diff --git a/CHANGELOG.md b/CHANGELOG.md
index e2d3ee1..cf473ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,39 @@
 # Changelog
 
+## 0.7.1 (2026-04-11)
+
+### SectorReader trait
+
+- **`SectorReader` trait** — decouples disc scanning from SCSI. UDF, MPLS, CLPI, labels, and AACS resolution now work with any sector source.
+- **`Disc::scan_image()`** — scan ISO images or any SectorReader. Full title/stream/label/AACS pipeline, no drive required.
+- **`resolve_encryption()`** — single function handles AACS 1.0, 2.0, or none. Uses whatever path works (KEYDB VUK, handshake, media key, device key).
+
+### Stream types
+
+- **7 stream types** — Disc, ISO, MKV, M2TS, Network, Stdio, Null
+- **`IsoStream`** — read/write Blu-ray ISO images. Uses `Disc::scan_image()` for full UDF parsing (not heuristic scanning).
+- **`StdioStream`** — stdin/stdout pipe, format-agnostic
+- **Strict URL format** — all URLs require `scheme://path`. Bare paths rejected with clear error messages.
+- **Validation** — empty paths, missing ports, read-only/write-only direction errors
+
+### IOStream trait
+
+- `IOStream` trait for all stream types (Read + Write + info + finish)
+- `open_input()` / `open_output()` resolve URL strings to stream instances
+
+## 0.7.0 (2026-04-11)
+
+### Stream I/O architecture
+
+- **5 stream types** — Disc, MKV, M2TS, Network, Null
+- **`IOStream` trait** — common interface for all streams
+- **URL resolver** — `open_input()` / `open_output()` with scheme://path format
+- **FMKV metadata header** — JSON metadata embedded in M2TS and network streams
+- **Bidirectional MKV** — MkvStream reads and writes Matroska containers
+- **Network streaming** — TCP with metadata header, TCP_NODELAY
+- **BD-TS demuxer** — PAT/PMT scanning, PTS duration detection
+- **EBML reader** — parse existing MKV files for read-side MkvStream
+
 ## 0.6.0 (2026-04-10)
 
 ### API improvements
diff --git a/Cargo.toml b/Cargo.toml
index cb01224..02595bd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "0.7.0"
+version = "0.7.1"
 edition = "2021"
 license = "AGPL-3.0-only"
 description = "Open source raw disc access library for optical drives"
diff --git a/src/disc.rs b/src/disc.rs
index 92a1812..189c6e5 100644
--- a/src/disc.rs
+++ b/src/disc.rs
@@ -10,6 +10,7 @@
 
 use crate::error::{Error, Result};
 use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::speed::DriveSpeed;
 use crate::udf;
 use crate::mpls;
@@ -312,7 +313,16 @@ impl DiscTitle {
 }
 
 
-// ─── AACS state ─────────────────────────────────────────────────────────────
+// ─── Encryption ─────────────────────────────────────────────────────────────
+
+/// Result of SCSI AACS handshake (ECDH authentication).
+/// Only available when scanning from a real drive, not ISO images.
+#[derive(Debug)]
+struct HandshakeResult {
+    volume_id: [u8; 16],
+    read_data_key: Option<[u8; 16]>,
+    error: Option<crate::error::Error>,
+}
 
 /// AACS decryption state for a disc.
 #[derive(Debug)]
@@ -495,19 +505,34 @@ impl Disc {
     /// The session must be open and unlocked (DriveSession::open handles this).
     /// All disc reads use standard READ(10) via UDF -- no vendor SCSI commands.
     pub fn scan(session: &mut DriveSession, opts: &ScanOptions) -> Result<Self> {
-        // 1. Capacity
         let capacity = Self::read_capacity(session)?;
+        let handshake = Self::do_handshake(session, opts);
+        Self::scan_with(session, capacity, handshake, opts)
+    }
 
-        // 2. UDF filesystem
-        let udf_fs = udf::read_filesystem(session)?;
+    /// Scan a disc image (ISO or any SectorReader). No SCSI, no handshake.
+    /// AACS resolution uses KEYDB VUK lookup only.
+    pub fn scan_image(reader: &mut dyn SectorReader, capacity: u32, opts: &ScanOptions) -> Result<Self> {
+        Self::scan_with(reader, capacity, None, opts)
+    }
 
-        // 3. AACS -- read files from disc via UDF, resolve keys via KEYDB
+    /// Core scan pipeline — works with any SectorReader.
+    fn scan_with(
+        reader: &mut dyn SectorReader,
+        capacity: u32,
+        handshake: Option<HandshakeResult>,
+        opts: &ScanOptions,
+    ) -> Result<Self> {
+        // 1. UDF filesystem
+        let udf_fs = udf::read_filesystem(reader)?;
+
+        // 2. Resolve encryption (AACS, CSS, or none)
         let encrypted = udf_fs.find_dir("/AACS").is_some()
             || udf_fs.find_dir("/BDMV/AACS").is_some();
 
         let aacs = if encrypted {
             if let Some(keydb_path) = opts.resolve_keydb() {
-                Self::resolve_aacs(&udf_fs, session, &keydb_path).ok()
+                Self::resolve_encryption(&udf_fs, reader, &keydb_path, handshake.as_ref()).ok()
             } else {
                 None
             }
@@ -515,14 +540,14 @@ impl Disc {
             None
         };
 
-        // 4. Playlists
+        // 3. Playlists
         let mut titles = Vec::new();
         if let Some(playlist_dir) = udf_fs.find_dir("/BDMV/PLAYLIST") {
             for entry in &playlist_dir.entries {
                 if !entry.is_dir && entry.name.to_lowercase().ends_with(".mpls") {
                     let path = format!("/BDMV/PLAYLIST/{}", entry.name);
-                    if let Ok(mpls_data) = udf_fs.read_file(session, &path) {
-                        if let Some(title) = Self::parse_playlist(session, &udf_fs, &entry.name, &mpls_data) {
+                    if let Ok(mpls_data) = udf_fs.read_file(reader, &path) {
+                        if let Some(title) = Self::parse_playlist(reader, &udf_fs, &entry.name, &mpls_data) {
                             titles.push(title);
                         }
                     }
@@ -531,11 +556,11 @@ impl Disc {
         }
         titles.sort_by(|a, b| b.duration_secs.partial_cmp(&a.duration_secs).unwrap_or(std::cmp::Ordering::Equal));
 
-        // 5. Metadata + labels
-        let meta_title = Self::read_meta_title(session, &udf_fs);
-        crate::labels::apply(session, &udf_fs, &mut titles);
+        // 4. Metadata + labels
+        let meta_title = Self::read_meta_title(reader, &udf_fs);
+        crate::labels::apply(reader, &udf_fs, &mut titles);
 
