Commit Graph
1212 Commits
Author SHA1 Message Date
Matthew Jackson 54d038e478 fix(udf): file_start_lba must skip a leading unrecorded extent
Regression from the round-8 change that started RETAINING ECMA-167
4/14.14.1.1 type-1 (allocated, not recorded) descriptors. Retaining them
is correct — dropping one slides every later extent's data down by the
hole's length, corrupting the file silently. But read_icb_extent still
took extents.first(), so the value it returns can now be a hole.

A type-1 extent's lba is where SPACE is allocated, not where bytes live.
IcbExtent's own doc says exactly that. file_start_lba hands the value
out as "the absolute starting LBA of a file's first data extent", and
ifo.rs uses it as the base for every VTS VOB extent:

    file_start_lba(IFO) + vtstt_vobs + cell.first_sector

So a DVD whose IFO's first descriptor is type-1 reads its entire video
title set from the wrong place on disc. No error anywhere — the reads
succeed, they just land on unrelated sectors. Verified: the test reports
2900 instead of 2040 with the old code.

Same shape as file_extents/extents_abs_at dropping the recorded flag,
and the same root cause: one change taught read_icb_extents about a new
extent type and did not visit the accessors that consume its output.
Three of them; two are still open (task filed).

Found by the round-9 opus escalation over the API contract, dispatched
because the sonnet pass over the same scope returned zero findings.
Seven of its eight items were absences rather than wrong lines — the
class a wrong-line scan structurally cannot see.
2026-07-30 20:00:15 -07:00
Matthew Jackson 6868b93b7e fix(udf): retry the customary VDS location when the recorded one holds nothing
The Main Volume Descriptor Sequence was selected from the anchor's
declared extent whenever that extent's SHAPE was usable — length >= 16
sectors (ECMA-167 3/10.2.1), non-zero location, no address wrap — and
the customary location was tried only when the shape failed.

Shape is a property of the field, not of what is there. An anchor can
pass all three checks and point at nothing: a mastering tool that wrote
the reserve location, a stale anchor on a rewritten volume, or
deliberate corruption on an untrusted disc. The sweep then finds no
Partition Descriptor, partition_start stays 0, and the volume is
rejected as UdfNotFilesystem — while the real sequence sits unread at
the location the old fixed sweep would have found.

So the branch a DAMAGED disc actually takes had no recovery path, which
is backwards: that is the branch recovery exists for.

Now both are candidates and the fallback is retried on OUTCOME. This is
the same principle the Metadata File Location chain in this same
function already uses — treat the recorded value as a candidate, fall
back when it does not pan out — applied one level up. The sibling was
added in d5a9e70 and the asymmetry has been sitting there since.

A read fault inside a sweep no longer aborts before the next candidate
is tried, but it does not vanish either: it is held and returned if no
candidate yields a partition. "Could not read" stays distinct from "read
fine and the bytes say no", because mux::resolve caches the second for
the whole disc.

Not addressed, and pre-existing: the RESERVE sequence at avdp[24..32]
exists in ECMA-167 3/8.4.2 for exactly a damaged main sequence and is
still not consulted. Worth doing; a bigger change than this one.
2026-07-30 19:49:03 -07:00
Matthew Jackson 8d39ccc613 fix(decrypt): an encrypted unit outside every key range fails, not passes
decrypt_sectors_mapped returned early for any LBA no map range covers,
on the reasoning that unmapped means clear filesystem or nav. "The map
has no key here" and "there is nothing to decrypt here" are different
statements, and only the second makes passing the unit through correct.

On a multi-CPS disc an orphan clip — referenced by no playlist, so in no
title extent and therefore in no range — hits the first and was treated
as the second. The early return fired BEFORE the aacs_unit_encrypted
gate below it, so nothing ever asked whether those bytes were
ciphertext. extract_tree then counted them as bytes_good, dropped the
.partial suffix, set complete = true and exited 0: a scrambled file on
disk with a clean bill of health.

FileResult's own doc already stated the intended contract — "unreadable
sectors AND undecryptable units both land here (extract fails a bad
decrypt loud)". The code did not implement it on this path.

The fix is one line of symmetry. The split-unit branch immediately above
already makes exactly this distinction, checking aacs_unit_seed_encrypted
before refusing. This branch did not, so the same question got two
answers eight lines apart — the duplication shape this release keeps
finding.

Deliberately NOT changed: the decrypt decision on an orphan is still to
refuse rather than guess. Blind trial-decrypt is what the keymap-only
model exists to remove, and extract has no CPS/forensic fetch source.
The defect was never that we declined to key it; it was that declining
looked like success.

The test asserts BOTH directions — a clear out-of-range unit must still
pass through byte-identical, because that is the ordinary whole-disc
read and breaking it would trade one silent defect for a loud one.
2026-07-30 19:44:37 -07:00
Matthew Jackson 8c0de5711e fix(mux): resync-gate drops reach errors(), including after the gap resolves
ResyncGate::dropped is zeroed the moment a keyframe disarms the gate,
and the only EOF warning fires for gates STILL armed. So a mid-title gap
that resolves left no trace anywhere — and most gaps do resolve. A rip
with several concealed gaps reported 0 errors and 0 lost bytes while
whole GOPs had been discarded, which disc.rs's own test comment calls
the ONLY channel through which loss is reported.

This is the other half of e99b634. Arming the gate after an 8 MiB
backstop discard is right — a picture with dangling references must not
ship — but until the drop is counted that trades silent corruption for
silent loss.

The gate now carries dropped_total alongside dropped: per-run answers
"how expensive was this gap", cumulative answers "what did the caller
lose". errors() sums the gates.

Summed in ONE place rather than counted at the three admit call sites.
Three copies of the same increment is how the mux-flush path ends up
counting and the main path not, or the reverse — the duplication shape
this release has been removing. The gate already knows its own total;
the accessor just has to ask.

Found independently by two round-9 lenses, which is what raised it from
plausible to worth acting on.

Both halves are pinned: removing the dropped_total increment reds the
resync test, and removing the sum from errors() reds the DiscStream one.
The second test asserts the ACCESSOR rather than the gate's counter,
because a test on the counter would have passed throughout the entire
period the defect existed.
2026-07-30 19:40:48 -07:00
Matthew Jackson 9f25a4c454 fix(mp4): refuse a video track with no resolved dimensions
Resolution::pixels() returned (0, 0) for Unknown, and the MP4 sink wrote
it verbatim into tkhd (ISO/IEC 14496-12 8.3.2) and VisualSampleEntry
(12.1.3). Both fields are MANDATORY there, so unlike Matroska — which
omits the optional PixelWidth/PixelHeight elements — MP4 has nothing to
leave out. The result was a structurally complete file that passes every
container check, declares a 0x0 video track, cannot be rendered, and is
written with no error anywhere.

WHY IT WAS POSSIBLE, which is the part worth keeping:

pixels() previously fabricated 1920x1080 for Unknown. That was wrong but
playable, so this sink never needed a guard and the absence of one was
invisible. Changing the sentinel to (0, 0) moved the defect instead of
removing it — a zero PAIR still reads as a usable value, so the sink
stored it and serialised it.

The accessor's doc comment then ENUMERATED the callers it believed were
safe: "the Matroska sink omits the optional elements, the VobSub writer
omits its size: line, and no caller divides by either dimension." Two of
those three are true. MP4 was not on the list because MP4 has no guard
at all, and a prose list cannot enforce itself. mkv.rs's own comment
even states the principle — "the check belongs in the one accessor
rather than in each caller that remembered to write it" — and
labels/mod.rs still carried its own duplicate Unknown test long after
the accessor took that job over.

So: pixels() now returns Option. Not because Option is tidier, but
because every caller genuinely needs a DIFFERENT answer and the compiler
is the only thing that reliably makes them choose one. Matroska and the
metadata sinks take unwrap_or((0, 0)) with the reason stated at each
site; the VobSub path degrades to a palette-only .idx; MP4 fails with
E_MP4_UNKNOWN_RESOLUTION (9055).

Six call sites, not the five my first grep showed — I piped it through
`head` and acted on a truncated list. The compiler caught the sixth.
That is the same mistake as trusting a lens that reported silence.
2026-07-30 19:34:54 -07:00
Matthew Jackson 30bea12392 fix(css): no provable key is a hard failure, matching AACS
descramble_region descrambled with the key a sector's own crib had just
proven stale, whenever the re-crack from that sector also failed. The
clear header is not scrambled, so it survives intact: the sector still
opens with a valid pack start and passes every structural check the PS
demuxer applies. Only the payload is corrupted — exactly where nothing
looks. Ok(0) dropped, exit 0.

CSS has no external key source. The title key comes only from cracking
the data, so on a READABLE sector "no key" is not a missing input, it is
recovery failing on bytes we can see. That should never happen, and when
it does the answer is not to emit something.

Now Error::DecryptFailed — the same verdict the AACS path already gives
for a unit no held key opens. Both alternatives to failing are bad data
reported as success: descrambled with a rejected key it is garbage
behind a valid header, and passed through untouched it is ciphertext
where plaintext is meant to be.

WHY IT WAS POSSIBLE, which matters more than the fix:

There is no single place that owns "what do we do when there is no key".
decrypt_sectors_impl looks like the central dispatch, but its AACS arm
is a `return Err` stub — AACS decrypts entirely through
decrypt_sectors_mapped, a separate top-level path. So CSS decided its
own policy inside css/, AACS decided in decrypt.rs and mux/resolve.rs,
and nothing held them to the same answer. The asymmetry was not an
oversight; it was structurally permitted.

How a disc decrypts is one process — resolve a key for this data, apply
it, refuse if it cannot be proven. Only the resolve-and-apply step is
scheme-specific. Filed as a task: the policy belongs in one orchestrator
with the schemes supplying only what genuinely differs.

Two tests changed rather than added, both of which pinned the old
behaviour: the unit test asserted the sector was descrambled, and the
integration test asserted the scramble flag was cleared, which is what
descrambling-with-any-key does. Neither established that the result was
CORRECT — the fourth bad-test shape.
2026-07-30 19:10:32 -07:00
Matthew Jackson b2b611fa3b fix(udf): a read fault locating the Metadata File is not a non-UDF disc
Regression I introduced in d5a9e70 earlier today. The Metadata File
Location fix replaced

    read_sector(reader, meta_file_lba, &mut meta_icb)?;

with a candidate loop guarded by `.is_ok()`, which discards the error.
A transient read fault — marginal sector, drive re-read, an ECC recovery
that reports failure once — then falls through to the block-0 fallback,
the File Set Descriptor read there finds the wrong tag, and the volume
comes back as Error::UdfNotFilesystem: the deterministic verdict "this
is not a UDF disc" for a retryable I/O event.

mux::resolve MEMOISES that negative for the whole disc, so one flaky
read silently demotes every remaining title to the base-Unit-Key-only
path — the AACS 2.1 forensic units garble and the demux drops them. The
mux completes with less content and no error, which resolve.rs's own
comment says must never happen.

This file already draws the same distinction twice in prose, at the AVDP
check and the FSD check: read fine but the bytes say no is structural;
could not read is transient. The loop erased it.

Two things I got wrong on the way, both worth recording:

The first guard was `meta_tag == 0` — nothing read at all. That misses
the damaging case, which is the RECORDED candidate faulting while block 0
reads fine and holds some other descriptor. meta_tag is then non-zero and
not 266, and the fault is still laundered into a structural negative. The
guard is now `meta_tag != 266`: any unread candidate leaves the verdict
unproven, so the fault wins.

The first test denied BOTH candidate LBAs, and passed WITHOUT the fix —
the block-0 read fails too, so a read error propagates from further down
either way. A test whose fixture never reaches the changed line. That is
the eleventh bad-test shape this audit catalogued, and I walked straight
into it while fixing a defect found by looking for it. The fixture now
denies only the recorded location, and removing the guard reds it.

Found by the round-9 opus escalation over correctness, dispatched
because the sonnet pass over the same scope returned zero findings.
Silence from a cheap model is not evidence.
2026-07-30 18:57:13 -07:00
Matthew Jackson 4f4b1ed222 fix(labels): make deluxe master-enum selection deterministic
identify_master_enums picks, for each fingerprint, the best candidate
class out of CandidatePool. Its tie-break only prefers an exact ldc
count over an inexact one, so two candidates that are BOTH inexact but
both within LDC_COUNT_TOLERANCE are decided purely by iteration order —
and the pool was a HashMap.

Rust seeds HashMap per instance, so this is not merely unstable across
runs: the new test resolves the SAME jar to both Alpha and Beta within a
single process, across 16 iterations. The same disc could emit different
commentary/SDH/descriptive labels on consecutive rips of unchanged
input, with nothing in the output saying the choice was arbitrary.

