demux: add demux:// per-track elementary-stream sink
New write-only pes::Stream sink that taps the per-track PesFrame stream
(the seam right before MKV muxing) and writes each track to its own
elementary-stream file, plus chapters and per-audio-track delay metadata.
Purely additive — the MKV mux path is untouched.
- mux/demux_sink.rs: DemuxSink + EsWriter dispatch. Pass-through for
codecs whose Frame.data is already standalone ES (MPEG-2, VC-1, AC3/
E-AC3, DTS/DTS-HD, TrueHD, LPCM). Non-trivial writers:
- AnnexBWriter: reframes hvcC/avcC 4-byte-length-prefixed NALs to
Annex-B and prepends VPS/SPS/PPS parsed out of the codec_private
configuration record (HEVC .hevc / H.264 .h264).
- PgsSupWriter: rebuilds the HDMV 'PG' segment framing the parser
strips, with 90kHz PTS/DTS (.sup).
- VobSubWriter: writes raw SPUs to .sub and synthesizes the .idx
sidecar (palette + per-SPU timestamp/filepos).
- Delay-in-filename (mkvmerge-readable 'DELAY <n>ms') + chapter XML/OGM
export. TimelineRebase ports the MKV muxer's seamless-branch epoch
logic so per-track ES timestamps stay continuous across clip joins.
- mux/resolve.rs: StreamUrl::Demux variant + scheme/path_str/parse_url/
input(write-only)/output arms.
- mux/mod.rs: module + public type re-exports.
16 unit tests: Annex-B reframing, hvcC/avcC param extraction, delay
sign/rounding + mkvmerge-regex match, PGS .sup framing, VobSub .idx
synthesis, chapter XML/OGM, timeline rebase, and end-to-end file-keying
by track + track selection.
This commit is contained in:
Matthew Jackson