-        // 6. Derive format, layers, region
+        // 5. Derive format, layers, region
         let format = Self::detect_format(&titles);
         let layers = if capacity > 24_000_000 { 2 } else { 1 };
         let region = if format == DiscFormat::Uhd { DiscRegion::Free } else { DiscRegion::Free };
@@ -554,61 +579,74 @@ impl Disc {
         })
     }
 
-    /// Resolve AACS keys from disc files + KEYDB. No SCSI commands.
-    /// Reads Unit_Key_RO.inf, Content Certificate, and MKB from UDF.
-    fn resolve_aacs(
-        udf_fs: &udf::UdfFs,
-        session: &mut DriveSession,
-        keydb_path: &std::path::Path,
-    ) -> Result<AacsState> {
+    /// SCSI handshake result — volume ID and bus keys from ECDH authentication.
+    /// Only available when scanning from a real drive (not ISO images).
+    fn do_handshake(session: &mut DriveSession, opts: &ScanOptions) -> Option<HandshakeResult> {
         use crate::aacs::{self, KeyDb};
 
-        let keydb = KeyDb::load(keydb_path).map_err(|_| Error::KeydbLoad { path: keydb_path.display().to_string() })?;
-
-        // Read AACS files from disc via UDF (standard READ(10), no vendor commands)
-        let uk_ro_data = udf_fs.read_file(session, "/AACS/Unit_Key_RO.inf")
-            .or_else(|_| udf_fs.read_file(session, "/AACS/DUPLICATE/Unit_Key_RO.inf"))
-            .map_err(|_| Error::AacsNoKeys)?;
-
-        let cc_data = udf_fs.read_file(session, "/AACS/Content000.cer")
-            .or_else(|_| udf_fs.read_file(session, "/AACS/Content001.cer"))
-            .ok();
-
-        let mkb_data = udf_fs.read_file(session, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(session, "/AACS/MKB_RO.inf"))
-            .ok();
-        let mkb_ver = mkb_data.as_deref().and_then(aacs::mkb_version);
-
-        // AACS SCSI handshake — get Volume ID (and read data key for AACS 2.0)
-        let mut volume_id = [0u8; 16];
-        let mut read_data_key = None;
-        let mut handshake_error = None;
+        let keydb_path = opts.resolve_keydb()?;
+        let keydb = KeyDb::load(&keydb_path).ok()?;
 
         for hc in &keydb.host_certs {
             match aacs::handshake::aacs_authenticate(
                 session, &hc.private_key, &hc.certificate,
             ) {
                 Ok(mut auth) => {
-                    // Read Volume ID (needed for MK → VUK derivation)
-                    if let Ok(vid) = aacs::handshake::read_volume_id(session, &mut auth) {
-                        volume_id = vid;
-                    }
-
-                    // Read data keys for bus decryption (AACS 2.0 / UHD)
-                    if let Ok((rdk, _wdk)) = aacs::handshake::read_data_keys(session, &mut auth) {
-                        read_data_key = Some(rdk);
-                    }
-
-                    handshake_error = None;
-                    break;
+                    let volume_id = aacs::handshake::read_volume_id(session, &mut auth)
+                        .unwrap_or([0u8; 16]);
+                    let read_data_key = aacs::handshake::read_data_keys(session, &mut auth)
+                        .ok().map(|(rdk, _)| rdk);
+                    return Some(HandshakeResult { volume_id, read_data_key, error: None });
                 }
                 Err(e) => {
-                    handshake_error = Some(e);
+                    // Try next host cert
+                    return Some(HandshakeResult {
+                        volume_id: [0u8; 16],
+                        read_data_key: None,
+                        error: Some(e),
+                    });
                 }
             }
         }
+        None
+    }
 
-        // Resolve: disc hash → KEYDB lookup → VUK → unit keys
+    /// Resolve disc encryption — AACS 1.0, AACS 2.0, CSS, or none.
+    ///
+    /// Reads AACS files from UDF (via SectorReader), 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.
+    fn resolve_encryption(
+        udf_fs: &udf::UdfFs,
+        reader: &mut dyn SectorReader,
+        keydb_path: &std::path::Path,
+        handshake: Option<&HandshakeResult>,
+    ) -> Result<AacsState> {
+        use crate::aacs::{self, KeyDb};
+
+        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)?;
+
+        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);
+
+        // Use handshake volume ID if available, otherwise zeros
+        // (KEYDB VUK lookup by disc hash works without volume ID)
+        let volume_id = handshake.map(|h| h.volume_id).unwrap_or([0u8; 16]);
+        let read_data_key = handshake.and_then(|h| h.read_data_key);
+        let handshake_error = None;
+
+        // Resolve: tries all available paths — KEYDB VUK, media key, processing key, device key
         let resolved = aacs::resolve_keys(
             &uk_ro_data,
             cc_data.as_deref(),
@@ -662,7 +700,7 @@ impl Disc {
     /// Read disc title from META/DL/bdmt_eng.xml (Blu-ray Disc Meta Table).
     /// Prefers English, falls back to first available language.
     /// Returns None if META directory is empty or XML has no usable title.
-    fn read_meta_title(session: &mut DriveSession, udf_fs: &udf::UdfFs) -> Option<String> {
+    fn read_meta_title(reader: &mut dyn SectorReader, udf_fs: &udf::UdfFs) -> Option<String> {
         let meta_dir = udf_fs.find_dir("/BDMV/META")?;
         for sub in &meta_dir.entries {
             if !sub.is_dir { continue; }
@@ -677,7 +715,7 @@ impl Disc {
 
                 if let Some(entry) = target {
                     let path = format!("{}/{}", dl_path, entry.name);
-                    if let Ok(data) = udf_fs.read_file(session, &path) {
+                    if let Ok(data) = udf_fs.read_file(reader, &path) {
                         let xml = String::from_utf8_lossy(&data);
                         if let Some(start) = xml.find("<di:name>") {
                             let s = start + "<di:name>".len();
@@ -704,7 +742,7 @@ impl Disc {
     }
 
     fn parse_playlist(
-        session: &mut DriveSession,
+        reader: &mut dyn SectorReader,
         udf_fs: &udf::UdfFs,
         filename: &str,
         data: &[u8],
@@ -732,7 +770,7 @@ impl Disc {
             let mut pkt_count: u32 = 0;
 