BTreeMap fixes it by construction rather than by a sort someone can
forget to keep. The pool is capped at MAX_CANDIDATE_CLASSES, so the
ordering cost is irrelevant.

The test runs the whole identification sixteen times and asserts one
distinct winner. A single run cannot distinguish deterministic from
lucky, and the seed does not change within a process — so repetition is
what makes this a test rather than a hope.

Found by the round-9 labels pass, which was dispatched specifically
because every one of the ten lenses had reported leaving deluxe.rs
unread. 1,159 new lines that nobody had opened.
2026-07-30 18:49:59 -07:00
Matthew Jackson 944e6a8b09 fix: align the Linux fsync error with macOS, and clear three stale docs
Round 9 findings, triaged and verified against the pinned tree.

writeback_file: a bounded-fsync WorkerLost returned bare ErrorKind::Other
on Linux where macOS returns EIO. Round 8 fixed the Linux arm to return
Err at all — the right fix — but stopped short of matching the value, so
a consumer distinguishing timeout / halt / lost-worker had nothing to
branch on for the third case on one platform. Now EIO on both.

Three doc comments described the pre-fix behaviour, one of them for
longer than the bug existed:

  linux.rs durable_sync still said "all three fallbacks return Ok(())"
  mod.rs sync_all still said Linux silently swallows fsync failures and
    callers must not treat Ok(()) as a durability barrier
  mod.rs SequentialSink::finish repeated the same caveat

All three now say what the code does: a bounded-fsync failure is an Err
on every platform, so Ok(()) IS a durability barrier. A doc that
describes a fixed bug is worse than no doc — it tells a caller to write
a workaround for something that no longer exists.

au_assembly: discard_gap_before duplicated drop_marks_before's
mark-retirement body verbatim and added one statement. Mine, from
earlier today. It now calls it. Two copies of the same retirement loop
is exactly how the two call sites would drift back together.

clpi: ClpiStream's audio_format / audio_rate / video_format / video_rate
are decoded from untrusted on-disc bytes on every parse and read by
nothing. The identically-named fields consumed in disc/bluray.rs belong
to mpls::StreamEntry, not to this struct — checked, because an earlier
round wrongly called a live function dead. Deleted, along with the seven
test assertions that pinned them; the tests that pin pid, coding_type
and language remain. Also removed a section-header comment orphaned by
the get_extents deletion, describing a fixture that no longer exists.
2026-07-30 18:39:47 -07:00
Matthew Jackson 5360f8d309 test: salvage the orphaned labels/disc triage, and extract build_labels
Thirteen agents triaging src/labels and src/disc died on a saturated
machine, leaving 5,836 insertions across 28 files uncommitted in a
worktree. Recovered by 3-way apply onto twelve commits of drift; zero
conflicts. The diff was archived to freemkv-private first, because a
worktree is not a backup and this one had already nearly been lost.

One production change, and it is the right one: mpls_universal::parse
read every playlist off the disc AND converted the entries to labels in
a single function, so the conversion — stream-type mapping, dedup key,
the dense global counters — could only be reached through a synthetic
UDF image. Extracted to build_labels(&[Playlist]), which unit tests can
drive from already-parsed values. Behaviour-preserving: same iteration
order, same skip-on-error.

Two collisions resolved by hand:

A second mod pass_progress_tests, written independently against the
same survivors as the one committed in c610285. Kept mine — it covers
the distinct-counters case and the Progress blanket impl, which theirs
does not — but theirs had three clamp tests mine lacked: good_pct,
bad_pct and pending_pct also clamp an overshoot, and I had only tested
that for work_pct. Merged those in as one test and proved each of the
three clamps load-bearing by removing them individually.

An unused_parens warning in a new fixture.

Method note, recorded because it cost real time: git apply --3way
STAGES its result, so `git diff` reads empty and the tree looks
untouched. I nearly concluded the patch had silently failed. Worse, the
first attempt piped through `head -20`, so `echo exit=$?` reported
head's status rather than git's — the same mistake this audit has
already documented once. Check the real exit status, and check
--cached, not just the working tree.
2026-07-30 16:36:13 -07:00
Matthew Jackson 8b8bcff106 test: pin five untrusted-input guards in the AACS 2.1 and CSS paths
Second pass over src/aacs and src/css. No production change; the only
non-test edits are two fixture bytes and one test rename.

Five latent panics on untrusted data, every guard correct and none
tested — so each was free to be deleted:

  variant.rs:224  a 0x04 record not a multiple of 5 indexes p_uv[0..4]
                  off a one-byte tail
  variant.rs:269  a 0x0c record shorter than the 0x04 slot count
                  slices past the cvalue table
  stevenson.rs:177  short sector read -> index 138 into a 129-byte slice
  stevenson.rs:208  a crib longer than the 1920-byte encrypted region
                    -> index 2058 into 2048
  stevenson.rs:272  a header periodic all the way to offset 0 ->
                    subtract with overflow

That last one is reachable from ORDINARY DVD data — constant or padding
bytes are periodic. Verified on HEAD: widening the guard to <= 0x80
passes all 64 css tests unmutated.

media_key_variant_from_kp had only a soft-correction test, so every
step past that early return was unexecuted. The new two-slot fixture
puts the covering slot at index 1, so the uvs[1 + 5*idx] and
cvalues[idx*16] strides stop multiplying by zero.

derive.rs:319 + -> - confirmed killable, as the first pass predicted:
p == 0 makes (p-1)..32 underflow. Every prior fixture used a uv whose
lowest set bit was 4, 10 or 11, so trailing_zeros() was never 0.

One fixture bug caught and fixed rather than papered over: a |= mutant
first SURVIVED because mk[14]'s 0x04 bit happened to be set, making OR
and XOR agree. The byte is now clear and an assert_eq! pins it, so the
fixture cannot drift back into agreeing with the mutation it exists to
catch.

walk_mkb_be24_high_byte_is_honored renamed to
walk_mkb_be24_middle_byte_is_honored. Its 0x00_0110 length exercises
the << 8 term only, which is why << 16 -> >> 16 survived it. The name
was the lie; both framings are worth having, and the comment now points
at the genuine high-byte test at 0x01_0004.

derive.rs 146:32 and 154:30 stay untested, now with a proof rather than
a judgement: bit_pos == -1 requires current_v_mask == 0xFFFF_FFFF, and
calc_v_mask can never return that — its loop condition holds at
!v_mask == 0, so it always shifts at least once. Both branches are
reachable only after the walk has gone non-convergent and is heading
for the bounded exit, where the return value is undefined. Termination
is already pinned.

Equivalents proven by observing green, including six more OR/XOR pairs
on provably disjoint bit fields, and the two KEY_CORRECTION_DATA sites
where the constant is the documented all-zero placeholder so x ^ 0 ==
x | 0. Those become killable only if a real per-licensee KCD is wired
in.

A partial confirmation sweep (138 of 415 mutants before the box
saturated) found 135 caught, one timeout that is itself a detection,
and exactly one survivor — the KEY_CORRECTION_DATA equivalent above.
2026-07-30 16:27:03 -07:00
Matthew Jackson d5a9e70700 fix(udf): read the Metadata File Location from the partition map
read_filesystem hardcoded the Metadata File's File Entry at block 0 of
the physical partition — 'the metadata file ICB is at physical
partition lba 0'. UDF 2.50 2.2.10 records where it actually lives, as a
partition-relative Uint32 at offset 40 of the Metadata Partition Map.
That field is the only thing on the volume that says where the entry
is; block 0 is merely where authoring tools usually put it.

On a conformant volume that recorded it elsewhere, block 0 holds
something that is not a File Entry, metadata_start falls back to
partition_start, the File Set Descriptor read there carries the wrong
tag, and the volume is rejected as UdfNotFilesystem. Worse, a volume
with a decoy file set at block 0 — as a rewritten or dual-structure
volume can have — does not error at all: it mounts a different
filesystem and reports success.

Verified on HEAD: reverting the lookup reds four tests, e.g. the
metadata partition beginning at 2000 where the map records 33754069.

The recorded location is trusted only when the map's partition type
identifier reads '*UDF Metadata Partition'. A Virtual (2.2.8) or
Sparable (2.2.9) map is ALSO ECMA-167 3/10.7.3 Type 2 and records
unrelated fields at offset 40, so its bytes must never be read as a
location. Deleting that guard reds its own test.

Block 0 stays in the candidate chain, so a volume whose map is absent
or wrong but whose Metadata File does sit there keeps mounting exactly
as before. This is additive, not a behaviour swap.

Also 30 tests and ~55 more mutants across read_icb_extents,
read_file_limited, read_inline_data, the prefetch stubs, parse_dstring
and parse_udf_name. The metadata-partition branch — the branch EVERY
real BD-ROM takes — had no test at all; nothing in the crate built a
two-partition-map volume.

Closes the max_bytes gap flagged earlier: 259 > -> == and > -> < now
die on both the declared-size and the inline-ICB paths.

Equivalents proven by application, notably two guards that read as
protective but are unreachable: pm1_len is a single byte so
440 + pm1_len < 2048 always holds, and ad_offset + l_ad <= 2048 is
enforced upstream so off + ad_size never exceeds the block.

Bit 0 (Existence) stays unread, deliberately. ECMA-167 4/14.4.4 makes
it a display hint, not a statement that the file is absent, and UDF
2.50 2.3.4.2 carries it through as the DOS hidden attribute. For a
ripper the consequences are asymmetric: honouring it can silently drop
a real .m2ts from the title list, ignoring it costs an extra name in a
listing.

Known structural limit, not fixed: read_filesystem takes only the FIRST
extent of the Metadata File, so a fragmented metadata partition would
map every sector past that extent to the wrong place. metadata_start
being a single base LBA is what forbids the fix.
2026-07-30 16:09:35 -07:00
Matthew Jackson 0bc8d7af9c test: constrain the AACS key-map gap fill, the PSI walk, and MP4 field offsets
Third pass over src/mux/. 40 survivors killed, no production change.

resolve.rs — the deleted-statement cluster is now fully constrained.
All 14 deletable statements probed; 9 were already caught, 5 survived:

  c.sort_unstable() in fill_base_key_gaps. Every existing case handed
  it cuts already in LBA order, but IndividualSegment.tbl is a record
  list. Verified on HEAD: deleting the sort passes all 54 resolve
  tests. The mutant lays a base-key fill straight over a forensic
  segment.

  last_idx = idx (FMTS gap fill) and last_idx = hit (multi-CPS cache
  hit). An extent with nothing to sample must inherit its neighbour's
  CPS unit; the mutants fall back to the first unit's key. Exactly the
  shape this file's own comments name — wrong key, no error,
  lost_bytes == 0.

  Both check_halt()? polls in probe_fmts_index_keys. These cannot be
  killed by outcome, since a later poll returns Halted too. The tests
  count reads instead, which is what the don't-hammer-a-struggling-
  drive rule actually says: after a Stop the drive is asked for zero
  content sectors.

The four unresolved += 1 arms each got a test, and deleting each fails
exactly one — one-to-one, so no fixture passes for the wrong reason. A
control test pins that the baseline table resolves, so an expect_err
cannot succeed for an unrelated reason.

ts.rs::scan_streams was never entered. Six killed, two of which return
wrong answers that look right: reading the PAT/PMT CRC as a table entry
invents a stream on PID 546 out of CRC bytes, and dropping the
ES_info_length skip decodes a descriptor as an entry and loses the one
after it. Every existing PMT fixture declares ES_info_length = 0; a
real BD PMT carries a registration descriptor on essentially every
entry. Also ISO/IEC 13818-1 2.4.4.3 program_number == 0 is the network
PID, not a program.

mp4/read.rs — 13. Height read as the width beside it; channelcount;
the 4-byte base-128 descriptor varint (every existing esds fixture uses
a single byte); all three optional ES_Descriptor fields, whose loss is
silent (an AAC track just loses its CodecPrivate); first-vs-last media
edit, which is A/V desync of the difference; and the version-1 mvhd
timescale offset, emitted by any writer whose duration exceeds 32 bits.

dts.rs — 7, from a real cargo-mutants run over the file rather than
guesswork. Including a buffer that IS the syncword, which is the state
a sync split across PES packets lands in the moment its last byte
arrives.

Equivalents proven by application, not argued: the sample_encrypted_units
guard pair is mutually redundant by construction (total*p/9 < total for
p <= 8), so either alone is equivalent and both together are not; the
PMT section_len guard is dead code where its PAT twin panics; three of
the seven EXSS_HEADER_MIN_BYTES arithmetic mutants still sum to 10.
2026-07-30 16:05:37 -07:00
Matthew Jackson e99b634635 fix(mux): a backstop discard is a discontinuity; a stream-start trim is not
drop_marks_before retired discontinuity marks alongside timing marks at
both of its call sites. At stream start that is right. At the
MAX_AU_BUFFER backstop it is not, and the two are now separate.

