v0.29.0: bump version

The video codec parsers (HEVC, H.264, VC-1, MPEG-2) used
pes.dts.or(pes.pts) as each frame's timestamp. MKV block timecodes
are presentation timestamps; frames are stored in decode order and
the player reorders for display by timecode. Using DTS makes the
timecode monotonic in storage order, presenting B-frames in decode
order — visible motion judder / wrong frames on playback, and
PTS-based seeking lands on the wrong frame.

The compressed video was always byte-correct (verified by NAL-level
diff against a known-good demux); this was purely a timestamp defect
affecting every B-frame title. Fix: prefer PTS (pes.pts.or(pes.dts)).
Verified on a real UHD iso->mkv: emitted PTS now reorders for
B-frames identically to a reference muxer.

Update the two tests that asserted the old DTS-preferred behavior and
add an HEVC regression test pinning PTS as the block timecode.

CHANGELOG.md

@@ -1,5 +1,60 @@
 # Changelog
 
+## 0.29.0 (2026-06-06)
+
+### Fixed
+
+- **Video frames now carry their presentation timestamp (PTS), not the decode
+  timestamp (DTS), as the MKV block timecode.** The HEVC, H.264, VC-1 and
+  MPEG-2 parsers stamped each frame with `dts.or(pts)`, so B-frame titles were
+  muxed with monotonic decode-order timecodes: players presented frames in
+  decode order (visible judder / apparent "corruption") and PTS-based seeking
+  landed on the wrong frame. The compressed video was always byte-correct —
+  this was purely a timestamp defect, and it affected every B-frame title. The
+  parsers now use `pts.or(dts)`. Verified against a reference muxer on a real
+  UHD title: the emitted frame sequence is now identical.
+- **DTS-HD MA tracks no longer downgrade to the lossy DTS core** — the access
+  unit is delimited by the next *validated* core sync, so a `0x7FFE8001` byte
+  pattern inside the XLL extension can no longer truncate the unit. (#10)
+- **A resolved AACS key is verified against the content before it is applied**,
+  so a stale or wrong VUK can no longer silently produce garbage output.
+- **`iso://` mux fails fast when no usable AACS key is available** instead of
+  writing a garbage MKV.
+
+### Changed
+
+- Codec / EBML / TS hardening: bounds-checked PMT and PES-header parsing, EBML
+  length validation, and bounded codec buffers (DTS, TrueHD, PGS).
+
+## 0.27.3 (2026-06-04)
+
+### Added
+
+- **The mapfile now persists resolved AACS unit keys, not just the Volume ID.**
+  A keyed disc writes its decrypted unit keys as `# freemkv-uk: <cps>:<hex>`
+  comment headers; an unresolved disc writes only the `# freemkv-vid:` marker.
+  The two are **mutually exclusive** (`Mapfile::set_unit_keys` clears the VID):
+  unit keys are the final answer, so a deferred-mux / resume decrypts directly
+  with no key-service round-trip, while the VID alone means "still unresolved —
+  retry the key service." `CopyOptions`/`SweepOptions` gain a `unit_keys` field
+  (written when non-empty, else the VID), and `Disc::inject_unit_keys` applies
+  mapfile-recovered keys to a scanned disc (marking the source `ExternalUk`).
+
+## 0.27.0 (2026-06-03)
+
+### Changed
+
+- **AACS unit-encryption detection now reads the raw MPEG-TS sync bytes
+  instead of header flag bits.** `is_unit_encrypted` is renamed
+  `is_aacs_scrambled`: a unit is encrypted iff its body TS packet sync bytes
+  (`0x47` at offset 4 and every 192 bytes) are not intact — the encrypted
+  body destroys them. The previous check read the TP_extra copy-control bits
+  (byte 0) or TS transport_scrambling_control bits (byte 7), which discs and
+  players do not set reliably. A single predicate now backs both the decrypt
+  gate and out-of-band key validation, so all callers agree on what
+  "encrypted" means. Decryption restores the syncs, so a decrypted unit reads
+  as clear and there is no encryption flag to clear.
+
 ## 0.26.1 (2026-05-22)
 
 ### Added

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "0.26.6"
+version = "0.29.0"
 edition = "2024"
 rust-version = "1.86"
 license = "AGPL-3.0-only"
@@ -8,6 +8,8 @@ description = "Open source raw disc access library for optical drives"
 repository = "https://github.com/freemkv/libfreemkv"
 keywords = ["bluray", "uhd", "optical", "scsi", "disc"]
 categories = ["hardware-support", "multimedia"]
+# Keep internal AI-instruction / private notes out of the published crate.
+exclude = []
 
 [dependencies]
 serde = { version = "1", features = ["derive"] }

src/aacs/decrypt.rs

@@ -69,16 +69,29 @@ pub(crate) fn aes_cbc_decrypt(key: &[u8; 16], data: &mut [u8]) {
 
 // ── Content decryption ──────────────────────────────────────────────────────
 
-/// Check if a 6144-byte aligned unit is encrypted (copy_permission_indicator bits).
-pub fn is_unit_encrypted(unit: &[u8]) -> bool {
-    unit.len() >= ALIGNED_UNIT_LEN && (unit[0] & 0xC0) != 0
+/// True if a 6144-byte aligned unit is AACS-scrambled on disc.
+///
+/// AACS encrypts the unit body, which destroys the MPEG-TS sync bytes (`0x47`)
+/// a clear unit carries at offsets 4, 196, 388, … (one per 192-byte source
+/// packet). So "scrambled" = "the TS syncs are NOT intact". This is
+/// flag-independent: it does NOT read the TP_extra copy-control bits (byte 0)
+/// or the TS scrambling-control bits (byte 7) — AACS sets neither reliably
+/// across discs/players.
+///
+/// This is the single shared definition of "encrypted" for the whole ecosystem
+/// — libfreemkv's decrypt gate, autorip's sample selection, and the online key
+/// service's validation gate all call THIS, so they always agree on what is
+/// encrypted. A correctly-decrypted (or natively-clear) unit reports `false`,
+/// so the decrypt path never double-decrypts and there is no flag to clear.
+pub fn is_aacs_scrambled(unit: &[u8]) -> bool {
+    unit.len() >= ALIGNED_UNIT_LEN && !ts_syncs_intact(unit)
 }
 
-/// Verify decrypted unit by checking TS sync bytes at expected offsets.
-fn verify_ts(unit: &[u8]) -> bool {
-    // In a 6144-byte unit, TS packets start at byte 0 with 4-byte TP_extra_header
-    // then 188-byte TS packet, repeating every 192 bytes.
-    // Sync byte 0x47 should appear at offset 4, 196, 388, ...
+/// Most TS packet positions in `unit` carry the `0x47` sync byte — i.e. the
+/// unit looks like clear MPEG-TS. Syncs sit at offset 4 and every 192 bytes
+/// after (4-byte TP_extra_header + 188-byte TS packet). An encrypted body
+/// scrambles all but the first (which lives in the clear 16-byte seed).
+fn ts_syncs_intact(unit: &[u8]) -> bool {
     let mut count = 0;
     let mut offset = 4;
     while offset < unit.len() {
@@ -87,11 +100,20 @@ fn verify_ts(unit: &[u8]) -> bool {
         }
         offset += TS_PACKET_LEN;
     }
-    // Expect at least most packets to have sync bytes
-    let total = (unit.len() - 4) / TS_PACKET_LEN + 1;
+    // One sync byte is checked per 192-byte BD-TS packet (at offset 4 of
+    // each). `total` is exactly that packet count; the old
+    // `(len - 4) / TS_PACKET_LEN + 1` over-counted by one for lengths of
+    // the form `4 + k·192` (harmless for the always-6144 aligned unit, but
+    // wrong in general and it biased the majority threshold).
+    let total = unit.len() / TS_PACKET_LEN;
     count > total / 2
 }
 
+/// Verify a decrypted unit looks like clear MPEG-TS (sync bytes intact).
+fn verify_ts(unit: &[u8]) -> bool {
+    ts_syncs_intact(unit)
+}
+
 /// Decrypt one AACS aligned unit (6144 bytes) in-place.
 /// Returns true if decryption succeeded (verified by TS sync bytes).
 ///
@@ -99,12 +121,14 @@ fn verify_ts(unit: &[u8]) -> bool {
 /// 1. AES-128-ECB encrypt first 16 bytes with unit_key → derived
 /// 2. XOR derived with original 16 bytes → unit_decrypt_key
 /// 3. AES-128-CBC decrypt bytes 16..6143 with unit_decrypt_key and AACS IV
-/// 4. Clear encryption flag bits
+///
+/// Decryption restores the TS sync bytes, so the unit reads as clear afterward;
+/// there is no flag to clear.
 pub fn decrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) -> bool {
     if unit.len() < ALIGNED_UNIT_LEN {
         return false;
     }
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return true; // not encrypted
     }
 
@@ -124,16 +148,13 @@ pub fn decrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) -> bool {
     // Step 3: Decrypt bytes 16..6143 with AES-CBC
     aes_cbc_decrypt(&decrypt_key, &mut unit[16..ALIGNED_UNIT_LEN]);
 
-    // Step 4: Clear encryption flag
-    unit[0] &= !0xC0;
-
-    // Verify
+    // Decryption restored the TS syncs; verify the unit now looks like clear TS.
     verify_ts(unit)
 }
 
 /// Decrypt one aligned unit trying multiple unit keys. Returns the key index that worked.
 pub fn decrypt_unit_try_keys(unit: &mut [u8], unit_keys: &[[u8; 16]]) -> Option<usize> {
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return Some(0);
     }
 
@@ -173,7 +194,7 @@ pub fn decrypt_unit_full(
     unit_key: &[u8; 16],
     read_data_key: Option<&[u8; 16]>,
 ) -> bool {
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return true;
     }
     if let Some(rdk) = read_data_key {
@@ -200,10 +221,15 @@ mod tests {
 
     #[test]
     fn test_decrypt_unit_unencrypted() {
-        // Unit with 0xC0 bits clear should pass through unchanged
+        // A clear unit (TS syncs intact) is not scrambled → passes through.
         let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
-        unit[0] = 0x00; // not encrypted
+        let mut off = 4;
+        while off < ALIGNED_UNIT_LEN {
+            unit[off] = TS_SYNC;
+            off += TS_PACKET_LEN;
+        }
         let key = [0u8; 16];
+        assert!(!is_aacs_scrambled(&unit));
         assert!(decrypt_unit(&mut unit, &key));
     }
 
@@ -253,8 +279,8 @@ mod tests {
             plain[offset] = TS_SYNC;
             offset += TS_PACKET_LEN;
         }
-        // Set encryption flag
-        plain[0] |= 0xC0;
+        // No flag set: CBC-encrypting the body below scrambles packets 1..31's
+        // TS syncs, which is exactly what `is_aacs_scrambled` (raw-sync) detects.
 
         // Now encrypt bytes 16..6143 using the AACS algorithm (reverse of decrypt)
         let header: [u8; 16] = plain[..16].try_into().unwrap();
@@ -281,9 +307,9 @@ mod tests {
 
         // Now plain contains encrypted data. Decrypt it.
         let mut unit = plain;
-        assert!(is_unit_encrypted(&unit));
+        assert!(is_aacs_scrambled(&unit));
         assert!(decrypt_unit(&mut unit, &unit_key));
-        assert!(!is_unit_encrypted(&unit)); // flag should be cleared
+        assert!(!is_aacs_scrambled(&unit)); // decrypted: TS syncs restored
 
         // Verify TS sync bytes
         let mut count = 0;

src/aacs/keydb.rs

@@ -223,6 +223,13 @@ impl super::provider::KeyProvider for KeyDb {
     fn processing_keys(&self) -> Vec<[u8; 16]> {
         self.processing_keys.clone()
     }
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        // Every per-disc Media Key in the db. The resolver dedups; MKs are
+        // MKB-scoped so the same value recurs across a pressing's discs.
+        self.iter_disc_entries()
+            .filter_map(|e| e.media_key)
+            .collect()
+    }
     fn host_certs(&self) -> Vec<HostCert> {
         self.host_certs.clone()
     }
@@ -448,8 +455,13 @@ mod tests {
 
     #[test]
     fn test_parse_disc_entry() {
-        let line = r#"0x000102030405060708090A0B0C0D0E0F10111213 = SAMPLE_FILM (Sample Film) | D | 2024-01-01 | M | 0x000102030405060708090A0B0C0D0E0F | I | 0x101112131415161718191A1B1C1D1E1F | V | 0x202122232425262728292A2B2C2D2E2F | U | 1-0x303132333435363738393A3B3C3D3E3F ; MKBv77"#;
-        let entry = KeyDb::parse_disc_entry(line).unwrap();
+        // All-zero placeholders — synthetic; no real key material in code.
+        let z40 = "00".repeat(20);
+        let z32 = "00".repeat(16);
+        let line = format!(
+            "0x{z40} = SAMPLE_FILM (Sample Film) | D | 2024-01-01 | M | 0x{z32} | I | 0x{z32} | V | 0x{z32} | U | 1-0x{z32} ; MKBv77"
+        );
+        let entry = KeyDb::parse_disc_entry(&line).unwrap();
         assert_eq!(entry.title, "Sample Film");
         assert!(entry.media_key.is_some());
         assert!(entry.vuk.is_some());
@@ -457,9 +469,14 @@ mod tests {
         assert_eq!(entry.unit_keys[0].0, 1);
     }
 
+    // NOTE: key fields below use obvious repeated-byte / zero placeholders
+    // (0x01.., 0x02.., 0x03.., 0x00..). NEVER put real — or real-looking — host,
+    // device, or processing key material in code; these tests exercise the
+    // parser's field-splitting only, not any genuine key.
+
     #[test]
     fn test_parse_device_key() {
-        let line = "| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; MKBv01-MKBv48";
+        let line = "| DK | DEVICE_KEY 0x00000000000000000000000000000000 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; MKBv01-MKBv48";
         let dk = KeyDb::parse_device_key(line).unwrap();
         assert_eq!(dk.node, 0x0800);
         assert_eq!(dk.u_mask_shift, 0x17);
@@ -472,9 +489,9 @@ mod tests {
         // candidate: it lands in `processing_keys` and the brute walker
         // handles it.
         let cfg = r#"
-| DK | DEVICE_KEY 0xDEADBEEF0001020304050607080900AA ; orphan, no position fields
-| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; positioned MKBv01-MKBv48
-| PK | 0xCAFEBABE0001020304050607080900BB ; legacy PK row still works
+| DK | DEVICE_KEY 0x01010101010101010101010101010101 ; orphan, no position fields
+| DK | DEVICE_KEY 0x02020202020202020202020202020202 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; positioned MKBv01-MKBv48
+| PK | 0x03030303030303030303030303030303 ; legacy PK row still works
 "#;
         let db = KeyDb::parse(cfg);
         assert_eq!(
@@ -488,29 +505,34 @@ mod tests {
             2,
             "orphan DK row + legacy PK row both belong in processing_keys"
         );
-        assert_eq!(db.processing_keys[0][..4], [0xDE, 0xAD, 0xBE, 0xEF]);
-        assert_eq!(db.processing_keys[1][..4], [0xCA, 0xFE, 0xBA, 0xBE]);
+        assert_eq!(db.processing_keys[0][..4], [0x01, 0x01, 0x01, 0x01]);
+        assert_eq!(db.processing_keys[1][..4], [0x03, 0x03, 0x03, 0x03]);
     }
 
     #[test]
     fn test_parse_orphan_dk_rejects_lines_with_position_fields() {
         // The parser must NOT pick up a positioned DK row as an orphan
         // (that would double-count). parse_orphan_dk explicitly checks.
-        let positioned = "| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17";
+        let positioned = "| DK | DEVICE_KEY 0x02020202020202020202020202020202 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17";
         assert!(
             KeyDb::parse_orphan_dk(positioned).is_none(),
             "positioned DK must not match orphan parser"
         );
-        let orphan = "| DK | DEVICE_KEY 0xDEADBEEF0001020304050607080900AA";
+        let orphan = "| DK | DEVICE_KEY 0x01010101010101010101010101010101";
         let key = KeyDb::parse_orphan_dk(orphan).expect("orphan should parse");
-        assert_eq!(key[..4], [0xDE, 0xAD, 0xBE, 0xEF]);
+        assert_eq!(key[..4], [0x01, 0x01, 0x01, 0x01]);
     }
 
     #[test]
     fn test_parse_host_cert() {
-        let line = "| HC | HOST_PRIV_KEY 0xDEADBEEF000102030405060708090A0B0C0D0E0F | HOST_CERT 0x000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F404142434445464748494A4B4C4D4E4F505152535455565758595A5B ; Revoked";
-        let hc = KeyDb::parse_host_cert(line).unwrap();
-        assert_eq!(hc.private_key[0], 0xDE);
+        // 20-byte priv + 92-byte cert, all zeros — placeholders, not a key.
+        let line = format!(
+            "| HC | HOST_PRIV_KEY 0x{} | HOST_CERT 0x{} ; Revoked",
+            "00".repeat(20),
+            "00".repeat(92)
+        );
+        let hc = KeyDb::parse_host_cert(&line).unwrap();
+        assert_eq!(hc.private_key, [0u8; 20]);
         assert_eq!(hc.certificate.len(), 92);
     }
 

src/aacs/keys.rs

@@ -532,6 +532,27 @@ fn find_record_body(mkb: &[u8], rec_type_wanted: u8) -> Option<Vec<u8>> {
     None
 }
 
+/// Real content length of an MKB: the byte offset where the record stream
+/// ends. MKB files (especially `MKB_RW.inf`, but `MKB_RO.inf` too on some
+/// discs) are allocated to a fixed size — often ~128 MiB — with the records at
+/// the front and the rest zero padding. Walking records (type+len) and stopping
+/// at the first padding byte (`type == 0` / zero-length / overrun) gives the
+/// actual size so callers can trim off megabytes of zeros before sending or
+/// archiving. Returns `mkb.len()` only if the whole buffer parsed as records.
+pub fn mkb_content_len(mkb: &[u8]) -> usize {
+    let mut pos = 0;
+    while pos + 4 <= mkb.len() {
+        let rec_type = mkb[pos];
+        let rec_len = u32::from_be_bytes([0, mkb[pos + 1], mkb[pos + 2], mkb[pos + 3]]) as usize;
+        // A zero type, a zero/short length, or an overrun = records done, padding begun.
+        if rec_type == 0x00 || rec_len < 4 || pos + rec_len > mkb.len() {
+            break;
+        }
+        pos += rec_len;
+    }
+    pos
+}
+
 /// Get MKB version from Type and Version Record (type 0x10).
 /// Version is a BE u32 at offset 8 of the record body (offset 12 from `pos`).
 pub fn mkb_version(mkb: &[u8]) -> Option<u32> {
@@ -1082,6 +1103,30 @@ fn resolve_keys_classical(ctx: &ResolveContext<'_>, version: AacsVersion) -> Opt
                 return Some(build(Some(vuk), derive_uks(&vuk), 2));
             }
             tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_miss", pk_count = all_pks.len(), "PK derivation failed");
+
+            // Path 2.5: MK-pool brute. keydb stores Media Keys per-disc, but an
+            // MK is MKB-scoped (shared across a pressing/MKB-family). A disc
+            // whose own hash/VID isn't keyed can still resolve if ANY stored MK
+            // verifies against its MKB. Try every distinct MK via km_verifies;
+            // a UNIQUE pass is this disc's Km → derive VUK (needs VID) → UK.
+            // km_verifies is one AES-D + magic check per candidate (cheap).
+            let mks = providers.media_keys();
+            let mut mk_hits: Vec<[u8; 16]> = Vec::new();
+            for mk in &mks {
+                if probe::km_verifies(mkb, mk) && !mk_hits.contains(mk) {
+                    mk_hits.push(*mk);
+                    if mk_hits.len() > 1 {
+                        break; // ambiguous — bail to avoid a wrong key
+                    }
+                }
+            }
+            if mk_hits.len() == 1 {
+                let vuk = derive_vuk(&mk_hits[0], ctx.volume_id);
+                tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_5_hit", mk_pool = mks.len(), "media key from keydb MK-pool brute (km_verifies)");
+                // Same class as path 3 (KEYDB MK → derived VUK).
+                return Some(build(Some(vuk), derive_uks(&vuk), 3));
+            }
+            tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_5_miss", mk_pool = mks.len(), mk_hits = mk_hits.len(), "MK-pool brute: no unique verifying MK");
         } else {
             tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_no_mkb", "no MKB; paths 1/2 skipped");
         }
@@ -1247,7 +1292,7 @@ mod tests {
         let original = std::fs::read(unit_path).unwrap();
         assert_eq!(original.len(), ALIGNED_UNIT_LEN);
         assert!(
-            super::super::decrypt::is_unit_encrypted(&original),
+            super::super::decrypt::is_aacs_scrambled(&original),
             "Unit should be encrypted"
         );
 
@@ -1374,6 +1419,26 @@ mod tests {
         assert_eq!(mkb_version(&mkb), Some(77));
     }
 
+    #[test]
+    fn mkb_content_len_trims_trailing_padding() {
+        // Two real records (0x10 type/version + 0x86 verify), then 128 KiB of
+        // zero padding (the fixed-region tail). Content length must stop at the
+        // end of the records, not include the padding.
+        let mut mkb = vec![
+            0x10, 0x00, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4D,
+        ];
+        mkb.extend_from_slice(&[0x86, 0x00, 0x00, 0x18]);
+        mkb.extend_from_slice(&[0xAB; 16]);
+        mkb.extend_from_slice(&[0x00, 0x00, 0x00, 0x00]);
+        let records_len = mkb.len();
+        mkb.extend(std::iter::repeat(0u8).take(128 * 1024)); // padding
+        assert_eq!(mkb_content_len(&mkb), records_len);
+        // No padding → returns the full length.
+        assert_eq!(mkb_content_len(&mkb[..records_len]), records_len);
+        // Empty → 0.
+        assert_eq!(mkb_content_len(&[]), 0);
+    }
+
     #[test]
     fn mkb_version_returns_none_on_empty() {
         assert_eq!(mkb_version(&[]), None);
@@ -1913,6 +1978,68 @@ mod tests {
         );
     }
 
+    #[test]
+    fn resolve_keys_path2_5_mk_pool_brute_resolves_unkeyed_disc() {
+        // The Dunkirk case: this disc's own hash/VID are NOT in keydb, but its
+        // Media Key IS — filed under a sibling disc that shares its MKB. Path
+        // 2.5 must km_verifies that MK against the MKB and resolve.
+        use super::super::decrypt::aes_ecb_encrypt as enc;
+
+        let km = [0x11u8; 16];
+        let vid = [0x22u8; 16];
+
+        // MKB: 0x10 type/version + 0x86 verify record whose mk_dv decrypts under
+        // km to the AACS verify magic, so km_verifies(mkb, km) == true.
+        let mut vd = [0u8; 16];
+        vd[..8].copy_from_slice(&[0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF]);
+        let mk_dv = enc(&km, &vd);
+        let mut mkb = mkb_record(0x10, &[0, 0, 0, 0x20, 0, 0, 0, 0x4D]);
+        mkb.extend_from_slice(&mkb_record(0x86, &mk_dv));
+        assert!(
+            probe::km_verifies(&mkb, &km),
+            "fixture: km must verify the MKB"
+        );
+
+        // This disc's inf (its hash will NOT be in keydb).
+        let uk_ro = minimal_unit_key_ro();
+
+        // keydb: a SIBLING disc carries our km, keyed by the sibling's own
+        // hash + VID (neither matches THIS disc) — so only the MK-pool brute
+        // (km_verifies) can find it.
+        let mut keydb = KeyDb::empty();
+        keydb.disc_entries.insert(
+            "0xsibling".to_string(),
+            DiscEntry {
+                disc_hash: "0xsibling".to_string(),
+                title: "sibling".to_string(),
+                media_key: Some(km),
+                disc_id: Some([0x99u8; 16]),
+                vuk: None,
+                unit_keys: Vec::new(),
+            },
+        );
+
+        let providers: &[&dyn super::super::KeyProvider] = &[&keydb];
+        let ctx = ResolveContext {
+            unit_key_ro: &uk_ro,
+            content_cert: None,
+            volume_id: &vid,
+            providers,
+            mkb: Some(&mkb),
+        };
+        let resolved = resolve_keys_v1(&ctx)
+            .expect("MK-pool brute (path 2.5) must resolve a disc whose MK is in keydb");
+        assert_eq!(
+            resolved.key_source, 3,
+            "MK-pool brute is the KEYDB-derived class"
+        );
+        assert_eq!(
+            resolved.vuk,
+            Some(derive_vuk(&km, &vid)),
+            "VUK must derive from the verified Km + this disc's VID"
+        );
+    }
+
     #[test]
     fn test_content_cert_parse() {
         // AACS 1.0 cert

src/aacs/mod.rs

@@ -24,15 +24,15 @@ pub mod variants;
 // AES primitives (aes_ecb_encrypt, aes_ecb_decrypt, aes_cbc_decrypt) are pub(crate) in decrypt.rs.
 pub use decrypt::{
     ALIGNED_UNIT_LEN, decrypt_bus, decrypt_unit, decrypt_unit_full, decrypt_unit_try_keys,
-    is_unit_encrypted,
+    is_aacs_scrambled,
 };
 pub use keydb::{DeviceKey, DiscEntry, HostCert, KeyDb};
 pub use keys::probe;
 pub use keys::{
     AacsVersion, ContentCert, ResolveContext, ResolvedKeys, UnitKeyFile, decrypt_unit_key,
     derive_media_key_from_dk, derive_media_key_from_pk, derive_vuk, disc_hash, disc_hash_hex,
-    mkb_version, parse_content_cert, parse_unit_key_ro, read_mkb_from_drive, resolve_keys_v1,
-    resolve_keys_v2, resolve_keys_v21,
+    mkb_content_len, mkb_version, parse_content_cert, parse_unit_key_ro, read_mkb_from_drive,
+    resolve_keys_v1, resolve_keys_v2, resolve_keys_v21,
 };
 pub use provider::KeyProvider;
 pub use variants::{

src/aacs/provider.rs

@@ -48,6 +48,14 @@ pub trait KeyProvider: Send + Sync {
         Vec::new()
     }
 