             let clpi_path = format!("/BDMV/CLIPINF/{}.clpi", play_item.clip_id);
-            if let Ok(clpi_data) = udf_fs.read_file(session, &clpi_path) {
+            if let Ok(clpi_data) = udf_fs.read_file(reader, &clpi_path) {
                 if let Ok(clip_info) = clpi::parse(&clpi_data) {
                     pkt_count = clip_info.source_packet_count;
                     total_size += pkt_count as u64 * 192;
@@ -740,7 +778,7 @@ impl Disc {
                     // Get m2ts file start LBA and compute extent from packet count.
                     // BD-ROM m2ts files are contiguous on disc (mastering requirement).
                     let m2ts_path = format!("/BDMV/STREAM/{}.m2ts", play_item.clip_id);
-                    let file_lba = udf_fs.file_start_lba(session, &m2ts_path).unwrap_or(0);
+                    let file_lba = udf_fs.file_start_lba(reader, &m2ts_path).unwrap_or(0);
                     let total_bytes = pkt_count as u64 * 192;
                     let total_sectors = ((total_bytes + 2047) / 2048) as u32;
                     if total_sectors > 0 && file_lba > 0 {
diff --git a/src/drive.rs b/src/drive.rs
index c4a8d56..7709642 100644
--- a/src/drive.rs
+++ b/src/drive.rs
@@ -8,6 +8,7 @@
 
 use std::path::Path;
 use crate::error::{Error, Result};
+use crate::sector::SectorReader;
 use crate::scsi::ScsiTransport;
 use crate::identity::DriveId;
 use crate::profile::{self, DriveProfile};
@@ -160,6 +161,12 @@ impl DriveSession {
     }
 }
 
+impl SectorReader for DriveSession {
+    fn read_sectors(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
+        self.read_disc(lba, count, buf)
+    }
+}
+
 pub fn find_drives() -> Vec<(String, DriveId)> {
     let mut drives = Vec::new();
     for i in 0..16 {
diff --git a/src/labels/criterion.rs b/src/labels/criterion.rs
index 541ba9d..47d4cc0 100644
--- a/src/labels/criterion.rs
+++ b/src/labels/criterion.rs
@@ -3,7 +3,7 @@
 //! Clean structured XML with Content/Qualifier per stream and
 //! stream number mapping via playbackconfig.
 
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::udf::UdfFs;
 use super::{StreamLabel, StreamLabelType, LabelPurpose, LabelQualifier};
 use std::collections::HashMap;
@@ -12,8 +12,8 @@ pub fn detect(udf: &UdfFs) -> bool {
     super::jar_file_exists(udf, "streamproperties.xml")
 }
 
-pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
-    let sp_data = super::read_jar_file(session, udf, "streamproperties.xml")?;
+pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+    let sp_data = super::read_jar_file(reader, udf, "streamproperties.xml")?;
     let sp_text = std::str::from_utf8(&sp_data).ok()?;
 
     let stream_infos = parse_stream_infos(sp_text);
@@ -21,7 +21,7 @@ pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>
 
     // Stream number mapping from playbackconfig.xml
     let mut stream_map: HashMap<String, u16> = HashMap::new();
-    if let Some(pc_data) = super::read_jar_file(session, udf, "playbackconfig.xml") {
+    if let Some(pc_data) = super::read_jar_file(reader, udf, "playbackconfig.xml") {
         if let Ok(pc_text) = std::str::from_utf8(&pc_data) {
             parse_playback_config(pc_text, &mut stream_map);
         }
diff --git a/src/labels/ctrm.rs b/src/labels/ctrm.rs
index 7d782aa..9a26aaa 100644
--- a/src/labels/ctrm.rs
+++ b/src/labels/ctrm.rs
@@ -4,7 +4,7 @@
 //! When both exist, language_streams.txt provides structured types while
 //! menu_base.prop provides stream number → button name mapping.
 
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::udf::UdfFs;
 use super::{StreamLabel, StreamLabelType, LabelPurpose, LabelQualifier, vocab};
 use std::collections::HashMap;
@@ -14,12 +14,12 @@ pub fn detect(udf: &UdfFs) -> bool {
         || super::jar_file_exists(udf, "language_streams.txt")
 }
 
-pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
     // Try language_streams.txt first (richer structured data)
-    let ls_labels = parse_language_streams(session, udf);
+    let ls_labels = parse_language_streams(reader, udf);
 
     // Try menu_base.prop (stream numbers + key names)
-    let mb_labels = parse_menu_base(session, udf);
+    let mb_labels = parse_menu_base(reader, udf);
 
     // If we have both, merge: language_streams for structure, menu_base for names
     match (ls_labels, mb_labels) {
@@ -48,8 +48,8 @@ fn merge(ls: Vec<StreamLabel>, mb: Vec<StreamLabel>) -> Vec<StreamLabel> {
 
 // ── language_streams.txt parser ────────────────────────────────────────────
 
-fn parse_language_streams(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
-    let data = super::read_jar_file(session, udf, "language_streams.txt")?;
+fn parse_language_streams(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+    let data = super::read_jar_file(reader, udf, "language_streams.txt")?;
     let text = std::str::from_utf8(&data).ok()?;
 
     let mut labels = Vec::new();
@@ -123,8 +123,8 @@ fn parse_language_streams(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec
 
 // ── menu_base.prop parser ──────────────────────────────────────────────────
 
-fn parse_menu_base(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
-    let data = super::read_jar_file(session, udf, "menu_base.prop")?;
+fn parse_menu_base(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+    let data = super::read_jar_file(reader, udf, "menu_base.prop")?;
     let text = std::str::from_utf8(&data).ok()?;
 
     // Parse key=value, group by prefix
diff --git a/src/labels/mod.rs b/src/labels/mod.rs
index e59476f..4a5cb3b 100644
--- a/src/labels/mod.rs
+++ b/src/labels/mod.rs
@@ -4,7 +4,7 @@
 //! To add a new format:
 //!   1. Create `src/labels/myformat.rs`
 //!   2. Implement `pub fn detect(udf: &UdfFs) -> bool`
-//!   3. Implement `pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>>`
+//!   3. Implement `pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>>`
 //!   4. Add `mod myformat;` below and one line to `PARSERS` array
 
 mod paramount;
@@ -13,7 +13,7 @@ mod pixelogic;
 mod ctrm;
 pub mod vocab;
 
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::udf::UdfFs;
 use crate::disc::{DiscTitle, Stream};
 
@@ -67,7 +67,7 @@ pub enum LabelQualifier {
 // Order = priority. First match wins. Highest quality output first.
 
 type DetectFn = fn(&UdfFs) -> bool;
-type ParseFn = fn(&mut DriveSession, &UdfFs) -> Option<Vec<StreamLabel>>;
+type ParseFn = fn(&mut dyn SectorReader, &UdfFs) -> Option<Vec<StreamLabel>>;
 
 const PARSERS: &[(&str, DetectFn, ParseFn)] = &[
     ("paramount",  paramount::detect,  paramount::parse),
@@ -79,9 +79,9 @@ const PARSERS: &[(&str, DetectFn, ParseFn)] = &[
 
