DiscStream (the live-drive single-pass path) enables AACS decrypt-loss
concealment (NULL-TS fill on an undecryptable unit) but, unlike the file-backed
PipelinedPesStream, had no B1 resync gate — so after a concealed gap it forwarded
inter-coded video frames referencing the now-missing data, producing
decode-broken MKV output (dangling-reference frames).
Mirror PipelinedPesStream: add per-stream ResyncGate + is_video, and route every
codec-frame emit on the TS path (in-stream parse, demuxer EOF flush, parser EOF
flush) through gate.admit(is_video, frame.discontinuity, frame.keyframe) so a
video track drops forward to the next keyframe after a concealment event. Warn
once if a gate is still armed at EOF (a concealed gap in the final GOP with no
trailing keyframe). Audio/subtitle always admit.
Matthew Jackson
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