Matthew Jackson
7d48d820e5
I broke DVD ripping earlier today and the real-media acceptance gate caught it on its first full run. Greenland.iso failed with E7013 "Decryption failed"; reverting only this change made it rip clean in 8 seconds. That is a regression I introduced, not a pre-existing defect. WHAT I GOT WRONG. Round 9's crypto lens reported that descramble_region "descrambles with a key it just proved wrong" when the crib check rejects the cached key and the re-crack also fails. I agreed, and made it Error::DecryptFailed to match the AACS path, on the reasoning that CSS has no external key source so a failed crack on a readable sector should never happen. The premise was wrong. `attack_crib` is a HEURISTIC, not a proof: it finds a periodic run in the unscrambled header and predicts the run continues past 0x80. When that prediction does not hold, the crib reports a mismatch even for a CORRECT key — and the re-crack then fails BECAUSE the crib was never valid. So crib mismatch plus crack failure is the signature of a crib false positive, not of a stale key. The cached key is not proven wrong; it remains the best available evidence, and on a real DVD it is very probably right. Real discs hit this constantly. The deeper error was treating "no key" as one thing across schemes. An AACS unit key either opens a unit or it does not — the Verify-Media-Key relation decides it, and a wrong key is provable. A CSS title key is recovered from the data itself by an attack whose success varies sector by sector, so "the crack failed here" says something about THIS SECTOR's plaintext, not about the key. Unifying the policy was right for the schemes that can prove a key wrong. CSS cannot, and I folded it in anyway. decrypt_span keeps its shape and the cross-scheme test keeps its two AACS arms, with CSS now explicitly excluded and the reason stated. Three tests asserted the wrong behaviour and are corrected, including one I rewrote earlier today to pin exactly this. Every one of them passed the whole time the code was broken — because none of them had ever seen a real disc. The lesson is the one I kept stating and then did not act on: 3,013 unit tests, ~400 mutants killed and nine audit rounds did not catch this, and one acceptance run did. Synthetic media cannot reproduce what a real disc does.
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. Drive-level unlocking is handled internally; consumers work with disc access and decryption only.
DVDs (CSS) decrypt out of the box. Blu-ray and UHD (AACS) require a keydb.cfg (default ~/.config/freemkv/keydb.cfg) supplying disc-specific volume unique keys; no AACS key material is compiled in.
12+ MB/s sustained read speeds on BD. Drive prep (init()) handles unlocking internally via the freemkv-unlock crate — clients never see it; when no drive unlock applies, the library rips via the host-certificate AACS handshake.
Multi-lingual by design — the library outputs structured data and numeric error codes, never English text. Build any UI or localization on top.
Part of the freemkv project.
Install
Consumed by git tag (not published to crates.io):
[dependencies]
libfreemkv = { git = "https://github.com/freemkv/libfreemkv", tag = "vX.Y.Z" }
Quick Start
use libfreemkv::{Drive, Disc, ScanOptions};
use std::path::Path;
// Open drive — identified via INQUIRY
let mut drive = Drive::open(Path::new("/dev/sg4"))?;
drive.wait_ready()?; // wait for disc
drive.init()?; // unlock + prep (handled internally)
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
Recovery moved OUT of this crate in 1.6.0. The sweep/patch strategy, the
ddrescue mapfile, damage classification and the multipass loop now live in the
freemkv-engine crate as freemkv_engine::recovery::{copy, sweep, patch}.
libfreemkv keeps the layers underneath: the raw single-shot read
(Drive::read) and the SCSI-fact translation (SenseFamily) that the engine's
strategy is built on. The dependency runs engine → libfreemkv, so this crate
cannot call into it; front-ends get recovery from the engine directly. See
docs/rip-recovery.md for what stayed here.
What It Does
- Drive access — open, identify, internal unlock + prep, speed control, 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 by freemkv_engine::recovery) |
| 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 a single unified pes::Stream trait (re-exported as PesStream) exposing read() and write() on one type. input() / output() resolve URL strings to PES stream instances. All URLs use the scheme://path format — bare paths are rejected.
Keys
DVDs (CSS) decrypt out of the box, with no external key file needed.
Blu-rays and UHD (AACS) require a keydb.cfg at ~/.config/freemkv/keydb.cfg (or passed via ScanOptions). No AACS key material is compiled into the binary.
Architecture
Drive — open, identify, init, single-shot read
├── ScsiTransport — SG_IO (Linux), IOKit (macOS), SPTI (Windows)
└── unlock_bridge — private seam to the freemkv-unlock crate
(firmware / AACS cert / CSS bus-auth unlockers)
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 (bus auth → player-key disc crack → known-plaintext title-key attack)
└── KEYDB — download + verify + save
Streams — unified PES pipeline
├── PesStream — pes::Stream: one trait, read()/write() PES frames
├── 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 |
| E9xxx | Stream / mux errors (URL, PES, ISO, pipeline, demux) |
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 capture your drive's identity for contribution. Drive-unlock profiles are maintained in the freemkv-unlock repository.
License
MIT