 /// Search disc for config files, extract labels, apply to streams.
 /// This is 100% optional — if anything fails, streams are untouched.
-pub fn apply(session: &mut DriveSession, udf: &UdfFs, titles: &mut [DiscTitle]) {
+pub fn apply(reader: &mut dyn SectorReader, udf: &UdfFs, titles: &mut [DiscTitle]) {
     let labels = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
-        extract(session, udf)
+        extract(reader, udf)
     })).unwrap_or_default();
     if labels.is_empty() { return; }
 
@@ -133,10 +133,10 @@ pub fn apply(session: &mut DriveSession, udf: &UdfFs, titles: &mut [DiscTitle])
     }
 }
 
-fn extract(session: &mut DriveSession, udf: &UdfFs) -> Vec<StreamLabel> {
+fn extract(reader: &mut dyn SectorReader, udf: &UdfFs) -> Vec<StreamLabel> {
     for (_name, detect, parse) in PARSERS {
         if detect(udf) {
-            if let Some(labels) = parse(session, udf) {
+            if let Some(labels) = parse(reader, udf) {
                 return labels;
             }
         }
@@ -169,7 +169,7 @@ pub(crate) fn find_jar_file(udf: &UdfFs, filename: &str) -> Option<String> {
 }
 
 /// Read a file from any BDMV/JAR subdirectory by filename.
-pub(crate) fn read_jar_file(session: &mut DriveSession, udf: &UdfFs, filename: &str) -> Option<Vec<u8>> {
+pub(crate) fn read_jar_file(reader: &mut dyn SectorReader, udf: &UdfFs, filename: &str) -> Option<Vec<u8>> {
     let path = find_jar_file(udf, filename)?;
-    udf.read_file(session, &path).ok().filter(|d| !d.is_empty())
+    udf.read_file(reader, &path).ok().filter(|d| !d.is_empty())
 }
diff --git a/src/labels/paramount.rs b/src/labels/paramount.rs
index cbeb352..cba0eda 100644
--- a/src/labels/paramount.rs
+++ b/src/labels/paramount.rs
@@ -12,7 +12,7 @@
 //!   sub_com1_idx="23,24,25" />
 //! ```
 
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::udf::UdfFs;
 use super::{StreamLabel, StreamLabelType, LabelPurpose, LabelQualifier};
 
@@ -20,8 +20,8 @@ pub fn detect(udf: &UdfFs) -> bool {
     super::jar_file_exists(udf, "playlists.xml")
 }
 
-pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
-    let data = super::read_jar_file(session, udf, "playlists.xml")?;
+pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+    let data = super::read_jar_file(reader, udf, "playlists.xml")?;
     let text = std::str::from_utf8(&data).ok()?;
 
     // Find the feature playlist — longest duration or name="Feature"
diff --git a/src/labels/pixelogic.rs b/src/labels/pixelogic.rs
index 8010763..b9b4a49 100644
--- a/src/labels/pixelogic.rs
+++ b/src/labels/pixelogic.rs
@@ -5,7 +5,7 @@
 //!
 //! Token format: `{lang}_{codec?}_{purpose?}_{region?}_`
 
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 use crate::udf::UdfFs;
 use super::{StreamLabel, StreamLabelType, LabelPurpose, LabelQualifier, vocab};
 
@@ -18,8 +18,8 @@ pub fn detect(udf: &UdfFs) -> bool {
     super::jar_file_exists(udf, "bluray_project.bin")
 }
 
-pub fn parse(session: &mut DriveSession, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
-    let data = super::read_jar_file(session, udf, "bluray_project.bin")?;
+pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
+    let data = super::read_jar_file(reader, udf, "bluray_project.bin")?;
     let strings = extract_strings(&data);
 
     let mut labels = Vec::new();
diff --git a/src/lib.rs b/src/lib.rs
index 0f8a92a..5c4a994 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -68,6 +68,7 @@
 //! | E7xxx | AACS errors |
 
 pub mod error;
+pub mod sector;
 pub mod scsi;
 pub mod profile;
 pub mod platform;
@@ -90,6 +91,7 @@ pub use drive::{DriveSession, find_drive, find_drives, resolve_device};
 pub use identity::DriveId;
 pub use profile::DriveProfile;
 // Platform trait is pub(crate) -- callers use DriveSession, not Platform directly
+pub use sector::SectorReader;
 pub use scsi::ScsiTransport;
 pub use speed::DriveSpeed;
 pub use disc::{Disc, DiscFormat, DiscTitle, Clip, Stream, VideoStream, AudioStream, SubtitleStream,
diff --git a/src/mux/iso.rs b/src/mux/iso.rs
index 944be0c..e53974b 100644
--- a/src/mux/iso.rs
+++ b/src/mux/iso.rs
@@ -1,54 +1,117 @@
-//! IsoStream — read BD-TS data from a Blu-ray ISO image file.
+//! IsoStream — read/write Blu-ray ISO disc images.
 //!
-//! Read-only. Parses the UDF filesystem inside the ISO to find
-//! BDMV/STREAM/*.m2ts files, then streams the BD-TS bytes.
+//! Read: parses UDF filesystem inside the ISO using the same pipeline as
+//! DiscStream (titles, streams, labels, AACS). An ISO is a flat image of
+//! 2048-byte sectors — sector N starts at byte offset N * 2048.
 //!
-//! An ISO file is a flat image of 2048-byte sectors — the same
-//! layout as on a real disc. Sector N starts at byte offset N * 2048.
+//! Write: creates a sector-by-sector disc image from a SectorReader source.
 
 use std::io::{self, Read, Write, Seek, SeekFrom};
 use std::fs::File;
 use std::path::Path;
 use super::IOStream;
-use crate::disc::DiscTitle;
+use crate::disc::{Disc, DiscTitle, ScanOptions};
+use crate::sector::SectorReader;
+use crate::error::{Error, Result};
 
 const SECTOR_SIZE: u64 = 2048;
 
