[FFmpeg-trac] #8456(undetermined:closed): Copy codec doubles video stream (was: Copy codec doubles duration of video stream)
FFmpeg
trac at avcodec.org
Sun Jan 5 11:04:30 EET 2020
#8456: Copy codec doubles video stream
-------------------------------------+-------------------------------------
Reporter: MarianD | Owner:
Type: defect | Status: closed
Priority: normal | Component:
| undetermined
Version: git-master | Resolution: invalid
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by mkver):
The video stream in this file has an edit list that says that the video
should be displayed twice. So actually looping the video is the correct
behaviour. But I think the file is actually invalid, as the duration of
the track in the tkhd and the mdhd box both shows 6s, although it is
double that after applying the edit list.
mkvmerge has a workaround for this kind of file (see
[https://gitlab.com/mbunkus/mkvtoolnix/commit/02bd23748a7c2d82bbc459a98b07baef5a7c17bb
here] and
[https://gitlab.com/mbunkus/mkvtoolnix/commit/aa99dd50f5d3a5a8b2d8c794422d484e175ce2ba
here]). I don't have a strong opinion on whether such a workaround should
be added to the mp4/mov demuxer, but I am leaning to no.
@balling: Repetition flags in the bitstream only ever say: "Output this
frame twice", but never "play the whole video twice".
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8456#comment:5>
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