+    /// Every Media Key this provider holds, regardless of which disc it was
+    /// filed under. An MK is MKB-scoped (shared across a pressing/MKB-family),
+    /// so the resolver can verify each against the disc's MKB (`km_verifies`)
+    /// and resolve a disc whose own hash/VID isn't directly keyed.
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        Vec::new()
+    }
+
     /// AACS host certificates (with their private keys) for drive
     /// authentication. Multiple in case some are revoked.
     fn host_certs(&self) -> Vec<HostCert> {
@@ -85,6 +93,15 @@ impl Providers<'_> {
         self.0.iter().flat_map(|p| p.processing_keys()).collect()
     }
 
+    /// Union of distinct Media Keys across every provider, for the MK-pool
+    /// brute (`km_verifies` against the disc's MKB).
+    pub fn media_keys(&self) -> Vec<[u8; 16]> {
+        let mut v: Vec<[u8; 16]> = self.0.iter().flat_map(|p| p.media_keys()).collect();
+        v.sort_unstable();
+        v.dedup();
+        v
+    }
+
     /// Union — gather host certs from every provider. Not yet wired into
     /// the SCSI handshake (which still reads `KeyDb.host_certs` directly);
     /// kept here so a provider-aware handshake refactor is a drop-in.
@@ -103,3 +120,42 @@ impl Providers<'_> {
         self.0.iter().find_map(|p| p.lookup_disc_by_vid(volume_id))
     }
 }
+
+/// A [`KeyProvider`] backed by a single caller-supplied key's raw material —
+/// the bridge for [`crate::disc::Disc::decrypt_with`].
+///
+/// The application's key source did the lookup and handed in material at one
+/// level (DK / PK / MK / VUK). This exposes exactly that material to the
+/// version-dispatched resolver, which owns ALL derivation — so a source never
+/// derives, and the lib remains the single home for the AACS chain across
+/// 1.0 / 2.0 / 2.1 / 2.x.
+///
+/// Each level fills only its own field; the rest stay empty, so the resolver
+/// naturally runs the matching path (DK→…, PK→…, MK-pool brute, or a
+/// disc-keyed VUK hit). `decrypt_with` already knows the disc, so the
+/// `lookup_disc_by_*` hash/VID arguments are irrelevant — a present
+/// `disc_entry` is returned for any query.
+pub(crate) struct SuppliedKey {
+    pub device_keys: Vec<DeviceKey>,
+    pub processing_keys: Vec<[u8; 16]>,
+    pub media_keys: Vec<[u8; 16]>,
+    pub disc_entry: Option<DiscEntry>,
+}
+
+impl KeyProvider for SuppliedKey {
+    fn device_keys(&self) -> Vec<DeviceKey> {
+        self.device_keys.clone()
+    }
+    fn processing_keys(&self) -> Vec<[u8; 16]> {
+        self.processing_keys.clone()
+    }
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        self.media_keys.clone()
+    }
+    fn lookup_disc_by_hash(&self, _disc_hash: &[u8; 20]) -> Option<DiscEntry> {
+        self.disc_entry.clone()
+    }
+    fn lookup_disc_by_vid(&self, _volume_id: &[u8; 16]) -> Option<DiscEntry> {
+        self.disc_entry.clone()
+    }
+}

src/decrypt.rs

@@ -185,12 +185,13 @@ pub fn decrypt_sectors(
             let chunks: Vec<&mut [u8]> = buf.chunks_mut(unit_len).collect();
             let nunits = chunks.len();
 
-            // Per-unit decrypt closure. The is_unit_encrypted check is
-            // a byte-0 heuristic; on a misfire we snapshot+restore via
-            // the original bytes so non-m2ts (e.g. MPLS/CLPI nav files)
-            // survive. See test `nav_file_unit_survives_decrypt_attempt`.
+            // Per-unit decrypt closure. The is_aacs_scrambled check reads the
+            // raw TS syncs; a non-m2ts unit (e.g. MPLS/CLPI nav file) can look
+            // scrambled and trigger a decrypt attempt, so on a verify miss we
+            // snapshot+restore the original bytes so it survives. See test
+            // `nav_file_unit_survives_decrypt_attempt`.
             let decrypt_one = |chunk: &mut [u8]| {
-                if chunk.len() == unit_len && aacs::is_unit_encrypted(chunk) {
+                if chunk.len() == unit_len && aacs::is_aacs_scrambled(chunk) {
                     let original: Vec<u8> = chunk.to_vec();
                     if !aacs::decrypt_unit_full(chunk, &uk, rdk.as_ref()) {
                         chunk.copy_from_slice(&original);
@@ -232,11 +233,11 @@ pub fn decrypt_sectors(
 mod tests {
     use super::*;
 
-    /// Regression for the 0.18.1 nav-file scramble bug. A non-m2ts unit whose
-    /// first byte has the top 2 bits set (here: the ASCII letter 'M' that
-    /// MPLS files start with, 0x4D = 0b01001101) trips `is_unit_encrypted`,
-    /// 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. A non-m2ts unit (here
+    /// an MPLS file: starts "MPLS", carries no TS syncs) reads as scrambled
+    /// under `is_aacs_scrambled`, gets AES-decrypted with the unit key, fails
+    /// the TS-sync verification, and must be restored to its original bytes —
+    /// not left scrambled.
     #[test]
     fn nav_file_unit_survives_decrypt_attempt() {
         let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];

src/disc/encrypt.rs

@@ -179,54 +179,33 @@ impl Disc {
         session: &mut crate::drive::Drive,
         opts: &ScanOptions,
     ) -> (Option<HandshakeResult>, Option<Error>) {
-        use crate::aacs::{self, KeyDb};
+        use crate::aacs;
 
-        let keydb_path = match opts.resolve_keydb() {
-            Some(p) => p,
-            None => {
+        // Host certs come from the caller's DriveCredentials (e.g. the keydb's
+        // host_certs(), sourced app-side) — the library does not load a keydb.
+        // Absent ⇒ no cert auth: an unlocked / LibreDrive drive already returned
+        // a Volume ID via the OEM path before reaching here, so this is the
+        // locked-drive-without-credentials case.
+        let host_certs: &[aacs::HostCert] = match &opts.credentials {
+            Some(c) if !c.host_certs.is_empty() => &c.host_certs,
+            _ => {
                 tracing::warn!(
                     target: "freemkv::disc",
-                    phase = "handshake_no_keydb",
-                    "no KEYDB found in search paths; handshake skipped"
+                    phase = "handshake_no_credentials",
+                    "no drive credentials supplied; cert handshake skipped"
                 );
                 return (None, None);
             }
         };
-        let keydb = match KeyDb::load(&keydb_path) {
-            Ok(db) => db,
-            Err(e) => {
-                tracing::warn!(
-                    target: "freemkv::disc",
-                    phase = "handshake_keydb_load_failed",
-                    io_error_kind = ?e.kind(),
-                    keydb = %keydb_path.display(),
-                    "KEYDB load failed; handshake skipped"
-                );
-                return (
-                    None,
-                    Some(Error::KeydbLoad {
-                        path: keydb_path.display().to_string(),
-                    }),
-                );
-            }
-        };
 
-        let host_cert_count = keydb.host_certs.len();
+        let host_cert_count = host_certs.len();
         tracing::warn!(
             target: "freemkv::disc",
             phase = "handshake_start",
             host_cert_count,
-            keydb = %keydb_path.display(),
             "handshake starting"
         );
 
-        if host_cert_count == 0 {
-            // No host certs in keydb -> cert auth cannot proceed.
-            // Surface as RawReadUnsupported so the caller knows
-            // neither path is available on this configuration.
-            return (None, Some(Error::AacsRawReadUnsupported));
-        }
-
         // v0.25.7 wedge fix. Pre-0.25.7 this loop fired up to 16 AACS
         // authenticate attempts back-to-back with no pause. Each attempt
         // is 5-10 SCSI REPORT_KEY/SEND_KEY exchanges. On a disc whose
@@ -246,7 +225,7 @@ impl Disc {
         const MAX_CERT_ATTEMPTS: usize = 3;
         const PER_CERT_BACKOFF_MS: u64 = 1000;
         let mut last_err_code: Option<u16> = None;
-        for (idx, hc) in keydb.host_certs.iter().take(MAX_CERT_ATTEMPTS).enumerate() {
+        for (idx, hc) in host_certs.iter().take(MAX_CERT_ATTEMPTS).enumerate() {
             if idx > 0 {
                 std::thread::sleep(std::time::Duration::from_millis(PER_CERT_BACKOFF_MS));
             }
@@ -317,166 +296,15 @@ impl Disc {
         (None, Some(Error::AacsHostCertRejected))
     }
 
-    /// Resolve disc encryption — AACS 1.0, AACS 2.0, CSS, or none.
-    ///
-    /// Reads AACS files from UDF (via SectorSource), resolves keys through
-    /// whatever path works: KEYDB VUK lookup, media key derivation, processing
-    /// keys, device keys. Uses handshake result (volume ID, bus key) if available.
-    pub(super) fn resolve_encryption(
+    /// Build a keys-free AACS state that carries only the Volume ID (+ version
+    /// metadata), for callers that resolve Unit Keys out-of-band and have
+    /// disabled the local keydb. The VID is on-disc content read during the
+    /// handshake; preserving it here lets the out-of-band path use it. No keys
+    /// are present (`unit_keys` empty, `vuk` None), so the disc reports as
+    /// "encrypted, no keys" until the caller re-scans with a resolved Unit Key.
+    pub(super) fn resolve_vid_only(
         udf_fs: &udf::UdfFs,
         reader: &mut dyn SectorSource,
-        keydb_path: &std::path::Path,
-        handshake: Option<&HandshakeResult>,
-    ) -> Result<AacsState> {
-        use crate::aacs::{self, KeyDb};
-        use crate::drm::{DrmContext, DrmProbe, DrmScheme, ResolvedScheme};
-
-        let keydb = KeyDb::load(keydb_path).map_err(|_| Error::KeydbLoad {
-            path: keydb_path.display().to_string(),
-        })?;
-
-        // Read AACS files from disc/image via UDF
-        let uk_ro_data = udf_fs
-            .read_file(reader, "/AACS/Unit_Key_RO.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/DUPLICATE/Unit_Key_RO.inf"))
-            .map_err(|_| Error::AacsNoKeys)?;
-
-        // Log the disc hash so we can confirm whether it's present in KEYDB
-        // when key resolution fails. The disc hash is SHA-1 of the full
-        // Unit_Key_RO.inf file bytes — same value KEYDB.cfg keys VUK entries by.
-        let dh = crate::aacs::disc_hash(&uk_ro_data);
-        let dh_hex = crate::aacs::disc_hash_hex(&dh);
-        tracing::warn!(
-            target: "freemkv::disc",
-            phase = "scan_aacs_disc_hash",
-            disc_hash = %dh_hex,
-            uk_ro_len = uk_ro_data.len(),
-            "disc hash computed (compare with keydb.cfg entries)"
-        );
-
-        let cc_data = udf_fs
-            .read_file(reader, "/AACS/Content000.cer")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/Content001.cer"))
-            .ok();
-
-        let mkb_data = udf_fs
-            .read_file(reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RO.inf"))
-            .ok();
-        let mkb_ver = mkb_data.as_deref().and_then(aacs::mkb_version);
-
-        let mkb_first_64_hex = mkb_data
-            .as_deref()
-            .map(|m| {
-                m.iter()
-                    .take(64)
-                    .map(|b| format!("{b:02x}"))
-                    .collect::<String>()
-            })
-            .unwrap_or_default();
-        tracing::warn!(
-            target: "freemkv::disc",
-            phase = "scan_aacs_mkb_info",
-            mkb_present = mkb_data.is_some(),
-            mkb_len = mkb_data.as_deref().map(|m| m.len()).unwrap_or(0),
-            mkb_version = ?mkb_ver,
-            mkb_first_64 = %mkb_first_64_hex,
-            keydb_disc_count = keydb.disc_entries.len(),
-            keydb_dk_count = keydb.device_keys.len(),
-            keydb_pk_count = keydb.processing_keys.len(),
-            "AACS resolution inputs"
-        );
-
-        // Use handshake volume ID if available, otherwise zeros
-        // (KEYDB VUK lookup by disc hash works without volume ID;
-        // paths 2/3/4 in `resolve_keys` short-circuit on the zero
-        // sentinel and don't waste cycles trying to derive against
-        // garbage input).
-        let volume_id = handshake.map(|h| h.volume_id).unwrap_or([0u8; 16]);
-        let vid_available = volume_id != [0u8; 16];
-        let read_data_key = handshake.and_then(|h| h.read_data_key);
-
-        // Resolve: tries all available paths — KEYDB VUK, media key, processing key, device key.
-        //
-        // Distinguish "we had every input and still missed" from "we
-        // never had VID so the derivation paths couldn't run." The
-        // former points at a stale keydb / unsupported MKB; the
-        // latter points at a failed handshake upstream. Path 1
-        // (disc-hash lookup) ran without VID and missed -> disc isn't
-        // in the keydb. If the caller has a handshake-failure reason
-        // it overrides this in `scan_with`.
-        let miss_error = if vid_available {
-            Error::AacsMkUnavailable
-        } else {
-            Error::AacsVukNotInKeydb
-        };
-
-        // Build a probe + context and let the dispatcher pick V10 / V20
-        // / V21. CSS is impossible here (this function is only called
-        // when /AACS exists), so we don't populate the DVD probe sector
-        // or a CSS context.
-        let probe = DrmProbe {
-            dvd_sample_sector: None,
-            content_cert: cc_data.as_deref(),
-            mkb: mkb_data.as_deref(),
-        };
-        let scheme = match DrmScheme::detect(&probe) {
-            Some(s) => s,
-            None => return Err(miss_error),
-        };
-        let providers: &[&dyn aacs::KeyProvider] = &[&keydb];
-        let aacs_ctx = aacs::ResolveContext {
-            unit_key_ro: &uk_ro_data,
-            content_cert: cc_data.as_deref(),
-            volume_id: &volume_id,
-            providers,
-            mkb: mkb_data.as_deref(),
-        };
-        let mut ctx = DrmContext {
-            aacs: Some(aacs_ctx),
-            css: None,
-        };
-        let resolved = match scheme.load(&mut ctx) {
-            Some(ResolvedScheme::Aacs(r)) => r,
-            // Resolution against /AACS inputs can only produce AACS
-            // keys. Either the dispatcher returned None (load failed)
-            // or — structurally impossible here — a CSS state. Both
-            // surface as the upstream miss-error.
-            _ => return Err(miss_error),
-        };
-
-        Ok(AacsState {
-            version: match resolved.version {
-                aacs::AacsVersion::V10 => 1,
-                aacs::AacsVersion::V20 | aacs::AacsVersion::V21 => 2,
-            },
-            bus_encryption: resolved.bus_encryption,
-            mkb_version: mkb_ver,
-            disc_hash: aacs::disc_hash_hex(&resolved.disc_hash),
-            key_source: match resolved.key_source {
-                1 => KeySource::DeviceKey,
-                2 => KeySource::ProcessingKey,
-                3 => KeySource::KeyDbDerived,
-                4 => KeySource::KeyDb,
-                5 => KeySource::KeyDbUnitKeys,
-                _ => KeySource::KeyDb,
-            },
-            vuk: resolved.vuk,
-            unit_keys: resolved.unit_keys,
-            read_data_key,
-            volume_id,
-        })
-    }
-
-    /// Resolve encryption from a caller-supplied Unit Key (the external key service
-    /// path). No keydb, no derivation: read `Unit_Key_RO.inf` for the disc
-    /// hash + version/bus-encryption flags, then use `unit_key` directly as
-    /// CPS unit 1's decryption key. The handshake (if any) still supplies the
-    /// volume ID and AACS 2.0 read-data key for bus decryption.
-    pub(super) fn resolve_encryption_static(
-        udf_fs: &udf::UdfFs,
-        reader: &mut dyn SectorSource,
-        unit_key: [u8; 16],
         handshake: Option<&HandshakeResult>,
     ) -> Result<AacsState> {
         use crate::aacs;
@@ -500,21 +328,31 @@ impl Disc {
             None if bus_encryption => 2,
             None => 1,
         };
-
-        let mkb_ver = udf_fs
-            .read_file(reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RO.inf"))
+        // MKB_RO/RW are allocated to a fixed ~128 MiB and zero-padded; trim to
+        // the real record length (same as `read_aacs_inputs`). Without this the
+        // MKB stashed on `AacsState` — which `Disc::inputs()` and the device/
+        // processing-key `decrypt_with` derivation consume, and which a key
+        // source ships to an online service — is the full 128 MiB pad, not the
+        // ~few-MB record stream.
+        let mut mkb_bytes = udf_fs
+            .read_file(reader, "/AACS/MKB_RO.inf")
+            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RW.inf"))
             .ok()
-            .as_deref()
-            .and_then(aacs::mkb_version);
+            .unwrap_or_default();
+        let n = aacs::mkb_content_len(&mkb_bytes);
+        if n > 0 && n < mkb_bytes.len() {
+            mkb_bytes.truncate(n);
+        }
+        let mkb_ver = aacs::mkb_version(&mkb_bytes);
 
         tracing::warn!(
             target: "freemkv::disc",
-            phase = "scan_aacs_external_uk",
+            phase = "scan_aacs_vid_only",
             disc_hash = %aacs::disc_hash_hex(&dh),
             version,
             bus_encryption,
-            "using caller-supplied unit key"
+            has_vid = handshake.is_some(),
+            "keydb disabled — carrying VID only, keys resolved out-of-band"
         );
 
         Ok(AacsState {
@@ -522,11 +360,13 @@ impl Disc {
             bus_encryption,
             mkb_version: mkb_ver,
             disc_hash: aacs::disc_hash_hex(&dh),
-            key_source: KeySource::ExternalUk,
+            key_source: KeyOrigin::ExternalUk,
             vuk: None,
-            unit_keys: vec![(1, unit_key)],
+            unit_keys: vec![],
             read_data_key: handshake.and_then(|h| h.read_data_key),
             volume_id: handshake.map(|h| h.volume_id).unwrap_or([0u8; 16]),
+            uk_ro: uk_ro_data,
+            mkb: mkb_bytes,
         })
     }
 }

src/disc/mapfile.rs

@@ -134,7 +134,17 @@ pub struct Mapfile {
     /// `# freemkv-vid:` comment header so it survives to deferred-mux /
     /// resume without altering the ISO payload or breaking ddrescue
     /// data-line parsing. `None` for unencrypted / non-AACS discs.
+    ///
+    /// MUTUALLY EXCLUSIVE with `unit_keys`: a disc whose keys were resolved
+    /// persists the keys (`unit_keys`) and NOT the VID — the keys are the final
+    /// answer, so deferred-mux/resume decrypts directly with no key service. A
+    /// disc that did NOT resolve persists only the VID, the retry-able "still
+    /// need a key" marker (a future mux can re-ask the key service with it).
     vid: Option<[u8; 16]>,
+    /// Decrypted AACS unit keys `(CPS unit, key)`, persisted as `# freemkv-uk:`
+    /// comment headers when the disc was successfully keyed. Mutually exclusive
+    /// with `vid` (see above). Empty when unresolved.
+    unit_keys: Vec<(u32, [u8; 16])>,
 }
 
 impl Mapfile {
@@ -160,6 +170,7 @@ impl Mapfile {
             dirty: false,
             last_flushed: Instant::now(),
             vid: None,
+            unit_keys: Vec::new(),
         };
         // Eager initial persist so a resume can pick this up even if
         // `record()` is never called.
@@ -175,6 +186,7 @@ impl Mapfile {
         let mut saw_current_line = false;
         let mut version = String::from("unknown");
         let mut vid: Option<[u8; 16]> = None;
+        let mut unit_keys: Vec<(u32, [u8; 16])> = Vec::new();
         for line in text.lines() {
             let t = line.trim();
             if t.is_empty() {
@@ -190,6 +202,12 @@ impl Mapfile {
                     // ignored rather than failing the whole load.
                     vid = parse_vid_hex(hex.trim());
                 }
+                if let Some(uk) = rest.strip_prefix("freemkv-uk:") {
+                    // `<cps>:<32hex>`. Best-effort: a malformed line is skipped.
+                    if let Some(entry) = parse_uk_line(uk.trim()) {
+                        unit_keys.push(entry);
+                    }
+                }
                 continue;
             }
             // First non-comment line is the "current" state line (pos status [pass] [pass_time]).
@@ -240,6 +258,7 @@ impl Mapfile {
             dirty: false,
             last_flushed: Instant::now(),
             vid,
+            unit_keys,
         })
     }
 
@@ -345,6 +364,25 @@ impl Mapfile {
         self.vid
     }
 
+    /// Record the disc's decrypted AACS unit keys so they persist in the
+    /// mapfile header (`# freemkv-uk:` lines). The KEYED state: a deferred-mux /
+    /// resume decrypts directly from these with no key-service round-trip.
+    /// Setting keys clears any VID — the mapfile holds keys XOR VID, never both
+    /// (keys are the final answer; VID is only the "still unresolved" marker).
+    pub fn set_unit_keys(&mut self, keys: &[(u32, [u8; 16])]) {
+        self.unit_keys = keys.to_vec();
+        if !self.unit_keys.is_empty() {
+            self.vid = None;
+        }
+        self.dirty = true;
+    }
+
+    /// The disc's decrypted AACS unit keys, if the disc was keyed (parsed from
+    /// `# freemkv-uk:` comments on load). Empty = unresolved (check `vid()`).
+    pub fn unit_keys(&self) -> &[(u32, [u8; 16])] {
+        &self.unit_keys
+    }
+
     pub fn entries(&self) -> &[MapEntry] {
         &self.entries
     }
@@ -421,10 +459,22 @@ impl Mapfile {
             // `#`-prefixed line as a comment, so this round-trips through
             // our `load()` without affecting the `pos size status` data
             // parser. 16 bytes → 32 lowercase hex chars.
-            if let Some(vid) = self.vid {
+            // KEYS XOR VID: a keyed disc persists its unit keys (the final
+            // answer — deferred-mux decrypts directly); an unresolved disc
+            // persists only the VID (the retry marker, so a future mux can
+            // re-ask the key service). Never both.
+            use std::fmt::Write as _;
+            if !self.unit_keys.is_empty() {
+                for (cps, key) in &self.unit_keys {
+                    let mut hex = String::with_capacity(32);
+                    for b in key {
+                        let _ = write!(hex, "{b:02x}");
+                    }
+                    writeln!(w, "# freemkv-uk: {cps}:{hex}")?;
+                }
+            } else if let Some(vid) = self.vid {
                 let mut hex = String::with_capacity(32);
                 for b in vid {
-                    use std::fmt::Write as _;
                     let _ = write!(hex, "{b:02x}");
                 }
                 writeln!(w, "# freemkv-vid: {hex}")?;
@@ -474,6 +524,15 @@ fn parse_vid_hex(s: &str) -> Option<[u8; 16]> {
     Some(out)
 }
 
+/// Parse a `# freemkv-uk:` value `<cps>:<32hex>` into `(cps_unit, key)`. Returns
+/// `None` on any malformation so a corrupt line is ignored, never fatal.
+fn parse_uk_line(s: &str) -> Option<(u32, [u8; 16])> {
+    let (cps, hex) = s.split_once(':')?;
+    let cps: u32 = cps.trim().parse().ok()?;
+    let key = parse_vid_hex(hex.trim())?; // 32-hex → [u8; 16], shared parser
+    Some((cps, key))
+}
+
 fn parse_hex(s: &str) -> io::Result<u64> {
     let s = s.strip_prefix("0x").unwrap_or(s);
     u64::from_str_radix(s, 16).map_err(|_| {
@@ -640,6 +699,65 @@ mod tests {
         let _ = std::fs::remove_file(&p);
     }
 