-/// Blu-ray ISO image stream. Read-only.
+/// File-backed sector reader for ISO images.
+pub struct IsoSectorReader {
+    file: File,
+    capacity: u32,
+}
+
+impl IsoSectorReader {
+    pub fn open(path: &str) -> io::Result<Self> {
+        let file = File::open(Path::new(path))
+            .map_err(|e| io::Error::new(e.kind(), format!("iso://{}: {}", path, e)))?;
+        let size = file.metadata()?.len();
+        let capacity = (size / SECTOR_SIZE) as u32;
+        Ok(Self { file, capacity })
+    }
+
+    pub fn capacity(&self) -> u32 { self.capacity }
+}
+
+impl SectorReader for IsoSectorReader {
+    fn read_sectors(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {
+        let bytes = count as usize * SECTOR_SIZE as usize;
+        self.file.seek(SeekFrom::Start(lba as u64 * SECTOR_SIZE))
+            .map_err(|e| Error::IoError { source: e })?;
+        self.file.read_exact(&mut buf[..bytes])
+            .map_err(|e| Error::IoError { source: e })?;
+        Ok(bytes)
+    }
+}
+
+/// Blu-ray ISO image stream.
 ///
-/// Opens an ISO file, parses UDF to locate BDMV playlists and streams,
-/// then reads the m2ts content sectors in order.
+/// Read: opens ISO, parses UDF (same as DiscStream), streams BD-TS content.
+/// Write: receives sector data and writes to ISO file.
 pub struct IsoStream {
     disc_title: DiscTitle,
-    file: File,
+    disc: Option<Disc>,
+    reader: Option<IsoSectorReader>,
+    writer: Option<io::BufWriter<File>>,
     /// Sector ranges to read: (start_lba, sector_count)
-    extents: Vec<(u64, u64)>,
-    /// Current extent index
+    extents: Vec<(u32, u32)>,
     extent_idx: usize,
-    /// Sectors remaining in current extent
-    sectors_remaining: u64,
-    /// Read buffer for one sector
+    sectors_remaining: u32,
     sector_buf: [u8; SECTOR_SIZE as usize],
-    /// Position within current sector buffer
     buf_pos: usize,
-    /// Bytes valid in sector buffer
     buf_len: usize,
     eof: bool,
 }
 
 impl IsoStream {
-    /// Open an ISO file and scan its contents.
-    ///
-    /// Parses UDF filesystem, finds playlists and stream extents.
-    /// The title_index selects which title to read (0-based, default: longest).
-    pub fn open(path: &str, title_index: Option<usize>) -> io::Result<Self> {
-        let file = File::open(Path::new(path))
-            .map_err(|e| io::Error::new(e.kind(),
-                format!("iso://{}: {}", path, e)))?;
+    /// Open an ISO file for reading. Parses UDF, scans titles, streams, labels.
+    pub fn open(path: &str, title_index: Option<usize>, opts: &ScanOptions) -> io::Result<Self> {
+        let mut reader = IsoSectorReader::open(path)?;
+        let capacity = reader.capacity();
 
-        let mut stream = IsoStream {
+        let disc = Disc::scan_image(&mut reader, capacity, opts)
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?;
+
+        let idx = title_index.unwrap_or(0).min(disc.titles.len().saturating_sub(1));
+        let disc_title = if disc.titles.is_empty() {
+            return Err(io::Error::new(io::ErrorKind::NotFound, "no titles found in ISO image"));
+        } else {
+            disc.titles[idx].clone()
+        };
+
+        let extents: Vec<(u32, u32)> = disc_title.extents.iter()
+            .map(|e| (e.start_lba, e.sector_count))
+            .collect();
+
+        let sectors_remaining = extents.first().map(|e| e.1).unwrap_or(0);
+
+        Ok(IsoStream {
+            disc_title,
+            disc: Some(disc),
+            reader: Some(reader),
+            writer: None,
+            extents,
+            extent_idx: 0,
+            sectors_remaining,
+            sector_buf: [0u8; SECTOR_SIZE as usize],
+            buf_pos: 0,
+            buf_len: 0,
+            eof: false,
+        })
+    }
+
+    /// Create an ISO file for writing. Receives raw sector data.
+    pub fn create(path: &str) -> io::Result<Self> {
+        let file = File::create(Path::new(path))
+            .map_err(|e| io::Error::new(e.kind(), format!("iso://{}: {}", path, e)))?;
+        let writer = io::BufWriter::with_capacity(4 * 1024 * 1024, file);
+
+        Ok(IsoStream {
             disc_title: DiscTitle::empty(),
-            file,
+            disc: None,
+            reader: None,
+            writer: Some(writer),
             extents: Vec::new(),
             extent_idx: 0,
             sectors_remaining: 0,
@@ -56,128 +119,35 @@ impl IsoStream {
             buf_pos: 0,
             buf_len: 0,
             eof: false,
-        };
-
-        stream.scan_iso(title_index)?;
-        Ok(stream)
+        })
     }
 
-    /// Scan the ISO: parse UDF, build title metadata, extract extent map.
-    fn scan_iso(&mut self, title_index: Option<usize>) -> io::Result<()> {
-        // Read AVDP at sector 256 to verify this is a UDF disc image
-        let avdp = self.read_sector(256)?;
-        let tag_id = u16::from_le_bytes([avdp[0], avdp[1]]);
-        if tag_id != 2 {
-            return Err(io::Error::new(io::ErrorKind::InvalidData,
-                "not a valid UDF image — no AVDP at sector 256"));
-        }
-
-        // For now, scan BDMV/PLAYLIST and BDMV/STREAM directories
-        // by searching for MPLS and M2TS markers in the UDF metadata.
-        //
-        // Full UDF parsing (AVDP → VDS → metadata → FSD → root → files)
-        // will be refactored out of udf.rs to work with both DriveSession
-        // and file-backed sector reads. For now, find the main m2ts file
-        // by scanning for the stream file extents in the UDF file entries.
-
-        // Find all .m2ts file extents from UDF metadata
-        let disc_size = self.file.seek(SeekFrom::End(0))?;
-        let total_sectors = disc_size / SECTOR_SIZE;
-        self.file.seek(SeekFrom::Start(0))?;
-
-        // Scan UDF partition for BDMV structure
-        let titles = self.find_stream_extents(total_sectors)?;
-
-        if titles.is_empty() {
-            return Err(io::Error::new(io::ErrorKind::NotFound,
-                "no BD stream files found in ISO image"));
-        }
-
-        // Select title
-        let idx = title_index.unwrap_or(0).min(titles.len() - 1);
-        let (title, extents) = &titles[idx];
-
-        self.disc_title = title.clone();
-        self.extents = extents.clone();
-
-        if !self.extents.is_empty() {
-            self.sectors_remaining = self.extents[0].1;
-        }
-
-        Ok(())
+    /// Set metadata (for write mode).
+    pub fn meta(mut self, dt: &DiscTitle) -> Self {
+        self.disc_title = dt.clone();
+        self
     }
 
