MattJackson 0bca7a11bd disc/read_error: unify Pass 1 and Pass N error handling
User's design call after watching the avoidance work prevent a wedge
on the live rip (no wedge events across 6 read errors): "Pass N
and 1 should both be very very similar in recovery. almost identical
just smaller sectors imo in pass n. pause times the same imo as a
failed read is a failed read."

The error-handling code path was already centralized (one
handle_read_error fn, called by both Disc::sweep and Disc::patch).
The TUNING was split — Pass 1 used 5 s inter-error pauses + a
wedge-skip-and-continue policy; Pass N used 1 s pauses + immediate
AbortPass on HARDWARE_ERROR / ILLEGAL_REQUEST. That asymmetry made
Pass N vulnerable to the same wedge that Pass 1's avoidance fixed.

Changes:

1. FAIL_PAUSE_SECS = 5 — single constant, applied uniformly to both
   passes. Dropped PASS_1_FAIL_PAUSE_SECS and POST_FAILURE_PAUSE_SECS
   in favor of one value. CONSECUTIVE_FAIL_LONG_PAUSE_SECS kept as a
   distinct (but currently equal) value for future tuning escalation.

2. HARDWARE_ERROR / ILLEGAL_REQUEST path is now symmetric:
   - Pass 1: JumpAhead WEDGE_JUMP_SECTORS (1 GB) + WEDGE_PAUSE_SECS
     cooldown, mark skipped region NonTrimmed.
   - Pass N: JumpAhead WEDGE_PASS_N_SKIP_SECTORS (64 sectors / 128 KB)
     + WEDGE_PAUSE_SECS cooldown. Pass N's batch=1 means a 1 GB skip
     would abandon the entire current NonTrimmed range; small skip
     moves past the bricked LBA + buffer, outer patch loop picks up
     the next sector.
   - Both share WEDGE_ABORT_THRESHOLD — same 16-skip budget before
     real AbortPass on a permanently stuck drive.

3. wedge_skip / wedge_abort tracing logs now include `pass=1|N`
   so post-mortems can see which pass hit the wedge condition.

Cost analysis:

Pre-reframe worry was "5 s × 5500 NonTrimmed sectors per Pass N
pass × 7 passes = 53 hours." Reality: most NonTrimmed sectors
recover on first or second retry, so most reads are successful and
pay 0 pause. The few that DON'T recover hit the 10-skip budget and
get marked Unreadable — bounded at 10 × 5 s = 50 s per truly-bad
sector. Worst-case Pass N pause overhead on a typical damaged disc
is single-digit minutes, not hours. And it's strictly cheaper than
the alternative (wedge kills the entire multi-pass recovery).

Tests:

- `both_passes_pause_on_failed_read_for_wedge_avoidance` — locks the
  unified pause-tuning policy (was pass_1_pauses_briefly).
- `pass_n_hardware_error_also_skips_not_aborts` — was
  `pass_n_hardware_error_still_aborts`. New behavior verified:
  JumpAhead with WEDGE_PASS_N_SKIP_SECTORS + WEDGE_PAUSE_SECS.
- `pass_n_hardware_error_aborts_after_threshold` — new. Confirms
  Pass N respects the same WEDGE_ABORT_THRESHOLD as Pass 1.
- pass_1_does_not_pause_on_skip is gone (it was the old "Pass 1
  pause=0" assertion, irrelevant after the avoidance work).

Empirical validation: avoidance was already proven on a live rip
tonight — 6 read errors on a damaged disc, sense_family=Medium
throughout, wedge_count=0, Pass 1 continued cleanly past 40%
where it previously died at 48%. This commit extends the same
discipline to Pass N's recovery loop.

Precommit (cargo +1.86 fmt + clippy + test) green.
2026-05-10 18:04:01 -07:00
2026-05-10 17:14:52 -07:00
2026-04-16 17:51:45 +00:00

Crates.io docs.rs License: AGPL-3.0

libfreemkv

Rust library for 4K UHD / Blu-ray / DVD optical drives. Drive access, disc scanning, stream labels, AACS decryption, CSS decryption, KEYDB updates, and content reading in one crate. Bundled drive profiles — no external files needed.

12+ MB/s sustained read speeds on BD. Full init: unlock, firmware upload, speed calibration — all from pure Rust.

Multi-lingual by design — the library outputs structured data and numeric error codes, never English text. Build any UI or localization on top.

API Documentation · Technical Docs

Part of the freemkv project.

Install

[dependencies]
libfreemkv = "0.18"

Quick Start

use libfreemkv::{Drive, Disc, ScanOptions};
use std::path::Path;

// Open drive — profiles are bundled, auto-identified
let mut drive = Drive::open(Path::new("/dev/sg4"))?;
drive.wait_ready()?;              // wait for disc
drive.init()?;                     // unlock + firmware upload
drive.probe_disc()?;               // probe disc surface for optimal speeds

// Scan disc — UDF, playlists, streams, AACS (all automatic)
let disc = Disc::scan(&mut drive, &ScanOptions::default())?;

for title in &disc.titles {
    println!("{}{} streams", title.duration_display(), title.streams.len());
}

// Stream pipeline — read PES frames from any source, write to any output
let opts = libfreemkv::InputOptions::default();
let mut input = libfreemkv::input("iso://Disc.iso", &opts)?;
let title = input.info().clone();
let mut output = libfreemkv::output("mkv://Movie.mkv", &title)?;
while let Ok(Some(frame)) = input.read() {
    output.write(&frame)?;
}
output.finish()?;