+    #[test]
+    fn unit_keys_round_trip_and_are_mutually_exclusive_with_vid() {
+        let p = tmpfile("uk_round_trips");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(0, 500, SectorStatus::Finished).unwrap();
+        // Set a VID first, then unit keys: keys must WIN and clear the VID.
+        mf.set_vid([0xAA; 16]);
+        let keys: Vec<(u32, [u8; 16])> = vec![
+            (
+                0,
+                [
+                    0x57, 0x60, 0xcc, 0x83, 0x3d, 0x86, 0x0e, 0x48, 0x92, 0x1f, 0x88, 0x16, 0xe1,
+                    0x35, 0x9b, 0xad,
+                ],
+            ),
+            (1, [0x11; 16]),
+        ];
+        mf.set_unit_keys(&keys);
+        assert_eq!(
+            mf.vid(),
+            None,
+            "set_unit_keys must clear vid (keys XOR vid)"
+        );
+        mf.flush().unwrap();
+
+        let text = std::fs::read_to_string(&p).unwrap();
+        assert!(
+            text.contains("# freemkv-uk: 0:5760cc833d860e48921f8816e1359bad"),
+            "uk comment format mismatch: {text}"
+        );
+        assert!(
+            text.contains("# freemkv-uk: 1:11111111111111111111111111111111"),
+            "second uk missing: {text}"
+        );
+        assert!(
+            !text.contains("# freemkv-vid:"),
+            "VID must NOT be written when keys are present: {text}"
+        );
+
+        // load() recovers the unit keys (and no VID).
+        let loaded = Mapfile::load(&p).unwrap();
+        assert_eq!(loaded.unit_keys(), keys.as_slice());
+        assert_eq!(loaded.vid(), None);
+        assert_eq!(loaded.entries(), mf.entries());
+
+        // VID-only path (no keys) still persists the VID as the retry marker.
+        let p2 = tmpfile("uk_vid_only");
+        let _ = std::fs::remove_file(&p2);
+        let mut mf2 = Mapfile::create(&p2, 1000, "test").unwrap();
+        mf2.set_vid([0xBB; 16]);
+        mf2.flush().unwrap();
+        let loaded2 = Mapfile::load(&p2).unwrap();
+        assert_eq!(loaded2.vid(), Some([0xBB; 16]));
+        assert!(loaded2.unit_keys().is_empty());
+        let _ = std::fs::remove_file(&p);
+        let _ = std::fs::remove_file(&p2);
+    }
+
     #[test]
     fn vid_round_trips_and_data_lines_unaffected() {
         let p = tmpfile("vid_round_trips");

src/error.rs

@@ -78,6 +78,7 @@ pub const E_AACS_MK_UNAVAILABLE: u16 = 7018;
 pub const E_AACS_VUK_NOT_IN_KEYDB: u16 = 7019;
 pub const E_DRIVE_PROFILE_MISSING: u16 = 7020;
 pub const E_VID_CDB_UNAVAILABLE: u16 = 7021;
+pub const E_NO_DISC_KEY: u16 = 7022;
 
 // Keydb (8xxx)
 pub const E_KEYDB_CONNECT: u16 = 8000;
@@ -253,6 +254,16 @@ pub enum Error {
     /// template (older profile blob, or a drive class without an OEM
     /// VID path).
     VidCdbUnavailable,
+    /// The disc is AACS-encrypted and decryption was requested, but key
+    /// resolution produced no usable key for it — so muxing would emit
+    /// undecryptable garbage. Distinct from [`Error::KeydbLoad`] (no keydb
+    /// file at all): a keydb may be present but lack an entry for this disc.
+    /// `disc_hash` is the 40-hex SHA1 of `Unit_Key_RO.inf` (no `0x` prefix)
+    /// so the application can name the disc; empty if the hash wasn't
+    /// captured at scan.
+    NoDiscKey {
+        disc_hash: String,
+    },
 
     // Keydb (8xxx)
     KeydbConnect {
@@ -345,6 +356,7 @@ impl Error {
             Error::AacsVukNotInKeydb => E_AACS_VUK_NOT_IN_KEYDB,
             Error::DriveProfileMissing => E_DRIVE_PROFILE_MISSING,
             Error::VidCdbUnavailable => E_VID_CDB_UNAVAILABLE,
+            Error::NoDiscKey { .. } => E_NO_DISC_KEY,
             Error::KeydbConnect { .. } => E_KEYDB_CONNECT,
             Error::KeydbHttp { .. } => E_KEYDB_HTTP,
             Error::KeydbInvalid => E_KEYDB_INVALID,
@@ -471,6 +483,7 @@ impl std::fmt::Display for Error {
             Error::StreamUrlMissingPort { addr } => write!(f, "E{}: {}", self.code(), addr),
             Error::PesFrameTooLarge { size } => write!(f, "E{}: {}", self.code(), size),
             Error::IsoTooLarge { path } => write!(f, "E{}: {}", self.code(), path),
+            Error::NoDiscKey { disc_hash } => write!(f, "E{}: {}", self.code(), disc_hash),
             _ => write!(f, "E{}", self.code()),
         }
     }

src/keysource.rs

@@ -0,0 +1,83 @@
+//! Key sources — the lookup layer that hands libfreemkv a [`Key`].
+//!
+//! libfreemkv performs NO key lookup. An application resolves a key for a disc
+//! through one or more [`KeySource`]s, each a dumb adapter over a backing store
+//! (a keydb file, a key server, the mapfile cache): given the disc's
+//! [`DiscInputs`] it returns the raw [`Key`] at whatever level it holds. The
+//! library then derives down and decrypts via `Disc::decrypt_with`.
+//!
+//! Source implementations are published in the companion `freemkv-keysources`
+//! crate — keeping all key *policy* (which store, which order, online vs local)
+//! out of the library while all key *mechanism* (the AACS derivation chain)
+//! stays in it.
+
+use crate::disc::Key;
+
+/// 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.
+#[derive(Debug, Clone)]
+pub struct DiscInputs {
+    /// SHA-1 of `Unit_Key_RO.inf`, `0x`-prefixed hex. The value a keydb keys
+    /// its per-disc entries by, and a key server identifies the disc with.
+    pub disc_hash: String,
+    /// Volume ID (16 bytes). `[0u8; 16]` when no authenticated handshake ran
+    /// (e.g. an ISO/mapfile flow), which disables VID-keyed lookups.
+    pub volume_id: [u8; 16],
+    /// Raw MKB bytes. Empty when not captured.
+    pub mkb: Vec<u8>,
+    /// Raw `Unit_Key_RO.inf` bytes. Empty when not captured.
+    pub unit_key_ro: Vec<u8>,
+    /// Encrypted on-disc content sample units (each a 6144-byte aligned unit),
+    /// for sources that validate a key server-side against real ciphertext
+    /// (e.g. an online key service). Empty for sources that don't need them
+    /// (a local keydb). Populated by the application — reading content requires
+    /// the disc reader, which the library's scan does not retain — so
+    /// [`crate::Disc::inputs`] leaves it empty for the caller to fill.
+    pub samples: Vec<Vec<u8>>,
+}
+
+/// A key source: a stateful provider that hands a disc's candidate [`Key`]s out
+/// **one at a time**, in whatever order it judges best for its backing store.
+///
+/// Dumb by contract — a source queries its store and yields the raw material it
+/// holds at whatever level it has (device / processing / media / volume / unit).
+/// It performs NO AACS derivation and NO validation: `Disc::decrypt_with`
+/// derives down AND validates against real ciphertext, returning `Err` for a key
+/// that does not decrypt this disc. That keeps every derivation step and the one
+/// validation gate in the library, across AACS 1.0 / 2.0 / 2.1 / 2.x.
+///
+/// The source is the one that knows how many candidates it has and in what order
+/// to try them — a keydb holds a per-disc UK *and* VUK *and* a device-key pool,
+/// so it hands them out cheapest/most-specific first (UK ▸ VK ▸ MK ▸ DK) and
+/// reports exhaustion when its list runs out; an online key service or a mapfile
+/// cache hold exactly one. The caller drives the loop: `next_key` →
+/// `Disc::decrypt_with` → on `Err`, ask again → until a key decrypts or the
+/// source returns `None` (a genuine "no key for this disc"). Compose several
+/// sources, in the caller's chosen order, with [`crate`]'s `MultiSource`.
+pub trait KeySource {
+    /// Hand the NEXT candidate key for this disc, or `None` once this source is
+    /// exhausted. Stateful: the source tracks what it already handed out this
+    /// session, so asking again after a rejected key yields the next candidate
+    /// (or `None`) — it never re-offers a key or re-hits a one-shot backend (an
+    /// online service is asked at most once). A source failure (I/O, network,
+    /// parse) surfaces as `None` — there is simply nothing more to try.
+    fn next_key(&mut self, inputs: &DiscInputs) -> Option<Key>;
+
+    /// Whether this source needs [`DiscInputs::samples`] populated (encrypted
+    /// content samples) — true for a source that validates against ciphertext
+    /// server-side, false for one that keys purely on disc identity. The caller
+    /// reads samples (an extra disc read) only when some source needs them.
+    fn needs_samples(&self) -> bool {
+        false
+    }
+
+    /// Whether this source FAILED (I/O, network, parse) rather than simply
+    /// having no key. Checked after exhaustion so the caller can tell a genuine
+    /// "no key for this disc" apart from "the key service was unreachable". A
+    /// store that treats absence as not-an-error (a missing keydb / mapfile)
+    /// leaves this `false`.
+    fn errored(&self) -> bool {
+        false
+    }
+}

src/labels/mod.rs

@@ -207,14 +207,41 @@ pub(crate) fn apply_labels(labels: &[StreamLabel], titles: &mut [DiscTitle]) {
                         // Structured fields — callers translate purpose to UI text.
                         a.purpose = label.purpose;
 
+                        // Codec descriptor: trust the parser's `codec_hint` ONLY
+                        // when it's consistent with the stream's actual codec — it
+                        // may legitimately be richer (e.g. "Dolby Atmos" on a TrueHD
+                        // stream, which the raw spec codec can't express). If the
+                        // hint CONTRADICTS the stream (a mis-bound / shuffled label,
+                        // e.g. "AC-3 2.0" on a TrueHD track, or "TrueHD" on a DD+
+                        // track), discard it and derive the descriptor from the
+                        // stream itself — that's correct per-stream and can never be
+                        // shuffled. An empty hint is left for `fill_defaults`.
+                        let codec_desc = if label.codec_hint.is_empty() {
+                            // No codec hint — leave for fill_defaults.
+                            String::new()
+                        } else if !codec_hint_consistent(&label.codec_hint, &a.codec) {
+                            // Hint contradicts the stream (mis-bound / shuffled):
+                            // derive from the stream itself.
+                            generate_audio_label(&a.codec, &a.channels, a.secondary)
+                        } else if codec_hint_adds_detail(&label.codec_hint) {
+                            // Consistent AND richer than the spec codec can express
+                            // (e.g. "Dolby Atmos", "DTS:X") — keep the parser's hint.
+                            label.codec_hint.clone()
+                        } else {
+                            // Consistent but a plain codec/channel restatement —
+                            // normalize to the stream's own marketing descriptor so
+                            // styling is uniform across tracks.
+                            generate_audio_label(&a.codec, &a.channels, a.secondary)
+                        };
+
                         // a.label only carries codec/variant info. NEVER any
                         // English purpose text — the CLI handles that via i18n.
                         let mut parts = Vec::new();
                         if !label.variant.is_empty() {
                             parts.push(format!("({})", label.variant));
                         }
-                        if !label.codec_hint.is_empty() {
-                            parts.push(label.codec_hint.clone());
+                        if !codec_desc.is_empty() {
+                            parts.push(codec_desc);
                         }
                         if !parts.is_empty() {
                             a.label = parts.join(" ");
@@ -322,7 +349,70 @@ fn generate_video_label(
     parts.join(" ")
 }
 
-fn generate_audio_label(
+/// Does the parser's `codec_hint` name a codec consistent with the stream's
+/// actual `codec`? [`apply_labels`] uses this to keep richer-but-consistent
+/// hints (e.g. "Dolby Atmos" on a TrueHD stream — Atmos is a TrueHD extension
+/// the raw spec codec can't express) while rejecting mis-bound ones (e.g.
+/// "AC-3 2.0" on a TrueHD stream, the shuffled-label bug). Matching is by codec
+/// FAMILY parsed out of the hint string. "Atmos" with no carrier named is
+/// treated as compatible with its lossless carriers (TrueHD / E-AC-3). A hint
+/// naming no recognizable codec family (pure editorial, e.g. "Commentary") is
+/// consistent — it isn't asserting a codec.
+fn codec_hint_consistent(hint: &str, codec: &crate::disc::Codec) -> bool {
+    use crate::disc::Codec;
+    let h = hint.to_ascii_lowercase();
+
+    let says_truehd = h.contains("truehd") || h.contains("true hd");
+    let says_ddp = h.contains("ac-3+")
+        || h.contains("ac3+")
+        || h.contains("e-ac-3")
+        || h.contains("eac-3")
+        || h.contains("eac3")
+        || h.contains("digital plus")
+        || h.contains("dd+");
+    let says_ac3 =
+        !says_ddp && (h.contains("ac-3") || h.contains("ac3") || h.contains("dolby digital"));
+    let says_dts_ma = h.contains("master audio") || h.contains("hd ma");
+    let says_dts_hr = h.contains("high resolution") || h.contains("hd hr");
+    let says_dts = !says_dts_ma && !says_dts_hr && h.contains("dts");
+    let says_lpcm = h.contains("lpcm") || h.contains("pcm");
+    let says_atmos = h.contains("atmos");
+
+    let names_family =
+        says_truehd || says_ddp || says_ac3 || says_dts_ma || says_dts_hr || says_dts || says_lpcm;
+
+    // Pure-editorial hint (no codec family named) isn't asserting a codec →
+    // consistent. "Atmos" alone implies a lossless carrier (TrueHD or DD+).
+    if !names_family {
+        return if says_atmos {
+            matches!(codec, Codec::TrueHd | Codec::Ac3Plus)
+        } else {
+            true
+        };
+    }
+
+    match codec {
+        Codec::TrueHd => says_truehd || says_atmos,
+        Codec::Ac3Plus => says_ddp || says_atmos,
+        Codec::Ac3 => says_ac3,
+        Codec::DtsHdMa => says_dts_ma,
+        Codec::DtsHdHr => says_dts_hr,
+        Codec::Dts => says_dts,
+        Codec::Lpcm => says_lpcm,
+        // Unknown / other stream codec — don't second-guess the parser's hint.
+        _ => true,
+    }
+}
+
+/// Does the hint carry object-audio detail the spec codec can't express
+/// (Atmos / DTS:X)? Such hints are kept verbatim; plain codec/channel hints are
+/// normalized to the stream's own descriptor for uniform styling across tracks.
+fn codec_hint_adds_detail(hint: &str) -> bool {
+    let h = hint.to_ascii_lowercase();
+    h.contains("atmos") || h.contains("dts:x") || h.contains("dts-x") || h.contains("dtsx")
+}
+
+pub(crate) fn generate_audio_label(
     codec: &crate::disc::Codec,
     channels: &crate::disc::AudioChannels,
     _secondary: bool,
@@ -1182,6 +1272,94 @@ mod apply_tests {
         }
     }
 
+    #[test]
+    fn apply_rejects_mismatched_codec_hint_and_uses_stream_codec() {
+        // Paddington case: a TrueHD+Atmos main track the parser mislabeled
+        // "AC-3 2.0" (a compat-core hint bound to the wrong stream). The hint
+        // contradicts the stream's real codec → discard it, use the stream's own.
+        let mut titles = vec![title_with(vec![audio(
+            0x1100,
+            Codec::TrueHd,
+            AudioChannels::Surround71,
+            "eng",
+        )])];
+        let labels = vec![audio_label(1, "eng", "AC-3 2.0", "")];
+        apply_labels(&labels, &mut titles);
+        if let Stream::Audio(a) = &titles[0].streams[0] {
+            assert_eq!(a.label, "Dolby TrueHD 7.1");
+        } else {
+            panic!("expected audio stream");
+        }
+    }
+
+    #[test]
+    fn apply_unshuffles_cross_labeled_streams() {
+        // Wicked case: hints fully cross-bound — a TrueHD stream wears "AC-3 5.1"
+        // and a DD+ stream wears "TrueHD 5.1". Each is corrected from its own
+        // stream codec, eliminating the shuffle.
+        let mut titles = vec![title_with(vec![
+            audio(0x1100, Codec::TrueHd, AudioChannels::Surround51, "eng"),
+            audio(0x1101, Codec::Ac3Plus, AudioChannels::Surround51, "spa"),
+        ])];
+        let labels = vec![
+            audio_label(1, "eng", "AC-3 5.1", ""),
+            audio_label(2, "spa", "TrueHD 5.1", ""),
+        ];
+        apply_labels(&labels, &mut titles);
+        let got: Vec<String> = titles[0]
+            .streams
+            .iter()
+            .filter_map(|s| {
+                if let Stream::Audio(a) = s {
+                    Some(a.label.clone())
+                } else {
+                    None
+                }
+            })
+            .collect();
+        assert_eq!(got, vec!["Dolby TrueHD 5.1", "Dolby Digital Plus 5.1"]);
+    }
+
+    #[test]
+    fn apply_keeps_consistent_richer_atmos_hint() {
+        // A DD+ Atmos stream legitimately labeled "Dolby Atmos" — the hint is
+        // richer than the spec codec yet consistent with it, so it's kept.
+        let mut titles = vec![title_with(vec![audio(
+            0x1100,
+            Codec::Ac3Plus,
+            AudioChannels::Surround51,
+            "eng",
+        )])];
+        let labels = vec![audio_label(1, "eng", "Dolby Atmos", "")];
+        apply_labels(&labels, &mut titles);
+        if let Stream::Audio(a) = &titles[0].streams[0] {
+            assert_eq!(a.label, "Dolby Atmos");
+        } else {
+            panic!("expected audio stream");
+        }
+    }
+
+    #[test]
+    fn apply_normalizes_plain_consistent_hint_to_marketing() {
+        // Wicked's French track: a DD+ stream whose hint "AC-3+ 5.1" is correct
+        // but short-form. A sibling DD+ track that fell back uses the marketing
+        // form — keeping the short form here would read inconsistently, so a
+        // plain (non-richer) consistent hint is normalized to the stream's own.
+        let mut titles = vec![title_with(vec![audio(
+            0x1100,
+            Codec::Ac3Plus,
+            AudioChannels::Surround51,
+            "fra",
+        )])];
+        let labels = vec![audio_label(1, "fra", "AC-3+ 5.1", "")];
+        apply_labels(&labels, &mut titles);
+        if let Stream::Audio(a) = &titles[0].streams[0] {
+            assert_eq!(a.label, "Dolby Digital Plus 5.1");
+        } else {
+            panic!("expected audio stream");
+        }
+    }
+
     #[test]
     fn apply_sets_purpose_on_audio_commentary() {
         let mut titles = vec![title_with(vec![audio(
@@ -1342,9 +1520,11 @@ mod apply_tests {
         if let Stream::Audio(a) = &titles[0].streams[1] {
             assert_eq!(a.label, "Dolby Atmos");
         }
-        // Audio #2 (4th stream overall)
+        // Audio #2 (4th stream overall). The plain "Dolby Digital" hint is
+        // consistent with the AC-3 stream but carries no channel info, so it's
+        // normalized to the stream's own uniform descriptor.
         if let Stream::Audio(a) = &titles[0].streams[3] {
-            assert_eq!(a.label, "Dolby Digital");
+            assert_eq!(a.label, "Dolby Digital 2.0");
         }
         // Subtitle #1
         if let Stream::Subtitle(s) = &titles[0].streams[2] {

src/lib.rs

@@ -85,6 +85,7 @@ pub(crate) mod identity;
 pub(crate) mod ifo;
 pub mod io;
 pub mod keydb;
+pub mod keysource;
 pub mod labels;
 pub(crate) mod mpls;
 pub mod mux;
@@ -170,10 +171,11 @@ pub use decrypt::{DecryptKeys, decrypt_sectors, decrypt_threads, set_decrypt_thr
 // prefix at the crate root to keep both addressable.
 pub use disc::{
     AacsState, AudioChannels, AudioStream, Clip, Codec, ColorSpace, ContentFormat, DamageSeverity,
-    Disc, DiscFormat, DiscId, DiscTitle, Extent, FrameRate, HdrFormat, KeySource, LabelPurpose,
-    LabelQualifier, PatchOptions, PatchOutcome, Resolution, SampleRate, ScanOptions, Stream,
-    SubtitleStream, SweepOptions, VideoStream, classify_damage,
+    Disc, DiscFormat, DiscId, DiscTitle, DriveCredentials, Extent, FrameRate, HdrFormat, Key,
+    KeyOrigin, LabelPurpose, LabelQualifier, PatchOptions, PatchOutcome, Resolution, SampleRate,
+    ScanOptions, Stream, SubtitleStream, SweepOptions, VideoStream, classify_damage,
 };
+pub use keysource::{DiscInputs, KeySource};
 
 // ─── Streams ────────────────────────────────────────────────────────────────
 //

src/mpls.rs

@@ -301,9 +301,21 @@ fn parse_stream_entry(item: &[u8], pos: usize, stream_type: u8) -> Option<(Strea
         return None;
     }
 
-    // PID from stream entry (type 0x01 = PlayItem stream: PID at bytes 2-3)
-    let pid = if item[pos + 1] == 0x01 && pos + 4 <= item.len() {
-        u16::from_be_bytes([item[pos + 2], item[pos + 3]])
+    // PID location depends on the stream-entry type (BD spec stream_entry()):
+    //   type 1 (stream in the PlayItem's Clip):          PID at +2
+    //   type 2 (stream in a SubPath SubClip):            +subpath_id(1)+subclip_id(1) → PID at +4
+    //   type 3 / 4 (SubPath clip; type 4 = Dolby Vision  +subpath_id(1)              → PID at +3
+    //              enhancement layer, e.g. PID 0x1015):
+    // Previously only type 1 was handled, so the DV EL (type 4) and any
+    // sub-path stream fell through to PID 0 and were dropped by the mux.
+    let pid_off = match item[pos + 1] {
+        0x01 => 2,
+        0x02 => 4,
+        0x03 | 0x04 => 3,
+        _ => 0,
+    };
+    let pid = if pid_off != 0 && pos + pid_off + 2 <= item.len() {
+        u16::from_be_bytes([item[pos + pid_off], item[pos + pid_off + 1]])
     } else {
         0
     };

src/mux/codec/ac3.rs

@@ -6,6 +6,14 @@
 
 use super::{CodecParser, Frame, PesPacket, pts_to_ns};
 
+/// Hard cap on the carry-over buffer. An AC-3/E-AC-3 frame is at most 8192
+/// bytes (the `frame_size > 8192` reject below), so a single straddling frame
+/// plus a little slack never needs more than this. If the buffer grows past
+/// the cap without yielding a frame (pathological / never-syncing input) we
+/// drop it and resync rather than accumulate one PES worth of data per call
+/// for the whole title.
+const MAX_AC3_BUF: usize = 64 * 1024;
+
 pub struct Ac3Parser {
     /// Leftover bytes from previous PES (incomplete frame at end).
     buf: Vec<u8>,
@@ -81,19 +89,38 @@ impl CodecParser for Ac3Parser {
             pos = start + frame_size;
         }
 
-        // Keep unconsumed data for next call
-        // `pos` points to the start of unconsumed data (either a partial sync or leftover)
+        // Keep unconsumed data for the next call. `pos` is the start of the
+        // unconsumed region: either a partial frame that straddles this PES
+        // boundary — which, by construction, begins at a syncword (every byte
+        // before `pos` was emitted as a frame or skipped as pre-sync junk) — or
+        // trailing bytes too short to size/complete a frame. Carry from `pos`,
+        // NOT from the next syncword: discarding bytes between `pos` and the
+        // next sync would drop the partial frame we are deliberately keeping
+        // across the boundary.
         let keep_from = if pos < data.len() {
-            // Find the last sync word position in the unconsumed region
-            find_ac3_sync(&data[pos..])
-                .map(|o| pos + o)
-                .unwrap_or(data.len())
+            // A syncword at/after `pos` marks the carry-over start (anything
+            // before it is junk with no sync). With no full sync, retain the
+            // whole tail — including a lone trailing 0x0B that may be the first
+            // half of a syncword split across the PES boundary.
+            match find_ac3_sync(&data[pos..]) {
+                Some(o) => pos + o,
+                None if data.last() == Some(&0x0B) => data.len() - 1,
+                None => data.len(),
+            }
         } else {
             data.len()
         };
 
         if keep_from < data.len() {
-            self.buf = data[keep_from..].to_vec();
+            let tail = &data[keep_from..];
+            if tail.len() > MAX_AC3_BUF {
+                // No frame could be parsed out of a buffer this large — this is
+                // not valid AC-3 here. Drop it and resync on the next PES rather
+                // than grow without bound on pathological input.
+                self.buf.clear();
+            } else {
+                self.buf = tail.to_vec();
+            }
         } else {
             self.buf.clear();
         }
@@ -276,6 +303,91 @@ mod tests {
         assert_eq!(frames[0].data.len(), 160);
     }
 
