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VFR maniac · 18th March 2013, 14:27

CODEC specific data (extradata) is written in the index file as well.
This makes more accurate seek possible.

For instance, H.264 allows IDR-picture without SPS/PPS.
For such IDR-pictures in TS, we can't treat as keyframe (random access point) but libavfomrat returns them as keyframe.
So, the result will be broken when the current SPS/PPS in extradata doesn't match (and libavcodec shall not update AVCodecContext.extradata).
This case is frequently present in BD m2ts.
LWLibavVideoSource can handle correctly this case.

About WMV3/VC-1 in ASF, libavformat may not return any PTS even if there is B-picture.
LWLibavVideoSource attempts to generate PTS from DTS and picture type by actual __decoding__, and realizes frame accurate seek.
So, creating the index file is to be slow.

About MPEG-1/2 Video, libavformat might return no PTS for some frames in certain contaniers such as MPEG-PS.
LWLibavVideoSource attempts to generate PTS from DTS and picture type, and realizes frame accurate seek.

LWLibavVideoSource can handle audio stream of DV-in-AVI Type-I without crash.
This format requires seek by special treatment in libavformat.

18th March 2013, 14:27	#10 \| Link
VFR maniac Spinner of yarns Join Date: May 2009 Posts: 164	CODEC specific data (extradata) is written in the index file as well. This makes more accurate seek possible. For instance, H.264 allows IDR-picture without SPS/PPS. For such IDR-pictures in TS, we can't treat as keyframe (random access point) but libavfomrat returns them as keyframe. So, the result will be broken when the current SPS/PPS in extradata doesn't match (and libavcodec shall not update AVCodecContext.extradata). This case is frequently present in BD m2ts. LWLibavVideoSource can handle correctly this case. About WMV3/VC-1 in ASF, libavformat may not return any PTS even if there is B-picture. LWLibavVideoSource attempts to generate PTS from DTS and picture type by actual __decoding__, and realizes frame accurate seek. So, creating the index file is to be slow. About MPEG-1/2 Video, libavformat might return no PTS for some frames in certain contaniers such as MPEG-PS. LWLibavVideoSource attempts to generate PTS from DTS and picture type, and realizes frame accurate seek. LWLibavVideoSource can handle audio stream of DV-in-AVI Type-I without crash. This format requires seek by special treatment in libavformat. __________________ 僕と契約して、L-SMASH developerになってよ！ L-SMASH \| L-SMASH Works \| Opus-in-ISOBMFF specification and reference software Last edited by VFR maniac; 18th March 2013 at 15:01.