The backstop fires when 8 MiB accumulate with no AU start code in them
— corrupt or hostile input — and throws the run away. There IS a prior
AU in that case, and whatever emits next definitively does not continue
it: a decoder handed that picture resolves its references against
frames separated from it by megabytes of discarded data. Retiring the
flag meant the resync gate (resync.rs, driven from mux/disc.rs) never
armed, so the broken picture went out looking sound. Silent corruption
is the one class of loss this crate refuses to have.

At stream start the opposite holds. Bytes ahead of the first
access-unit delimiter are the tail of an AU that began before sync, and
there is no prior AU to be discontinuous from. Marking it would arm the
gate at the head of every title and drop its opening GOP. That risk is
why this was a decision rather than a fix, and splitting the call sites
is what avoids paying it.

Recorded as a sticky flag, not an offset mark. A mark placed at the new
base is retired moments later by the pre-sync trim that follows resync
— the gap has to outlive the bytes that caused it. I found that by
writing the test first and watching it fail with the mark approach.

The discard is a discontinuity whether or not the source signalled one,
and a signalled one on discarded bytes still reaches the AU that
follows; both directions are tested.

Note the first over-cap run is NOT a discard: the next AU's delimiter
is still at buf[0], so it force-flushes as an over-long access unit and
loses nothing. Only a run with no opener at all reaches the backstop.
The tests push twice for that reason — the single-push version passes
without the fix.

Swapping either call site for the other fails: reverting the backstop
reds the two gap tests, and arming the gate at stream start reds the
third.
2026-07-30 14:52:39 -07:00
Matthew Jackson f9d081ed45 test: drive the AACS 2.1 variant chain to a Media Key, and pin AES-G3
163 of 322 surviving mutants across src/aacs and src/css. No production
line changed — every function read correct; the finding was always an
absent test.

Two structural holes, both verified against HEAD before landing.

variant.rs had no test that ever produced a Media Key. Every terminal
assertion in the module was an Err classification — NotVariantMkb,
SoftCorrectionRequired, OnlineChallengeRequired. So the entire 2.1
success path (VARIANTS lookup, VKD selection, Kpnew, the final unwrap,
the verify gate) was pinned by nothing, and that path produces the
Media Key that becomes the VUK that decrypts every byte of a 2.1 disc.
Built the first complete planted variant MKB: the VARIANTS entry is
chosen as Kvn ^ 1 so the real VKD sits behind a decoy at table index 1,
making the lookup load-bearing rather than incidentally correct. That
one fixture kills 23 operator mutants across three functions.

aesg3 — the subset-difference tree node function — was in the survivor
list as replaceable by [0; 16], meaning every device key in the crate
would derive the same Processing Key. It is caught today only as a side
effect of a negative test added after the mutation run; nothing asserted
the relation itself. Pinned now via the spec relation ([C] 3.2.2) using
the FORWARD primitive, with s0 transcribed independently rather than
read back from AESG3_SEED, so the test cannot agree with a mutated
constant.

Same shape in derive.rs: plant_mkb was one slot with zero descent, so
slot indexing was the identity permutation and the ancestor-descent
branch never ran — which is why 39 of recover_dk_position's mutants
survived. Added a 3-slot fixture keyed at index 2 and a four-level
descent fixture whose expected Processing Key is written out as an
explicit aesg3 chain rather than computed by calc_pk_from_dk; a fixture
built by the function under test moves with its own mutations.

Two latent panics on untrusted input now have tests: a 0x05 cvalue
table shorter than the 0x04 slot index, and a drive declaring more
payload than the 32772-byte response buffer holds.

23 equivalents claimed with reasoning, and confirmed empirically where
possible — all eight css/lfsr mutants were run and exactly the seven
disjoint-bit-lane ones survived.

Explicitly NOT claimed equivalent: derive.rs 146:32 and 154:30 are
reachable, but only on the non-convergent bounded-exit path where the
function's sole contract is termination. A test there would pin
defined-but-meaningless output.

Noted for the next pass: the pre-existing walk_mkb_be24_high_byte_is_honored
used total length 0x0110, whose high byte is zero — it exercised the
middle byte only, which is why << 16 -> >> 16 survived it. Left in
place; a real one was added at 0x01_0004.
2026-07-30 14:44:35 -07:00
Matthew Jackson 3e13a155fa refactor(clpi): delete the unused EP-map to sector-extent path
get_extents had no caller anywhere in the ecosystem, and neither did
anything feeding it. Removed: get_extents, resolved_ep_map, full_pts,
full_spn, parse_cpi, EpCoarse, EpFine, the ep_coarse/ep_fine fields,
the unused version field, and the 35 tests that exercised them.

This reverses the fix in b2e1982, deliberately. That commit corrected a
real truncation — out_time past the last EP entry resolved to
last_ep_spn + 1, dropping everything from the final I-frame to EOF —
and the fix stands in history as the record of what was wrong. But the
defect existed for eight audit rounds precisely because the code had no
caller: nothing exercised it, so nothing noticed. Keeping speculative
infrastructure alive on the strength of a comment saying it is reserved
for a path that does not exist is how that happens again.

ClipInfo keeps source_packet_count (read by disc/bluray.rs) and streams
(the CLPI/MPLS cross-validation in labels/clpi_audit.rs). 1,139 lines
out, gate green in debug and release.
2026-07-30 14:39:22 -07:00
Matthew Jackson b2e1982051 fix(clpi): resolve out_time past the last EP entry to the end of the clip
ClipInfo::get_extents fell back to `last EP SPN + 1` whenever out_time
lay past the last entry-point. EP entries mark I-frames (BD-ROM Part 3,
CPI / EP map) and a clip's final GOP lies after the last one, so a
PlayItem covering a whole clip — whose OUT_time is the presentation end
— always lands in that arm. The extent then stopped one source packet
after the last I-frame.

Measured on a fixture with 200,000 source packets and the last EP at
SPN 131,072: sector_count came back 12,289 where covering the clip
needs 18,750. Everything from the last entry point to EOF is outside
the returned extent.

Scope, stated plainly: get_extents has NO callers anywhere in the
ecosystem today — it is #[allow(dead_code)] and documented as reserved
for the timestamp-range read path. Nothing ships this loss. It is
fixed now because a latent truncation in extent arithmetic is far
cheaper to correct before it has callers than after.

The SPN at-or-after an out-of-range out_time is the end of the clip,
source_packet_count, with .max(last + 1) so a disc that under-declares
its own packet count against its own EP map still yields a sane bound.

Also 174 mutants killed across clpi, mpls, ifo and ebml — the first
time any of these four files has been examined. And ebml's 8-byte VINT
back-patch was duplicated verbatim in end_master and end_master_buf
with its top four payload octets unreachable through either (they need
a 16 MiB..256 TiB buffer); extracted to fixed_width_vint8 and tested
across the full 56-bit payload, no behaviour change.

38 of ebml's 46 survivors are one equivalence cluster: every | in
write_size / read_id / read_size / read_uint_val ORs into disjoint bit
lanes, where ^ is the identical operation. Applied all 38 at once —
green — then spot-checked four individually.
2026-07-30 14:24:57 -07:00
Matthew Jackson 84a77f6a0e test: pin FMTS read_plan unit indexing to an unaligned range start
Five surviving mutants in AacsKeyMap::read_plan, all in the arithmetic
that decides which half of a forensic segment this disc's key opens.

The existing coverage used a forensic range starting exactly on the
extent's first unit. Under that shape several wrong formulas agree with
the right one by arithmetic accident: (lba + range_start) / us and
(lba - range_start) * us both produce the correct kept set.

Real ranges are not shaped like that. A range start comes from a source
packet number — start_spn * 192 through clip_byte_to_lba in
mux/resolve.rs — and 192-byte packets bear no relation to the 3-sector
aligned unit, so range_start % 3 is whatever the disc says.

Getting the parity wrong does not crash. It reads and decrypts the
ALTERNATE variant's half: the units this key does not open decrypt to
garbage, the units it does open are skipped. AACS 2.1 forensic marking
is precisely what makes the two halves differ, so the failure is silent
— a full-length rip carrying the wrong variant.

Two fixtures are needed because no single one kills both: an unaligned
range start with the extent beginning on it inverts the halves under
the + form, and an extent offset one unit-remainder from the range
start inverts them under the * form.

Also pinned the short-tail guard.  is for a remnant
SMALLER than a unit — bytes with no following unit to desync. Widened
to <=, the last whole unit of every extent bypasses the phase gate, so
a forensic segment ending at an extent boundary contributes one
alternate-variant unit to the rip.
2026-07-30 14:18:39 -07:00
Matthew Jackson 9de88969ca test: constrain the DiscStream loss surface and the empty-title guards
Second mutation pass over src/mux/. 26 survivors killed, no production
change. Verified on HEAD before landing: each mutation below passes all
1,237 mux tests unmutated-suite.

The priority item was the honest-loss-reporting surface. Both
DiscStream::errors and DiscStream::lost_bytes could return a constant
with nothing failing — a rip that lost sectors would report zero loss
to the caller. This project has already shipped one defect of that
shape (a total decryption failure reported as an empty title, exit 0).
Driven now through two short-read fills so both land on values that are
neither 0 nor 1 and differ from each other; no constant and no field
swap survives.

MkvStream::finish -> Ok(()) also survived. MkvMuxer::finish has the
zero-frame MkvInvalid guard and two tests cover it, but the Stream
wrapper above it could return Ok unconditionally and bypass the guard
entirely — the empty-title defence was one layer thinner than it looked.

au_assembly: pinned au_opener_from behaviourally to the normative byte
values for all four modes, with negative cases for codes that are
explicitly not openers (MPEG-2 slice 0x01..0xAF, user data 0xB2,
extension 0xB5, sequence end 0xB7 per 13818-2 Table 6-1; VC-1
0x0A/0x0B/0x0C; H.264 SPS/PPS/IDR-slice). au_assembly and codec/ hold
independent copies of these constants; they agree today, and comparing
constants would not catch logic drifting apart, so both sides are now
pinned to the spec instead of to each other.

demux_sink::sanitize: every filename component demux:// writes comes
from disc-controlled text, so the path-separator arm is a traversal
guard. Deleting it now fails, including an end-to-end case where
base = "../evil/Title" must produce exactly one file inside the
chosen directory.

stts_and_ctts_expand renamed to stts_expands_runs_to_per_sample_deltas_in_order
and given runs with distinct deltas AND distinct lengths. Its old name
claimed ctts coverage it never had, which is why the composition-time
chain went unconstrained for eight rounds; the doc comment now points
at the tests that do cover ctts.

Correction to the previous pass: codec/truehd.rs flush -> vec![] IS
equivalent. Applied it, full mux suite green. TrueHD buffers across PES
but parse emits every complete unit immediately, so a residual buffer
at EOF is a truncated access unit and is correctly discarded. The
vec![Default::default()] variants are genuinely different and are
killed.

Deliberately not constrained: mkv::set_opening_capture (diagnostics
behind a process-global tracing check, flaky under the parallel
runner), and the three stdio.rs header paths (StdioStream holds
concrete io::Stdin/Stdout and cannot be driven without a production
refactor to injectable Read/Write).
2026-07-30 14:13:33 -07:00
Matthew Jackson 170fd0c064 test: constrain MP4 composition timing, MLP substream directory, and codec-private absence
Mutation testing over src/mux/. No production change — 49 survivors
killed, all proven red before green.

The MP4 composition-time chain was entirely unconstrained: VideoTiming::ctts,
build_ctts and parse_ctts could each return a constant and the suite
stayed green. Confirmed on HEAD: build_ctts -> vec![] passes all 1,220
mux tests. A demuxed B-frame title presenting in decode order would
have shipped.

The cause is a test whose name asserts coverage its body does not
deliver — stts_and_ctts_expand builds an stts box and never touches
ctts, and write_then_read_round_trip asserts sample sizes and keyframe
flags but not one PTS. Same shape as the set_speed forwarding finding,
different disguise.

mlp_num_substreams / mlp_substr_header_size: every TrueHD fixture in
the crate uses one substream and no extraword, so both could return a
constant and agree with all of them. These position mlp_parity_ok's
window over the AU header, so a constant mis-windows the parity check
on exactly the multi-substream AUs that carry 7.1 and Atmos.

