Matthew Jackson
6e14fc0c0c
Security - Remove the unsafe Vec::set_len over recycled sector buffers — UB reachable from safe code (GHSA-j8ww-f5fg-9pmh, low). Uses Vec::resize; pooling unchanged. CI / tooling - clippy on stable with the MSRV single-sourced from Cargo.toml; cargo-deny dependency-audit gate with first-party git sources allowed (#15); audience-based comment-guard (#17). Docs - README (keydb ownership, BD-J parser count), drive-access transport/reset notes, mux timeline module-doc links.
1.3 KiB
BD/DVD LPCM wire format
BD LPCM PES packets (TS stream type 0x80) carry a 4-byte header on the elementary-stream payload:
Bytes 0-1: audio frame number
Byte 2: reserved
Byte 3: quantization (bits 7-6), sample rate (bits 5-4), channel assignment (bits 3-0)
This header is part of the ES payload, so the BD parser must strip it.
DVD LPCM lives in private stream 1 (sub-stream 0xA0-0xA7). Its 7-byte
private sub-header (sub_id + frames + first-access-unit-ptr(2) + emphasis +
quant/freq + channels) is stripped by PsDemuxer while demuxing the
Program Stream. By the time a DVD LPCM PesPacket reaches this parser its
data is already raw PCM, so the parser must NOT strip any further bytes —
doing so drops one sample pair per PES and drifts the audio.
The two origins are distinguished by the strip_header flag: BD = strip,
DVD = leave intact. The raw PCM data is otherwise one complete audio frame
per PES; no framing is needed.
For MKV: both BD and DVD LPCM map to codec ID "A_PCM/INT/BIG" (big-endian).
DVD-Video LPCM is big-endian per the DVD-Video spec, and mkv.rs emits
"A_PCM/INT/BIG" unconditionally for Codec::Lpcm — there is no DVD/BD branch
and no "A_PCM/INT/LIT" path, so no byte-swap or alternate codec ID applies.
All frames are keyframes (uncompressed audio).