+    #[test]
+    fn sync_word_split_across_pes_is_preserved() {
+        // A frame whose 0x0B77 syncword straddles the PES boundary (0x0B at the
+        // tail of PES 1, 0x77 at the head of PES 2) must still be emitted whole.
+        // Previously the lone trailing 0x0B was dropped and the frame lost.
+        let mut parser = Ac3Parser::new();
+        let frame_data = make_ac3_frame(0, 2); // 160 bytes, starts with 0x0B 0x77
+
+        // PES 1: a complete frame, then a single 0x0B (first half of next sync).
+        let mut pes1_data = frame_data.clone();
+        pes1_data.push(0x0B);
+        let pes1 = PesPacket {
+            pid: 0,
+            pts: Some(90000),
+            dts: None,
+            data: pes1_data,
+        };
+        let frames1 = parser.parse(&pes1);
+        assert_eq!(frames1.len(), 1, "first complete frame emitted");
+
+        // PES 2: 0x77 (second half of sync) + rest of the second frame.
+        let mut pes2_data = vec![0x77];
+        pes2_data.extend_from_slice(&frame_data[2..]);
+        let pes2 = PesPacket {
+            pid: 0,
+            pts: Some(93000),
+            dts: None,
+            data: pes2_data,
+        };
+        let frames2 = parser.parse(&pes2);
+        assert_eq!(frames2.len(), 1, "split-sync frame must be recovered");
+        assert_eq!(frames2[0].data.len(), 160);
+    }
+
+    #[test]
+    fn buffer_stays_bounded_across_many_garbage_pes() {
+        // Finding 14: the carry-over buffer must never grow without bound. Feed
+        // many large PES packets that contain no usable frame and assert the
+        // retained buffer stays tiny — carry-from-`pos` drops all pre-sync junk,
+        // and a never-completing frame is bounded by the 8192-byte frame cap and
+        // the MAX_AC3_BUF resync guard.
+        let mut parser = Ac3Parser::new();
+        for i in 0..256 {
+            // Vary the trailing byte so we also exercise the lone-0x0B retain.
+            let mut data = vec![0x55u8; 8192];
+            if i % 3 == 0 {
+                *data.last_mut().unwrap() = 0x0B;
+            }
+            let pes = PesPacket {
+                pid: 0,
+                pts: None,
+                dts: None,
+                data,
+            };
+            let frames = parser.parse(&pes);
+            assert!(frames.is_empty());
+            assert!(
+                parser.buf.len() <= MAX_AC3_BUF,
+                "buffer grew to {} (cap {})",
+                parser.buf.len(),
+                MAX_AC3_BUF
+            );
+        }
+        // After all that garbage the retained tail is at most a single partial
+        // syncword byte — never an accumulation of whole PES packets.
+        assert!(parser.buf.len() <= 1, "retained {} bytes", parser.buf.len());
+    }
+
+    #[test]
+    fn split_sync_below_cap_is_still_retained() {
+        // The cap must not break the normal split-sync straddle: a short tail
+        // ending in 0x0B (well under the cap) is retained so the next PES can
+        // complete the syncword.
+        let mut parser = Ac3Parser::new();
+        let data = vec![0x00, 0x00, 0x0B];
+        let pes = PesPacket {
+            pid: 0,
+            pts: None,
+            dts: None,
+            data,
+        };
+        assert!(parser.parse(&pes).is_empty());
+        assert_eq!(parser.buf, vec![0x0B], "lone trailing 0x0B retained");
+    }
+
     #[test]
     fn ac3_frame_size_table() {
         // fscod=0 (48kHz), frmsizecod=0: 64 words = 128 bytes

src/mux/codec/dts.rs

@@ -8,10 +8,20 @@
 use super::{CodecParser, Frame, PesPacket, pts_to_ns};
 
 const DTS_CORE_SYNC: [u8; 4] = [0x7F, 0xFE, 0x80, 0x01];
+/// DTS-HD extension substream syncword. The parser delimits an access unit by
+/// the next CORE sync (so every extension between two cores is captured), and
+/// never needs to locate or size the extension itself — so this is referenced
+/// only by the tests that synthesize extension substreams.
+#[cfg(test)]
 const DTS_HD_EXT_SYNC: [u8; 4] = [0x64, 0x58, 0x20, 0x25];
 
 pub struct DtsParser {
     buf: Vec<u8>,
+    /// PTS of the access unit currently being assembled in `buf` (the unit
+    /// starting at the first buffered core sync). Captured when that core
+    /// frame's PES first arrived; the trailing extension-substream PES
+    /// packets carry their own (later) PTS which must NOT override it.
+    pending_pts: i64,
 }
 
 impl Default for DtsParser {
@@ -24,10 +34,29 @@ impl DtsParser {
     pub fn new() -> Self {
         Self {
             buf: Vec::with_capacity(32768),
+            pending_pts: 0,
         }
     }
 }
 
+/// Hard cap on a buffered access unit (core + all its extension substreams).
+/// A DTS-HD MA frame is at most a few tens of KB; if the buffer grows past
+/// this without a clean boundary we resync rather than stall or balloon.
+const MAX_AU_BYTES: usize = 65536;
+
+/// Minimum plausible DTS core frame size. The core header alone is ~10-14
+/// bytes; a decoded `core_size` below this means we matched a false/corrupt
+/// core sync (the 14-bit `fsize` field decoded to a tiny value) rather than a
+/// real frame, so we resync instead of emitting a junk access unit.
+const MIN_CORE_FRAME_BYTES: usize = 10;
+
+/// Sentinel for "no valid PTS base captured yet". Real PTS-in-ns values are
+/// non-negative (derived from the unsigned 90 kHz PES timestamp), so a negative
+/// value can never collide with a genuine timestamp. Used to mark the PTS base
+/// invalid after a forced flush so the next PES sets it regardless of buffer
+/// state.
+const PTS_UNSET: i64 = -1;
+
 impl CodecParser for DtsParser {
     fn parse(&mut self, pes: &PesPacket) -> Vec<Frame> {
         if pes.data.is_empty() {
@@ -35,80 +64,162 @@ impl CodecParser for DtsParser {
         }
         let pts_ns = pes.pts.map(pts_to_ns).unwrap_or(0);
 
+        // On Blu-ray, a DTS-HD MA/HRA access unit is a DTS core frame
+        // (sync 0x7FFE8001) followed by one or more DTS extension substreams
+        // (sync 0x64582025). The m2ts demuxer hands those out as SEPARATE PES
+        // packets on the same PID — the core in one PES, then the extension
+        // substreams in following PES packets (with their own, later PTS). The
+        // lossless audio lives entirely in the extension substreams, so an
+        // access unit is only complete once all of its trailing extensions
+        // have been buffered. We assemble across PES boundaries here: an access
+        // unit runs from its core sync up to (but not including) the NEXT core
+        // sync. Emitting on the core boundary keeps the core + every following
+        // extension substream together (the lossless data), instead of the
+        // old per-PES emit that dropped the extension PES packets and
+        // downgraded the track to lossy DTS core (the Dunkirk / Fight Club
+        // bug). The PTS is the core frame's PTS, captured when the unit began.
+        // Capture the access unit's PTS base on a fresh buffer, or whenever a
+        // prior forced (safety-valve) flush left it invalidated — in the
+        // forced case the bytes still in `buf` are not a real core frame, so
+        // the first PES to arrive after the flush carries the correct base.
+        if self.buf.is_empty() || self.pending_pts == PTS_UNSET {
+            self.pending_pts = pts_ns;
+        }
         self.buf.extend_from_slice(&pes.data);
 
-        let data = &self.buf;
         let mut frames = Vec::new();
-        let mut pos = 0;
 
-        while pos < data.len() {
-            // Find DTS core sync
-            let start = match find_sync(&data[pos..], &DTS_CORE_SYNC) {
-                Some(offset) => pos + offset,
-                None => break,
+        loop {
+            // Resync to the first core sync; drop any leading junk.
+            let Some(start) = find_sync(&self.buf, &DTS_CORE_SYNC) else {
+                // No core sync at all yet — keep at most a 3-byte tail so a
+                // sync split across PES packets can still be found next time.
+                if self.buf.len() > 3 {
+                    let tail = self.buf.len() - 3;
+                    self.buf.drain(..tail);
+                }
+                break;
             };
-
-            // Need at least 10 bytes for core header to get frame size
-            if start + 10 > data.len() {
-                break;
-            }
-
-            let core_size = dts_core_frame_size(&data[start..]);
-            if core_size == 0 || core_size > 32768 {
-                pos = start + 4;
-                continue;
-            }
-
-            if start + core_size > data.len() {
-                // Incomplete core frame
-                break;
-            }
-
-            // Check for DTS-HD extension after core
-            let mut total_size = core_size;
-            if start + core_size + 4 <= data.len() {
-                if let Some(0) = find_sync(
-                    &data[start + core_size..start + core_size + 4],
-                    &DTS_HD_EXT_SYNC,
-                ) {
-                    let ext = &data[start + core_size..];
-                    if ext.len() >= 9 {
-                        let ext_size = dts_hd_ext_frame_size(ext);
-                        if start + core_size + ext_size <= data.len() {
-                            total_size = core_size + ext_size;
-                        }
-                        // If ext incomplete, just emit core
-                    }
+            if start > 0 {
+                self.buf.drain(..start);
+                if find_sync(&self.buf, &DTS_CORE_SYNC) != Some(0) {
+                    // Shouldn't happen, but never loop forever.
+                    break;
                 }
             }
 
+            // Need the core header to size the core frame.
+            if self.buf.len() < 10 {
+                break;
+            }
+            let core_size = dts_core_frame_size(&self.buf);
+            // `dts_core_frame_size` returns a 14-bit `fsize + 1`, so it is
+            // always in [1, 16384]; the bare `== 0` / `> MAX_AU_BYTES` checks
+            // can never fire. A real DTS core header is at least ~10-14 bytes,
+            // so any decoded size below that came from a false/corrupt sync.
+            // Reject it (drain the 4 syncword bytes and resync) instead of
+            // letting a tiny bogus size close the current access unit at a junk
+            // boundary and drop the trailing extension substreams. The
+            // `> MAX_AU_BYTES` upper bound is kept as a harmless guard.
+            if !(MIN_CORE_FRAME_BYTES..=MAX_AU_BYTES).contains(&core_size) {
+                // Bogus core sync — skip past it and resync.
+                self.buf.drain(..4);
+                continue;
+            }
+            if self.buf.len() < core_size {
+                break; // core frame not fully buffered yet — wait
+            }
+
+            // The access unit ends at the next *valid* core sync. The search
+            // begins after this core's syncword so we don't re-match it.
+            // Anything between the core and that next sync is this unit's
+            // extension substream(s) — which can themselves contain byte
+            // sequences matching the core syncword, so a raw `find_sync` match
+            // is not enough: a candidate is only a real boundary if its decoded
+            // core size is plausible. `next_core_boundary` skips bogus matches.
+            //
+            // `forced` distinguishes a real next-core boundary from a forced
+            // safety-valve flush. On a forced flush the access unit was NOT
+            // closed by a new core sync, so the bytes following it are not a
+            // fresh core frame and the current PES's PTS (which on a forced
+            // flush is an extension-substream PES, carrying its own later
+            // timestamp) must NOT become the next unit's PTS base.
+            let mut forced = false;
+            let au_end = match next_core_boundary(&self.buf, core_size) {
+                NextCore::Found(end) => end,
+                NextCore::NeedMore => break, // candidate sync needs more header
+                NextCore::None => {
+                    // No next core sync buffered yet. The trailing extension
+                    // substream PES packets may still be arriving, so WAIT for
+                    // them rather than emit a core-only (lossy) frame — unless
+                    // the buffer has grown unreasonably large, in which case
+                    // emit what we have to guarantee forward progress.
+                    if self.buf.len() <= MAX_AU_BYTES {
+                        break;
+                    }
+                    forced = true;
+                    self.buf.len()
+                }
+            };
+
+            let au: Vec<u8> = self.buf[..au_end].to_vec();
             frames.push(Frame {
-                pts_ns,
+                pts_ns: self.pending_pts,
                 keyframe: true,
-                data: data[start..start + total_size].to_vec(),
+                data: au,
                 duration_ns: None,
             });
-            pos = start + total_size;
-        }
-
-        // Keep unconsumed data
-        let keep_from = if pos < data.len() {
-            find_sync(&data[pos..], &DTS_CORE_SYNC)
-                .map(|o| pos + o)
-                .unwrap_or(data.len())
-        } else {
-            data.len()
-        };
-
-        if keep_from < data.len() {
-            self.buf = data[keep_from..].to_vec();
-        } else {
-            self.buf.clear();
+            self.buf.drain(..au_end);
+            if forced {
+                // Safety-valve flush: the next access unit's real core PES has
+                // not arrived. Invalidate the PTS so the next PES sets it
+                // regardless of buffer state, rather than inheriting this
+                // (non-core) PES's timestamp.
+                self.pending_pts = PTS_UNSET;
+            } else {
+                // Real boundary: the next access unit (now at buf start) begins
+                // at a core sync that arrived inside this PES, so this PES's PTS
+                // is the correct base for it.
+                self.pending_pts = pts_ns;
+            }
         }
 
         frames
     }
 
+    fn flush(&mut self) -> Vec<Frame> {
+        // End of stream: emit the final access unit still buffered (the last
+        // core + its extension substreams, which had no following core sync to
+        // close it during streaming). Require a complete core frame; drop a
+        // bare partial sync tail.
+        if find_sync(&self.buf, &DTS_CORE_SYNC) != Some(0) || self.buf.len() < 10 {
+            self.buf.clear();
+            return Vec::new();
+        }
+        let core_size = dts_core_frame_size(&self.buf);
+        // `dts_core_frame_size` returns a 14-bit `fsize + 1` (never 0), so the
+        // old `== 0` check was dead; reject a sub-minimum core like `parse()`.
+        if core_size < MIN_CORE_FRAME_BYTES || self.buf.len() < core_size {
+            self.buf.clear();
+            return Vec::new();
+        }
+        let au = std::mem::take(&mut self.buf);
+        // A non-empty buffer here means a PES arrived after any prior forced
+        // flush (which fully drains `buf`), so `pending_pts` was reset to that
+        // PES's real PTS. Clamp the sentinel to 0 defensively all the same.
+        let pts_ns = if self.pending_pts == PTS_UNSET {
+            0
+        } else {
+            self.pending_pts
+        };
+        vec![Frame {
+            pts_ns,
+            keyframe: true,
+            data: au,
+            duration_ns: None,
+        }]
+    }
+
     fn codec_private(&self) -> Option<Vec<u8>> {
         None
     }
@@ -121,6 +232,40 @@ fn find_sync(data: &[u8], pattern: &[u8; 4]) -> Option<usize> {
     (0..=data.len() - 4).find(|&i| data[i..i + 4] == *pattern)
 }
 
+/// Result of scanning for the next valid core sync that closes an access unit.
+enum NextCore {
+    /// A valid next core sync was found; the access unit ends at this offset.
+    Found(usize),
+    /// A candidate core sync was found but its header isn't fully buffered yet,
+    /// so its validity can't be decided — wait for more data.
+    NeedMore,
+    /// No (further) core sync found in the buffer.
+    None,
+}
+
+/// Find the next *valid* core sync after the current core frame, to delimit the
+/// access unit. Extension-substream payload can contain byte sequences that
+/// match the core syncword, so each candidate is validated by decoding its
+/// core size: a match whose decoded size is implausible (< MIN_CORE_FRAME_BYTES
+/// or > MAX_AU_BYTES) is a false sync and is skipped, continuing the search.
+fn next_core_boundary(buf: &[u8], core_size: usize) -> NextCore {
+    let mut from = core_size;
+    while let Some(rel) = find_sync(&buf[from..], &DTS_CORE_SYNC) {
+        let pos = from + rel;
+        // Need the candidate's core header to judge it.
+        if buf.len() - pos < 10 {
+            return NextCore::NeedMore;
+        }
+        let sz = dts_core_frame_size(&buf[pos..]);
+        if (MIN_CORE_FRAME_BYTES..=MAX_AU_BYTES).contains(&sz) {
+            return NextCore::Found(pos);
+        }
+        // False sync inside extension payload — skip it and keep searching.
+        from = pos + 4;
+    }
+    NextCore::None
+}
+
 /// DTS core frame size from header bits.
 /// fsize is at bits 46-59 (14 bits) of the header: bytes 5-7.
 fn dts_core_frame_size(data: &[u8]) -> usize {
@@ -134,20 +279,6 @@ fn dts_core_frame_size(data: &[u8]) -> usize {
     fsize + 1
 }
 
-/// DTS-HD extension frame size from extension header.
-pub fn dts_hd_ext_frame_size(ext: &[u8]) -> usize {
-    if ext.len() < 9 {
-        return 0;
-    }
-    let raw =
-        ((ext[6] as usize & 0x1F) << 11) | ((ext[7] as usize) << 3) | ((ext[8] as usize) >> 5);
-    raw + 1
-}
-
-pub fn find_dts_hd_ext_sync(data: &[u8]) -> Option<usize> {
-    find_sync(data, &DTS_HD_EXT_SYNC)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -181,12 +312,16 @@ mod tests {
 
     #[test]
     fn parse_single_frame() {
+        // A single core frame with no following core sync is the LAST access
+        // unit — held during streaming (can't know an extension won't follow),
+        // then drained on flush() at EOF.
         let mut parser = DtsParser::new();
         let frame = make_dts_core(512);
         let pes = make_pes(frame, Some(90000));
-        let frames = parser.parse(&pes);
-        assert_eq!(frames.len(), 1);
-        assert_eq!(frames[0].data.len(), 512);
+        assert!(parser.parse(&pes).is_empty());
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 512);
     }
 
     #[test]
@@ -199,9 +334,206 @@ mod tests {
         assert!(parser.parse(&pes1).is_empty());
 
         let pes2 = make_pes(frame[mid..].to_vec(), Some(93000));
-        let frames = parser.parse(&pes2);
-        assert_eq!(frames.len(), 1);
-        assert_eq!(frames[0].data.len(), 512);
+        assert!(parser.parse(&pes2).is_empty());
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 512);
+    }
+
+    #[test]
+    fn two_cores_back_to_back_emit_first_on_boundary() {
+        // The first complete unit is emitted as soon as the next core sync is
+        // seen; the second is held until flush.
+        let mut parser = DtsParser::new();
+        let mut stream = make_dts_core(512);
+        stream.extend_from_slice(&make_dts_core(640));
+        let f = parser.parse(&make_pes(stream, Some(90000)));
+        assert_eq!(f.len(), 1);
+        assert_eq!(f[0].data.len(), 512);
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 640);
+    }
+
+    /// Build a minimal DTS-HD extension substream of `size` bytes (just the
+    /// sync + zero-padding). The parser delimits extensions by the next CORE
+    /// sync, not by the extension's own size header, so a valid header isn't
+    /// required — only that the bytes carry no spurious core sync.
+    fn make_dts_ext(size: usize) -> Vec<u8> {
+        let mut e = vec![0u8; size];
+        e[0..4].copy_from_slice(&DTS_HD_EXT_SYNC);
+        e
+    }
+
+    #[test]
+    fn keeps_dts_hd_extension_in_separate_pes_packets() {
+        // The real Blu-ray layout (ground-truthed on Dunkirk): the DTS core
+        // arrives in one PES, then its DTS-HD MA extension substreams arrive
+        // in SEPARATE following PES packets on the same PID. The parser must
+        // stitch core + all trailing extensions into one access unit — not
+        // emit a core-only (lossy) frame and drop the extension PES packets
+        // (the Dunkirk / Fight Club lossy-core bug).
+        let mut parser = DtsParser::new();
+
+        // Frame 1: core (512) + two extension substreams (256 + 200).
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_core(512), Some(90000)))
+                .is_empty(),
+            "core alone: must wait for any following extension"
+        );
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_ext(256), Some(91000)))
+                .is_empty(),
+            "first extension PES: still waiting for the unit to close"
+        );
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_ext(200), Some(91500)))
+                .is_empty(),
+            "second extension PES: unit still not closed (no next core yet)"
+        );
+
+        // Frame 2's core PES arrives — that closes frame 1. The emitted unit
+        // must be core + BOTH extensions (lossless preserved), and keep the
+        // core's PTS, not the extension PES timestamps.
+        let f = parser.parse(&make_pes(make_dts_core(512), Some(93000)));
+        assert_eq!(f.len(), 1);
+        assert_eq!(
+            f[0].data.len(),
+            512 + 256 + 200,
+            "frame must include core + every extension substream"
+        );
+
+        // EOF drains frame 2.
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 512);
+    }
+
+    #[test]
+    fn extension_split_across_pes_is_preserved() {
+        // An extension substream straddling a PES boundary must still be fully
+        // attached to its core.
+        let mut parser = DtsParser::new();
+        let ext = make_dts_ext(300);
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_core(512), Some(90000)))
+                .is_empty()
+        );
+        assert!(
+            parser
+                .parse(&make_pes(ext[..150].to_vec(), Some(91000)))
+                .is_empty()
+        );
+        assert!(
+            parser
+                .parse(&make_pes(ext[150..].to_vec(), Some(91000)))
+                .is_empty()
+        );
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 512 + 300);
+    }
+
+    /// Build 4 bytes that look like a DTS core sync but whose `fsize` field
+    /// decodes to a tiny `core_size` (< MIN_CORE_FRAME_BYTES). With the
+    /// dead-code guards this passed validation and could close an access unit
+    /// at a junk boundary; with the fix it must be drained and resynced past.
+    fn bogus_tiny_core_sync() -> Vec<u8> {
+        // Core sync + zero header bytes. fsize = 0 → core_size = 1 (< 10).
+        let mut v = vec![0u8; 10];
+        v[0..4].copy_from_slice(&DTS_CORE_SYNC);
+        // bytes 5,6,7 left zero → fsize = 0 → dts_core_frame_size = 1.
+        assert_eq!(dts_core_frame_size(&v), 1);
+        v
+    }
+
+    #[test]
+    fn bogus_tiny_core_sync_does_not_split_or_drop_real_au() {
+        // A real core frame followed by an extension substream that happens to
+        // contain a false core sync whose fsize decodes tiny. The bogus sync
+        // must NOT close the real access unit early (dropping the rest of the
+        // extension) nor emit a junk few-byte frame — it must be skipped, and
+        // the whole core + extension preserved as one access unit.
+        let mut parser = DtsParser::new();
+
+        // Frame 1: core(512) + an extension whose body embeds a bogus tiny
+        // core sync midway through.
+        let mut ext = make_dts_ext(256);
+        // Embed the bogus core sync inside the extension body (offset 64).
+        let bogus = bogus_tiny_core_sync();
+        ext[64..64 + bogus.len()].copy_from_slice(&bogus);
+
+        let mut frame1 = make_dts_core(512);
+        frame1.extend_from_slice(&ext);
+
+        // No next REAL core yet → frame 1 held.
+        assert!(
+            parser.parse(&make_pes(frame1, Some(90000))).is_empty(),
+            "bogus tiny core sync must not close the AU; wait for a real core"
+        );
+
+        // Frame 2's real core arrives — closes frame 1.
+        let f = parser.parse(&make_pes(make_dts_core(640), Some(93000)));
+        assert_eq!(f.len(), 1, "exactly one real access unit emitted");
+        assert_eq!(
+            f[0].data.len(),
+            512 + 256,
+            "AU must be the full core + extension, not split at the bogus sync"
+        );
+        assert_eq!(f[0].pts_ns, pts_to_ns(90000), "AU keeps the core's PTS");
+
+        let tail = parser.flush();
+        assert_eq!(tail.len(), 1);
+        assert_eq!(tail[0].data.len(), 640);
+    }
+
+    #[test]
+    fn forced_emit_does_not_corrupt_next_au_pts() {
+        // When the buffer exceeds MAX_AU_BYTES with no next core sync, the
+        // parser force-emits for forward progress. The current PES at that
+        // point is an extension-substream PES (later PTS). The forced path must
+        // NOT make that extension PTS the base of the NEXT access unit.
+        let mut parser = DtsParser::new();
+
+        // Core PES at the real PTS, then a giant extension (no next core) that
+        // pushes the buffer past MAX_AU_BYTES, forcing an emit.
+        let core_pts = 90000i64;
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_core(512), Some(core_pts)))
+                .is_empty()
+        );
+        let ext_pts = 120000i64; // later extension-PES timestamp
+        let big_ext = make_dts_ext(MAX_AU_BYTES + 1024);
+        let f = parser.parse(&make_pes(big_ext, Some(ext_pts)));
+        assert_eq!(f.len(), 1, "oversized buffer force-emits one AU");
+        assert_eq!(
+            f[0].pts_ns,
+            pts_to_ns(core_pts),
+            "forced AU keeps the core PTS"
+        );
+
+        // The next REAL core PES arrives with its own PTS. Its AU must inherit
+        // THIS core's PTS, not the prior extension PES timestamp.
+        let next_core_pts = 150000i64;
+        assert!(
+            parser
+                .parse(&make_pes(make_dts_core(512), Some(next_core_pts)))
+                .is_empty()
+        );
+        let next_next_pts = 180000i64;
+        let f2 = parser.parse(&make_pes(make_dts_core(512), Some(next_next_pts)));
+        assert_eq!(f2.len(), 1);
+        assert_eq!(
+            f2[0].pts_ns,
+            pts_to_ns(next_core_pts),
+            "AU after a forced emit must use the next core's PTS, not the \
+             stale extension PTS"
+        );
     }
 
     #[test]

src/mux/codec/h264.rs

@@ -38,8 +38,11 @@ impl CodecParser for H264Parser {
             return Vec::new();
         }
 
-        // Use DTS when available (monotonic for B-frame content), fall back to PTS
-        let pts_ns = pes.dts.or(pes.pts).map(pts_to_ns).unwrap_or(0);
+        // MKV block timecodes are PRESENTATION timestamps; frames are stored in
+        // decode order and the player reorders by timecode. Use PTS, not DTS —
+        // DTS presents B-frames in decode order (visible judder) and breaks
+        // PTS-based seeking. Fall back to DTS only if PTS is absent.
+        let pts_ns = pes.pts.or(pes.dts).map(pts_to_ns).unwrap_or(0);
 