CodecPrivate absent vs empty: mkv.rs writes Some(bytes) verbatim and
omits the element on None (RFC 9559 5.1.4.1.24), so a zero-length Some
emits a track header asserting the config IS empty. Four parsers could
return Some(vec![]) before any frame.

Also: mandatory ISO/IEC 14496-12 boxes (tkhd, vmhd, smhd, dinf, mdhd)
could each build empty; HEVC num_extra_slice_header_bits (H.265 7.3.2.3)
was never non-zero in any fixture, so the slice-type offset skip was
unexercised; chapter names from the disc go straight into
<ChapterString> and the & escape must run first; a stray 0x47 in a
payload must not latch a TS resync.

Documented as equivalent rather than killed: CodecParser::flush and the
three parser flush bodies that differ from the mutant only by a tracing
call, and DropTally::log_summary.
2026-07-30 13:39:02 -07:00
Matthew Jackson 55b97ac576 fix(udf): skip deleted File Identifier Descriptors
read_directory decoded file-characteristics bit 1 (Directory) and bit 3
(Parent) but never bit 2 (Deleted) — ECMA-167 4/14.4.4. It followed the
ICB of a descriptor naming a file that no longer exists.

4/14.4.3 permits a deleted FID's ICB field to specify an extent of
length zero, so it need not point at a File Entry at all. Following it
reads whatever descriptor occupies that metadata LBA:

- deleted DIRECTORY FID: recursion lands on the File Set Descriptor
  (tag 256), hits the not-a-File-Entry arm and returns Err. One stale
  descriptor in one directory fails enumeration of the entire volume.
- deleted FILE FID: read_file_size returns Ok(0) for a non-File-Entry
  tag, so a deleted name is reported as a real zero-byte file.

Both directions of the same shape at once: a recoverable condition
becoming a hard failure, and a non-existent entry becoming a plausible
success.

Bit 0 (Existence) is still unread. Skipping hidden files could hide
real content, so it is left alone deliberately rather than folded in.

Found by mutation testing: 48 of the 51 surviving mutants in
read_directory are killed by the 17 tests added here, covering the
short_ad decode byte by byte (ECMA-167 4/14.14.1), the extent-type
mask, the AD bounds guard at the exact sector end, the tag-261 File
Entry directory arm that no test reached at all, the multi-sector
read offset, the FID stride including L_IU, and the nesting cap.

Three survivors are genuine equivalents and are documented as such:
l_fi > 0 vs >= 0 (the emptiness guard below reaches the same state),
and the << 32 / | in the visited-set key (meta_start is constant
across a walk, and the two halves are disjoint).
2026-07-30 13:32:06 -07:00
Matthew Jackson c610285910 test: constrain SectorSource speed forwarding and PassProgress percentages
Mutation testing left both unconstrained.

sector/mod.rs — set_speed on the Box<dyn> and &mut dyn forwarding impls
could be replaced with an empty body and nothing failed. This one hides
better than the read methods because the trait's own default body is
already a no-op, so a forwarder that swallowed the call is
indistinguishable from a source with no speed control. Consequence is a
silently absent value, not a wrong one: the recovery path lowers read
speed through a damaged region, and a swallowed call leaves the drive
at full speed while the caller believes it slowed down. Routed through
a generic S: SectorSource bound, since a direct call on a &mut dyn
receiver auto-derefs to the vtable and never enters the forwarding body.

progress.rs — 42 survivors. All four percentage accessors could return
a constant, read the wrong byte counter, or have their divide-by-zero
guard inverted. Added exact-value tests (25%, not 'some percentage'),
both sides of each guard, the overshoot clamp, and one test setting all
three disc counters to distinct values at once — without it, a swapped
field still passes every single-counter test.

The Progress blanket impl for closures could return a constant true.
That return value is the cancellation signal, so a constant-true body
makes every closure-based consumer uncancellable.

Each mutation applied, observed red, reverted.
2026-07-30 13:26:31 -07:00
Matthew Jackson e4b1e5b19e docs: correct info invocation and read timeouts
TROUBLESHOOTING step 2 said `freemkv info`, which needs a source URL;
the drive route is `freemkv info disc://`.

architecture.md quoted 1.5 s / 30 s for the read timeouts. The
constants are READ_TIMEOUT_MS = 10_000 and READ_RECOVERY_TIMEOUT_MS =
60_000 (src/scsi/mod.rs:72,94).
2026-07-30 13:21:04 -07:00
Matthew Jackson 8d4a6d54a4 Constrain five behaviours that mutation testing showed nothing constrained
Fifteen surviving mutants killed, from the highest-risk class: functions a
mutant could replace wholesale with a constant while all 2,555 tests
passed. None of the code was wrong. In every case a test was absent, which
is why eight rounds of reading never found any of them.

The one that generalises is in sector/mod.rs. Its existing test READS as
covering `read_sectors` on the `&mut dyn SectorSource` forwarding impl —
it takes a `&mut dyn`, calls the method, checks the spy. But the receiver
auto-derefs and dispatches through the vtable straight to the spy, so the
forwarding body is never entered. An earlier round hit this exact trap on
`set_unit_base` and fixed it with a generic helper; the read path kept the
test that looked right. Verified by stubbing the forwarding impl to Ok(0):
the new test fails, the old one passes. That makes a tenth distinct shape
of bad test in this audit, and the mutation list is how to find the rest —
any forwarding-impl method in it has the same problem.

decrypt.rs's two existing gate tests assert only `dropped == 0`, which is
precisely what the `Ok(0)` mutant returns; one asserts nothing else at all.
A wrapper that decrypts nothing therefore looked correct while the caller
muxed scrambled MPEG. Now pinned by descrambling a real CSS sector and
comparing against the plaintext it was built from — not against a
re-derived descramble, which would only assert the code agrees with
itself.

css/mod.rs's `is_scrambled_uncracked` turns out to have no production
callers at all; the enum is matched directly. Its three tests all assert
only the true direction, which is exactly why the `-> true` mutant
survived. It is public API, so a consumer routing on it would, under that
mutant, refuse to rip every clear DVD.

aacs/inf.rs's MKB drive read had no test whatsoever. Now pinned
byte-for-byte across multi-pack concatenation, the single-pack case, a
genuinely empty response, and error propagation — an unreadable MKB must
surface as an error, not as an empty one.

aacs/derive.rs's nine mutants are killed with planted MKBs built by
inverting the AACS relations, so no real key material is involved. The
assertions land on the derived Media Key rather than the intermediate
positions: a recovered position that does not actually walk to the planted
key is no better than None. A fixture-guard test asserts the planted MKB
parses, since an unparseable one would make every `-> None` body look
right.

2570 lib tests, debug and release.
2026-07-30 12:41:28 -07:00
Matthew Jackson 93e1436fc0 Test that the Media Key verifier actually rejects a wrong key
`km_verifies` is the gate deciding whether a candidate Media Key belongs
to the disc. The MK-pool brute force in resolve.rs runs every candidate
through it, so a version that said yes to everything would accept
whichever candidate it tried first and the rip would continue with a wrong
Media Key — wrong VUK, wrong title keys, garbage plaintext, and no error
raised anywhere.

Nothing tested it. Whole-crate mutation testing reported
`replace km_verifies -> bool with true` as SURVIVING: the body could be
replaced with `true` and all 2,556 tests still passed. A verification
routine whose verification was itself unverified, in the most
safety-critical function in the crate.

The implementation is correct — it matches the AACS relation
`AES-D(km, mk_dv)[0..8] == 01 23 45 67 89 AB CD EF`. Only the defence was
missing.

No real key material is required to test it. That relation means a valid
record for any chosen km is just `AES-E(km, <the constant> || anything)`,
so the fixture is self-contained. The test asserts three things: the key
the record was built for verifies; a key differing by ONE BIT does not,
which is the assertion that kills the mutant and is a near-miss rather
than a random key; and an MKB carrying no verify record does not default
to yes, because unverifiable and verified are different answers.

Confirmed by reintroducing the exact reported mutation and watching this
test fail.

This is the first defect found by mutation testing rather than by reading.
Eight audit rounds and a security lens that read this file in full all
missed it, because it is not a wrong line — it is an absent test, and only
an instrument that asks "would anything notice if this were broken?" can
see that.
2026-07-30 12:14:14 -07:00
Matthew Jackson 18f8b285c4 Bound the BD-J label parsers, and stop a crafted disc hanging the scan
Ten defects in code no previous round had ever scoped. `src/labels/`
identifies a disc's studio by parsing jar archives and JVM class files off
untrusted media, so every byte here is attacker-controllable — and 813 of
its lines were executed by no test at all.

The worst is a non-terminating loop. A fallback stream-number scan
advanced with `saturating_add`, and the comment says why: a crafted XML
"must not overflow (panic in debug, wrap-to-0 in release)". Once the
counter pins at u16::MAX and that number is taken, the loop cannot exit.
So a fix for an overflow panic produced an unbounded hang, which is
strictly worse — a panic is observable and catchable, and catch_unwind
cannot interrupt a live loop. Reachable from about 8 MB of XML.

Where the same overflow appears in the deluxe decoder the fix is
checked_add and stop, NOT saturation — twice wrong there, because
saturating would peg every stream past the ceiling at one number and
apply_labels binds on (type, number), silently mislabelling tracks. A
correctness bug wearing the costume of success.

Round 7 capped the ldc-string retention per class; nothing capped the
aggregate, so a 64 MiB jar held that budget for every class at once. Same
defect one level up, which is the shape that keeps recurring in this
directory. Four other amplifications are bounded the same way, each with a
stated headroom and a paired test proving real media passes untouched —
the tightest is 5x on a label length, the loosest 2000x on the stream
numbering space, against BD's 32-per-type STN_table limit.

Two are not caps at all: a quadratic membership scan became a set, and an
attacker-derived length added to a cursor without saturation now cannot
wrap. Nothing is excluded by either.

A `#[cfg(test)]` hand-copy of a shipping parser was the ninth bad test
this audit has found, and the first proven by mutation rather than
inspection: deleting the guard from the REAL function left all 26 tests
green, including the one named for that guard. Pointed at the real
function, the same mutation fails.

Separately, all three failure arms of the bounded fsync returned Ok(()) on
both macOS and Linux, so sync_all reported success for a durability
barrier that never ran. Only macOS was in scope; the Linux twin is fixed
here too, because a platform disagreeing with its sibling about whether a
failed sync is an error is the class that already produced an over-length
SCSI CDB macOS rejected and the other two truncated. Note the behaviour
change: a mux whose final sync times out on a wedged mount now fails
rather than exiting 0.

Three of the caps are proven by wall-clock deadline rather than an
operation count, with 18-80x margin on the passing side. On a heavily
oversubscribed machine those could flake.
2026-07-30 11:30:24 -07:00
Matthew Jackson c63dafcf1a Key each FMTS extent from its own CPS unit, and stop a bad ICB tag reading
as an empty directory

On an AACS 2.1 disc the non-forensic gap fill hardcoded pool slot 0 as
"the" base Unit Key, so every content LBA outside a forensic segment was
keyed with CPS unit 1's key even on a disc carrying several CPS units. It
does not fail loudly — it produces garbage plaintext. The gap fill now
resolves each extent's own base key from its ciphertext, sharing the
sampling and slot-picking the multi-CPS path already had rather than
adding a second copy, and memoised in the existing per-disc cache. A disc
with one base key still short-circuits with zero extra reads, which the
existing probe-cost test pins. Forcing the slot back to a constant fails
four tests, so the choice is load-bearing rather than incidental.

A directory ICB whose descriptor tag is neither File Entry nor Extended
File Entry (ECMA-167 4/14.9, 4/14.17) was turned into a successfully-read
EMPTY directory, indistinguishable from a genuinely empty one, while the
same tag on a file ICB was already a hard error. Fifth instance in this
audit of a failure converted into a plausible success value, and the
second in this very function — round 5 fixed a read error becoming a file
size of zero here.

An unrecorded extent (ECMA-167 4/14.14.1.1: allocated but not recorded,
logically zeros that still occupy file space) was dropped entirely rather
than contributing its length, so every later extent landed at the wrong
file offset. Silent corruption, not an error. Extents now carry a recorded
flag and the hole emits zeros without touching the media.

The Volume Descriptor Sequence was swept at hardcoded sectors 32..64 while
the anchor's own Main VDS Extent pointer was parsed into a comment and
ignored; ECMA-167 3/10.2.1 defines that extent by the field, not by
position, so a conformant volume placing it elsewhere failed to mount.

drive_status decoded byte 5 as Media Status without checking the event
header's NEA bit or notification class (MMC-6 §6.7), so a reply carrying
no media event descriptor decoded as "no disc". The drive is untrusted
input here, and this is the works-on-my-drive class.

