Delete re-implementations in the demux:// sink and wire to proven helpers;
keep only genuinely-new functionality.
- AnnexB reframing: delete the sink's local length_prefixed_to_annexb (it
break'd on a zero-length NAL, dropping the rest of the access unit) and
call the canonical append_length_prefixed_as_annex_b in mux::hevc, which
skips just the empty NAL.
- HEVC param sets: delete hvcc_param_sets; reuse hvcc_to_annex_b.
- avcC param sets: hoist as the new canonical avcc_to_annex_b in mux::hevc,
next to hvcc_to_annex_b (the symmetry point); the sink calls it.
- PGS .sup: emit a synthetic clear display set (empty PCS + END) at
pts + duration_ns so subtitles time out instead of lingering to EOF.
- TimelineContinuity: move verbatim into the shared mux::timeline module
(with the prev_offset straggler-remap intact) and use it from both the
MKV muxer and the demux sink; delete the sink's drifted TimelineRebase
copy (which lacked the straggler branch).
- VobSub .idx: emit the conventional 'id: <lang2>, index: 0' line mkvmerge
reads to assign the subtitle language; palette reuse unchanged.
- output(): seed DemuxOptions.base from title.playlist when non-empty.
New constants for the PGS clear-segment framing and avcC header cite the
public HDMV PGS (BD-ROM Part 3) and ISO/IEC 14496-15 specs.
Tests: a zero-length NAL mid-frame no longer truncates the AU; a frame with
duration_ns produces a .sup clear segment; existing demux tests stay green.
Matthew Jackson
9b6a48e9d9