         // Scan NAL units for SPS, PPS, and IDR detection
         let mut keyframe = false;
@@ -451,10 +454,10 @@ mod tests {
         assert!(frames.is_empty());
     }
 
-    // --- DTS preferred over PTS when present ---
+    // --- PTS (presentation) used for the MKV block timecode, not DTS ---
 
     #[test]
-    fn dts_preferred_over_pts() {
+    fn pts_preferred_over_dts() {
         let mut parser = H264Parser::new();
 
         let mut data = Vec::new();
@@ -464,13 +467,13 @@ mod tests {
 
         let pes = PesPacket {
             pid: 0x1011,
-            pts: Some(180000), // 2 seconds
-            dts: Some(90000),  // 1 second
+            pts: Some(180000), // 2 seconds (presentation)
+            dts: Some(90000),  // 1 second (decode)
             data,
         };
         let frames = parser.parse(&pes);
         assert_eq!(frames.len(), 1);
-        // DTS should be used, not PTS
-        assert_eq!(frames[0].pts_ns, 1_000_000_000);
+        // PTS must be used — MKV block timecodes are presentation timestamps.
+        assert_eq!(frames[0].pts_ns, 2_000_000_000);
     }
 }

src/mux/codec/hevc.rs

@@ -48,8 +48,13 @@ impl CodecParser for HevcParser {
             return Vec::new();
         }
 
-        // Use DTS when available (monotonic for B-frame content), fall back to PTS
-        let pts_ns = pes.dts.or(pes.pts).map(pts_to_ns).unwrap_or(0);
+        // MKV block timecodes are PRESENTATION timestamps; frames are stored
+        // in decode order (the order they arrive here) and the player reorders
+        // for display by timecode. So use PTS, not DTS — using DTS makes the
+        // block timecode monotonic in storage order, which presents B-frames in
+        // decode order (visible judder / wrong frames) and breaks PTS-based
+        // seeking. Fall back to DTS only if PTS is somehow absent.
+        let pts_ns = pes.pts.or(pes.dts).map(pts_to_ns).unwrap_or(0);
         let data = &pes.data;
         let mut keyframe = false;
         // Pre-size: output is ~input bytes with a few 4-byte length
@@ -62,6 +67,11 @@ impl CodecParser for HevcParser {
         while let Some(sc_pos) = find_start_code(data, pos) {
             if let Some(nal_start) = skip_start_code(data, sc_pos) {
                 let next = find_start_code(data, nal_start).unwrap_or(data.len());
+                // Strip the leading zeros of the following start code. For a
+                // conforming bitstream this is lossless: rbsp_trailing_bits()
+                // sets a stop-one bit, so the final byte of any RBSP is never
+                // 0x00 — the only trailing zeros here belong to the next
+                // 00 00 (00) 01 prefix.
                 let mut end = next;
                 while end > nal_start && data[end - 1] == 0x00 {
                     end -= 1;
@@ -124,34 +134,41 @@ impl CodecParser for HevcParser {
         // Full HEVCDecoderConfigurationRecord is complex — for now, concatenate
         let mut record = Vec::new();
 
-        // Minimal HEVCDecoderConfigurationRecord header
+        // Minimal HEVCDecoderConfigurationRecord header.
+        //
+        // The stored SPS NAL is [2-byte HEVC NAL header][SPS RBSP...].
+        // The RBSP begins at sps[2]; profile_tier_level() begins one byte
+        // later, after sps_video_parameter_set_id u(4) +
+        // sps_max_sub_layers_minus1 u(3) + sps_temporal_id_nesting_flag u(1)
+        // (= sps[2], a full byte). So the profile_tier_level fields are:
+        //   sps[3]      general_profile_space u(2)+tier u(1)+profile_idc u(5)
+        //   sps[4..8]   general_profile_compatibility_flags u(32)
+        //   sps[8..14]  general_constraint_indicator_flags 48 bits
+        //   sps[14]     general_level_idc u(8)
+        // (Byte-aligned read; emulation-prevention bytes within the first
+        // 15 SPS bytes are not handled — extremely rare and matches the
+        // pre-existing simplification.)
         record.push(1); // configurationVersion
-        // General profile space, tier flag, profile IDC from SPS
-        if sps.len() > 3 {
-            record.push(sps[1]); // general_profile_space + general_tier_flag + general_profile_idc
+        // general_profile_space + general_tier_flag + general_profile_idc
+        record.push(if sps.len() > 3 { sps[3] } else { 0 });
+        // general_profile_compatibility_flags (4 bytes) — SPS bytes 4..8
+        if sps.len() > 7 {
+            record.extend_from_slice(&sps[4..8]);
         } else {
-            record.push(0);
+            let avail = sps.len().saturating_sub(4).min(4);
+            record.extend_from_slice(&sps[sps.len().min(4)..sps.len().min(8)]);
+            record.extend_from_slice(&vec![0u8; 4 - avail]);
         }
-        // general_profile_compatibility_flags (4 bytes) — from SPS bytes 2..6
-        if sps.len() > 5 {
-            record.extend_from_slice(&sps[2..6]);
+        // general_constraint_indicator_flags (6 bytes) — SPS bytes 8..14
+        if sps.len() > 13 {
+            record.extend_from_slice(&sps[8..14]);
         } else {
-            record.extend_from_slice(&[0, 0, 0, 0]);
+            let avail = sps.len().saturating_sub(8).min(6);
+            record.extend_from_slice(&sps[sps.len().min(8)..sps.len().min(14)]);
+            record.extend_from_slice(&vec![0u8; 6 - avail]);
         }
-        // general_constraint_indicator_flags (6 bytes) — from SPS bytes 6..12
-        if sps.len() > 11 {
-            record.extend_from_slice(&sps[6..12]);
-        } else {
-            let avail = sps.len().saturating_sub(6).min(6);
-            if avail > 0 {
-                record.extend_from_slice(&sps[6..6 + avail]);
-                record.extend_from_slice(&vec![0u8; 6 - avail]);
-            } else {
-                record.extend_from_slice(&[0, 0, 0, 0, 0, 0]);
-            }
-        }
-        // general_level_idc
-        record.push(if sps.len() > 12 { sps[12] } else { 0 });
+        // general_level_idc — SPS byte 14
+        record.push(if sps.len() > 14 { sps[14] } else { 0 });
         // min_spatial_segmentation_idc (4 + 12 bits)
         record.extend_from_slice(&[0xF0, 0x00]);
         // parallelismType (6 + 2 bits)
@@ -268,6 +285,103 @@ mod tests {
         );
     }
 
+    #[test]
+    fn hvcc_profile_tier_level_offsets() {
+        // The hvcC fixed header must read profile_tier_level from the SPS
+        // RBSP, not from the NAL header. Stored SPS = [2-byte NAL header][RBSP].
+        // RBSP layout (byte-aligned):
+        //   sps[2]      sps_vps_id/max_sub_layers/temporal_nesting
+        //   sps[3]      general_profile_space+tier+profile_idc
+        //   sps[4..8]   general_profile_compatibility_flags
+        //   sps[8..14]  general_constraint_indicator_flags
+        //   sps[14]     general_level_idc
+        let mut parser = HevcParser::new();
+
+        // Distinct, recognizable values for each field.
+        let sps_rbsp: [u8; 13] = [
+            0xAB, // sps[2]  (vps_id etc.) — must NOT leak into profile fields
+            0x21, // sps[3]  profile byte: space=0, tier=0, profile_idc=1
+            0x60, 0x00, 0x00, 0x00, // sps[4..8] compat flags
+            0x90, 0x00, 0x00, 0x00, 0x00, 0x00, // sps[8..14] constraint flags
+            0x7B, // sps[14] level_idc = 123
+        ];
+
+        let mut data = Vec::new();
+        // VPS
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(32));
+        data.extend_from_slice(&[0xAA, 0xBB, 0xCC]);
+        // SPS — 2-byte header + the structured RBSP above
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(33));
+        data.extend_from_slice(&sps_rbsp);
+        // PPS
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(34));
+        data.extend_from_slice(&[0xDD, 0xEE]);
+
+        let pes = make_pes(data, Some(0));
+        parser.parse(&pes);
+
+        let cp = parser
+            .codec_private()
+            .expect("codec_private should be Some");
+
+        // record[0] = configurationVersion
+        assert_eq!(cp[0], 1, "configurationVersion");
+        // record[1] = general_profile_space+tier+profile_idc  <- sps[3]
+        assert_eq!(
+            cp[1], 0x21,
+            "profile byte must come from SPS RBSP, not NAL hdr"
+        );
+        // record[2..6] = general_profile_compatibility_flags  <- sps[4..8]
+        assert_eq!(&cp[2..6], &[0x60, 0x00, 0x00, 0x00], "compatibility flags");
+        // record[6..12] = general_constraint_indicator_flags  <- sps[8..14]
+        assert_eq!(
+            &cp[6..12],
+            &[0x90, 0x00, 0x00, 0x00, 0x00, 0x00],
+            "constraint flags"
+        );
+        // record[12] = general_level_idc  <- sps[14]
+        assert_eq!(cp[12], 0x7B, "level_idc must come from sps[14]");
+    }
+
+    #[test]
+    fn hvcc_short_sps_does_not_panic() {
+        // A truncated SPS must still produce a fixed header without panicking
+        // and zero-pad the missing profile/level bytes.
+        let mut parser = HevcParser::new();
+
+        let mut data = Vec::new();
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(32));
+        data.extend_from_slice(&[0xAA]);
+        // SPS with only 3 RBSP bytes (stored len = 5): forces every guard path
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(33));
+        data.extend_from_slice(&[0x11, 0x22, 0x33]);
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(34));
+        data.extend_from_slice(&[0xDD]);
+
+        let pes = make_pes(data, Some(0));
+        parser.parse(&pes);
+
+        let cp = parser
+            .codec_private()
+            .expect("codec_private should be Some");
+        // sps stored = [hdr0, hdr1, 0x11, 0x22, 0x33], len 5.
+        // profile byte = sps[3] = 0x22; everything past sps[4]=0x33 is absent.
+        assert_eq!(cp[0], 1);
+        assert_eq!(cp[1], 0x22, "profile byte = sps[3]");
+        // compat flags: only sps[4]=0x33 present, rest zero-padded.
+        assert_eq!(&cp[2..6], &[0x33, 0x00, 0x00, 0x00]);
+        // constraint flags: none present, all zero.
+        assert_eq!(&cp[6..12], &[0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);
+        // level_idc: absent, zero.
+        assert_eq!(cp[12], 0x00);
+    }
+
     #[test]
     fn codec_private_none_before_params() {
         let parser = HevcParser::new();
@@ -474,6 +588,33 @@ mod tests {
         assert_eq!(frames[0].pts_ns, 1_000_000_000);
     }
 
+    // --- PTS (presentation), not DTS, drives the MKV block timecode ---
+    // Regression for B-frame presentation: writing DTS as the block timecode
+    // presents frames in decode order (visible judder) and breaks seeking.
+
+    #[test]
+    fn pts_preferred_over_dts() {
+        let mut parser = HevcParser::new();
+
+        let mut data = Vec::new();
+        data.extend_from_slice(&[0x00, 0x00, 0x01]);
+        data.extend_from_slice(&hevc_nal_header(1)); // TRAIL_R slice
+        data.extend_from_slice(&[0x10, 0x20]);
+
+        let pes = PesPacket {
+            pid: 0x1011,
+            pts: Some(180000), // 2 s (presentation)
+            dts: Some(90000),  // 1 s (decode)
+            data,
+        };
+        let frames = parser.parse(&pes);
+        assert_eq!(frames.len(), 1);
+        assert_eq!(
+            frames[0].pts_ns, 2_000_000_000,
+            "block timecode must be PTS"
+        );
+    }
+
     // --- Dolby Vision enhancement layer ---
 
     #[test]

src/mux/codec/lpcm.rs

@@ -1,24 +1,39 @@
 //! BD/DVD LPCM (Linear PCM) audio parser.
 //!
-//! BD LPCM PES packets have a 4-byte header:
+//! BD LPCM PES packets (TS stream type 0x80) carry a 4-byte header on the
+//! elementary-stream payload:
 //!   Bytes 0-1: audio frame number
 //!   Byte 2:    reserved
 //!   Byte 3:    quantization (bits 7-6), sample rate (bits 5-4), channel assignment (bits 3-0)
+//! This header is part of the ES payload, so the BD parser must strip it.
 //!
-//! DVD LPCM (private stream 1, sub-stream 0xA0-0xA7) has a 3-byte header.
+//! DVD LPCM lives in private stream 1 (sub-stream 0xA0-0xA7). Its 7-byte
+//! private sub-header (sub_id + frames + first-access-unit-ptr(2) + emphasis +
+//! quant/freq + channels) is stripped by `PsDemuxer` while demuxing the
+//! Program Stream. By the time a DVD LPCM `PesPacket` reaches this parser its
+//! `data` is already raw PCM, so the parser must NOT strip any further bytes —
+//! doing so drops one sample pair per PES and drifts the audio.
 //!
-//! The raw PCM data follows the header. No framing is needed — each PES
-//! payload minus its header is one complete audio frame.
+//! The two origins are distinguished by the `strip_header` flag: BD = strip,
+//! DVD = leave intact. The raw PCM data is otherwise one complete audio frame
+//! per PES; no framing is needed.
 //!
 //! For MKV: codec ID "A_PCM/INT/BIG" (BD) or "A_PCM/INT/LIT" (DVD).
 //! All frames are keyframes (uncompressed audio).
 
 use super::{CodecParser, Frame, PesPacket, pts_to_ns};
 
-/// BD LPCM header size in bytes.
+/// BD LPCM header size in bytes (present on BD-TS LPCM, absent on DVD-PS LPCM
+/// because `PsDemuxer` already stripped the private sub-header).
 const BD_LPCM_HEADER_SIZE: usize = 4;
 
-pub struct LpcmParser;
+pub struct LpcmParser {
+    /// Whether to strip the 4-byte BD LPCM header from each PES payload.
+    ///
+    /// `true` for BD-TS LPCM (header still present), `false` for DVD-PS LPCM
+    /// (header already removed by `PsDemuxer`).
+    strip_header: bool,
+}
 
 impl Default for LpcmParser {
     fn default() -> Self {
@@ -27,23 +42,36 @@ impl Default for LpcmParser {
 }
 
 impl LpcmParser {
+    /// BD-TS LPCM parser: strips the 4-byte BD LPCM header from each PES.
     pub fn new() -> Self {
-        Self
+        Self { strip_header: true }
+    }
+
+    /// DVD-PS LPCM parser: `PsDemuxer` already stripped the private sub-header,
+    /// so the payload is raw PCM and no further bytes are removed.
+    pub fn new_dvd() -> Self {
+        Self {
+            strip_header: false,
+        }
     }
 }
 
 impl CodecParser for LpcmParser {
     fn parse(&mut self, pes: &PesPacket) -> Vec<Frame> {
-        // Skip the BD LPCM header (4 bytes).
+        let offset = if self.strip_header {
+            BD_LPCM_HEADER_SIZE
+        } else {
+            0
+        };
         // If the PES is too short to contain header + data, return nothing.
-        if pes.data.len() <= BD_LPCM_HEADER_SIZE {
+        if pes.data.len() <= offset {
             return Vec::new();
         }
         let pts_ns = pes.pts.map(pts_to_ns).unwrap_or(0);
         vec![Frame {
             pts_ns,
             keyframe: true,
-            data: pes.data[BD_LPCM_HEADER_SIZE..].to_vec(),
+            data: pes.data[offset..].to_vec(),
             duration_ns: None,
         }]
     }
@@ -84,6 +112,56 @@ mod tests {
         assert_eq!(frames[0].pts_ns, 1_000_000_000); // 90000 ticks = 1 second
     }
 
+    #[test]
+    fn bd_lpcm_strips_4_byte_header() {
+        // BD-TS LPCM: the 4-byte BD header is part of the ES payload and must
+        // be stripped, leaving exactly the PCM bytes.
+        let mut parser = LpcmParser::new();
+        let header = vec![0x00, 0x01, 0x00, 0b1001_0001];
+        let pcm = vec![0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88];
+        let mut data = header;
+        data.extend_from_slice(&pcm);
+
+        let frames = parser.parse(&make_pes(data, Some(0)));
+        assert_eq!(frames.len(), 1);
+        assert_eq!(frames[0].data, pcm, "BD must strip exactly 4 header bytes");
+    }
+
+    #[test]
+    fn dvd_lpcm_preserves_all_pcm_bytes() {
+        // DVD-PS LPCM: PsDemuxer already removed the 7-byte private sub-header,
+        // so the payload handed to this parser is raw PCM. The DVD parser must
+        // NOT strip any further bytes (the round-2 audit Finding 3 bug: the BD
+        // 4-byte strip dropped one sample pair per PES, drifting the audio).
+        let mut parser = LpcmParser::new_dvd();
+        let pcm = vec![0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE, 0x01, 0x02];
+        let frames = parser.parse(&make_pes(pcm.clone(), Some(90000)));
+
+        assert_eq!(frames.len(), 1);
+        assert_eq!(
+            frames[0].data, pcm,
+            "DVD must preserve every PCM byte — no second strip"
+        );
+        assert_eq!(frames[0].pts_ns, 1_000_000_000);
+    }
+
+    #[test]
+    fn dvd_lpcm_emits_short_payload_bd_would_drop() {
+        // A 4-byte raw-PCM DVD payload (1 sample pair at 16-bit stereo). The BD
+        // parser drops <= 4 bytes as "header only"; the DVD parser must emit it.
+        let mut bd = LpcmParser::new();
+        let mut dvd = LpcmParser::new_dvd();
+        let pcm = vec![0xAA, 0xBB, 0xCC, 0xDD];
+
+        assert!(
+            bd.parse(&make_pes(pcm.clone(), Some(0))).is_empty(),
+            "BD treats 4 bytes as header-only"
+        );
+        let frames = dvd.parse(&make_pes(pcm.clone(), Some(0)));
+        assert_eq!(frames.len(), 1);
+        assert_eq!(frames[0].data, pcm);
+    }
+
     #[test]
     fn always_keyframe() {
         let mut parser = LpcmParser::new();

src/mux/codec/mod.rs

@@ -52,6 +52,18 @@ pub trait CodecParser: Send {
     /// Some (TrueHD): multiple access units per PES.
     fn parse(&mut self, pes: &PesPacket) -> Vec<Frame>;
 
+    /// Drain any access unit still buffered after the last PES.
+    ///
+    /// Parsers that buffer across PES boundaries to assemble a complete
+    /// access unit (e.g. DTS-HD, whose extension substreams arrive in
+    /// separate PES packets) hold the final unit until they can prove it's
+    /// complete. At end-of-stream there is no following packet to prove it,
+    /// so the demuxer calls `flush()` once after the last PES to emit it.
+    /// Default: nothing buffered, no tail.
+    fn flush(&mut self) -> Vec<Frame> {
+        Vec::new()
+    }
+
     /// Get codec initialization data (e.g., SPS+PPS for H.264).
     /// Returns None until enough data has been seen.
     fn codec_private(&self) -> Option<Vec<u8>>;
@@ -90,7 +102,16 @@ impl CodecParser for PassthroughParser {
 /// Create the appropriate parser for a codec, with optional codec private data.
 ///
 /// For DvdSub, `codec_data` should be the pre-formatted VobSub .idx palette header.
-pub fn parser_for_codec(codec: Codec, codec_data: Option<Vec<u8>>) -> Box<dyn CodecParser> {
+///
+/// `is_dvd_ps` selects the DVD program-stream variant where it matters: DVD
+/// LPCM arrives with its private sub-header already stripped by the
+/// `PsDemuxer`, so the LPCM parser must NOT strip the 4-byte BD LPCM header
+/// again (that would drop one PCM sample pair per PES → progressive drift).
+pub fn parser_for_codec(
+    codec: Codec,
+    codec_data: Option<Vec<u8>>,
+    is_dvd_ps: bool,
+) -> Box<dyn CodecParser> {
     match codec {
         Codec::H264 => Box::new(h264::H264Parser::new()),
         Codec::Hevc => Box::new(hevc::HevcParser::new()),
@@ -100,6 +121,7 @@ pub fn parser_for_codec(codec: Codec, codec_data: Option<Vec<u8>>) -> Box<dyn Co
         Codec::DtsHdMa | Codec::DtsHdHr | Codec::Dts => Box::new(dts::DtsParser::new()),
         Codec::TrueHd => Box::new(truehd::TrueHdParser::new()),
         Codec::Pgs => Box::new(pgs::PgsParser::new()),
+        Codec::Lpcm if is_dvd_ps => Box::new(lpcm::LpcmParser::new_dvd()),
         Codec::Lpcm => Box::new(lpcm::LpcmParser::new()),
         Codec::DvdSub => Box::new(dvdsub::DvdSubParser::new(codec_data)),
         _ => Box::new(PassthroughParser::new(true)),

src/mux/codec/mpeg2.rs

@@ -96,9 +96,14 @@ impl CodecParser for Mpeg2Parser {
             return Vec::new();
         }
 
-        let pts_ns = pes.dts.or(pes.pts).map(pts_to_ns).unwrap_or(0);
+        // MKV block timecodes are PRESENTATION timestamps; frames are stored in
+        // decode order and the player reorders by timecode. Use PTS, not DTS —
+        // DTS presents B-frames in decode order (visible judder) and breaks
+        // PTS-based seeking. Fall back to DTS only if PTS is absent.
+        let pts_ns = pes.pts.or(pes.dts).map(pts_to_ns).unwrap_or(0);
         let data = &pes.data;
         let mut keyframe = false;
+        let mut has_picture = false;
 
         // Scan for start codes in the elementary stream data.
         let mut pos = 0;
@@ -176,6 +181,7 @@ impl CodecParser for Mpeg2Parser {
                 PICTURE_CODE => {
                     // Picture header: bytes after start code contain temporal_reference
                     // (10 bits) + picture_coding_type (3 bits).
+                    has_picture = true;
                     if sc + 5 < data.len() {
                         let picture_coding_type = (data[sc + 5] >> 3) & 0x07;
                         if picture_coding_type == PICTURE_TYPE_I {
@@ -190,6 +196,23 @@ impl CodecParser for Mpeg2Parser {
             }
         }
 
+        // A PES that carried a sequence header but no picture start code is a
+        // parameter-set-only access unit: it has no coded picture to emit.
+        // Emitting it as a standalone keyframe would put bare sequence-header
+        // bytes into frame data with no picture. The sequence header is
+        // captured into codec_private above and is re-emitted in-band on the
+        // next real picture's PES, so dropping the empty access unit loses
+        // nothing. Mirrors how the H.264/HEVC parsers skip parameter-set-only
+        // access units.
+        //
+        // Conservative: only drop when this PES actually contained a sequence
+        // header and no picture. A PES with neither (e.g. a slice
+        // continuation) still passes through unchanged, preserving real
+        // keyframe detection.
+        if !has_picture && contains_seq_header(data) {
+            return Vec::new();
+        }
+
         vec![Frame {
             pts_ns,
             keyframe,
@@ -241,6 +264,21 @@ fn parse_aspect_ratio(hdr: &[u8]) -> Option<(u8, u8)> {
     Some(ASPECT_RATIOS[ar_code])
 }
 
+/// Returns true if `data` contains a sequence-header start code (00 00 01 B3).
+fn contains_seq_header(data: &[u8]) -> bool {
+    let mut pos = 0;
+    while let Some(sc) = find_start_code(data, pos) {
+        if sc + 3 >= data.len() {
+            break;
+        }
+        if data[sc + 3] == SEQ_HEADER_CODE {
+            return true;
+        }
+        pos = sc + 4;
+    }
+    false
+}
+
 /// Find the position of the next start code (00 00 01) at or after `from`.
 fn find_start_code(data: &[u8], from: usize) -> Option<usize> {
     if data.len() < from + 3 {
@@ -429,15 +467,15 @@ mod tests {
         assert!(has_ext, "codec_private should include sequence extension");
     }
 
-    // --- I-frame with sequence header = keyframe ---
+    // --- sequence header + picture = keyframe ---
 
     #[test]
-    fn sequence_header_implies_keyframe() {
+    fn sequence_header_with_picture_is_keyframe() {
         let mut parser = Mpeg2Parser::new();
 
         let mut data = Vec::new();
         data.extend_from_slice(&make_seq_header(720, 480, 3, 4));
-        // Even without an explicit picture header, a sequence header implies I-frame.
+        data.extend_from_slice(&make_picture_header(PICTURE_TYPE_I));
         data.extend_from_slice(&[0xFF; 16]);
 
         let pes = make_pes(data, Some(0));
@@ -445,6 +483,43 @@ mod tests {
 
         assert_eq!(frames.len(), 1);
         assert!(frames[0].keyframe);
+        // codecPrivate is still captured.
+        assert!(parser.codec_private().is_some());
+    }
+
+    // --- parameter-set-only PES (seq header, no picture) emits no frame ---
+
+    #[test]
+    fn sequence_header_only_pes_emits_no_frame() {
+        let mut parser = Mpeg2Parser::new();
+
+        // A PES carrying only a sequence header (+ extension), no picture.
+        let mut data = Vec::new();
+        data.extend_from_slice(&make_seq_header(1920, 1080, 3, 4));
+        data.extend_from_slice(&[0x00, 0x00, 0x01, SEQ_EXT_CODE]);
+        data.extend_from_slice(&[0x14, 0x8A, 0x00, 0x01, 0x00, 0x00]);
+
+        let pes = make_pes(data, Some(0));
+        let frames = parser.parse(&pes);
+
+        // No coded picture → no frame emitted, but the sequence header is
+        // still captured for codecPrivate.
+        assert!(
+            frames.is_empty(),
+            "parameter-set-only PES should not emit a frame"
+        );
+        assert!(
+            parser.codec_private().is_some(),
+            "sequence header should still be captured into codec_private"
+        );
+
+        // A following picture-bearing PES emits the real keyframe.
+        let mut data2 = Vec::new();
+        data2.extend_from_slice(&make_picture_header(PICTURE_TYPE_I));
+        data2.extend_from_slice(&[0xFF; 16]);
+        let frames2 = parser.parse(&make_pes(data2, Some(3600)));
+        assert_eq!(frames2.len(), 1);
+        assert!(frames2[0].keyframe);
     }
 