Two more tests were found asserting the defects they sit next to — one
requiring unrecorded extents to be dropped, one that four drive fixtures
built non-conformant replies the corrected decoder rightly rejects. Both
rewritten. Combined with the DTS one in the previous commit that makes
three tests this round that locked a bug in as intended behaviour, which
is a different and worse failure than the tautological tests found so far:
a tautology fails to catch a regression, these actively defend the defect.

Not fixed, adjacent: extract_one_file streams extents sequentially and
will now READ an unrecorded extent's sectors rather than writing
guaranteed zeros. Offsets are right, and pressed media reads as zeros
there, but it is not zero-guaranteed the way read_file now is; that needs
a recorded flag through PlannedFile.
2026-07-30 11:15:52 -07:00
Matthew Jackson 46eb88c51f Feed the CSS crack the canonical extent order, and stop Resolution faking 1080p
Seven defects in the code the test suite executes least — 913 lines of
disc/mod.rs alone are run by no test at all, which is why this round scoped
from coverage rather than from what previous rounds said they had read.

Disc::scan_image kept its own copy of the crack's extent ordering and fed
crack_key_outcome largest-cell-first. That is the fifth instance in this
audit of a local reimplementation drifting from the canonical one, and the
cost here is a key that does not descramble the feature: picking by sector
count bypasses the capacity gate and can select a different VTS entirely.
The copy is gone — which title comes from the canonical order the scan
already applied, and the extents are handed over in playback order,
exactly as decrypt_keys_for_title does. Its doc records why the duplicate
existed so it cannot grow back.

Resolution::pixels returned 1920x1080 for Unknown. That is the FOURTH
instance of one trap and the other three were in this same file, two of
them fixed hours earlier — without sweeping for siblings, which is the
whole reason this one survived. It now returns (0, 0), and the sweep was
done properly this time: every remaining Unknown arm across the crate is
honest, and the two ColorSpace sites that look like fabrication are
emitting H.273 code point 2, which is the spec's own "unspecified". Two
callers carried local Unknown-to-zero workarounds — precisely the cost of
making callers responsible for a lie — and one is now redundant.

BD-ROM Part 3 code 0xA2 is the lossy secondary DTS stream, not lossless
Master Audio. A test asserted the wrong mapping as intended behaviour, so
correcting the code failed it; the test is deleted with a note pointing at
its replacement. That is a NEW failure mode for this audit: not a test
that cannot fail, but one that locks the defect in. There is no
DtsExpress variant to map to, so it takes the lossy DTS-HD member and the
approximation is documented.

Also: DiscSession::identify could panic through drive_mut once the public
API allows an absent drive — two siblings were converted in an earlier
round and this one was missed; an extent end that added without saturating
where the rest of the crate saturates; a diag reason string restating the
comparator's sort keys and drifting from them, now derived from them; and
a short read that advanced the offset by the full request, silently
skipping the gap. That last one existed twice, in two reads with the same
shape, now merged so they cannot drift apart.

The short-read policy is a judgement call I could not derive from a spec:
no skip_errors is a hard error, with skip_errors zero-fills and charges
the loss. It deliberately does not retry mid-unit, because resuming inside
an AACS aligned unit would trade a silent gap for a silent decrypt
desync — the worse of the two.
2026-07-30 11:12:55 -07:00
Matthew Jackson dea968f32b Stop AudioChannels and SampleRate fabricating a value for Unknown
Three copies of the same two mappings existed. The canonical accessors
returned 6 channels and 48000 Hz for Unknown; a third copy in diag.rs
returned 0. The honest one was the copy.

A plausible wrong answer is worse than an obvious one. Six channels at
48 kHz is indistinguishable from a real 5.1 track, so every caller became
responsible for remembering to check the variant first — and this crate
walked into exactly that: the json:// sink reported a confident 5.1 for
audio whose neighbouring fields said "unknown". That was fixed at the call
site earlier in this audit; this fixes it at the source.

The accessors now return 0, which is what both in-crate call sites already
coerced Unknown to by hand, so their guards are gone and the behaviour is
unchanged. Zero is also obviously wrong if it ever reaches output, where
six is not.

The diag.rs duplicates are deleted rather than corrected — a fourth copy
would have drifted too. Their only caller was a trace line in the same
file, now on the canonical accessors. Their tests moved across and gained
the Unknown case, which is the point: restoring either fabricated value
fails both.

Found by the round-7 correctness agent while fixing the json:// sink; it
flagged the third copy as out of its scope rather than touching it.
2026-07-30 10:09:01 -07:00
Matthew Jackson 079c9b1327 Add a seeded robustness harness for the untrusted-input parsers
Five parsers that take bytes straight off a disc are now swept with
generated input asserting one property: they return Ok or Err and never
panic. That is this crate's own hard rule, and the class seven rounds of
reading is worst at.

Written in-crate rather than with cargo-fuzz, which needs a nightly
toolchain this project does not use, and without proptest or arbitrary,
because one dev-dependency is a deliberate posture and the parsers take
plain byte slices. What is given up is coverage-guided mutation, which is
the real loss. What is gained is determinism: the same seed replays the
same cases anywhere, so a CI failure reproduces locally verbatim.

Three generators, and the second is the one that matters. Pure random
bytes die at the magic check and exercise the entry guards only; prefixing
valid magic is what reaches the parser body; mutating a mostly-zero record
is what reaches the offset and count arithmetic a hostile image would lie
about.

That claim is MEASURED, not asserted. A harness whose cases all bounce off
the entry guards is the fuzzing equivalent of a test that cannot fail, so
one test counts how many generated cases parse to completion: 15,606 of
60,000, about 26%. If a future change to a guard drops that to zero, the
test fails rather than continuing to report a meaningless pass. Two further
tests pin that the three generators produce different bytes and that a seed
replays identically.

1.2M cases across all five targets found nothing. On this evidence that is
a real negative rather than an empty one.

The first version of this file was itself broken in the way this audit
keeps finding: its two meta-tests set FREEMKV_HARNESS_CASES and raced,
because the test harness runs them in parallel and env mutation is unsound
there. The budget is a parameter now, and the environment is read once at
the call site.

Two crate-internal parsers widened from private to pub(crate) so the
harness can reach them. No public API change.
2026-07-30 09:45:56 -07:00
Matthew Jackson 327087c70e Make five tests capable of failing, and stop the presence probe unmounting the disc
The worst of the five was a regression suite that never touched the code
it guarded: nine batch-count tests called `safe_batch_count` and
`buggy_batch_count`, both defined in the test file itself. The u16
truncation they exist to prevent could be reintroduced in
sector/prefetched.rs with every one of them green. They now drive the real
producer through the public API, and reinstating the truncation fails five
of the nine. Worth recording that the symptom has changed since the
original fix: the unit-alignment clamp below floors a zero batch at three
sectors, so the bug is now a twenty-fold throughput cliff rather than the
stall it once was.

The MP4 reserve test's only numeric case was dominated by the floor and
the buffer, so BYTES_PER_SAMPLE could be zeroed without failing it. It now
has a case where the per-sample term dominates. The zero-count guard in
FileSectorSource was likewise unfalsifiable — seek-past-EOF and a
zero-length read both succeed — so the test now observes the file cursor.
The AACS media-key ambiguity guard had no test at all; the pool scan is
extracted so the verifier can be injected, because a genuine two-key
collision needs one ciphertext decrypting under two AES-128 keys to
plaintexts sharing a 64-bit magic, which is a 2^64 search and not a
fixture.

macOS implemented the documented cheap, side-effect-free presence probe by
building a full exclusive transport — which force-unmounts the disc. Linux
and Windows issue one TEST UNIT READY with no unmount; macOS was the
outlier. It now walks the IOKit registry for the media object instead.

The C shim's registry reads assumed CoreFoundation types the registry does
not guarantee, so a driver publishing a CFNumber where a CFString was
expected aborted the process from inside public API. Types are checked and
a wrong type treated as absent. The unbounded waitpid on the unmount child
is now a polled deadline, and the last-resort match gained the NULL check
its two siblings already had.

The empty-CDB guard existed only on Linux while a shared helper's comment
claimed all three backends had it. Moved into the helper, so the comment
is now true and macOS and Windows are covered.

One finding was REJECTED with evidence rather than fixed. The TrueHD
buffer-cap test was indeed bogus, but MAX_TRUEHD_BUF turns out to be
unreachable by any input: the parser only retains data when the buffer is
shorter than the declared AU, and that declaration is twelve bits, so the
worst case is 8189 bytes against a 256 KiB cap. An exhaustive sweep over
all 65536 AU headers confirmed it. The fixture now sits at the reachable
ceiling and asserts that instead. The cap itself is left in place as
defence, unreachable by construction, matching how the AC-3 resync guard
was handled earlier in this audit.

Two behaviour changes worth naming: Linux's empty-CDB error becomes
InvalidCdbLength rather than a transport failure, and an unknown device
now reports absent media rather than a not-found error, because the
registry cannot tell an empty drive from a missing one. The latter is a
conflation of the kind this audit has fixed three times; it is recorded
for the next round rather than left silent.
2026-07-30 09:26:56 -07:00
Matthew Jackson b8fa5e74dc Stop the live rip path muxing Blu-ray 3D differently from the ISO path
Five defects, four of them the same shape: a local reimplementation of
logic the crate already had, which had drifted from it. Each is now fixed
by calling the canonical version rather than by patching the copy.

DiscStream::new — the live disc:// path — built every parser through the
plain codec lookup and never asked whether a video stream was an MVC
dependent view, though resolve::build_demux_state does. The same 3D disc
therefore muxed correctly from an ISO and incorrectly ripped live. The
open-coded loop is gone; both paths now call build_demux_state.

collect_psi_section reimplemented the continuity-counter gap test and
disagreed with process_packet in the same file: it tolerated neither a
duplicate packet nor an adaptation-field-only packet, which per ISO/IEC
13818-1 §2.4.3.3 does not increment the counter. A spec-legal PMT
continuation was read as desync and the title's stream list came back
empty. Both callers now share one `cc_is_gap`, and a duplicate packet's
payload is no longer appended twice — doing so would have corrupted the
section the check exists to protect.

The json:// sink called the channel-count and sample-rate accessors
unconditionally, and both fabricate a concrete value for Unknown, so it
reported a confident 5.1 at 48 kHz for audio whose format was unknown
while its own neighbouring string fields said "unknown". The keys are now
omitted, matching mkv.rs. This matters more than it did: a sample-rate
ladder fixed earlier in this audit means Unknown now reaches consumers
that used to receive a wrong-but-concrete value.

For an audio:// or sub:// sink the reference video track's output is
filtered out, so its first PTS was never recorded and every delay was
computed against zero — baking a wrong DELAY into the filename. The
reference is now recorded whenever a frame is on the reference track,
independent of whether that track has an output, so a normal title gets a
correct delay; where no reference is ever observed the tag is omitted
rather than guessed.

A third copy of the channel/sample-rate mapping exists in src/diag.rs and
was left alone as outside the confirmed set. It is the same drift shape
and is recorded for the next round.
2026-07-30 09:18:33 -07:00
Matthew Jackson 3f7d7af472 Bound three allocations an untrusted disc can drive without limit
The Program Stream demuxer appended every fed byte and enforced its 4 MiB
cap only inside a branch reached once a start code had been found. Input
containing no start code anywhere therefore hit no cap at all, and since a
whole title is fed through this demuxer, a zero-filled or ciphertext VOB
extent buffered the entire title — up to ~90 GB. When the buffer holds no
start code, only a two-byte `00 00` prefix can begin a PS unit on the next
feed, so that is kept and the rest dropped. The bound is exact rather than
a heuristic: a start code can straddle a feed boundary by at most its
first two bytes, so no real byte is discarded, and a test feeding
`FF FF 00 00` then `01 E0 ...` pins that.

The existing test named for this case fed a real start code first, so the
cap it exercised was the in-PES one. Renamed to say what it covers.

The BD-J label path had a different shape to anything found so far: the
cap is on the COMPRESSED size of a disc file while the allocation scales
with the decompressed size. A `.class` gated only by a path prefix
inflates to the 64 MiB ceiling, yielding ~33M retained strings from `ldc`
operands or ~67M pushes onto a symbolic stack whose depth was unbounded
despite the Code attribute's own `max_stack` being parsed and then
ignored. Bounded both, the stack by `max_stack` itself (JVMS §4.7.3).

The VMG TT_SRPT title count is an untrusted u16 with no de-duplication,
so ~800 KB of crafted IFO re-parsed one PGC 65535 times. Capped at 99, the
DVD-Video maximum, so no conformant disc is clipped.

