,
     /// Sanity bound on trace length — patch makes a finite number of
     /// reads bounded by `MAX_SKIPS_PER_RANGE * range_sectors` plus
     /// retries. Asserted as an UPPER bound only (so any reduction in
@@ -319,7 +317,6 @@ fn profile_01_clean_all_recoverable() {
         bytes_good: capacity_sectors as u64 * 2048,
         bytes_unreadable: 0,
         bytes_pending: 0,
-        wedged_exit: false,
         max_reads: 8, // adaptive batch=32 reads finishes 16 sectors in 1 read; allow up to 8.
     };
     assert_eq!(stats.bytes_good, expected.bytes_good, "01_clean bytes_good");
@@ -796,29 +793,190 @@ fn profile_08_batch_fail_singles_ok() {
 
 // ─────────────────────────────────────────────────────────────────────────
 //
-// Suppressed for now: NOT_READY-then-recover, HARDWARE_ERROR (wedge),
-// ILLEGAL_REQUEST (wedge), and ABORTED_COMMAND profiles. Each would
-// trigger long real-time sleeps inside `handle_read_failure`:
+// Sense-family error paths in `Disc::patch`: NOT_READY-then-recover,
+// HARDWARE_ERROR, ILLEGAL_REQUEST, and ABORTED_COMMAND.
 //
-//   - NOT_READY (sense_key=0x02, asc=0x02/0x03/0x04): 15 s pause per
-//     occurrence (`patch_not_ready_pause`), and retries the same LBA
-//     in-place. Even one NOT_READY costs the test 15 s wall-time.
+// These drive `disc.patch(...)` DIRECTLY rather than through `run_profile`
+// (which drives `Disc::copy`, whose SWEEP path really sleeps on NOT_READY /
+// wedge cooldowns via `sleep_secs_or_halt`). The patch handler chain itself
+// uses an injectable deadline clock (`Instant::now` in production) and never
+// `thread::sleep`s, so these paths run at full speed with no wall-time cost —
+// the earlier "sleeps aren't injectable" suppression only ever applied to the
+// copy/sweep driver, not to patch.
 //
-//   - HARDWARE_ERROR / ILLEGAL_REQUEST: 30 s per occurrence
-//     (`WEDGE_FAMILY_COOLDOWN_SECS`), bounded by
-//     `WEDGE_ABORT_THRESHOLD=16` before wedged-exit. Worst case ~8
-//     minutes per profile.
-//
-// The sleeps are not injectable. Adding them would require either a
-// `now()` / `sleep()` trait injection (out of scope for the unification
-// task) or a "test mode" compile-time flag (architectural smell). The
-// behavioural contracts for those paths are captured in
-// `read_error.rs`'s in-module tests instead — they exercise the
-// classifier without invoking the patch loop's sleep side-effects.
-//
-// If the unification ever proceeds, the next step is to add a clock
-// injection point in `handle_read_failure` and extend this fixture
-// with the wedge/NOT_READY profiles too.
+// The load-bearing invariant asserted across every PERSISTENT failure sense is
+// the recovery contract: a patch pass NEVER promotes a sector to Unreadable
+// (the orchestrator does that only after the final pass) and NEVER silently
+// drops bytes — a still-bad sector stays NonTrimmed (pending), so
+// good + pending always conserves the total. Exact good/pending splits are
+// left loose so wedge-skip tuning can't spuriously fail these.
+
+/// Run a single-always-bad-sector (LBA 130, inside a NonTrimmed [128,192)
+/// range) patch pass with the given failure step and return the final map
+/// stats. 256-sector synthetic disc; everything outside the range is Finished.
+fn single_dead_sector_patch_stats(step: ScriptStep) -> libfreemkv::disc::mapfile::MapStats {
+    let capacity_sectors: u32 = 256;
+    let (mut reader, _trace) = ScriptedSectorReader::new(capacity_sectors);
+    reader.always(130, step);
+
+    let total_bytes = capacity_sectors as u64 * SECTOR_SIZE as u64;
+    let disc = synthetic_disc(capacity_sectors);
+    let tmp = tempfile::NamedTempFile::new().unwrap();
+    let iso_path = tmp.path().to_path_buf();
+    drop(tmp);
+    let nontrimmed = [(128 * 2048, 64 * 2048)];
+    let finished = [
+        (0, 128 * 2048),
+        (192 * 2048, (capacity_sectors as u64 - 192) * 2048),
+    ];
+    prep_iso_and_mapfile(&iso_path, total_bytes, &finished, &nontrimmed);
+
+    let opts = libfreemkv::disc::PatchOptions {
+        decrypt: false,
+        block_sectors: Some(32),
+        full_recovery: true,
+        reverse: true,
+        wedged_threshold: 50,
+        progress: None,
+        halt: None,
+        key_fetch: None,
+    };
+    disc.patch(&mut reader, &iso_path, &opts)
+        .expect("patch must not error on a per-sector failure sense");
+
+    let map_path = libfreemkv::disc::mapfile_path_for(&iso_path);
+    let stats = Mapfile::load(&map_path).unwrap().stats();
+    let _ = std::fs::remove_file(&iso_path);
+    let _ = std::fs::remove_file(&map_path);
+    stats
+}
+
+/// A persistent sense that never clears must obey the pass contract: nothing
+/// Unreadable, nothing lost (good + pending == total), and at least the dead
+/// sector left pending.
+fn assert_persistent_sense_contract(step: ScriptStep, label: &str) {
+    let stats = single_dead_sector_patch_stats(step);
+    let total = 256u64 * 2048;
+    assert_eq!(
+        stats.bytes_unreadable, 0,
+        "{label}: a patch pass must NEVER mark Unreadable"
+    );
+    assert_eq!(
+        stats.bytes_good + stats.bytes_pending,
+        total,
+        "{label}: conservation — no byte may be silently dropped"
+    );
+    assert!(
+        stats.bytes_pending >= 2048,
+        "{label}: the always-dead sector must remain pending (NonTrimmed)"
+    );
+}
+
+#[test]
+fn patch_persistent_hardware_error_conserves_and_never_unreadable() {
+    // HARDWARE_ERROR (sense_key=0x04) — wedge family.
+    assert_persistent_sense_contract(
+        ScriptStep::Err {
+            sense_key: 0x04,
+            asc: 0x11,
+            ascq: 0x00,
+        },
+        "HARDWARE_ERROR",
+    );
+}
+
+#[test]
+fn patch_persistent_illegal_request_conserves_and_never_unreadable() {
+    // ILLEGAL_REQUEST (sense_key=0x05) — wedge family.
+    assert_persistent_sense_contract(
+        ScriptStep::Err {
+            sense_key: 0x05,
+            asc: 0x21,
+            ascq: 0x00,
+        },
+        "ILLEGAL_REQUEST",
+    );
+}
+
+#[test]
+fn patch_persistent_aborted_command_conserves_and_never_unreadable() {
+    // ABORTED_COMMAND (sense_key=0x0B).
+    assert_persistent_sense_contract(
+        ScriptStep::Err {
+            sense_key: 0x0B,
+            asc: 0x00,
+            ascq: 0x00,
+        },
+        "ABORTED_COMMAND",
+    );
+}
+
+#[test]
+fn patch_not_ready_then_recovers_fully() {
+    // NOT_READY (sense_key=0x02, asc=0x04) that clears after two attempts must
+    // recover the sector in-pass — no residual loss, no Unreadable, no hang.
+    let capacity_sectors: u32 = 256;
+    let (mut reader, _trace) = ScriptedSectorReader::new(capacity_sectors);
+    reader.sequence(
+        130,
+        vec![
+            ScriptStep::Err {
+                sense_key: 0x02,
+                asc: 0x04,
+                ascq: 0x00,
+            },
+            ScriptStep::Err {
+                sense_key: 0x02,
+                asc: 0x04,
+                ascq: 0x00,
+            },
+            ScriptStep::Ok,
+        ],
+    );
+
+    let total_bytes = capacity_sectors as u64 * SECTOR_SIZE as u64;
+    let disc = synthetic_disc(capacity_sectors);
+    let tmp = tempfile::NamedTempFile::new().unwrap();
+    let iso_path = tmp.path().to_path_buf();
+    drop(tmp);
+    let nontrimmed = [(128 * 2048, 64 * 2048)];
+    let finished = [
+        (0, 128 * 2048),
+        (192 * 2048, (capacity_sectors as u64 - 192) * 2048),
+    ];
+    prep_iso_and_mapfile(&iso_path, total_bytes, &finished, &nontrimmed);
+
+    let opts = libfreemkv::disc::PatchOptions {
+        decrypt: false,
+        block_sectors: Some(32),
+        full_recovery: true,
+        reverse: true,
+        wedged_threshold: 50,
+        progress: None,
+        halt: None,
+        key_fetch: None,
+    };
+    disc.patch(&mut reader, &iso_path, &opts)
+        .expect("patch must not error on a transient NOT_READY");
+
+    let map_path = libfreemkv::disc::mapfile_path_for(&iso_path);
+    let stats = Mapfile::load(&map_path).unwrap().stats();
+    assert_eq!(
+        stats.bytes_unreadable, 0,
+        "NOT_READY recovery must not mark Unreadable"
+    );
+    assert_eq!(
+        stats.bytes_pending, 0,
+        "a NOT_READY that clears must leave nothing pending"
+    );
+    assert_eq!(
+        stats.bytes_good,
+        capacity_sectors as u64 * 2048,
+        "every sector recovers once NOT_READY clears"
+    );
+    let _ = std::fs::remove_file(&iso_path);
+    let _ = std::fs::remove_file(&map_path);
+}
 