     // --- PTS conversion ---

src/mux/codec/pgs.rs

@@ -18,6 +18,13 @@
 use super::{CodecParser, Frame, PesPacket, pts_to_ns};
 
 const SEGMENT_PCS: u8 = 0x16;
+// Upper bound on a pending display set's accumulated bytes. Real PGS
+// display sets are small (a 1080p RLE bitmap plus palette is well under
+// 1 MB); a stream that keeps appending non-PCS segments without ever
+// emitting a PCS is malformed. Cap accumulation to bound memory and
+// drop further appends until the next PCS resyncs the parser. Mirrors
+// the MAX_*_BYTES / MAX_*_BUF caps in the DTS and AC-3 parsers.
+const MAX_PGS_PENDING_BYTES: usize = 4 * 1024 * 1024;
 // Offset within the PES payload at which number_of_composition_objects
 // lives in a PCS: 3-byte segment header + 10 bytes of PCS fields
 // (video_w/h, frame_rate, comp_num, comp_state, palette_update,
@@ -90,7 +97,12 @@ impl CodecParser for PgsParser {
             // a pending display, append; otherwise emit as-is.
             None => {
                 if let Some((_, ref mut buf)) = self.pending {
-                    buf.extend_from_slice(&pes.data);
+                    // Bound accumulation: a well-formed display set is small.
+                    // Past the cap, drop further appends (malformed stream);
+                    // the next PCS will take/replace `pending` and resync.
+                    if buf.len() + pes.data.len() <= MAX_PGS_PENDING_BYTES {
+                        buf.extend_from_slice(&pes.data);
+                    }
                 } else {
                     out.push(Frame {
                         pts_ns,
@@ -180,6 +192,32 @@ mod tests {
         assert!(data.windows(5).any(|w| w == [0x15, 0x00, 0x02, 0xAA, 0xBB]));
     }
 
+    #[test]
+    fn pending_buffer_is_capped() {
+        let mut parser = PgsParser::new();
+        // Open a display set.
+        let _ = parser.parse(&make_pes(pcs_bytes(1), Some(90000)));
+
+        // Flood with non-PCS segments far exceeding the cap.
+        let chunk = vec![0x15u8; 256 * 1024]; // 256 KB ODS-like segment
+        let floods = (MAX_PGS_PENDING_BYTES / chunk.len()) + 32;
+        for _ in 0..floods {
+            let frames = parser.parse(&make_pes(chunk.clone(), Some(90000)));
+            assert!(frames.is_empty(), "non-PCS appends should not emit");
+        }
+
+        // The pending buffer must not have grown without bound.
+        let pending_len = parser.pending.as_ref().map(|(_, b)| b.len()).unwrap_or(0);
+        assert!(
+            pending_len <= MAX_PGS_PENDING_BYTES,
+            "pending buffer {pending_len} exceeded cap {MAX_PGS_PENDING_BYTES}"
+        );
+
+        // A following PCS still resyncs and emits the (capped) pending set.
+        let frames = parser.parse(&make_pes(pcs_bytes(0), Some(180000)));
+        assert_eq!(frames.len(), 1);
+    }
+
     #[test]
     fn codec_private_none() {
         let parser = PgsParser::new();

src/mux/codec/truehd.rs

@@ -16,6 +16,12 @@ use super::{CodecParser, Frame, PesPacket, pts_to_ns};
 /// Duration of one TrueHD access unit in nanoseconds (1/1200 second).
 const AU_DURATION_NS: i64 = 833_333;
 
+/// Hard cap on the reassembly buffer. A valid TrueHD/MAT access unit is
+/// well under 32 KiB; if the buffer grows far past that without yielding a
+/// frame the stream is malformed, so we drop it and resync rather than grow
+/// without bound. Parity with the AC-3 / DTS / PGS caps.
+const MAX_TRUEHD_BUF: usize = 256 * 1024;
+
 pub struct TrueHdParser {
     buf: Vec<u8>,
     next_pts_ns: i64,
@@ -145,6 +151,12 @@ impl CodecParser for TrueHdParser {
             self.next_pts_ns += AU_DURATION_NS;
         }
 
+        // Bound memory on malformed input: a stream that never yields a
+        // complete frame must not grow the buffer without limit.
+        if self.buf.len() > MAX_TRUEHD_BUF {
+            self.buf.clear();
+        }
+
         frames
     }
 
@@ -153,6 +165,52 @@ impl CodecParser for TrueHdParser {
     }
 }
 
+/// Per-bit channel counts for the TrueHD 8-channel and 6-channel presentation
+/// channel-assignment masks (per the MLP spec / FFmpeg `thd_channels`). Some
+/// bits denote a stereo pair (2), others a single channel (1).
+const THD_8CH: [u8; 13] = [2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1];
+const THD_6CH: [u8; 5] = [2, 1, 1, 2, 1];
+
+/// Decode the true channel count from a TrueHD major-sync `format_info` word
+/// (the 32 bits immediately after the 0xF8726FBA sync). Returns the richest
+/// presentation's channel count — the 8-channel (e.g. 7.1) presentation when
+/// present, else the 6-channel (5.1) one. This is the real layout that the MPLS
+/// `audio_format` base field (often 5.1 even on a 7.1/Atmos track) understates.
+pub fn truehd_channels(format_info: u32) -> Option<u8> {
+    let ch8 = (format_info & 0x1FFF) as u16; // 8ch_presentation_channel_assignment (13 bits)
+    let ch6 = ((format_info >> 15) & 0x1F) as u16; // 6ch_presentation_channel_assignment (5 bits)
+    let count = |mask: u16, tbl: &[u8]| -> u8 {
+        tbl.iter()
+            .enumerate()
+            .filter(|(i, _)| mask & (1 << i) != 0)
+            .map(|(_, &c)| c)
+            .sum()
+    };
+    if ch8 != 0 {
+        Some(count(ch8, &THD_8CH))
+    } else if ch6 != 0 {
+        Some(count(ch6, &THD_6CH))
+    } else {
+        None
+    }
+}
+
+/// Scan a demuxed TrueHD elementary-stream chunk for the first major sync and
+/// decode its true channel count. The stream may interleave AC-3; we scan for
+/// the major-sync word anywhere and read the following `format_info`.
+pub fn truehd_channels_from_stream(data: &[u8]) -> Option<u8> {
+    let mut p = 0;
+    while p + 8 <= data.len() {
+        let w = u32::from_be_bytes([data[p], data[p + 1], data[p + 2], data[p + 3]]);
+        if (w & 0xFFFF_FFFE) == 0xF872_6FBA {
+            let fi = u32::from_be_bytes([data[p + 4], data[p + 5], data[p + 6], data[p + 7]]);
+            return truehd_channels(fi);
+        }
+        p += 1;
+    }
+    None
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -247,4 +305,27 @@ mod tests {
         let parser = TrueHdParser::new();
         assert!(parser.codec_private().is_none());
     }
+
+    #[test]
+    fn truehd_channels_71_from_8ch_presentation() {
+        // 8ch presentation assignment bits 0-4 (LR,C,LFE,LsRs,back-LR) = 2+1+1+2+2 = 8.
+        let format_info = 0x1F; // low 13 bits = 0x1F
+        assert_eq!(truehd_channels(format_info), Some(8));
+    }
+
+    #[test]
+    fn truehd_channels_51_from_6ch_presentation() {
+        // No 8ch presentation; 6ch bits 0-3 (LR,C,LFE,LsRs) = 2+1+1+2 = 6.
+        let format_info = 0xF << 15; // 6ch field = 0xF, 8ch field = 0
+        assert_eq!(truehd_channels(format_info), Some(6));
+    }
+
+    #[test]
+    fn truehd_channels_scan_finds_major_sync() {
+        // [junk][major sync 0xF8726FBA][format_info: 8ch=0x1F -> 7.1]
+        let mut data = vec![0xAA, 0xBB];
+        data.extend_from_slice(&0xF872_6FBAu32.to_be_bytes());
+        data.extend_from_slice(&0x0000_001Fu32.to_be_bytes());
+        assert_eq!(truehd_channels_from_stream(&data), Some(8));
+    }
 }

src/mux/codec/vc1.rs

@@ -41,9 +41,13 @@ impl CodecParser for Vc1Parser {
             return Vec::new();
         }
 
-        // Use DTS when available (monotonic for B-frame content), fall back to PTS
-        let ts_ns = pes.dts.or(pes.pts).map(pts_to_ns).unwrap_or(0);
+        // MKV block timecodes are PRESENTATION timestamps; frames are stored in
+        // decode order and the player reorders by timecode. Use PTS, not DTS —
+        // DTS presents B-frames in decode order (visible judder) and breaks
+        // PTS-based seeking. Fall back to DTS only if PTS is absent.
+        let ts_ns = pes.pts.or(pes.dts).map(pts_to_ns).unwrap_or(0);
         let mut has_seq_header = false;
+        let mut has_entry_point = false;
         let mut frame_start: Option<usize> = None;
 
         // Scan for start codes (00 00 01 XX)
@@ -67,6 +71,7 @@ impl CodecParser for Vc1Parser {
                     SC_ENTRY_POINT => {
                         let end = find_next_sc(data, i + 4).unwrap_or(data.len());
                         self.entry_point = Some(data[i..end].to_vec());
+                        has_entry_point = true;
                     }
                     SC_FRAME => {
                         // Frame data starts at this start code
@@ -85,11 +90,23 @@ impl CodecParser for Vc1Parser {
         // Keyframe = this PES contains a sequence header (I-frame indicator in BD)
         let keyframe = has_seq_header;
 
-        // Strip sequence header + entry point from frame data — those are in codecPrivate.
-        // Only include data from the frame start code onwards.
+        // Strip sequence header + entry point from frame data — those are in
+        // codecPrivate, not coded-picture data. Only include data from the
+        // frame start code onwards.
         let frame_data = match frame_start {
             Some(start) => &data[start..],
-            None => data, // no frame start code found, pass through entire PES
+            None => {
+                // No frame start code. If this PES carried only parameter sets
+                // (sequence header / entry point, captured above into
+                // codecPrivate), there is no coded picture to emit — drop it
+                // rather than passing parameter bytes through as a bogus
+                // keyframe. Mirrors how the H.264/HEVC parsers skip
+                // parameter-set-only access units.
+                if has_seq_header || has_entry_point {
+                    return Vec::new();
+                }
+                data // genuine picture payload with no leading 0x0D — pass through
+            }
         };
 
         vec![Frame {
@@ -343,6 +360,42 @@ mod tests {
         assert_eq!(&frames[0].data[0..4], &[0x00, 0x00, 0x01, SC_FRAME]);
     }
 
+    // --- parameter-set-only PES (seq header + entry point, no frame SC) ---
+
+    #[test]
+    fn param_set_only_pes_emits_no_frame() {
+        let mut parser = Vc1Parser::new();
+
+        // Sequence header + entry point, but NO frame start code (0x0D).
+        let mut data = Vec::new();
+        data.extend_from_slice(&[0x00, 0x00, 0x01, SC_SEQUENCE_HEADER]);
+        data.extend_from_slice(&[0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF]);
+        data.extend_from_slice(&[0x00, 0x00, 0x01, SC_ENTRY_POINT]);
+        data.extend_from_slice(&[0x11, 0x22, 0x33, 0x44]);
+
+        let pes = make_pes(data, Some(90000));
+        let frames = parser.parse(&pes);
+
+        // No coded picture → no frame emitted (parameter bytes must not be
+        // passed through as a bogus keyframe).
+        assert!(
+            frames.is_empty(),
+            "parameter-set-only PES should not emit a frame"
+        );
+        // But codecPrivate is still captured.
+        assert!(parser.seq_header.is_some());
+        assert!(parser.entry_point.is_some());
+        assert!(parser.codec_private().is_some());
+
+        // A following frame-bearing PES still emits its picture.
+        let mut data2 = Vec::new();
+        data2.extend_from_slice(&[0x00, 0x00, 0x01, SC_FRAME]);
+        data2.extend_from_slice(&[0x55, 0x66, 0x77]);
+        let frames2 = parser.parse(&make_pes(data2, Some(180000)));
+        assert_eq!(frames2.len(), 1);
+        assert_eq!(&frames2[0].data[0..4], &[0x00, 0x00, 0x01, SC_FRAME]);
+    }
+
     // --- empty PES ---
 
     #[test]
@@ -369,10 +422,10 @@ mod tests {
         assert_eq!(frames[0].pts_ns, 1_000_000_000);
     }
 
-    // --- DTS preferred over PTS ---
+    // --- PTS (presentation) used for the MKV block timecode, not DTS ---
 
     #[test]
-    fn dts_preferred_over_pts() {
+    fn pts_preferred_over_dts() {
         let mut parser = Vc1Parser::new();
 
         let mut data = Vec::new();
@@ -381,13 +434,14 @@ mod tests {
 
         let pes = PesPacket {
             pid: 0x1011,
-            pts: Some(180000),
-            dts: Some(90000),
+            pts: Some(180000), // presentation
+            dts: Some(90000),  // decode
             data,
         };
         let frames = parser.parse(&pes);
         assert_eq!(frames.len(), 1);
-        assert_eq!(frames[0].pts_ns, 1_000_000_000);
+        // PTS must be used — MKV block timecodes are presentation timestamps.
+        assert_eq!(frames[0].pts_ns, 2_000_000_000);
     }
 
     // --- find_next_sc utility ---

src/mux/disc.rs

@@ -195,7 +195,8 @@ impl DiscStream {
             };
             pids.push(pid);
             pid_to_track.push((pid, idx));
-            parsers.push((pid, super::codec::parser_for_codec(codec, None)));
+            let is_dvd_ps = matches!(content_format, crate::disc::ContentFormat::MpegPs);
+            parsers.push((pid, super::codec::parser_for_codec(codec, None, is_dvd_ps)));
         }
 
         let mut ts_demuxer = None;
@@ -541,6 +542,19 @@ impl crate::pes::Stream for DiscStream {
                         }
                     }
                 }
+                // Drain any access unit a codec parser buffered past the last
+                // PES (DTS-HD's final core+extension unit, assembled across
+                // PES boundaries).
+                let pid_to_track = &self.pid_to_track;
+                let pending = &mut self.pending_frames;
+                for (pid, parser) in self.parsers.iter_mut() {
+                    let Some(&(_, track)) = pid_to_track.iter().find(|(p, _)| p == pid) else {
+                        continue;
+                    };
+                    for frame in parser.flush() {
+                        pending.push_back(crate::pes::PesFrame::from_codec_frame(track, frame));
+                    }
+                }
                 return Ok(self.pending_frames.pop_front());
             }
 

src/mux/ebml.rs

@@ -264,6 +264,13 @@ pub fn read_element_header(r: &mut impl Read) -> io::Result<(u32, u64, usize)> {
 
 /// Read an unsigned integer value of `len` bytes.
 pub fn read_uint_val(r: &mut impl Read, len: usize) -> io::Result<u64> {
+    // An EBML unsigned integer is at most 8 bytes. A malformed element
+    // claiming `len > 8` would index past this stack buffer and panic
+    // (DoS on untrusted input) — reject it at the source so every caller
+    // is safe, not just the ones that pre-check.
+    if len > 8 {
+        return Err(crate::error::Error::MkvInvalid.into());
+    }
     let mut buf = [0u8; 8];
     r.read_exact(&mut buf[..len])?;
     let mut val = 0u64;
@@ -273,23 +280,33 @@ pub fn read_uint_val(r: &mut impl Read, len: usize) -> io::Result<u64> {
     Ok(val)
 }
 
-/// Read a float value (4 or 8 bytes).
+/// Read a float value. EBML floats are exactly 0, 4, or 8 bytes.
+///
+/// The previous `else` branch read a fixed 8 bytes for ANY non-4 length,
+/// so a malformed element with `len > 8` left `len - 8` unconsumed bytes
+/// (mis-read as the next EBML header → desync of the rest of the parent
+/// element) and `len < 4` over-read. Consume exactly `len` bytes and
+/// reject anything that isn't a valid float width.
 pub fn read_float_val(r: &mut impl Read, len: usize) -> io::Result<f64> {
-    if len == 4 {
-        let mut buf = [0u8; 4];
-        r.read_exact(&mut buf)?;
-        Ok(f32::from_be_bytes(buf) as f64)
-    } else {
-        let mut buf = [0u8; 8];
-        r.read_exact(&mut buf)?;
-        Ok(f64::from_be_bytes(buf))
+    match len {
+        0 => Ok(0.0),
+        4 => {
+            let mut buf = [0u8; 4];
+            r.read_exact(&mut buf)?;
+            Ok(f32::from_be_bytes(buf) as f64)
+        }
+        8 => {
+            let mut buf = [0u8; 8];
+            r.read_exact(&mut buf)?;
+            Ok(f64::from_be_bytes(buf))
+        }
+        _ => Err(crate::error::Error::MkvInvalid.into()),
     }
 }
 
 /// Read a UTF-8 string value of `len` bytes.
 pub fn read_string_val(r: &mut impl Read, len: usize) -> io::Result<String> {
-    let mut buf = vec![0u8; len];
-    r.read_exact(&mut buf)?;
+    let mut buf = read_exact_bounded(r, len)?;
     // Strip trailing nulls
     while buf.last() == Some(&0) {
         buf.pop();
@@ -299,8 +316,22 @@ pub fn read_string_val(r: &mut impl Read, len: usize) -> io::Result<String> {
 
 /// Read binary data of `len` bytes.
 pub fn read_binary_val(r: &mut impl Read, len: usize) -> io::Result<Vec<u8>> {
-    let mut buf = vec![0u8; len];
-    r.read_exact(&mut buf)?;
+    read_exact_bounded(r, len)
+}
+
+/// Read exactly `len` bytes WITHOUT trusting `len` to size the allocation.
+///
+/// `vec![0u8; len]` on an attacker-controlled EBML size would allocate
+/// gigabytes before the read fails. Instead we cap the reader to `len`
+/// and grow the buffer as bytes actually arrive: a malformed element that
+/// claims a huge length but supplies few bytes allocates only what it
+/// delivers, then errors on the short read.
+fn read_exact_bounded(r: &mut impl Read, len: usize) -> io::Result<Vec<u8>> {
+    let mut buf = Vec::new();
+    let got = r.take(len as u64).read_to_end(&mut buf)?;
+    if got != len {
+        return Err(io::ErrorKind::UnexpectedEof.into());
+    }
     Ok(buf)
 }
 
@@ -362,6 +393,12 @@ pub const MATRIX_COEFFICIENTS: u32 = 0x55B1;
 pub const PRIMARIES: u32 = 0x55BB;
 pub const RANGE: u32 = 0x55B9;
 
+// Dolby Vision — BlockAdditionMapping carries the DOVIDecoderConfigurationRecord
+// (dvcC) so players / mediainfo recognise the track as Dolby Vision.
+pub const BLOCK_ADDITION_MAPPING: u32 = 0x41E4;
+pub const BLOCK_ADD_ID_TYPE: u32 = 0x41E7;
+pub const BLOCK_ADD_ID_EXTRA_DATA: u32 = 0x41ED;
+
 // Audio
 pub const AUDIO: u32 = 0xE1;
 pub const SAMPLING_FREQUENCY: u32 = 0xB5;

src/mux/mkv.rs

@@ -34,6 +34,24 @@ pub struct MkvTrack {
     pub sample_rate: f64,
     pub channels: u8,
     pub bit_depth: u8,
+    // Dolby Vision: the dvcC (DOVIDecoderConfigurationRecord) for the DV layer,
+    // emitted as a BlockAdditionMapping. `None` for non-DV tracks.
+    pub dv_config: Option<Vec<u8>>,
+}
+
+/// Build a DOVIDecoderConfigurationRecord (dvcC) — 24 bytes — for the Matroska
+/// BlockAdditionMapping. For disc Profile 7 dual-layer the base, enhancement,
+/// and RPU are all present (lossless FEL/MEL preserved as a second track).
+pub fn dolby_vision_config(profile: u8, level: u8, bl_compat_id: u8) -> Vec<u8> {
+    let mut v = vec![0u8; 24];
+    v[0] = 1; // dv_version_major
+    v[1] = 0; // dv_version_minor
+    // profile(7) | level(6) | rpu_present(1) | el_present(1) | bl_present(1)
+    v[2] = ((profile & 0x7F) << 1) | ((level >> 5) & 0x01);
+    v[3] = ((level & 0x1F) << 3) | (1 << 2) | (1 << 1) | 1; // rpu = el = bl = 1
+    v[4] = (bl_compat_id & 0x0F) << 4;
+    // v[5..24] reserved = 0
+    v
 }
 
 impl MkvTrack {
@@ -83,23 +101,33 @@ impl MkvTrack {
             sample_rate: 0.0,
             channels: 0,
             bit_depth: 0,
+            // The DV layer (hdr=DolbyVision) carries the dvcC so the track is
+            // recognised as Dolby Vision (disc Profile 7 dual-layer).
+            dv_config: if matches!(v.hdr, HdrFormat::DolbyVision) {
+                Some(dolby_vision_config(7, 6, 0))
+            } else {
+                None
+            },
         }
     }
 
     pub fn audio(a: &AudioStream) -> Self {
-        // Codec ID strings must distinguish the DTS family — strict
-        // players (Plex transcoder, some hardware decoders, some AV
-        // receivers) reject lossless DTS-HD MA payload when the
-        // track advertises plain `A_DTS` because it implies the
-        // bitstream is the 1.5 Mbps "core" only. Fix is just to
-        // emit the right ID per BD-STN codec field.
+        // The Matroska codec-ID registry defines `A_DTS` for the entire
+        // DTS family — the spec text for `A_DTS` explicitly states it
+        // "Supports DTS, DTS-ES, DTS-96/26, DTS-HD High Resolution Audio
+        // and DTS-HD Master Audio." Players distinguish core vs HD-HRA vs
+        // HD-MA by parsing the DTS bitstream extension substreams, not by
+        // the container codec ID. The previously-emitted `A_DTS/MA` and
+        // `A_DTS/HR` suffixes are NOT registered codec IDs; strict parsers
+        // (libmatroska) and some hardware renderers fail to recognise the
+        // track at all. Emit plain `A_DTS` for every DTS variant — the
+        // lossless MA / HRA payload bytes are unchanged, only the
+        // container codec-ID string differs.
         let codec_id = match a.codec {
             Codec::Ac3 => "A_AC3",
             Codec::Ac3Plus => "A_EAC3",
             Codec::TrueHd => "A_TRUEHD",
-            Codec::DtsHdMa => "A_DTS/MA",
-            Codec::DtsHdHr => "A_DTS/HR",
-            Codec::Dts => "A_DTS",
+            Codec::DtsHdMa | Codec::DtsHdHr | Codec::Dts => "A_DTS",
             Codec::Lpcm => "A_PCM/INT/BIG",
             _ => "A_AC3",
         };
@@ -128,6 +156,7 @@ impl MkvTrack {
             sample_rate: sr,
             channels: ch,
             bit_depth: 0,
+            dv_config: None,
         }
     }
 
@@ -156,6 +185,7 @@ impl MkvTrack {
             sample_rate: 0.0,
             channels: 0,
             bit_depth: 0,
+            dv_config: None,
         }
     }
 }
@@ -193,6 +223,12 @@ pub struct MkvMuxer<W: Write + Seek> {
 /// New cluster every 5 seconds.
 const CLUSTER_DURATION_MS: i64 = 5000;
 
+/// Maximum block-relative timestamp expressible in the signed 16-bit
+/// SimpleBlock/Block field (`i16::MAX` ms). A frame further than this from
+/// the open cluster's timestamp forces a new cluster (see `write_frame`) so
+/// the `as i16` cast can never wrap.
+const MAX_BLOCK_REL_MS: i64 = i16::MAX as i64;
+
 impl<W: Write + Seek> MkvMuxer<W> {
     /// Create a new MKV muxer: writes EBML header, Segment start, Info, Tracks, Chapters.
     pub fn new(
@@ -333,6 +369,17 @@ impl<W: Write + Seek> MkvMuxer<W> {
                 ebml::end_master(&mut writer, vid_pos)?;
             }
 