Every cap carries stated headroom against real media, and each has a test
locking that real media still passes.

I rewrote three of the new assertions before landing them. They compared
the result against the very constant under test — `total <= MAX_TT_SRPT_TITLES`
— which passes vacuously the moment someone raises the constant, the most
likely future regression and the seventh instance of this tautology shape
in this audit. They now assert literals derived from the spec.

The TT_SRPT fixture also had to change: with 65535 identical entries the
de-duplication collapsed them on its own and the cap was never what
bounded the result, so the test passed with the cap removed entirely.
Distinct entries defeat dedup and leave the cap as the only guard;
de-duplication now has its own fixture. Verified by raising each of the
three constants and confirming all three tests fail.
2026-07-30 09:17:16 -07:00
Matthew Jackson fdd473d7e9 Remove emulation-prevention bytes before reading the H.264 slice header
The bytes after a NAL header are EBSP, not RBSP: ISO/IEC 14496-10 §7.4.1
has the encoder insert 0x03 after any 0x00 0x00, and §7.3.1 removes it
before parsing. The measured-picture-type parse read the raw NAL instead,
on the stated reasoning that slice_type is too early for an escape to
intervene.

That holds only up to a point. first_mb_in_slice is ue(v), so a value of
65535 or more needs sixteen leading zero bits and opens the payload with
0x00 0x00, which an encoder must then escape. A UHD frame is ~32,400
macroblocks, so a conforming Blu-ray never reaches it — but 8K does, and
the disc is untrusted input. Such a stream decoded slice_type against a
byte the encoder had inserted and reported the wrong picture type: a wrong
result rather than an error, which is the class this lens exists for.

The prefix is un-escaped into a 16-octet buffer rather than the whole NAL:
the two ue(v) fields are at most 32 bits each, so nothing longer can be
needed, and it keeps a per-frame allocation proportional to the frame off
the path.

The test pins both directions. It asserts the un-escaped prefix decodes to
first_mb_in_slice = 65535 and slice_type = 2, AND that the raw EBSP does
NOT — without that second assertion the test would pass whether or not the
fix were present, which is the failure mode this audit has now found four
times. The bit string was derived independently rather than by hand: my
first attempt at the fixture was wrong by one nibble and the test caught
it.

Also covers the cases that must NOT be unescaped: a 0x03 not preceded by
00 00 is ordinary payload, and 00 00 03 03 keeps its second 0x03 because
the escape resets the zero run.
2026-07-30 08:49:51 -07:00
Matthew Jackson 05fed1b0e0 Log the OS error when a SCSI command fails on Windows and macOS
Both backends discarded the platform's own error code on the execute hot
path — the one every READ(10) of a rip goes through — and collapsed every
cause to the same status-0xFF transport failure.

On Windows, open() and reset() in the same file both capture the Win32
error; execute() did not. That left ERROR_INVALID_PARAMETER (a struct
layout regression, the exact class this file's SDK-layout tests exist to
catch), ERROR_ACCESS_DENIED and ERROR_GEN_FAILURE (a genuinely wedged
drive) indistinguishable, with nothing in the log to tell a code bug from
a hardware one.

On macOS the same, and worse: the file had no tracing calls at all, where
the Linux and Windows backends both log their execute failures. Its open()
carefully decodes the shim's sentinel into typed variants instead of
flattening them, but execute() threw the IOKit return away — so another
process taking exclusive access mid-rip and a real hardware wedge produced
identical, empty diagnostics.

Logged rather than added to the error type: the typed variant is public
API, and the recovery classification is deliberately the same for all of
these. What was missing is the breadcrumb, not the distinction.

Two further findings from the same sweep were rejected. Windows reset()
always returning Ok(()) and macOS ignoring timeout_ms are both already
documented in the code as deliberate, and the reporter flagged them for
completeness rather than as defects.

Neither fix has a test: reaching either branch needs a failing ioctl or a
failing IOKit call, and both files are compiled only on their own platform.
2026-07-30 08:42:02 -07:00
Matthew Jackson d444afbdfc Turn a release-only slice panic into an error, and stop calling 32 kHz 48 kHz
Four round-6 findings.

FileSectorSource::read_sectors guarded its output buffer with a
debug_assert, which is compiled out in release — so an undersized buffer
panicked with 'range end index out of range' instead of returning an
error, out of a public SectorSource impl where the length is caller input.
Drive::read_fua already carries this exact guard, with a comment recording
the same panic being fixed there, and PrefetchedSectorSource has a
regression test for the same case; this impl had been given neither. The
new test is red in release for precisely the predicted reason: 'range end
index 8192 out of range for slice of length 2049'.

parse_track's sample-rate ladder ended in an unconditional S48, so any
SamplingFrequency below 44100 was recorded as 48 kHz. A 32000 Hz AC-3 or
DTS track is legal and common in broadcast-sourced content, and the wrong
rate then propagated into the reconstructed AudioStream. Anything below
the lowest mapped rate is now Unknown, which is what the crate's canonical
SampleRate::from_hz already returned — the ladder disagreed with it. The
ladder itself stays, because the MKV element is a float and wants
tolerance rather than exact equality.

shim_open_exclusive used the mach port from IOMainPort without checking
the return; on failure the port is left untouched and every IOKit call
below ran against an uninitialised value. shim_list_drives in the same
file does check it.

build.rs treated cc and ar as successful if the process merely SPAWNED, so
a genuine compile error in the macOS C shim produced no object file and
surfaced later as an unexplained link failure against a missing symbol.
The shim is macOS-only and is neither linted nor compiled on the other two
platforms, so a mistake in it has exactly one chance to be noticed.

The last two have no test: one needs IOMainPort to fail, the other needs a
deliberately broken C shim, and neither is reachable from the test
harness. Both mirror a correct sibling in the same file, which is the
evidence available.
2026-07-29 22:56:33 -07:00
Matthew Jackson 921404d135 Fix five clippy errors that only appear on the target CI lints
CI's clippy job runs on ubuntu-latest, so cfg(target_os = "linux") code is
what the gate actually compiles — and none of it is built by clippy on a
Mac. Five `-D warnings` errors were sitting in drive/linux.rs,
scsi/linux.rs, io/writeback/linux.rs and the Linux arm of drive/mod.rs:
four collapsible let-chains and one manual `% n == 0`. CI was red on the
lint job while the local gate reported all green.

Collapsed into let-chains, which the declared toolchain supports, and
folded drive/mod.rs's length precondition into its chain so the body no
longer needs a nested block.

Found because an agent working on the SCSI backends reported the lints in
passing while checking that a Windows-only file compiled. Worth noting how
it stayed hidden: every one of these files is cfg-gated to a platform this
machine is not, so no amount of local gating would have surfaced them. The
companion change to the precommit script closes that hole.
2026-07-29 22:37:47 -07:00
Matthew Jackson 399c3d2769 Reject an over-length CDB on every transport, splice H.264 param sets in place
Two fixes from round 5.

The Linux and Windows backends truncated a CDB longer than 16 bytes
(`cdb.len().min(16)`) where macOS returned InvalidCdbLength. Under SPC-4 a
command's length is fixed by its opcode group code, so a shortened CDB is
not a shorter form of the same command — it is a DIFFERENT command, and
the drive executes it and answers GOOD with data for a request nobody
made. A silently wrong result on the layer everything else sits on.

Rather than mirror the guard a third time it now lives in scsi::mod as
checked_cdb_len, with all three backends routed through it, so it cannot
drift per platform again. That also makes it testable everywhere: each
platform module is cfg-gated to its own host, so a guard inlined into
linux.rs and windows.rs would have had no test coverage on any single
machine. The shared helper is the only place the behaviour can be
asserted on every platform's CI.

The two existing macOS tests were tautological — they replicated the
guard's logic inline instead of calling it, so they would have passed with
the guard deleted. They now call the real helper.

Separately, the H.264 keyframe parameter-set re-assert grew a
few-hundred-byte prefix buffer to the full access-unit size, copied the
whole frame into it, and dropped the presized buffer: one extra
whole-frame allocation and copy per keyframe. A UHD title is ~200,000
frames of 150-400 KB with a keyframe every second or two, so that is
thousands of avoidable multi-hundred-KB copies per title, each large
enough to go through mmap. It now splices into the reserved headroom in
place. This mirrors the identical fix already made in hevc.rs, which the
H.264 path had drifted from.

Byte-for-byte equivalence is pinned by a test whose expected literals
were captured from the pre-change implementation, and which I confirmed
still passes when the old build-and-copy code is restored. The
no-reallocation claim is measured rather than argued: a counter over 30
bare keyframes, which reports 30 of 30 against the old path and 0 with
the splice.

The reallocation test initially passed even with PARAM_REASSERT_HEADROOM
set to zero, because a small parameter set fits in the presize's
incidental slack — it proved the fixture did not reallocate, not that the
headroom prevented it. Its SPS is now large enough that the constant is
load-bearing, so zeroing it fails the test.

Not verified: no runtime behaviour on Linux or Windows: no drive, no
ioctl. Both files were confirmed to compile for their own targets.
2026-07-29 22:34:22 -07:00
Matthew Jackson dc5b67ed46 Stop reporting an uncrackable CSS disc as N empty titles
Same shape as the mkv:// conflation fixed earlier in this round, found by
looking for it deliberately. E7023 carried two conditions with opposite
correct responses: one title on a multi-VTS DVD failing its own re-crack,
where skipping it and finishing the rest is right, and the main feature's
crack failing outright, which is disc-wide and dooms every title
identically. Because both raised the same code and that code is in
is_skippable_title_stub, an uncrackable disc walked all N titles printing
"title skipped, it was empty" and exited 0.

The disc-wide condition gets E7027 CssNoDiscKey, mirroring the AACS-side
E7022 NoDiscKey it is the analogue of, and joins is_disc_level_no_key.
The per-title raise keeps E7023 and stays skippable. Because the engine's
classifier already tests is_disc_level_no_key before the skippable
branch, this reaches the right outcome downstream with no change there:
such a disc now stops on the first title and reports no-key instead of
returning success with nothing written.

Disc::css_error deliberately still stores CssKeyMissing — autorip matches
that variant on the field to pick the CSS rather than AACS message, and
what consumers classify on is the gate's returned verdict, which is the
only thing that changed.

Two neighbouring CSS raises were examined and deliberately left alone:
the no-key branch in the same function is genuinely unreachable via
ensure_decryptable and documented as defensive, and resolve_dvd_title_key
is per-title on both of its call paths.

Verified by removing the new code from is_disc_level_no_key, which fails
both new tests; each pins both directions so neither can silently flip.
Not proven end to end against a real uncrackable disc — none available.
2026-07-29 22:29:51 -07:00
Matthew Jackson 5c6a6d0785 Round 5: reject a degenerate fixed lace, bound the pending buffer by bytes
Five fixes. Three are real defects with regression tests; two are bounds
that were expressible but not expressed.

A fixed-size lace (RFC 9559 §10.3.4) whose body is empty declared n
frames and carried none. The divisibility check passed, because 0 % n is
0, and `chunks` yields nothing on an empty slice whatever width it is
given — so the clamp that existed to avoid chunks(0) returned zero frames
where the Lacing Head said n. The whole lace vanished with no error
raised and the caller saw a clean short block. A zero-size frame cannot
be a valid frame, so it is now malformed.

A disc read failure while fetching a directory entry's ICB became a file
size of zero rather than an error. Zero is indistinguishable from a
genuinely empty file, so an unreadable ICB on a damaged disc silently
changed which titles a caller saw as present — read_directory already
fails hard on its entry-budget guard, so propagating is also what the
surrounding code does. read_file_size still returns Ok(0) for an ICB
whose tag is neither File Entry nor Extended File Entry, which is a real
zero and not a failure.

The pending-frame buffer was capped at 4096 frames, which does not bound
memory: frames are arbitrarily large and a UHD video frame runs to a few
hundred KB, so the existing cap permitted over a gigabyte. Now bounded by
bytes as well, at 64 MiB.

round_up_grain overflowed for inputs within one grain of u64::MAX —
div_ceil then multiply — and the wrapped product is small, turning the
largest possible estimate into a negligible reserve. It saturates, and
the reserve is clamped to what a `free` box's 32-bit size field can
actually hold, since writing a larger one truncated the size and left
mdat beyond a box claiming to be far shorter. No real title comes close;
a 90 GB UHD title estimates a few MiB.

The AC-3 resync guard now advances the PTS cadence like both of its
sibling branches, so the three paths out of that block cannot disagree.
This one is defensive and has NO test: reaching it needs input that both
parses frames and leaves a megabyte of residue, and the parser's own
carry rules drop pre-sync junk and cap a partial frame at 8192 bytes, so
no such input was found. Stated here rather than covered by a test that
would pass either way.