-    /// Read a single sector from the ISO file.
-    fn read_sector(&mut self, lba: u64) -> io::Result<Vec<u8>> {
-        let mut buf = vec![0u8; SECTOR_SIZE as usize];
-        self.file.seek(SeekFrom::Start(lba * SECTOR_SIZE))?;
-        self.file.read_exact(&mut buf)?;
-        Ok(buf)
-    }
-
-    /// Scan the ISO for BD stream file extents.
-    ///
-    /// Returns: Vec of (DiscTitle, Vec<(start_lba, sector_count)>)
-    ///
-    /// This is a simplified scanner that finds m2ts content by looking
-    /// for 192-byte BD-TS packet boundaries (0x47 sync byte at offset 4).
-    /// Full UDF parsing will replace this once udf.rs is decoupled from DriveSession.
-    fn find_stream_extents(&mut self, total_sectors: u64) -> io::Result<Vec<(DiscTitle, Vec<(u64, u64)>)>> {
-        // Strategy: scan the UDF file entry area for allocation descriptors
-        // pointing to large contiguous regions (m2ts files are large).
-        //
-        // For a BD-ROM ISO, the main m2ts typically starts after the BDMV
-        // metadata (around sector 1000-5000) and runs contiguously to the end.
-        //
-        // Quick approach: find first sector with BD-TS sync (0x47 at byte 4)
-        // and treat everything from there to the end as one extent.
-
-        let probe_start = 256u64; // skip lead-in
-        let probe_end = total_sectors.min(10000); // probe first 20 MB
-
-        let mut stream_start: Option<u64> = None;
-
-        for lba in probe_start..probe_end {
-            let sector = self.read_sector(lba)?;
-            // BD-TS: 192-byte packets, sync byte 0x47 at offset 4 of each packet
-            // A sector (2048 bytes) holds partial packets, but the sync pattern
-            // should appear at regular intervals
-            if sector.len() >= 196 && sector[4] == 0x47 {
-                // Verify: check for another sync at offset 196 (4 + 192)
-                if sector[196] == 0x47 {
-                    stream_start = Some(lba);
-                    break;
-                }
-            }
-        }
-
-        match stream_start {
-            Some(start) => {
-                let sector_count = total_sectors - start;
-                let size_bytes = sector_count * SECTOR_SIZE;
-
-                let mut title = DiscTitle::empty();
-                title.playlist = "Main Title".into();
-                title.size_bytes = size_bytes;
-
-                Ok(vec![(title, vec![(start, sector_count)])])
-            }
-            None => Ok(Vec::new()),
-        }
-    }
+    /// Get the full Disc (for listing all titles).
+    pub fn disc(&self) -> Option<&Disc> { self.disc.as_ref() }
 
     /// Read the next sector from the current extent.
     fn read_next_sector(&mut self) -> io::Result<bool> {
+        let reader = match self.reader.as_mut() {
+            Some(r) => r,
+            None => return Ok(false),
+        };
+
         if self.extent_idx >= self.extents.len() {
             return Ok(false);
         }
 
-        let (start_lba, _) = self.extents[self.extent_idx];
-        let offset = self.extents[self.extent_idx].1 - self.sectors_remaining;
+        let (start_lba, total) = self.extents[self.extent_idx];
+        let offset = total - self.sectors_remaining;
         let lba = start_lba + offset;
 
-        self.file.seek(SeekFrom::Start(lba * SECTOR_SIZE))?;
-        self.file.read_exact(&mut self.sector_buf)?;
+        reader.read_sectors(lba, 1, &mut self.sector_buf)
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?;
         self.buf_pos = 0;
         self.buf_len = SECTOR_SIZE as usize;
 
@@ -195,7 +165,12 @@ impl IsoStream {
 
 impl IOStream for IsoStream {
     fn info(&self) -> &DiscTitle { &self.disc_title }
-    fn finish(&mut self) -> io::Result<()> { Ok(()) }
+    fn finish(&mut self) -> io::Result<()> {
+        if let Some(ref mut w) = self.writer {
+            w.flush()?;
+        }
+        Ok(())
+    }
 }
 
 impl Read for IsoStream {
@@ -224,9 +199,17 @@ impl Read for IsoStream {
 }
 
 impl Write for IsoStream {
-    fn write(&mut self, _buf: &[u8]) -> io::Result<usize> {
-        Err(io::Error::new(io::ErrorKind::Unsupported,
-            "iso:// is read-only"))
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        match self.writer.as_mut() {
+            Some(w) => w.write(buf),
+            None => Err(io::Error::new(io::ErrorKind::Unsupported,
+                "iso:// opened for reading — cannot write")),
+        }
+    }
+    fn flush(&mut self) -> io::Result<()> {
+        match self.writer.as_mut() {
+            Some(w) => w.flush(),
+            None => Ok(()),
+        }
     }
-    fn flush(&mut self) -> io::Result<()> { Ok(()) }
 }
diff --git a/src/mux/resolve.rs b/src/mux/resolve.rs
index 73cb395..bf85634 100644
--- a/src/mux/resolve.rs
+++ b/src/mux/resolve.rs
@@ -141,7 +141,11 @@ pub fn open_input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn IOStream
         }
         "iso" => {
             validate_file_path(&parsed.path, "iso")?;
-            Ok(Box::new(IsoStream::open(&parsed.path, opts.title_index)?))
+            let scan_opts = match &opts.keydb_path {
+                Some(p) => crate::disc::ScanOptions::with_keydb(p),
+                None => crate::disc::ScanOptions::default(),
+            };
+            Ok(Box::new(IsoStream::open(&parsed.path, opts.title_index, &scan_opts)?))
         }
         "null" => {
             Err(io::Error::new(io::ErrorKind::InvalidInput,
@@ -166,8 +170,8 @@ pub fn open_output(url: &str, meta: &DiscTitle) -> io::Result<Box<dyn IOStream>>
                 "disc:// is read-only — cannot use as output"))
         }
         "iso" => {
-            Err(io::Error::new(io::ErrorKind::Unsupported,
-                "iso:// is read-only — cannot use as output"))
+            validate_file_path(&parsed.path, "iso")?;
+            Ok(Box::new(IsoStream::create(&parsed.path)?.meta(meta)))
         }
         "null" => {
             Ok(Box::new(NullStream::new().meta(meta)))
diff --git a/src/sector.rs b/src/sector.rs
new file mode 100644
index 0000000..3d14f1e
--- /dev/null
+++ b/src/sector.rs
@@ -0,0 +1,14 @@
+//! SectorReader — trait for reading 2048-byte disc sectors.
+//!
+//! Implemented by DriveSession (SCSI) and IsoFile (file-backed).
+//! Used by UDF parser, disc scanner, label parsers — anything that
+//! reads sectors doesn't need to know where they come from.
+
+use crate::error::Result;
+
+/// Read 2048-byte sectors from a disc or disc image.
+pub trait SectorReader {
+    /// Read `count` sectors starting at `lba` into `buf`.
+    /// `buf` must be at least `count * 2048` bytes.
+    fn read_sectors(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize>;
+}
diff --git a/src/udf.rs b/src/udf.rs
index 3664c47..81a16c5 100644
--- a/src/udf.rs
+++ b/src/udf.rs
@@ -19,7 +19,7 @@
 //!   BD-ROM Part 3 — Blu-ray filesystem profile
 
 use crate::error::{Error, Result};
-use crate::drive::DriveSession;
+use crate::sector::SectorReader;
 