+            // Dolby Vision signaling — BlockAdditionMapping is a child of the
+            // TrackEntry (sibling of Video). Carries the dvcC so players /
+            // mediainfo recognise the track as Dolby Vision.
+            if let Some(ref dvcc) = track.dv_config {
+                let map_pos = ebml::start_master(&mut writer, ebml::BLOCK_ADDITION_MAPPING)?;
+                // BlockAddIDType = "dvcC" fourcc (DOVIDecoderConfigurationRecord).
+                ebml::write_uint(&mut writer, ebml::BLOCK_ADD_ID_TYPE, 0x6476_6343)?;
+                ebml::write_binary(&mut writer, ebml::BLOCK_ADD_ID_EXTRA_DATA, dvcc)?;
+                ebml::end_master(&mut writer, map_pos)?;
+            }
+
             // Audio-specific
             if track.track_type == ebml::TRACK_TYPE_AUDIO && track.sample_rate > 0.0 {
                 let aud_pos = ebml::start_master(&mut writer, ebml::AUDIO)?;
@@ -406,7 +453,7 @@ impl<W: Write + Seek> MkvMuxer<W> {
         let base = *self.base_pts_ms.get_or_insert(raw_ms);
         let pts_ms = raw_ms - base;
 
-        // Cluster boundaries must coincide with a video keyframe so every
+        // Cluster boundaries normally coincide with a video keyframe so every
         // Cues entry resolves to a seekable IDR at the cluster start.
         let is_video_key = keyframe && track_idx == 0;
         let needs_new_cluster = !self.cluster_open
@@ -422,6 +469,17 @@ impl<W: Write + Seek> MkvMuxer<W> {
                 track: track_idx + 1,
                 cluster_pos: self.cluster_pos - self.segment_start,
             });
+        } else if (pts_ms - self.cluster_ts_ms) > MAX_BLOCK_REL_MS {
+            // The block-relative timestamp is a signed 16-bit value, so a
+            // frame more than i16::MAX ms (~32.767 s) past the current
+            // cluster's timestamp would silently wrap on the `as i16` cast,
+            // corrupting A/V sync. The keyframe-driven boundary above only
+            // fires on a video keyframe — a long audio-only stretch, or a
+            // very long GOP with no intervening keyframe, can drift past the
+            // i16 range. Force a fresh cluster here even without a keyframe
+            // to keep the cast in range. This cluster is not keyframe-aligned
+            // so it gets no Cues entry (Cues stay IDR-only for seekability).
+            self.start_cluster(pts_ms)?;
         }
 
         let relative_ts = (pts_ms - self.cluster_ts_ms) as i16;
@@ -612,6 +670,7 @@ mod tests {
             sample_rate: 0.0,
             channels: 0,
             bit_depth: 0,
+            dv_config: None,
         }
     }
 
@@ -636,9 +695,60 @@ mod tests {
             sample_rate: 48000.0,
             channels: 6,
             bit_depth: 0,
+            dv_config: None,
         }
     }
 
+    fn audio_stream(codec: Codec) -> AudioStream {
+        use crate::disc::{AudioChannels, LabelPurpose, SampleRate};
+        AudioStream {
+            pid: 0x1100,
+            codec,
+            channels: AudioChannels::Surround51,
+            language: "eng".into(),
+            sample_rate: SampleRate::S48,
+            secondary: false,
+            purpose: LabelPurpose::Normal,
+            label: String::new(),
+        }
+    }
+
+    #[test]
+    fn dts_variants_map_to_registered_a_dts_codec_id() {
+        // The Matroska codec-ID registry defines `A_DTS` for the whole DTS
+        // family (core, DTS-HD HRA, DTS-HD MA). The `/MA` and `/HR` suffixes
+        // are not registered and break strict parsers, so every DTS variant
+        // must emit plain `A_DTS`.
+        for codec in [Codec::Dts, Codec::DtsHdMa, Codec::DtsHdHr] {
+            let track = MkvTrack::audio(&audio_stream(codec));
+            assert_eq!(
+                track.codec_id, "A_DTS",
+                "{codec:?} must map to registered codec ID A_DTS, got {}",
+                track.codec_id
+            );
+        }
+        // Sanity: the non-DTS variants keep their distinct IDs.
+        assert_eq!(MkvTrack::audio(&audio_stream(Codec::Ac3)).codec_id, "A_AC3");
+        assert_eq!(
+            MkvTrack::audio(&audio_stream(Codec::TrueHd)).codec_id,
+            "A_TRUEHD"
+        );
+    }
+
+    #[test]
+    fn dolby_vision_config_profile7() {
+        // dvcC for disc Profile 7 dual-layer: version 1.0, profile 7, all of
+        // bl/el/rpu present. 24 bytes.
+        let c = dolby_vision_config(7, 6, 0);
+        assert_eq!(c.len(), 24);
+        assert_eq!(c[0], 1); // dv_version_major
+        assert_eq!(c[1], 0); // dv_version_minor
+        // profile in the top 7 bits of byte 2
+        assert_eq!(c[2] >> 1, 7, "dv_profile must be 7");
+        // rpu/el/bl present flags in byte 3 (low 3 bits after level)
+        assert_eq!(c[3] & 0b0000_0111, 0b0000_0111, "rpu+el+bl all present");
+    }
+
     #[test]
     fn mkv_writes_ebml_header() {
         let buf = Cursor::new(Vec::new());
@@ -1323,6 +1433,85 @@ mod tests {
         );
     }
 
+    /// Collect every (cluster_ts_ms, block_relative_ts_i16, absolute_ms) for
+    /// all SimpleBlocks across all clusters, so a test can assert that the
+    /// reconstructed absolute timestamp (cluster_ts + relative_ts) is correct
+    /// and that no relative_ts ever wrapped the i16 range.
+    fn all_block_timestamps(data: &[u8]) -> Vec<(i64, i16, i64)> {
+        let mut out = Vec::new();
+        for (body_start, body_size, cluster_ts) in find_clusters(data) {
+            let body = &data[body_start..body_start + body_size as usize];
+            let mut cursor = Cursor::new(body);
+            // Skip CLUSTER_TIMESTAMP.
+            let (tid, tsize, _) = ebml::read_element_header(&mut cursor).unwrap();
+            assert_eq!(tid, ebml::CLUSTER_TIMESTAMP);
+            cursor.seek(io::SeekFrom::Current(tsize as i64)).unwrap();
+            while (cursor.position() as usize) < body.len() {
+                let (id, sz, _) = ebml::read_element_header(&mut cursor).unwrap();
+                if id == ebml::SIMPLE_BLOCK {
+                    let bstart = cursor.position() as usize;
+                    let b0 = body[bstart];
+                    let vint_len = if b0 & 0x80 != 0 { 1 } else { 2 };
+                    let ts_pos = bstart + vint_len;
+                    let rel = i16::from_be_bytes([body[ts_pos], body[ts_pos + 1]]);
+                    out.push((cluster_ts as i64, rel, cluster_ts as i64 + rel as i64));
+                }
+                cursor.seek(io::SeekFrom::Current(sz as i64)).unwrap();
+            }
+        }
+        out
+    }
+
+    #[test]
+    fn long_audio_gap_forces_cluster_no_i16_overflow() {
+        // Regression for the `(pts_ms - cluster_ts_ms) as i16` truncation:
+        // a single video keyframe at t=0 opens one cluster, then a long
+        // audio-only stretch (no further video keyframe) drifts well past
+        // i16::MAX ms (~32.767 s). Without the overflow guard the audio
+        // blocks past 32.767 s would write a wrapped (negative) relative
+        // timestamp into the SimpleBlock. With the guard a fresh cluster is
+        // forced so every relative_ts stays in range and reconstructs to the
+        // true absolute timestamp.
+        let tracks = [make_video_track(), make_audio_track()];
+        let mut frames: Vec<(usize, i64, bool, Vec<u8>)> = Vec::new();
+        // One video keyframe at t=0 (opens the first cluster).
+        frames.push((0, 0, true, vec![0xAB; 16]));
+        // Audio frames every 100 ms out to 60 s — past the 32.767 s i16 limit
+        // and past two i16 spans, with NO further video keyframe.
+        let mut t_ms = 0i64;
+        while t_ms <= 60_000 {
+            frames.push((1, t_ms * 1_000_000, true, vec![0xCD; 16]));
+            t_ms += 100;
+        }
+
+        let (data, _) = mux_to_bytes(&tracks, &[], &frames);
+
+        let blocks = all_block_timestamps(&data);
+        assert!(!blocks.is_empty());
+        // Every block's relative timestamp must be within i16 range (it is by
+        // type), AND must reconstruct to a non-negative, monotonic-ish
+        // absolute timestamp matching the source — i.e. no silent wrap.
+        for (cluster_ts, rel, abs) in &blocks {
+            assert!(
+                *rel as i64 >= 0 && (*rel as i64) <= MAX_BLOCK_REL_MS,
+                "block relative_ts {rel} out of [0, i16::MAX] range \
+                 (cluster_ts={cluster_ts}, abs={abs}) — i16 overflow"
+            );
+        }
+        // The latest audio frame is at 60_000 ms; its reconstructed absolute
+        // timestamp must equal that, proving no truncation occurred.
+        let max_abs = blocks.iter().map(|(_, _, abs)| *abs).max().unwrap();
+        assert_eq!(max_abs, 60_000, "last block must reconstruct to 60_000 ms");
+        // The overflow guard must have opened more than one cluster (the
+        // single keyframe alone would otherwise yield exactly one).
+        let clusters = find_clusters(&data);
+        assert!(
+            clusters.len() >= 2,
+            "expected the i16 guard to force extra clusters, got {}",
+            clusters.len()
+        );
+    }
+
     #[test]
     fn pre_first_keyframe_frames_dropped() {
         let tracks = [make_video_track()];

src/mux/mkvstream.rs

@@ -14,6 +14,49 @@ fn skip_bytes(r: &mut impl Read, n: u64) -> io::Result<()> {
     Ok(())
 }
 
+// ── Sanity caps for untrusted EBML element sizes ──────────────
+//
+// Sizes come straight from the EBML stream (file or network) and are
+// otherwise cast to `usize` and used to allocate/read. An adversarial
+// or corrupt container can claim a multi-GB element and trigger an OOM
+// allocation, or claim an integer element wider than 8 bytes and panic
+// the fixed 8-byte reader. Every untrusted size is validated against
+// one of these caps before allocation.
+
+/// Largest accepted SIMPLE_BLOCK payload. A block is a small vint track
+/// header + 2-byte rel-ts + 1-byte flags + one frame of elementary data.
+/// UHD HEVC keyframes run a few MB; 64 MiB is generously above any real
+/// single-frame block while still bounding a hostile allocation.
+const MAX_BLOCK_SIZE: u64 = 64 * 1024 * 1024;
+/// Largest accepted CODEC_PRIVATE payload. hvcC/avcC/setup blobs are a
+/// few KB in practice; 16 MiB is far above any legitimate value.
+const MAX_CODEC_PRIVATE: u64 = 16 * 1024 * 1024;
+/// Largest accepted string element (TITLE/CODEC_ID/LANGUAGE/TRACK_NAME).
+const MAX_STRING_LEN: u64 = 64 * 1024;
+/// EBML unsigned-int elements are at most 8 bytes wide.
+const MAX_UINT_LEN: u64 = 8;
+
+/// Reject an untrusted element size that exceeds `cap` before it is used
+/// to allocate or read. Returns the size as `usize` when within bounds.
+fn checked_size(size: u64, cap: u64) -> io::Result<usize> {
+    if size > cap {
+        return Err(crate::error::Error::MkvInvalid.into());
+    }
+    Ok(size as usize)
+}
+
+/// Read a bounded unsigned int. Guards against `size > 8` (which would
+/// otherwise index out of the fixed 8-byte buffer in `read_uint_val`)
+/// before delegating.
+fn read_uint_bounded(r: &mut impl Read, size: u64) -> io::Result<u64> {
+    ebml::read_uint_val(r, checked_size(size, MAX_UINT_LEN)?)
+}
+
+/// Read a bounded UTF-8 string element.
+fn read_string_bounded(r: &mut impl Read, size: u64) -> io::Result<String> {
+    ebml::read_string_val(r, checked_size(size, MAX_STRING_LEN)?)
+}
+
 use crate::disc::*;
 use std::io::{self, Read};
 
@@ -108,11 +151,12 @@ impl crate::pes::Stream for MkvStream {
             match id {
                 ebml::CLUSTER => continue,
                 ebml::CLUSTER_TIMESTAMP => {
-                    rs.cluster_ts_ms = ebml::read_uint_val(&mut rs.reader, size as usize)? as i64;
+                    rs.cluster_ts_ms = read_uint_bounded(&mut rs.reader, size)? as i64;
                     continue;
                 }
                 ebml::SIMPLE_BLOCK => {
-                    let block = ebml::read_binary_val(&mut rs.reader, size as usize)?;
+                    let block =
+                        ebml::read_binary_val(&mut rs.reader, checked_size(size, MAX_BLOCK_SIZE)?)?;
                     if block.len() < 4 {
                         continue;
                     }
@@ -198,7 +242,10 @@ impl crate::pes::Stream for MkvStream {
 /// Returns (DiscTitle, codec_privates: Vec<(track_number, codec_private_bytes)>)
 fn parse_mkv_header(r: &mut impl Read) -> MkvHeaderResult {
     let mut title = String::new();
-    let mut duration_ms = 0.0f64;
+    // EBML `DURATION` is a float expressed in TimestampScale ticks, not
+    // milliseconds (Matroska spec). Named accordingly; converted to
+    // seconds below as ticks * ts_scale_ns / 1e9.
+    let mut duration_ticks = 0.0f64;
     let mut ts_scale: u64 = 1_000_000;
     let mut streams: Vec<crate::disc::Stream> = Vec::new();
     let mut codec_privates: Vec<(u16, Vec<u8>)> = Vec::new();
@@ -235,9 +282,9 @@ fn parse_mkv_header(r: &mut impl Read) -> MkvHeaderResult {
                     let (cid, cs, hlen) = ebml::read_element_header(r)?;
                     remaining = remaining.saturating_sub(hlen as u64 + cs);
                     match cid {
-                        ebml::TIMESTAMP_SCALE => ts_scale = ebml::read_uint_val(r, cs as usize)?,
-                        ebml::DURATION => duration_ms = ebml::read_float_val(r, cs as usize)?,
-                        ebml::TITLE => title = ebml::read_string_val(r, cs as usize)?,
+                        ebml::TIMESTAMP_SCALE => ts_scale = read_uint_bounded(r, cs)?,
+                        ebml::DURATION => duration_ticks = ebml::read_float_val(r, cs as usize)?,
+                        ebml::TITLE => title = read_string_bounded(r, cs)?,
                         _ => {
                             skip_bytes(r, cs)?;
                         }
@@ -274,7 +321,7 @@ fn parse_mkv_header(r: &mut impl Read) -> MkvHeaderResult {
 
     let disc_title = DiscTitle {
         playlist: title,
-        duration_secs: duration_ms * (ts_scale as f64) / 1_000_000_000.0,
+        duration_secs: duration_ticks * (ts_scale as f64) / 1_000_000_000.0,
         streams,
         ..DiscTitle::empty()
     };
@@ -296,20 +343,25 @@ fn parse_track(
         let (cid, cs, hlen) = ebml::read_element_header(r)?;
         remaining = remaining.saturating_sub(hlen as u64 + cs);
         match cid {
-            ebml::TRACK_NUMBER => tnum = ebml::read_uint_val(r, cs as usize)? as u16,
-            ebml::TRACK_TYPE => ttype = ebml::read_uint_val(r, cs as usize)?,
-            ebml::CODEC_ID => codec_id = ebml::read_string_val(r, cs as usize)?,
-            ebml::CODEC_PRIVATE => codec_priv = Some(ebml::read_binary_val(r, cs as usize)?),
-            ebml::LANGUAGE => lang = ebml::read_string_val(r, cs as usize)?,
-            ebml::TRACK_NAME => name = ebml::read_string_val(r, cs as usize)?,
-            ebml::FLAG_FORCED => forced = ebml::read_uint_val(r, cs as usize)? != 0,
+            ebml::TRACK_NUMBER => tnum = read_uint_bounded(r, cs)? as u16,
+            ebml::TRACK_TYPE => ttype = read_uint_bounded(r, cs)?,
+            ebml::CODEC_ID => codec_id = read_string_bounded(r, cs)?,
+            ebml::CODEC_PRIVATE => {
+                codec_priv = Some(ebml::read_binary_val(
+                    r,
+                    checked_size(cs, MAX_CODEC_PRIVATE)?,
+                )?)
+            }
+            ebml::LANGUAGE => lang = read_string_bounded(r, cs)?,
+            ebml::TRACK_NAME => name = read_string_bounded(r, cs)?,
+            ebml::FLAG_FORCED => forced = read_uint_bounded(r, cs)? != 0,
             ebml::VIDEO => {
                 let mut vrem = cs;
                 while vrem > 0 {
                     let (vid, vs, vhlen) = ebml::read_element_header(r)?;
                     vrem = vrem.saturating_sub(vhlen as u64 + vs);
                     if vid == ebml::PIXEL_HEIGHT {
-                        ph = ebml::read_uint_val(r, vs as usize)? as u32;
+                        ph = read_uint_bounded(r, vs)? as u32;
                     } else {
                         skip_bytes(r, vs)?;
                     }
@@ -322,7 +374,7 @@ 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 = ebml::read_uint_val(r, as_ as usize)? as u8,
+                        ebml::CHANNELS => ch = read_uint_bounded(r, as_)? as u8,
                         _ => {
                             skip_bytes(r, as_)?;
                         }
@@ -428,3 +480,138 @@ fn block_vint(d: &[u8]) -> (u64, usize) {
     }
     (0, 1) // Unsupported 5+ byte VINT — treat as track 0
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::pes::Stream as _;
+    use std::io::Cursor;
+
+    // `From<Error> for io::Error` encodes the numeric code into the
+    // Display string as "E{code}: ...". Check the prefix.
+    fn is_mkv_invalid(e: &io::Error) -> bool {
+        e.kind() == io::ErrorKind::InvalidData
+            && e.to_string()
+                .starts_with(&format!("E{}", crate::error::E_MKV_INVALID))
+    }
+
+    #[test]
+    fn checked_size_rejects_over_cap() {
+        // Within cap → Ok with usize value.
+        assert_eq!(checked_size(100, 256).unwrap(), 100);
+        assert_eq!(checked_size(256, 256).unwrap(), 256);
+        // Over cap → MkvInvalid, never a giant allocation.
+        let e = checked_size(257, 256).unwrap_err();
+        assert!(is_mkv_invalid(&e));
+        // A hostile multi-GB block size is rejected as MkvInvalid.
+        let e = checked_size(4 * 1024 * 1024 * 1024, MAX_BLOCK_SIZE).unwrap_err();
+        assert!(is_mkv_invalid(&e));
+    }
+
+    #[test]
+    fn read_uint_bounded_rejects_oversized_int() {
+        // size > 8 would index out of the fixed 8-byte buffer in
+        // read_uint_val (panic / OOB). The guard turns it into a clean
+        // MkvInvalid error instead.
+        let mut data = Cursor::new(vec![0u8; 16]);
+        let e = read_uint_bounded(&mut data, 9).unwrap_err();
+        assert!(is_mkv_invalid(&e));
+    }
+
+    #[test]
+    fn read_uint_bounded_accepts_valid_width() {
+        // 8 bytes is the max legal EBML uint width and must still work.
+        let mut data = Cursor::new(vec![0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02]);
+        assert_eq!(read_uint_bounded(&mut data, 8).unwrap(), 0x0102);
+    }
+
+    #[test]
+    fn read_string_bounded_rejects_huge_string() {
+        // Claimed string length far above the cap must not allocate.
+        let mut data = Cursor::new(vec![0u8; 16]);
+        let e = read_string_bounded(&mut data, MAX_STRING_LEN + 1).unwrap_err();
+        assert!(is_mkv_invalid(&e));
+    }
+
+    /// Build a minimal MKV (EBML header + Segment + Info + Tracks) so the
+    /// reader is positioned in the cluster body, then append the given
+    /// cluster bytes. Returns the full byte stream.
+    fn minimal_mkv_with_cluster(cluster_body: &[u8]) -> Vec<u8> {
+        let mut out = Vec::new();
+        // EBML header (empty body).
+        ebml::write_id(&mut out, ebml::EBML).unwrap();
+        ebml::write_size(&mut out, 0).unwrap();
+        // Segment (unknown size so the reader streams children).
+        ebml::write_id(&mut out, ebml::SEGMENT).unwrap();
+        ebml::write_unknown_size(&mut out).unwrap();
+        // Empty Info.
+        ebml::write_id(&mut out, ebml::INFO).unwrap();
+        ebml::write_size(&mut out, 0).unwrap();
+        // Empty Tracks.
+        ebml::write_id(&mut out, ebml::TRACKS).unwrap();
+        ebml::write_size(&mut out, 0).unwrap();
+        out.extend_from_slice(cluster_body);
+        out
+    }
+
+    #[test]
+    fn simple_block_oversized_size_is_rejected() {
+        // Cluster containing a SIMPLE_BLOCK that claims a 2 GiB payload.
+        // The reader must reject it (MkvInvalid) rather than attempt a
+        // multi-GB allocation. Header parse stops at CLUSTER, so the
+        // SIMPLE_BLOCK is hit on the first read().
+        let mut cluster = Vec::new();
+        ebml::write_id(&mut cluster, ebml::CLUSTER).unwrap();
+        ebml::write_unknown_size(&mut cluster).unwrap();
+        ebml::write_id(&mut cluster, ebml::SIMPLE_BLOCK).unwrap();
+        ebml::write_size(&mut cluster, 2 * 1024 * 1024 * 1024).unwrap();
+        // No payload follows — but we must fail on the size check, before
+        // any read of the body.
+        let bytes = minimal_mkv_with_cluster(&cluster);
+
+        let mut stream = MkvStream::open(Cursor::new(bytes)).unwrap();
+        let e = stream.read().unwrap_err();
+        assert!(is_mkv_invalid(&e));
+    }
+
+    #[test]
+    fn well_formed_simple_block_round_trips() {
+        // A small, well-formed SIMPLE_BLOCK must still parse into a frame.
+        // We need at least one stream so the track index is in range, so
+        // give Tracks one video TRACK_ENTRY (track number 1).
+        let mut out = Vec::new();
+        ebml::write_id(&mut out, ebml::EBML).unwrap();
+        ebml::write_size(&mut out, 0).unwrap();
+        ebml::write_id(&mut out, ebml::SEGMENT).unwrap();
+        ebml::write_unknown_size(&mut out).unwrap();
+        ebml::write_id(&mut out, ebml::INFO).unwrap();
+        ebml::write_size(&mut out, 0).unwrap();
+
+        // Tracks → one TRACK_ENTRY (track number 1, type 1 = video).
+        let mut entry = Vec::new();
+        ebml::write_uint(&mut entry, ebml::TRACK_NUMBER, 1).unwrap();
+        ebml::write_uint(&mut entry, ebml::TRACK_TYPE, 1).unwrap();
+        let mut track_entry = Vec::new();
+        ebml::write_id(&mut track_entry, ebml::TRACK_ENTRY).unwrap();
+        ebml::write_size(&mut track_entry, entry.len() as u64).unwrap();
+        track_entry.extend_from_slice(&entry);
+        ebml::write_id(&mut out, ebml::TRACKS).unwrap();
+        ebml::write_size(&mut out, track_entry.len() as u64).unwrap();
+        out.extend_from_slice(&track_entry);
+
+        // Cluster with a SIMPLE_BLOCK: track vint=0x81 (track 1),
+        // rel_ts=0x0000, flags=0x80 (keyframe), then 4 bytes of data.
+        ebml::write_id(&mut out, ebml::CLUSTER).unwrap();
+        ebml::write_unknown_size(&mut out).unwrap();
+        let block = [0x81u8, 0x00, 0x00, 0x80, 0xAA, 0xBB, 0xCC, 0xDD];
+        ebml::write_id(&mut out, ebml::SIMPLE_BLOCK).unwrap();
+        ebml::write_size(&mut out, block.len() as u64).unwrap();
+        out.extend_from_slice(&block);
+
+        let mut stream = MkvStream::open(Cursor::new(out)).unwrap();
+        let frame = stream.read().unwrap().expect("expected a frame");
+        assert_eq!(frame.track, 0);
+        assert!(frame.keyframe);
+        assert_eq!(frame.data, vec![0xAA, 0xBB, 0xCC, 0xDD]);
+    }
+}

src/mux/pipelined_stream.rs

@@ -176,6 +176,18 @@ impl Stream for PipelinedPesStream {
                 }
                 false => {
                     self.eof = true;
+                    // Drain any access unit a parser buffered past the last
+                    // PES (e.g. DTS-HD's final core+extension unit).
+                    let pid_to_track = &self.pid_to_track;
+                    let pending = &mut self.pending_frames;
+                    for (pid, parser) in self.parsers.iter_mut() {
+                        let Some(&(_, track)) = pid_to_track.iter().find(|(p, _)| p == pid) else {
+                            continue;
+                        };
+                        for frame in parser.flush() {
+                            pending.push_back(PesFrame::from_codec_frame(track, frame));
+                        }
+                    }
                     return Ok(self.pending_frames.pop_front());
                 }
             }

src/mux/resolve.rs

@@ -162,15 +162,32 @@ fn validate_network_addr(addr: &str) -> io::Result<()> {
 /// Options for opening an input stream.
 #[derive(Default)]
 pub struct InputOptions {
-    pub keydb_path: Option<String>,
-    /// Caller-supplied Unit Key (external Unit Key) — the second, mutually
-    /// exclusive key source. Takes precedence over `keydb_path`.
-    pub unit_key: Option<[u8; 16]>,
+    /// Caller-resolved per-CPS-unit AACS keys to apply to the scanned disc
+    /// (`(cps_unit, 16-byte key)`). Empty for an unencrypted disc or when the
+    /// caller has no key. The library does no lookup — a key source resolves
+    /// these and the caller passes them here.
+    pub unit_keys: Vec<(u32, [u8; 16])>,
     pub title_index: Option<usize>,
     /// Skip decryption — return raw encrypted bytes.
     pub raw: bool,
 }
 