Two findings from this round were rejected on inspection. A reported
panic in the .mpls suffix check does not exist: the `.get(..)` on the
line above returns None off a char boundary and `filter` never runs its
closure, so the byte index is unreachable. A test written for it passed
against the unfixed code, which is what surfaced the error.
2026-07-29 22:28:43 -07:00
Matthew Jackson f5e169efb3 Stop reporting a corrupt mkv:// source as an empty title
E6008 meant two unrelated things: "this title produced no muxable
frames", which is a benign stub worth skipping, and "the source file is
malformed", which is not. Because a single code carried both,
is_skippable_title_stub answered yes to the second one — so feeding a
truncated or corrupt mkv:// input made the engine classify it
SkippableStub, print a notice saying the title was empty, and exit 0.
Silent data loss reported as success.

Split into E9053 MkvSourceInvalid for the read path (25 raise sites
across mkvstream.rs and ebml.rs's read primitives) and E9054
MkvUnencodable for the four write-side sites, which are the encoder
refusing to emit a body at or above the 56-bit VINT limit — an output
limit with no input involved, so calling it a corrupt source would be
wrong in the other direction. E6008 keeps only the zero-frame guard it
was documented to mean.

Kept one code for the whole read path rather than one per raise site:
nothing a consumer does differs between a bad VINT, a non-UTF-8 string
element, a truncated body and a child overrunning its parent. E9052 is
the model for when a carve-out earns its keep — laced blocks name one
specific RFC 9559 §10.3 feature with its own diagnosis.

Also fixed meta_sink.rs raising MkvInvalid for a serde_json encode
failure in the json:// sink, where no MKV is involved at all; it now
matches the identical guard in mux/meta.rs.

Reverting the split at the single code() arm reproduces the old
classification: 22 tests fail, including both new assertions. The
opposite direction is pinned too — dropping E6008 from the predicate
fails the genuine-stub test, which drives the real muxer end to end.
2026-07-29 22:11:53 -07:00
Matthew Jackson 0bbceed985 Round 4: fix 26 defects across crypto, resource use and codec paths
Twenty-six confirmed findings from the fourth audit round, landed as one
cluster because they were found by agents working over disjoint file sets.

The one worth calling out is a pair of AACS tests that could not fail.
Both asserted CBC behaviour against a hand-rolled expectation that
happened to be IV-independent, so replacing AACS_IV with sixteen zero
bytes left them passing — they were pinning the code's own arithmetic,
not the published constant. Replaced with a literal witness of the
published IV plus the NIST SP 800-38A F.2.2 CBC-AES128 vector, and
verified the other way round: zeroing AACS_IV now fails three tests.

The rest are allocation and correctness work on hot paths: the Annex-B
writer in demux_sink allocated and freed a whole-frame Vec per frame,
which for a UHD title is ~200,000 allocations over the mmap threshold
plus the page faults to first-touch each one; it now reuses a buffer on
the writer, and still takes the NAL prefix width from the configuration
record rather than assuming four.

Six findings whose real fix lives in a consumer crate are recorded for
re-filing rather than patched here.
2026-07-29 22:09:52 -07:00
Matthew Jackson 4fcd28b487 Parse MKV lacing, route by real TrackNumber, honour NAL length size and edit lists
Four conformance defects in the read paths, two of them silent corruption.

**Lacing was ignored entirely.** RFC 9559 §10.2 defines Xiph, EBML and
fixed-size lacing, where one Block carries several frames; the reader took the
Block payload verbatim, so a laced Block became a single "frame" consisting of a
lacing header followed by concatenated frames — garbage to the codec parser, no
error. Audio tracks from other muxers commonly use lacing, so an ordinary
foreign MKV was silently mangled.

All three modes are now parsed: Xiph 255-run sizes including the trailing-zero
rule for exact multiples of 255, EBML unsigned first size plus SIGNED VINT deltas
with the 2^((7*n)-1)-1 bias of §10.3.3, and fixed-size even division, with the
last frame's size deduced from the remainder. Laced timestamps follow §10.3.5:
the first frame takes the Block timestamp and the rest are spaced by the track's
DefaultDuration, else BlockDuration/count, else shared with a warn.

Parsing was chosen over refusing because refusal would leave freemkv unable to
remux common foreign audio at all, and each mode is about fifteen lines.

A malformed lacing header now raises a NEW code, E_MKV_LACING_INVALID = 9052,
deliberately NOT MkvInvalid — because is_skippable_title_stub classifies
MkvInvalid as a skippable nav stub, so reusing it would have recreated the exact
conflation that is still open as a separate finding. A test asserts the new code
is not skippable.

**TrackNumber was assumed to be 1..N in TrackEntry order.** RFC 9559 §5.1.4.1.1
only requires it to be non-zero and unique, so sparse or unordered numbers are
legal. Block routing and codec_private both computed track + 1. A real
TrackNumber map is now built, recorded only for TrackEntries that yield a stream
so dropped track types no longer shift the mapping.

Verified red here independently, and the failure mode is worse than mis-routing:
with track + 1 restored, a buttons track's payload was attributed to the AUDIO
stream — wrong payload into the wrong codec parser.

**The NAL length prefix was hardcoded to 4 bytes.** lengthSizeMinusOne lives in
avcC byte 4 and hvcC byte 21 (ISO/IEC 14496-15 §5.3.3.1.2, §8.3.3.1.2) and was
never read, so a source declaring 1- or 2-byte prefixes had its raw prefixed
bytes emitted verbatim with no start codes. All four conversion sites now derive
the width from the track's own configuration record.

**Edit lists were ignored.** No edts/elst was parsed, so the presentation
timeline an edit list defines (ISO/IEC 14496-12 §8.6.5/§8.6.6) was dropped —
which is how encoder delay is normally expressed. Leading empty edits and the
first media edit's media_time are now applied to both dts and pts, with the movie
vs media timescale distinction respected. A list needing more than a constant
shift applies the leading edit and warns rather than presenting the result as
faithful.

17 tests. I reproduced the lacing mutant independently: returning the body whole
kills five of them, including the exact-payload and malformed-header cases.

Still open and deliberately untouched: the MkvInvalid / is_skippable_title_stub
conflation across ~20 reader raise sites. It is a cross-cutting error.rs change
and E_MKV_LACING_INVALID is the template for it.
2026-07-29 21:53:19 -07:00
Matthew Jackson 9527bc1e13 Anchor forensic segments to the forensic clip, and stop CPS branching on resolve order
Two correctness defects in AACS 2.1 / FMTS key-map resolution, both order- or
anchor-dependent, and both able to abort a whole disc or silently garble it.

**The single-CPS short-circuit depended on which title resolved first.**
`pool_len` counted the WHOLE unit-key pool, and resolve_fmts_key_map appends the
disc's forensic index keys to that same caller-owned pool. The count was captured
before THIS call's FMTS branch but not before earlier titles', so once any forensic
title resolved, every later title saw a pool larger than one and fell into
multi-CPS sampling — 8 random reads per extent, and a whole-disc DecryptFailed if
no pooled key opened a menu extent's samples. A disc that ripped fine when a
non-forensic playlist sorted first failed when a forensic one did.

Forensic keys are now tagged FMTS_POOL_TAG_BASE = 1 << 24 and the short-circuit
asks single_base_key_slot(), which excludes them. The old 1000 tag was NOT kept,
and the reasoning is worth recording: base CPS ids are Unit_Key_RO.inf position + 1
and that count is a BE16, so 1000 sits inside a genuinely reachable id space. 1<<24
cannot collide. The id field is cosmetic — decrypt.rs indexes the pool by slot and
reads only the key — so widening the tag is safe.

**Forensic segment SPNs were anchored to the wrong clip.** They live in the
forensic feature clip's byte space, but were mapped through
clip_byte_to_lba(&title.extents, ..), which treats byte 0 as the start of the
title's FIRST extent. Any playlist not beginning with the forensic clip mapped
every segment to the wrong LBA: either the anchor probe sampled the wrong clip and
the whole-disc resolve aborted with FmtsKeyMissing, or — worse — a forensic index
key was applied to non-forensic sectors while the real forensic units kept the base
key, giving silently garbled output with no error at all.

The correct anchor turns out to be a DISC fact, not title data: an AACS 2.1 disc
names its forensic feature BDMV/STREAM/<clip>.fmts, and carries one
IndividualSegment.tbl, so the SPNs are in that one clip's byte space. A new
forensic_clip_extents() finds the unique .fmts in the already-walked UDF tree, and
those extents now drive the segment arithmetic, the addressability filter, and the
index probe — whose title parameter is gone, since its reads were mis-anchored too.
"Does this title carry forensic content" is now "does it read the forensic clip's
sectors" rather than "do the segment bytes land somewhere in the concatenation".

Where the clip is NOT identifiable — no .fmts, or several, making the SPN space
ambiguous — on a disc that does carry a non-empty table, the resolve now fails loud
with FmtsKeyMissing rather than guessing an anchor. That is a deliberate behaviour
change: a hypothetical disc with two .fmts clips hard-fails where it previously
produced a possibly-wrong map. Failing loud beats silently garbled output, and
inventing an anchor was not acceptable.

This site had been flagged independently three times — by the agent that added the
FMTS per-disc memo, by the round-4 correctness lens with a concrete scenario, and
by the round-4 conformance pass.

Verified red here independently: reverting single_base_key_slot to count the whole
pool fails both new tests. The agent's own evidence was probe_reads 48 vs 40 (the
8 extra sampling reads) and an E7013 DecryptFailed whole-disc abort, and for the
anchor an E7026 FmtsKeyMissing on a [trailer, forensic] extent list.

All six pre-existing FMTS tests pass unchanged through the new anchor, including
the exact-cost assertions (40 probe reads, one key-service call per disc, one UDF
walk for 60 titles), so the round-3 memoisation wins are intact.
2026-07-29 21:37:50 -07:00
Matthew Jackson 58bdb42f8e Group whole E-AC-3 frame sets, and keep short reads unit-aligned
Two defects in fixes landed the same day, both found by round 4 auditing round 3's
work rather than trusting it.

**The E-AC-3 grouping ignored substreamid, so the timeline still doubled.**
Confirmed independently by the correctness and conformance lenses and verified by
hand: substreamid appeared only in test helpers, never in the production path. Per
ETSI TS 102 366 (A/52) Annex E a frame set is independent substream 0 — mandatory,
always first — with its dependents, then the OPTIONAL additional independent
substreams 1..7 with theirs, all covering the same time period. Treating an
additional independent substream as a new access unit advanced the clock a second
time for the same 32 ms, which is exactly the doubling the grouping fix existed to
prevent. No fixture caught it because every fixture used substreamid 0.

is_dependent_substream becomes substream_role -> Starts | Extends: strmtyp 1
extends; strmtyp 0/2 with substreamid != 0 now extends (this was the bug); strmtyp
0/2 with substreamid == 0, legacy AC-3, and reserved strmtyp 3 start. Reserved 3
starts regardless of its id bits, because its BSI layout is undefined so those bits
cannot be trusted — an unknown frame is neither merged into an unrelated programme
nor silently discarded.

The frame set stays ONE sample rather than being split into a separate track for
the associated service, and the reasoning is in the module doc: a substream
numbered 1..7 with no substream 0 is not conforming, so extracting one would mean
renumbering ids and rebuilding frame sets — a transcode, not a remux. Programme
selection is the player's job.

A stream joined mid-frame-set (first sync is substreamid 3) is skipped with a debug
and resyncs at the next id-0, mirroring the orphan-dependent rule: its mandatory
id-0 substream was never seen, so it is neither decodable alone nor timeable.

MAX_AC3_BUF 128 KiB -> 1 MiB, because an AU is now a whole frame set: worst case 8
independent x 9 substreams x 8192 B = 576 KiB, which the old cap could have dropped
mid-hold.

**The forced probe's two round-3 fixes cancelled each other.** CHUNK_SECTORS = 1023
exists (with a const assert) so every read starts on a 3-sector AACS aligned-unit
boundary; the short-read fix advanced by actual bytes, making the advance a
non-multiple of 3. Every later read was then misaligned, DecryptingSectorSource
refused it before reading, the stop became ReadFailed, and no verdict was asserted
— so content-based forced detection silently fell back to the vendor label on
exactly the encrypted discs the 1023 change was written for.

A partially-satisfied read now advances only by whole aligned units and re-reads
the <=2 residue sectors from the next boundary, feeding only the aligned prefix so
nothing is double-fed and no partial unit reaches the parsers. A read that fully
satisfies its request still advances by all of it. When less than one aligned unit
comes back the bytes are fed and the same LBA is retried twice before stopping, so
a starved source cannot spin — verified by raising the retry limit and watching the
test hang.