Multi-pass recovery rip

For damaged discs the library exposes two flat verbs — Disc::sweep for the forward Pass 1 and Disc::patch for retrying bad ranges. The library never loops; the multipass policy is the caller's job. See docs/rip-recovery.md and the design notes in (internal)/memory/0_18_redesign.md.

use libfreemkv::{SweepOptions, PatchOptions};
use libfreemkv::disc::{mapfile, mapfile_path_for};
use std::path::Path;

let iso = Path::new("disc.iso");

// Pass 1: disc → ISO. Skip-on-error, zero-fill, write the sidecar mapfile.
disc.sweep(&mut drive, iso, &SweepOptions {
    decrypt: true,
    resume: false,
    batch_sectors: None,
    skip_on_error: true,
    progress: None,
    halt: None,
})?;

// Pass 2..N: retry every non-finished range. Idempotent.
loop {
    let map = mapfile::Mapfile::load(&mapfile_path_for(iso))?;
    let stats = map.stats();
    if stats.bytes_pending + stats.bytes_unreadable == 0 { break; }

    let outcome = disc.patch(&mut drive, iso, &PatchOptions {
        decrypt: true,
        block_sectors: None,
        full_recovery: true,
        reverse: true,
        wedged_threshold: 50,
        progress: None,
        halt: None,
    })?;
    if outcome.bytes_recovered_this_pass == 0 { break; }
}

// Mux from the ISO via the normal stream pipeline (no drive involvement).

What It Does

  • Drive access — open, identify, unlock, firmware upload, speed calibration, eject
  • 12+ MB/s reads — auto-detects kernel transfer limits, sustained full speed
  • Disc scanning — UDF 2.50 filesystem, MPLS playlists, CLPI clip info
  • Stream labels — 5 BD-J format parsers (Paramount, Criterion, Pixelogic, CTRM, Deluxe)
  • AACS decryption — transparent key resolution and content decrypt (1.0 + 2.0 bus decryption)
  • KEYDB updates — download, verify, save from any HTTP URL (zero deps, raw TCP)
  • Content reading — adaptive batch reads with automatic decryption
  • Stream I/O — unified stream pipeline for reading and writing any format

Streams

Stream Input Output Transport
DiscStream Yes -- Optical drive via SCSI
IsoStream Yes -- Blu-ray ISO image file (read via stream pipeline; written via Disc::sweep())
MkvStream Yes Yes Matroska container
M2tsStream Yes Yes BD transport stream with FMKV metadata header
NetworkStream Yes (listen) Yes (connect) TCP with FMKV metadata header
StdioStream Yes (stdin) Yes (stdout) Raw byte pipe
NullStream -- Yes Discard sink (byte counter for benchmarks)

Streams implement FrameSource (read) and/or FrameSink (write); direction is type-checked. input() / output() resolve URL strings to PES stream instances. All URLs use the scheme://path format — bare paths are rejected.

AACS decryption requires a KEYDB.cfg file. If available at ~/.config/aacs/KEYDB.cfg or passed via ScanOptions, the library handles everything — handshake, key derivation, and per-sector decryption — without the application needing to know anything about encryption.

Architecture

Drive                  — open, identify, init, unlock, single-shot read
  ├── ScsiTransport    — SG_IO (Linux), IOKit (macOS), SPTI (Windows)
  ├── DriveProfile     — per-drive unlock parameters (bundled)
  └── PlatformDriver   — MediaTek (supported), Renesas (planned)

Disc                   — scan titles, streams, AACS/CSS state
  ├── UDF reader       — Blu-ray UDF 2.50 with metadata partitions
  ├── MPLS parser      — playlists → titles + clips + streams
  ├── CLPI parser      — clip info → EP map → sector extents
  ├── IFO parser       — DVD title sets, PGC chains, cell addresses
  ├── Labels           — 5 BD-J format parsers (detect + parse)
  ├── AACS             — key resolution + content decryption
  ├── CSS              — DVD CSS cipher (table-driven, no keys needed)
  └── KEYDB            — download + verify + save

Streams                — unified PES pipeline
  ├── FrameSource      — read() PES frames (direction-typed)
  ├── FrameSink        — write() PES frames (direction-typed)
  ├── DiscStream       — sectors → decrypt → TS demux → PES
  ├── IsoStream        — ISO file → decrypt → TS demux → PES
  ├── MkvStream        — MKV mux/demux
  ├── M2tsStream       — BD transport stream
  ├── NetworkStream    — TCP with FMKV metadata header
  ├── StdioStream      — stdin/stdout pipe
  └── NullStream       — discard sink

See docs/ for detailed technical documentation on each module.

Error Codes

All errors are structured with numeric codes. No user-facing English text — applications format their own messages.

Range Category
E1xxx Device errors (not found, permission)
E2xxx Profile errors (unsupported drive)
E3xxx Unlock errors (failed, signature)
E4xxx SCSI errors (command failed, timeout)
E5xxx I/O errors
E6xxx Disc format errors
E7xxx AACS errors
E8xxx KEYDB update errors

Platform Support

Platform Status Backend
Linux Supported SG_IO ioctl
macOS Supported IOKit SCSITask
Windows Supported SPTI

Contributing

Run freemkv info disc:// --share with the freemkv CLI to contribute your drive's profile.

License

AGPL-3.0-only

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Description
Internal mirror of libfreemkv 1.1-beta HEAD for private kdb builds (tag drops flate2; kdb needs HEAD symbols)
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