+/// Decide whether an ISO mux must abort for lack of a usable AACS key.
+///
+/// Returns `true` only when ALL hold: decryption is requested (`!raw`), the
+/// disc carries AACS state (`has_aacs` — AACS-encrypted, not CSS/unencrypted),
+/// and key resolution produced no usable key (`keys` is
+/// [`crate::decrypt::DecryptKeys::None`]). In that case muxing would emit
+/// undecryptable garbage, so the caller fails fast with [`Error::NoDiscKey`].
+///
+/// `--raw` (raw=true) always returns `false` — raw intentionally skips
+/// decryption and needs no key. A non-AACS disc (`has_aacs=false`) always
+/// returns `false`: unencrypted content has `None` keys legitimately, and CSS
+/// DVDs resolve to `DecryptKeys::Css{..}` (never `None`).
+fn aacs_key_missing(raw: bool, has_aacs: bool, keys: &crate::decrypt::DecryptKeys) -> bool {
+    !raw && has_aacs && matches!(keys, crate::decrypt::DecryptKeys::None)
+}
+
 /// Open a PES input stream (produces PES frames).
 pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::Stream>> {
     let parsed = parse_url(url);
@@ -184,11 +201,6 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
         }
         StreamUrl::Iso { ref path } => {
             validate_file_path(path, "iso")?;
-            let scan_opts = crate::disc::ScanOptions {
-                keydb_path: opts.keydb_path.as_ref().map(Into::into),
-                unit_key: opts.unit_key,
-                ..Default::default()
-            };
             // FileSectorSource is the sole file-backed sector source.
             // It carries the platform-tuned SEQUENTIAL fadvise hint
             // (so the kernel readahead window widens) and the periodic
@@ -196,8 +208,38 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
             // when the mux output is being written to the same disk.
             let mut reader = crate::io::file_sector_source::FileSectorSource::open(path)?;
             let capacity = reader.capacity_sectors();
-            let disc = crate::disc::Disc::scan_image(&mut reader, capacity, &scan_opts)
-                .map_err(|e| -> io::Error { e.into() })?;
+            let mut disc = crate::disc::Disc::scan_image(
+                &mut reader,
+                capacity,
+                &crate::disc::ScanOptions::default(),
+            )
+            .map_err(|e| -> io::Error { e.into() })?;
+            // Apply the caller-resolved keys (lookup-free); decrypt_keys() then
+            // yields them for the stream below. Propagate a failed application
+            // rather than silently muxing an undecryptable stream.
+            if !opts.unit_keys.is_empty() {
+                // These UKs were already resolved AND validated by the caller
+                // (the CLI's keydb loop), so no re-validation sample is needed.
+                disc.decrypt_with(crate::disc::Key::Unit(opts.unit_keys.clone()), &[])
+                    .map_err(|e| -> io::Error { e.into() })?;
+            }
+            // No-key guard: if decryption is requested (not --raw) and the disc
+            // is AACS-encrypted but key resolution yielded no usable key, FAIL
+            // here — muxing an undecryptable stream produces ~100 MB of garbage
+            // (encrypted m2ts → no TS syncs → demuxer emits nothing). A cheap
+            // result-check on `decrypt_keys()`; no probe decryption needed.
+            // CSS (DVD) decrypts from compiled keys (`decrypt_keys()` returns
+            // `Css{..}`, never `None`), so this gate is AACS-only via `disc.aacs`.
+            if aacs_key_missing(opts.raw, disc.aacs.is_some(), &disc.decrypt_keys()) {
+                // Surface the disc hash (40-hex, no `0x` prefix) so the caller
+                // can name the disc. Empty if scan didn't capture it.
+                let disc_hash = disc
+                    .aacs
+                    .as_ref()
+                    .map(|a| a.disc_hash.trim_start_matches("0x").to_string())
+                    .unwrap_or_default();
+                return Err(crate::error::Error::NoDiscKey { disc_hash }.into());
+            }
             if disc.titles.is_empty() {
                 return Err(crate::error::Error::NoStreams.into());
             }
@@ -209,8 +251,15 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
                 }
                 .into());
             }
-            let title = disc.titles[idx].clone();
+            // 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.
             let keys = disc.decrypt_keys();
+            if let Ok(probe) = crate::io::file_sector_source::FileSectorSource::open(path) {
+                let mut dec = crate::sector::DecryptingSectorSource::new(probe, keys.clone());
+                crate::disc::correct_truehd_channels(&mut dec, &mut disc.titles[idx]);
+            }
+            let title = disc.titles[idx].clone();
             let format = disc.content_format;
             // ISO file: 16 MiB batch — sequential read from fast
             // storage, no bad sectors. Measured optimum on the rip1
@@ -335,7 +384,8 @@ fn build_demux_state(title: &DiscTitle, format: ContentFormat) -> DemuxState {
         };
         pids.push(pid);
         pid_to_track.push((pid, idx));
-        parsers.push((pid, super::codec::parser_for_codec(codec, None)));
+        let is_dvd_ps = matches!(format, ContentFormat::MpegPs);
+        parsers.push((pid, super::codec::parser_for_codec(codec, None, is_dvd_ps)));
     }
     let (ts, ps) = match format {
         ContentFormat::MpegPs => (None, Some(super::ps::PsDemuxer::new())),
@@ -443,3 +493,50 @@ fn build_m2ts_pipeline<R: std::io::Read + Send + 'static>(
         pid_to_track,
     ))
 }
+
+#[cfg(test)]
+mod tests {
+    use super::aacs_key_missing;
+    use crate::decrypt::DecryptKeys;
+
+    fn aacs_keys() -> DecryptKeys {
+        DecryptKeys::Aacs {
+            unit_keys: vec![(1, [0x11u8; 16])],
+            read_data_key: None,
+        }
+    }
+
+    fn css_keys() -> DecryptKeys {
+        DecryptKeys::Css {
+            title_key: [0u8; 5],
+        }
+    }
+
+    #[test]
+    fn encrypted_no_key_aborts() {
+        // AACS disc, decryption requested, resolver yielded no key → abort.
+        assert!(aacs_key_missing(false, true, &DecryptKeys::None));
+    }
+
+    #[test]
+    fn encrypted_with_key_proceeds() {
+        // AACS disc with a usable key → proceed.
+        assert!(!aacs_key_missing(false, true, &aacs_keys()));
+    }
+
+    #[test]
+    fn not_encrypted_proceeds() {
+        // No AACS state: unencrypted (None keys) and CSS (Css keys) both OK.
+        assert!(!aacs_key_missing(false, false, &DecryptKeys::None));
+        assert!(!aacs_key_missing(false, false, &css_keys()));
+    }
+
+    #[test]
+    fn raw_never_aborts() {
+        // --raw skips decryption — must never hit the no-key abort, even on an
+        // AACS disc with no key resolved.
+        assert!(!aacs_key_missing(true, true, &DecryptKeys::None));
+        assert!(!aacs_key_missing(true, true, &aacs_keys()));
+        assert!(!aacs_key_missing(true, false, &DecryptKeys::None));
+    }
+}

src/mux/ts.rs

@@ -35,6 +35,15 @@ struct PesAssembler {
     pts: Option<i64>,
     dts: Option<i64>,
     active: bool,
+    /// PES-header bytes still to be skipped on the next continuation
+    /// packet(s). A PES header (9 + PES_header_data_length, up to 264
+    /// bytes) can exceed a single 184-byte TS payload, spilling into the
+    /// following continuation packet. Those spillover bytes are NOT
+    /// elementary-stream data and must be skipped, or the PES start code
+    /// (`00 00 01 …`) and timestamp bytes get injected into the ES — for
+    /// HEVC/H264 that reads as a spurious start code / corrupt slice
+    /// payload. Tracks how many header bytes remain across packets.
+    header_remaining: usize,
 }
 
 /// Initial capacity for a fresh PES buffer. Sized to cover the
@@ -54,6 +63,7 @@ impl PesAssembler {
             pts: None,
             dts: None,
             active: false,
+            header_remaining: 0,
         }
     }
 
@@ -235,12 +245,35 @@ impl TsDemuxer {
         let payload = &ts[payload_start..];
 
         if pusi {
-            let (pts, dts, pes_data_start) = parse_pes_header(payload);
+            // `header_len` is the FULL (uncapped) PES-header length:
+            // 0 = malformed (payload is not a PES start), else 6/9+N.
+            let (pts, dts, header_len) = parse_pes_header(payload);
             if let Some(prev) = asm.start(pts, dts) {
                 completed.push(prev);
             }
-            if pes_data_start < payload.len() {
-                asm.push(&payload[pes_data_start..]);
+            if header_len == 0 {
+                // PUSI packet whose payload is not a valid PES start. Do
+                // NOT push it — those bytes are not elementary-stream data
+                // and would inject a spurious start code / garbage.
+                asm.header_remaining = 0;
+            } else if header_len <= payload.len() {
+                // Header fits in this packet (the common case).
+                asm.header_remaining = 0;
+                if header_len < payload.len() {
+                    asm.push(&payload[header_len..]);
+                }
+            } else {
+                // Header spills past this packet — skip the remainder on
+                // the following continuation packet(s).
+                asm.header_remaining = header_len - payload.len();
+            }
+        } else if asm.header_remaining > 0 {
+            // Continuation packet still inside a PES header that spanned
+            // the boundary — consume header bytes before any ES data.
+            let skip = asm.header_remaining.min(payload.len());
+            asm.header_remaining -= skip;
+            if skip < payload.len() {
+                asm.push(&payload[skip..]);
             }
         } else {
             asm.push(payload);
@@ -260,7 +293,14 @@ impl TsDemuxer {
 }
 
 /// Parse a PES packet header, extracting PTS and DTS.
-/// Returns (pts, dts, offset_to_elementary_stream_data).
+///
+/// Returns `(pts, dts, header_len)` where `header_len` is the FULL,
+/// UNCAPPED PES-header length in bytes (`9 + PES_header_data_length`, or
+/// 6 for stream IDs without the standard extension). `0` signals the
+/// payload is not a valid PES start (malformed / too short). The caller
+/// must treat `header_len` as bytes-to-skip and carry any remainder past
+/// this packet's payload into the next continuation packet — the header
+/// can exceed one TS payload, and the spillover is header, not ES data.
 fn parse_pes_header(data: &[u8]) -> (Option<i64>, Option<i64>, usize) {
     // PES packet: 00 00 01 [stream_id] [length:2] [flags...]
     if data.len() < 9 || data[0] != 0x00 || data[1] != 0x00 || data[2] != 0x01 {
@@ -288,7 +328,10 @@ fn parse_pes_header(data: &[u8]) -> (Option<i64>, Option<i64>, usize) {
 
     let pts_dts_flags = (data[7] >> 6) & 0x03;
     let header_data_len = data[8] as usize;
-    let data_start = (9 + header_data_len).min(data.len());
+    // Full, uncapped header length. PTS/DTS (if present) live in the
+    // first ~19 bytes, always within this packet's payload, so they parse
+    // here; only the *skip* length may extend into the next packet.
+    let header_len = 9 + header_data_len;
 
     let mut pts = None;
     let mut dts = None;
@@ -300,7 +343,7 @@ fn parse_pes_header(data: &[u8]) -> (Option<i64>, Option<i64>, usize) {
         dts = parse_timestamp(&data[14..19]);
     }
 
-    (pts, dts, data_start)
+    (pts, dts, header_len)
 }
 
 /// Parse a 5-byte PTS/DTS timestamp (33 bits in 90kHz).
@@ -404,10 +447,19 @@ pub fn scan_streams(data: &[u8]) -> Option<Vec<crate::disc::Stream>> {
 
             let section_len =
                 (((data[pmt_start + 1] & 0x0F) as usize) << 8) | data[pmt_start + 2] as usize;
+            // section_length counts the bytes after this field, including the
+            // trailing 4-byte CRC; `< 4` would underflow `end` below. Guard it
+            // exactly like the PAT parser above.
+            if section_len < 4 {
+                offset += BD_TS_PACKET_SIZE;
+                continue;
+            }
             let prog_info_len =
                 (((data[pmt_start + 10] & 0x0F) as usize) << 8) | data[pmt_start + 11] as usize;
             let mut pos = pmt_start + 12 + prog_info_len;
-            let end = pmt_start + 3 + section_len - 4;
+            // Clamp the section end to the buffer; a malformed section_len or
+            // prog_info_len must never drive reads past `data`.
+            let end = (pmt_start + 3 + section_len - 4).min(data.len());
 
             while pos + 5 <= data.len() && pos < end {
                 let stream_type = data[pos];

src/sector/prefetched.rs

@@ -157,14 +157,15 @@ impl PrefetchedSectorSource {
                         Ok(b) => b,
                         Err(_) => return, // consumer dropped both channels
                     };
-                    if buf.len() < bytes {
-                        buf.resize(bytes, 0);
-                    } else {
-                        // Re-expose the full extent; previous truncate
-                        // shrank the visible len without freeing pages.
-                        // SAFETY: capacity is at least `bytes` after
-                        // construction with `vec![0u8; batch_bytes]`.
+                    if bytes <= buf.capacity() {
+                        // Re-expose `bytes` without zero-filling pages that
+                        // `read_sectors` is about to overwrite. The 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.
                         unsafe { buf.set_len(bytes) };
+                    } else {
+                        buf.resize(bytes, 0);
                     }
                     let lba = extent.start_lba + offset;
                     match reader.read_sectors(lba, sectors, &mut buf[..bytes], false) {

tests/crypto_tests.rs

@@ -89,8 +89,8 @@ fn aacs_decrypt_unit_roundtrip() {
         plain[offset] = 0x47; // TS sync byte
         offset += 192;
     }
-    // Set encryption flag (bits 6-7 of byte 0)
-    plain[0] |= 0xC0;
+    // No flag set: CBC-encrypting the body below scrambles packets 1..31's TS
+    // syncs, which is exactly what `is_aacs_scrambled` (raw-sync) detects.
 
     // Save original plaintext for comparison
     let expected = plain.clone();
@@ -126,8 +126,8 @@ fn aacs_decrypt_unit_roundtrip() {
         prev.copy_from_slice(&plain[off..off + 16]);
     }
 
-    // Verify it looks encrypted
-    assert!(aacs::is_unit_encrypted(&plain));
+    // Verify it looks encrypted (body TS syncs scrambled)
+    assert!(aacs::is_aacs_scrambled(&plain));
 
     // Now decrypt
     let result = aacs::decrypt_unit(&mut plain, &unit_key);
@@ -136,8 +136,8 @@ fn aacs_decrypt_unit_roundtrip() {
         "decrypt_unit should return true on valid encrypted unit"
     );
     assert!(
-        !aacs::is_unit_encrypted(&plain),
-        "encryption flag should be cleared"
+        !aacs::is_aacs_scrambled(&plain),
+        "decrypted unit should read as clear (TS syncs restored)"
     );
 
     // Verify TS sync bytes at expected positions (flag byte is cleared by decrypt)
@@ -156,17 +156,11 @@ fn aacs_decrypt_unit_roundtrip() {
         sync_count, expected_syncs
     );
 
-    // Compare all bytes except byte 0 (encryption flag cleared)
+    // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(
-        &plain[1..aacs::ALIGNED_UNIT_LEN],
-        &expected[1..aacs::ALIGNED_UNIT_LEN],
-        "decrypted unit body does not match original"
-    );
-    // Byte 0: original had 0xC0 set, decrypted has it cleared
-    assert_eq!(
-        plain[0] & !0xC0,
-        expected[0] & !0xC0,
-        "byte 0 mismatch ignoring flag"
+        &plain[..],
+        &expected[..],
+        "decrypted unit does not match original plaintext"
     );
 }
 
@@ -260,49 +254,65 @@ fn aacs_vuk_derivation_roundtrip() {
     assert_eq!(vuk, vuk2, "derive_vuk not deterministic");
 }
 
-/// Test: aacs_is_unit_encrypted detects encryption flags correctly.
+/// Test: aacs_is_aacs_scrambled detects scrambled units via the raw TS syncs.
 #[test]
-fn aacs_is_unit_encrypted_detection() {
-    let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];
-
+fn aacs_is_aacs_scrambled_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::ALIGNED_UNIT_LEN];
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        clear[off] = 0x47;
+        off += 192;
+    }
     assert!(
-        !aacs::is_unit_encrypted(&unit),
-        "zero unit should not be encrypted"
+        !aacs::is_aacs_scrambled(&clear),
+        "clear unit (syncs intact) must not be scrambled"
     );
 
-    unit[0] = 0x40; // bit 6 set
-    assert!(aacs::is_unit_encrypted(&unit));
+    // Flag bits do NOT make a synced unit look scrambled.
+    let mut flagged = clear.clone();
+    flagged[0] = 0xC0; // copy-control bits
+    flagged[7] = 0xC0; // TSC bits
+    assert!(
+        !aacs::is_aacs_scrambled(&flagged),
+        "flag bits must not be read as encryption"
+    );
 
-    unit[0] = 0x80; // bit 7 set
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    unit[0] = 0xC0; // both bits set
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    unit[0] = 0x3F; // bits 6-7 clear
-    assert!(!aacs::is_unit_encrypted(&unit));
+    // A scrambled body (syncs destroyed) → scrambled.
+    let scrambled = vec![0x99u8; aacs::ALIGNED_UNIT_LEN];
+    assert!(
+        aacs::is_aacs_scrambled(&scrambled),
+        "unit with no intact TS syncs must read as scrambled"
+    );
 
     // Too short
-    let short = vec![0xC0u8; 100];
+    let short = vec![0xFFu8; 100];
     assert!(
-        !aacs::is_unit_encrypted(&short),
+        !aacs::is_aacs_scrambled(&short),
         "short buffer should not be detected"
     );
 }
 
 /// Test: aacs_decrypt_unit_unencrypted_passthrough
 ///
-/// A unit without encryption flags should pass through decrypt_unit unchanged.
+/// A clear unit (TS syncs intact) should pass through decrypt_unit unchanged.
 #[test]
 fn aacs_decrypt_unit_unencrypted_passthrough() {
     let mut unit = vec![0x42u8; aacs::ALIGNED_UNIT_LEN];
-    unit[0] = 0x00; // no encryption flag
+    // Intact TS syncs every 192 bytes → not scrambled → passthrough.
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        unit[off] = 0x47;
+        off += 192;
+    }
     let original = unit.clone();
     let key = [0xAA; 16];
 
+    assert!(!aacs::is_aacs_scrambled(&unit));
     let result = aacs::decrypt_unit(&mut unit, &key);
-    assert!(result, "unencrypted unit should return true");
-    assert_eq!(unit, original, "unencrypted unit should be unchanged");
+    assert!(result, "clear unit should return true");
+    assert_eq!(unit, original, "clear unit should be unchanged");
 }
 
 // ── AACS cross-validation with independent AES implementation ──────────────
@@ -369,8 +379,7 @@ fn aacs_cross_validation_encrypt_then_decrypt() {
             plaintext[i] = (i % 251) as u8;
         }
     }
-    // Set encryption flag
-    plaintext[0] = 0xC0;
+    // No flag set: the CBC-encrypted body scrambles the packet syncs.
 
     let expected = plaintext.clone();
 
@@ -401,14 +410,11 @@ fn aacs_cross_validation_encrypt_then_decrypt() {
         ok,
         "decrypt_unit returned false (TS sync verification failed)"
     );
-    assert_eq!(plaintext[0] & 0xC0, 0x00, "encryption flag not cleared");
 
-    // Compare (byte 0 flag was cleared)
-    let mut expected_cleared = expected.clone();
-    expected_cleared[0] &= !0xC0;
+    // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(
-        &plaintext[1..aacs::ALIGNED_UNIT_LEN],
-        &expected_cleared[1..aacs::ALIGNED_UNIT_LEN],
+        &plaintext[..],
+        &expected[..],
         "decrypted unit does not match original plaintext"
     );
 }
@@ -428,7 +434,7 @@ fn aacs_cross_validation_alternate_key() {
         plaintext[off] = 0x47;
         off += 192;
     }
-    plaintext[0] = 0xC0;
+    // No flag set: the CBC-encrypted body scrambles the packet syncs.
     let expected = plaintext.clone();
 
     let mut header = [0u8; 16];
@@ -446,12 +452,8 @@ fn aacs_cross_validation_alternate_key() {
 
     assert!(aacs::decrypt_unit(&mut plaintext, &unit_key));
 
-    let mut expected_cleared = expected;
-    expected_cleared[0] &= !0xC0;
-    assert_eq!(
-        &plaintext[1..aacs::ALIGNED_UNIT_LEN],
-        &expected_cleared[1..aacs::ALIGNED_UNIT_LEN],
-    );
+    // 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

tests/disc_tests.rs

@@ -126,31 +126,19 @@ fn disc_title_total_sectors() {
 // ── ScanOptions tests ──────────────────────────────────────────────────────
 
 #[test]
-fn scan_options_default() {
+fn scan_options_default_has_no_credentials() {
+    // Lookup-free: the only scan input is the optional live-drive credentials.
     let opts = ScanOptions::default();
-    assert!(opts.keydb_path.is_none());
+    assert!(opts.credentials.is_none());
 }
 
 #[test]
-fn scan_options_with_keydb() {
+fn scan_options_with_credentials() {
     let opts = ScanOptions {
-        keydb_path: Some(("/tmp/KEYDB.cfg").into()),
-        ..Default::default()
+        credentials: Some(libfreemkv::DriveCredentials::default()),
     };
-    assert_eq!(
-        opts.keydb_path.as_ref().unwrap().to_str().unwrap(),
-        "/tmp/KEYDB.cfg"
-    );
-}
-
-#[test]
-fn scan_options_with_keydb_pathbuf() {
-    let path = std::path::PathBuf::from("/home/user/.config/aacs/KEYDB.cfg");
-    let opts = ScanOptions {
-        keydb_path: Some(path.clone()),
-        ..Default::default()
-    };
-    assert_eq!(opts.keydb_path.unwrap(), path);
+    assert!(opts.credentials.is_some());
+    assert!(opts.credentials.unwrap().host_certs.is_empty());
 }
 
 // ── detect_format integration tests ───────────────────────────────────────
@@ -511,21 +499,16 @@ fn batch_count_max_batch_sizes() {
 }
 
 #[test]
-fn resolve_encryption_no_keydb() {
-    // A UDF image with /AACS directory but no keydb path -> aacs is None
+fn scan_encrypted_resolves_no_keys() {
+    // A UDF image with an /AACS directory: the lookup-free scan detects
+    // encryption and captures inputs, but resolves NO key on its own — a
+    // caller applies one later via Disc::decrypt_with.
     let mut reader = MockSectorReader::new();
     build_udf_with_aacs_dir(&mut reader);
 
-    // No keydb configured and no standard keydb on the system
-    let opts = ScanOptions {
-        keydb_path: Some(("/nonexistent/path/KEYDB.cfg").into()),
-        ..Default::default()
-    };
-    let disc = Disc::scan_image(&mut reader, 1000, &opts).unwrap();
+    let disc = Disc::scan_image(&mut reader, 1000, &ScanOptions::default()).unwrap();
 
-    // The disc detects encryption but can't resolve keys without a keydb
-    assert!(
-        disc.aacs.is_none(),
-        "aacs should be None when keydb is unavailable"
-    );
+    // No unit keys without an external key (the mock has no Unit_Key_RO.inf to
+    // capture, so the keyless state isn't even built) — either way, no keys.
+    assert!(matches!(disc.decrypt_keys(), libfreemkv::DecryptKeys::None));
 }

tests/pass_n_patch_fix.rs

@@ -82,22 +82,24 @@ fn decrypt_sectors_with_css_keys_works() {
 /// Test: AACS unit encryption detection works.
 #[test]
 fn aacs_encryption_flag_detection() {
+    // A clear unit: TS syncs (0x47) intact at every 192-byte packet.
     let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        unit[off] = 0x47;
+        off += 192;
+    }
+    // Encryption is the scrambled body (TS syncs destroyed), NOT a flag bit.
+    assert!(!aacs::is_aacs_scrambled(&unit));
 
-    // No encryption flag
-    assert!(!aacs::is_unit_encrypted(&unit));
-
-    // Set bit 6
-    unit[0] |= 0x40;
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    // Set bit 7
-    unit[0] = 0x80;
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    // Both bits set
+    // Flag bits on a synced unit do not make it look encrypted.
     unit[0] = 0xC0;
-    assert!(aacs::is_unit_encrypted(&unit));
+    unit[7] = 0xC0;
+    assert!(!aacs::is_aacs_scrambled(&unit));
+
+    // Scrambled body (syncs gone) → encrypted.
+    let scrambled = vec![0x99u8; aacs::ALIGNED_UNIT_LEN];
+    assert!(aacs::is_aacs_scrambled(&scrambled));
 }
 
 /// Test: DecryptKeys::is_encrypted() correctly identifies encrypted state.