Verified red independently here: reverting substream_role to strmtyp-only fails
eac3_additional_independent_substream_stays_in_the_frame_set (6 access units where
3 are correct — the doubling, literally) and the mid-frame-set resync test.

Reported, not fixed: dec3_box still hardcodes num_ind_sub - 1 = 0 and
num_dep_sub = 0, so it under-declares any stream carrying additional independent
or dependent substreams now that frame sets arrive whole. DolbyConfig has no
fields for either; a real fix needs the parser to surface observed substream
counts. That file is another lens's this round.

Unverified: no real multi-programme DD+ stream exists here, so defect 1 rests on
synthetic Annex-E fixtures. The retail DD+ check (No Time to Die, all substreamid
0) confirms single-programme discs are unaffected.
2026-07-29 21:33:18 -07:00
Matthew Jackson 62450e19bd Make two public-API panics return errors, and drop two shipped citations
**The session panics are reachable, and my earlier triage of them was wrong.**
`DiscSession::scan` and `resolve_keys` both did
`self.drive.as_mut().expect(..)`. I previously downgraded these to LOW on the
grounds that no shipped consumer calls them after the drive has been staged into
the reader slot. That is the wrong test: `stage_drive_as_reader` is a PUBLIC
method that empties the drive slot, so the public surface permits the sequence,
and a library must not panic from public API regardless of what current callers
happen to do. Both now return Error::DeviceNotReady.

**A shipped doc comment cited a third-party source FILE** as the authority for
the CLPI ProgramInfo layout ("Layout per the BD CLPI spec clpi_parse.c"). Now
cites the Blu-ray Disc Read-Only Format Part 3 CLIPINF specification.

**The CHANGELOG justified a muxer decision by naming a commercial competitor**
("MakeMKV's rip of the same disc omits it", "matching MakeMKV"). Reworded to
stand on its own terms: the element is optional in RFC 9559, nothing requires it
for interlaced SD, and the 40 ms DefaultDuration is the frame rate the source
actually carries.

The leak gate is extended for both new classes — third-party `*_parse.c` /
`*_dec.c` / `*_demux.c` style filenames, and a competitor named as authority.

Narrowing that rule took two attempts, which is worth recording. A bare
`\.(c|cpp|cc)` pattern produced eight false positives: this repo has its own C
shim (`macos_shim.c`) that build.rs and the docs legitimately reference, and the
pattern also matched the Rust field access `p.cc`. It now matches only the
suffixes typical of third-party media-library sources. This is the second
false-positive round on this rule — the first flagged ffmpeg INVOCATIONS in the
test harness — so the lesson is that a hygiene pattern needs testing in both
directions before it lands, exactly like any other code.
2026-07-29 21:21:29 -07:00
Matthew Jackson 013881ac06 Restore the MP4 conformance fixes I clobbered while landing another agent's work
detect_rate's nearest-match fix, the colr HLG/BT.470 fix and their four tests
were silently reverted. Cause: the r3fix-silent worktree was cut BEFORE the
conformance commit landed, and I landed its work by copying whole files into the
main tree. mp4/mod.rs was in both agents' file sets, so silent's copy — built on
the older base — overwrote the conformance changes wholesale. The gate stayed
green throughout, because reverting a fix and its tests together is perfectly
consistent.

Re-applied the conformance commit's diff for that file with a three-way merge;
both agents' changes to mp4/mod.rs now coexist (final_report, UndescribableAudio
and the max(track_id) id fix are all still present alongside RATE_TOLERANCE_FPS
and the colr resolver delegation).

Only mp4/mod.rs was affected. mp4/audio.rs and mkv.rs were in no other agent's
file set and were intact.

Process lesson, recorded because I would otherwise repeat it: NEVER land a
parallel agent's work by copying whole files, when its worktree was cut at an
older base than HEAD. Apply its DIFF (git apply -3), or rebase its worktree
first. Copying files silently discards anything committed to those files in the
interim, and no test can catch it because the tests disappear with the code.
2026-07-29 21:03:26 -07:00
Matthew Jackson 5f8dc392c0 Sweep the pinned toolchain to Rust 1.97
The Windows UI needs current winsafe, whose real minimum is 1.89 (its manifest
under-declares 1.87 while it uses NonNull::from_ref). Rather than stop at the
minimum, this goes to current stable and fixes what that costs.

The counter-intuitive result: 1.97 is CHEAPER than 1.89. libfreemkv had 54
clippy errors at 1.89 and 6 at 1.97, because clippy tightened the noisy
collapsible_if lint in between. Stopping at the minimum would have been the most
expensive choice available.

Roughly 47 lints across the eight repos, the large majority auto-fixed:
libfreemkv 6, freemkv-engine 14, bdemu 8, freemkv-keysources 7, autorip 6,
freemkv-unlock 3, freemkv-i18n 3. The hand-fixed ones are a descending sort to
sort_by_key(Reverse), four manual checked-division sites, a loop counter replaced
by enumerate, and a loop whose first let-else became a while-let.

Worth recording for whoever bumps next: clippy is MSRV-AWARE. Those 54 lints only
appear once the crate DECLARES 1.89 or later, because let-chains become
available. A bare `cargo +1.89 clippy` against a manifest still pinned at 1.87
reports clean and is meaningless — gate with the real precommit script, which is
also the only thing that covers build scripts.

The pin still sits below the Mac default, so it keeps doing its job: catching
lint drift locally before CI sees it.
2026-07-29 21:00:55 -07:00
Matthew Jackson a32373ff40 Fix fifteen defects across perf, resource, panics and key hygiene
All 21 findings held up under verification; 15 fixed here, 6 deferred to files
another agent held this round, 0 rejected.

**A defect in my own round-2 probe fix.** CHUNK_SECTORS was 1024, and
1024 % 3 == 1 — verified — so every chunk after the first was misaligned against
the 6144-byte AACS aligned unit and would be REJECTED by
DecryptingSectorSource's alignment gate. On an encrypted disc the forced-subtitle
probe I added last round would have read almost nothing past its first chunk.
Now 1023 sectors (341 aligned units) with a const assertion that fails the build
if it stops dividing, plus set_unit_base per extent so the source's gate is
anchored where the extent actually starts.

**The same probe skipped sectors on a short read**, advancing by the REQUESTED
count rather than the bytes actually returned, so a partial read silently left a
gap in the middle of the evidence. It now advances by n/SECTOR_BYTES and clamps n
to the buffer.

**Its cache key omitted the PGS PID set**, so a playlist declaring an extra
subtitle PID got another playlist's verdict for a track that had never been
probed. And the key was the whole extent list, so partial clip sharing missed
entirely. Both fixed by keying (start_lba, sector_count, pid) — and per-extent
keying was shown SOUND rather than assumed: ForcedTracker is two monotone
booleans, so per-extent evidence composes by field-wise OR, order- and
grouping-independently. Making that honest required per-extent demux state, so an
extent's evidence comes only from its own bytes, and memoising only extents whose
read reached a designed stop.

**A reachable panic in the timeline.** mkvstream::parse_block accepts a
TimestampScale up to i64::MAX, so a video frame can set high_ns = i64::MAX and the
next passive frame panicked adding the backstep. In release it wrapped negative
instead, firing the straggler clamp for essentially every passive frame — audio
and subtitles rewritten onto the wrong point of the output timeline. All four
sites saturate.

**A public constructor divided by zero**: PrefetchedSectorSource::new_with_events
with unit_align == 0. Now InvalidInput, matching its batch_sectors sibling.

**Two Debug impls printed key material.** DiscInputs (volume_id, mkb, unit_key_ro,
samples) and UnitKeyFile both derived Debug. Nothing logs them today — fixed as
prevention, because the next tracing::debug! someone adds is the leak. A doc claim
that DiscInputs "contains no secrets" was false and is corrected.

**An env-var multiply could overflow** in file_sector_source; now bounded at 64 GiB
like its writeback sibling, with the parse split out so the bound is testable
without touching process env.

**The mp4 demuxer allowed one sample per file byte** — ~64x RAM amplification.
Now file_len/16, since only vide/soun tracks are indexed and the shortest legal
AC-3 frame is 128 bytes.

**Two pipeline concurrency defects**: a consumer apply() error was invisible to the
producer, and abandon/finalise had a TOCTOU where a caller could report an
unfinalised output. Both fixed with compare-exchange state rather than a bool.

**Two per-frame copies removed**, both MEASURED rather than reasoned: the AU
assembler now hands its allocation to the frame (same pointer, unchanged capacity,
proven by asserting the pointer) and tsmux reuses one Annex-B buffer across
frames. Both keep capacity deliberately — a naive split_off would have cost more
than it saved.

**A comment pointed at the wrong file** for a mirrored constant; the mirror is now
compiler-enforced with a const assertion converting 90 kHz ticks to ns, so drift
fails the build.

Deferred to another agent's files, all confirmed: detect_rate's fractional-twin
snap, the mp4 reserve's u32 truncation, round_up_grain's overflow, the quadratic
base-key gap fill, and MkvStream's frame cap counting frames rather than bytes.

Every fix verified red by reverting it. Also noted for later:
DecodeSampleSet still derives Debug over multi-MB of on-disc ciphertext.
2026-07-29 20:47:31 -07:00
Matthew Jackson 3efa6211f3 Make six silent mux failures observable
All six confirmed against the code. The governing rule this cluster serves: a
lossy or degraded outcome is never silent, because a corrupt rip the user does
not know about is the worst failure available.

**A 3D MKV re-mux silently lost one eye.** The BlockGroup read path had arms for
BLOCK / BLOCK_DURATION / REFERENCE_BLOCK only, so BLOCK_ADDITIONS fell into the
skip arm — while the writer does emit BlockAdditions > BlockMore > BlockAdditional
for the MVC dependent view. Reconstruction was judged out of scope and the
reasoning is recorded: PesFrame has no side-payload field and the header parser
never reads BlockAdditionMapping, so there is no dependent-view track to route the
AU to. Instead the loss is now LOUD — counted in bytes and events, warned once,
and surfaced through MkvStream's errors()/lost_bytes(), which the driver already
samples into MuxOutcome. One detail in the finding was wrong and is corrected: the
re-mux does NOT still advertise the mvcC mapping, because the header parser
ignores that element, so the output is a plain 2D H.264 track.

**An all-titles rip silently skipped real titles.** The header-buffer-cap
overflow returned Error::MkvInvalid, and is_skippable_title_stub matches exactly
E_MKV_INVALID | E_CSS_KEY_MISSING — verified here — so a 512 MiB-of-frames title
was classified as an empty nav/menu PGC stub and dropped. It now has its own
E9051 / MuxHeaderBufferExceeded { bytes }, outside the skippable set.

**The public pre-mux report contradicted the file.** Mp4Sink::finish() drops an
audio track it cannot describe, which I chose last round over failing an export
whose video is fine — but mp4_fit_report still listed that stream as included, so
the application's plan and the actual output disagreed. Fixed at both levels:
Mp4SkipReason is now non_exhaustive with NoSamples and UndescribableAudio,
Mp4Sink::final_report() describes the FILE rather than the plan, and for the
boxed dyn Stream path a defaulted Stream::undelivered_streams() carries the
information out to MuxOutcome::undelivered_streams with a driver-side warn.

**MP4 track ids could collide.** ids were assigned before the retain that drops
sample-less tracks, while next_id came from the post-retain count, so [1,3]
yielded next_id 3. Now max(track_id) + 1, saturating.

**Stream selection silently skipped its codec_privates prune** when the lists were
not the same length — but codec_privates is consumed POSITIONALLY and trailing
extras are documented as benign, so the length-equality guard was itself the bug.
The prune now runs unconditionally by index.

**The m2ts_mux scaffolding armed params_written on both the absent and the
unparseable codec_private arms** — the same defect already fixed in tsmux.rs.
Split into params_attempted (a latch, since retrying identical bytes cannot help)
and params_emitted, with a warn on each failure arm and an accessor so the
eventual wiring and its test can observe it.

Each fix verified red by mutating back to the prior behaviour: errors() 0 vs 1,
E6008 vs E9051, final_report [0,1] vs [0], next_track_id 3 vs [1,3], and the
selection prune resolving index 1 to the wrong track's record.

API surface deliberately widened: MuxOutcome gains a public field and Mp4Sink
becomes public. Nothing in-repo breaks. Note a behaviour change on the mkv://
input path — a 3D re-mux now reports non-zero loss, so a consumer treating
errors > 0 as disc damage will trip on it. That is intended: the outcome IS
degraded.
2026-07-29 20:46:10 -07:00