 // ──────── Handler chain recovers re-readable sectors inside a bad block ────────
 //
@@ -826,9 +984,10 @@ fn profile_08_batch_fail_singles_ok() {
 // handler chain's linear pass narrows a failed batch to per-sector reads, so it
 // recovers EVERY re-readable sector and leaves ONLY the dead sector NonTrimmed —
 // strictly better than the old fast-capture path, which left the whole failed
-// 32-block untouched. (`fast_capture` is now inert: the chain supersedes it. The
-// breadth-first "fast on all ranges, then escalate" ORDERING it once provided is
-// a scheduling concern for the handler scheduler, tracked separately.)
+// 32-block untouched. (The old `fast_capture` knob was removed: the handler
+// chain supersedes it. The breadth-first "fast on all ranges, then escalate"
+// ORDERING it once provided is a scheduling concern for the handler scheduler,
+// tracked separately.)
 //
 // The load-bearing invariant is unchanged: NO data is dropped. A still-bad
 // sector becomes NonTrimmed (pending, retried by a later pass), NEVER Unreadable.
@@ -869,10 +1028,9 @@ fn handler_chain_recovers_readable_sectors_leaving_only_dead_pending() {
         progress: None,
         halt: None,
         key_fetch: None,
-        fast_capture: true,
     };
     disc.patch(&mut reader, &iso_path, &opts)
-        .expect("fast-capture patch must not error");
+        .expect("handler-chain patch must not error");
 
     let map_path = libfreemkv::disc::mapfile_path_for(&iso_path);
     let stats = Mapfile::load(&map_path).unwrap().stats();