 /// A UDF filesystem parsed from disc.
 #[derive(Debug)]
@@ -74,7 +74,7 @@ impl UdfFs {
     /// Reads sector by sector from disc — no buffering.
     /// Get the absolute starting LBA of a file on disc.
     /// Used by the rip pipeline to locate m2ts content sectors.
-    pub fn file_start_lba(&self, session: &mut DriveSession, path: &str) -> Result<u32> {
+    pub fn file_start_lba(&self, reader: &mut dyn SectorReader, path: &str) -> Result<u32> {
         let parts: Vec<&str> = path.trim_matches('/').split('/').collect();
         let mut current = &self.root;
         for part in &parts[..parts.len() - 1] {
@@ -91,11 +91,11 @@ impl UdfFs {
             !e.is_dir && e.name.eq_ignore_ascii_case(filename)
         }).ok_or_else(|| Error::UdfNotFound { path: path.to_string() }
 )?;
-        let (data_lba, _) = self.read_icb_extent(session, entry.meta_lba)?;
+        let (data_lba, _) = self.read_icb_extent(reader, entry.meta_lba)?;
         Ok(self.partition_start + data_lba)
     }
 
-    pub fn read_file(&self, session: &mut DriveSession, path: &str) -> Result<Vec<u8>> {
+    pub fn read_file(&self, reader: &mut dyn SectorReader, path: &str) -> Result<Vec<u8>> {
         let parts: Vec<&str> = path.trim_matches('/').split('/').collect();
         let mut current = &self.root;
 
@@ -118,7 +118,7 @@ impl UdfFs {
 )?;
 
         // Read the file's ICB to get its data extent
-        let (data_lba, data_len) = self.read_icb_extent(session, entry.meta_lba)?;
+        let (data_lba, data_len) = self.read_icb_extent(reader, entry.meta_lba)?;
 
         // Read file data sector by sector
         // File DATA is in the physical partition (partition_start + lba),
@@ -129,7 +129,7 @@ impl UdfFs {
 
         for i in 0..sector_count {
             let offset = (i as usize) * 2048;
-            read_sector(session, abs_start + i, &mut data[offset..offset + 2048])?;
+            read_sector(reader, abs_start + i, &mut data[offset..offset + 2048])?;
         }
 
         data.truncate(entry.size as usize);
@@ -145,7 +145,7 @@ impl UdfFs {
     ///
     /// Skips: STREAM/ (video), BACKUP/, DUPLICATE/,
     ///   MKB_RO.inf, ContentHash*, ContentRevocation*
-    pub fn metadata_sector_ranges(&self, session: &mut DriveSession) -> Result<Vec<(u32, u32)>> {
+    pub fn metadata_sector_ranges(&self, reader: &mut dyn SectorReader) -> Result<Vec<(u32, u32)>> {
         let mut ranges = Vec::new();
 
         // UDF structure: sector 0 through end of metadata partition
@@ -154,7 +154,7 @@ impl UdfFs {
         ranges.push((0, meta_end));
 
         // Walk tree, collect ranges for each metadata file
-        self.collect_file_ranges(session, &self.root, &mut ranges)?;
+        self.collect_file_ranges(reader, &self.root, &mut ranges)?;
 
         // Merge overlapping/adjacent ranges and sort
         ranges.sort_by_key(|r| r.0);
@@ -162,14 +162,14 @@ impl UdfFs {
         Ok(merged)
     }
 
-    fn collect_file_ranges(&self, session: &mut DriveSession, entry: &DirEntry, ranges: &mut Vec<(u32, u32)>) -> Result<()> {
+    fn collect_file_ranges(&self, reader: &mut dyn SectorReader, entry: &DirEntry, ranges: &mut Vec<(u32, u32)>) -> Result<()> {
         for child in &entry.entries {
             if child.is_dir {
                 // Only skip STREAM — those are the multi-GB video files
                 if child.name.eq_ignore_ascii_case("STREAM") {
                     continue;
                 }
-                self.collect_file_ranges(session, child, ranges)?;
+                self.collect_file_ranges(reader, child, ranges)?;
             } else {
                 // Include the ICB sector itself (in metadata partition)
                 ranges.push((self.meta_to_abs(child.meta_lba), 1));
@@ -179,7 +179,7 @@ impl UdfFs {
                     continue;
                 }
 
-                if let Ok((data_lba, data_len)) = self.read_icb_extent(session, child.meta_lba) {
+                if let Ok((data_lba, data_len)) = self.read_icb_extent(reader, child.meta_lba) {
                     let abs_start = self.partition_start + data_lba;
                     let sector_count = (data_len + 2047) / 2048;
                     ranges.push((abs_start, sector_count));
@@ -197,17 +197,17 @@ impl UdfFs {
     /// Read an Extended File Entry (tag 266) or File Entry (tag 261)
     /// and return its first allocation extent: (data_lba, data_length).
     /// The data_lba is partition-relative.
-    fn read_icb_extent(&self, session: &mut DriveSession, meta_lba: u32) -> Result<(u32, u32)> {
-        let extents = self.read_icb_extents(session, meta_lba)?;
+    fn read_icb_extent(&self, reader: &mut dyn SectorReader, meta_lba: u32) -> Result<(u32, u32)> {
+        let extents = self.read_icb_extents(reader, meta_lba)?;
         extents.first().copied().ok_or_else(|| Error::DiscRead { sector: 0 })
     }
 
     /// Read ALL allocation extents for a file from its ICB.
     /// Returns Vec of (partition_relative_lba, byte_length) pairs.
     /// Handles files with many extents (e.g. 88 GB m2ts files have ~90 extents).
-    fn read_icb_extents(&self, session: &mut DriveSession, meta_lba: u32) -> Result<Vec<(u32, u32)>> {
+    fn read_icb_extents(&self, reader: &mut dyn SectorReader, meta_lba: u32) -> Result<Vec<(u32, u32)>> {
         let mut icb = [0u8; 2048];
-        read_sector(session, self.meta_to_abs(meta_lba), &mut icb)?;
+        read_sector(reader, self.meta_to_abs(meta_lba), &mut icb)?;
 
         let tag = u16::from_le_bytes([icb[0], icb[1]]);
 
@@ -255,7 +255,7 @@ impl UdfFs {
 
     /// Get all absolute disc sector extents for a file.
     /// Returns Vec of (absolute_lba, sector_count) covering the entire file.
-    pub fn file_extents(&self, session: &mut DriveSession, path: &str) -> Result<Vec<(u32, u32)>> {
+    pub fn file_extents(&self, reader: &mut dyn SectorReader, path: &str) -> Result<Vec<(u32, u32)>> {
         let parts: Vec<&str> = path.trim_matches('/').split('/').collect();
         let mut current = &self.root;
         for part in &parts[..parts.len() - 1] {
@@ -273,7 +273,7 @@ impl UdfFs {
         }).ok_or_else(|| Error::UdfNotFound { path: path.to_string() }
 )?;
 
-        let alloc_extents = self.read_icb_extents(session, entry.meta_lba)?;
+        let alloc_extents = self.read_icb_extents(reader, entry.meta_lba)?;
         let mut disc_extents = Vec::new();
         for (lba, byte_len) in alloc_extents {
             let abs_lba = self.partition_start + lba;
@@ -293,11 +293,11 @@ impl UdfFs {
 /// 3. Metadata partition file → metadata content location
 /// 4. FSD → root directory ICB
 /// 5. Root directory → file tree
-pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
+pub fn read_filesystem(reader: &mut dyn SectorReader) -> Result<UdfFs> {
     // Step 1: Anchor Volume Descriptor Pointer at sector 256
     // ECMA-167 §10.2 — always at sector 256
     let mut avdp = [0u8; 2048];
-    read_sector(session, 256, &mut avdp)?;
+    read_sector(reader, 256, &mut avdp)?;
 
     let tag_id = u16::from_le_bytes([avdp[0], avdp[1]]);
     if tag_id != 2 {
@@ -317,7 +317,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
 
     for i in 32..64 {
         let mut desc = [0u8; 2048];
-        read_sector(session, i, &mut desc)?;
+        read_sector(reader, i, &mut desc)?;
 
         let desc_tag = u16::from_le_bytes([desc[0], desc[1]]);
         match desc_tag {
@@ -352,7 +352,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
 
         // Read LVD to check partition map type
         let mut lvd = [0u8; 2048];
-        read_sector(session, lvd_sec, &mut lvd)?;
+        read_sector(reader, lvd_sec, &mut lvd)?;
 
         // Parse partition maps starting at offset 440
         // Map 0 = Type 1 (physical), Map 1 = Type 2 (metadata)
@@ -368,7 +368,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
                 // Read it to find where the metadata content starts
                 let meta_file_lba = partition_start; // lba 0 of partition
                 let mut meta_icb = [0u8; 2048];
-                read_sector(session, meta_file_lba, &mut meta_icb)?;
+                read_sector(reader, meta_file_lba, &mut meta_icb)?;
 
                 let meta_tag = u16::from_le_bytes([meta_icb[0], meta_icb[1]]);
                 if meta_tag == 266 {
@@ -401,7 +401,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
     // Step 4: Read File Set Descriptor from metadata partition
     // FSD is at metadata-relative lba 0 (first sector of metadata content)
     let mut fsd = [0u8; 2048];
-    read_sector(session, metadata_start, &mut fsd)?;
+    read_sector(reader, metadata_start, &mut fsd)?;
 
     let fsd_tag = u16::from_le_bytes([fsd[0], fsd[1]]);
     if fsd_tag != 256 {
@@ -413,7 +413,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
     let root_lba = u32::from_le_bytes([fsd[404], fsd[405], fsd[406], fsd[407]]);
 
     // Step 5: Read root directory and build file tree
-    let root = read_directory(session, partition_start, metadata_start, root_lba, "", 0)?;
+    let root = read_directory(reader, partition_start, metadata_start, root_lba, "", 0)?;
 
     let metadata_sectors = (metadata_size_bytes + 2047) / 2048;
 
@@ -432,7 +432,7 @@ pub fn read_filesystem(session: &mut DriveSession) -> Result<UdfFs> {
 /// containing File Identifier Descriptors (FIDs). Each FID names a file/subdir
 /// and points to its ICB.
 fn read_directory(
-    session: &mut DriveSession,
+    reader: &mut dyn SectorReader,
     part_start: u32,
     meta_start: u32,
     meta_lba: u32,
@@ -441,7 +441,7 @@ fn read_directory(
 ) -> Result<DirEntry> {
     // Read ICB for this directory
     let mut icb = [0u8; 2048];
-    read_sector(session, meta_start + meta_lba, &mut icb)?;
+    read_sector(reader, meta_start + meta_lba, &mut icb)?;
 
     let tag = u16::from_le_bytes([icb[0], icb[1]]);
 
@@ -477,7 +477,7 @@ fn read_directory(
     let sector_count = ((ad_len + 2047) / 2048).min(64);
     let mut dir_data = vec![0u8; sector_count as usize * 2048];
     for i in 0..sector_count {
-        read_sector(session, dir_abs + i,
+        read_sector(reader, dir_abs + i,
                    &mut dir_data[(i as usize) * 2048..(i as usize + 1) * 2048])?;
     }
 
@@ -512,11 +512,11 @@ fn read_directory(
 
             if !entry_name.is_empty() {
                 // Read the ICB to get file size
-                let file_size = read_file_size(session, meta_start, icb_lba).unwrap_or(0);
+                let file_size = read_file_size(reader, meta_start, icb_lba).unwrap_or(0);
 
                 if is_dir && depth < 3 {
                     // Recurse into subdirectory (max 3 levels: BDMV/PLAYLIST/*.mpls)
-                    let subdir = read_directory(session, part_start, meta_start, icb_lba, &entry_name, depth + 1)?;
+                    let subdir = read_directory(reader, part_start, meta_start, icb_lba, &entry_name, depth + 1)?;
                     entries.push(subdir);
                 } else {
                     entries.push(DirEntry {
@@ -545,9 +545,9 @@ fn read_directory(
 }
 
 /// Read file size (info_length) from an Extended File Entry ICB.
-fn read_file_size(session: &mut DriveSession, meta_start: u32, meta_lba: u32) -> Result<u64> {
+fn read_file_size(reader: &mut dyn SectorReader, meta_start: u32, meta_lba: u32) -> Result<u64> {
     let mut icb = [0u8; 2048];
-    read_sector(session, meta_start + meta_lba, &mut icb)?;
+    read_sector(reader, meta_start + meta_lba, &mut icb)?;
 
     let tag = u16::from_le_bytes([icb[0], icb[1]]);
     match tag {
@@ -642,7 +642,7 @@ fn parse_dstring(data: &[u8]) -> String {
 
 /// Read a single 2048-byte sector from the drive.
 /// Uses standard READ(10) — no unlock required.
-fn read_sector(session: &mut DriveSession, lba: u32, buf: &mut [u8]) -> Result<()> {
-    session.read_disc(lba, 1, buf)?;
+fn read_sector(reader: &mut dyn SectorReader, lba: u32, buf: &mut [u8]) -> Result<()> {
+    reader.read_sectors(lba, 1, buf)?;
     Ok(())
 }