#5713: Can't Recalculate the Timestamp of Fragmentary Video Streams
------------------------------------+----------------------------------
Reporter: PureOcean | Owner:
Type: defect | Status: new
Priority: normal | Component: ffmpeg
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
------------------------------------+----------------------------------
Changes (by PureOcean):
* component: undetermined => ffmpeg
Comment:
Okay. I '''finally''' found the root cause.
FFmpeg can't recalculate only the timestamp of fragmentary video streams.
Although it's can be resync properly to audio streams. Is it not strange?
(A more interesting: '''MEncoder''' can recalculate/resync the timestamp
both of fragmentary video & audio streams).
'''Steps for Analyze & Re-produce:'''
''1) Download to example a fragmentary sample:''
[https://mega.nz/#!htBQUDJD!Pr-TkZN5GmyCe99k1RfBkVh7ahp-9npjX74HE36ktfo]
The Purpose: If the file's timestamp seems as '''00:14:48''', it is need
resync/recalculate. Because of the file is fragmentary/brokenly.
''2) Run (remux only audio stream):''
{{{
FFmpeg -i Random_Seeking_Stream-Sintel_Sample.mkv -vn -async -1
only_audio-timestamp_can_be_resynced_properly.mkv
}}}
The Result: New timestamp is '''00:03:48''' which it's properly timecode!
Incredible, well done FFmpeg (thanks to all who contributed)!
''3) Run (remux only video stream):''
{{{
FFmpeg -i Random_Seeking_Stream-Sintel_Sample.mkv -c:v copy -an -vsync -1
only_video-timestamp_not_resynced.mkv
}}}
The Result: The only video track's timestamp is still remaining the same
input file, it can't resynced.
''4) Run (remux both of video + audio stream):''
{{{
FFmpeg -i Random_Seeking_Stream-Sintel_Sample.mkv -c:v copy -c:a copy
-vsync -1 -async -1 not_synced.mkv
}}}
The Result: The output MKV's timecode not changed, still remains same (due
to can't resynced to video stream). The video now plays with anormal
speed, because of actually only the audio track is resynced properly.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/5713#comment:4>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
_______________________________________________
FFmpeg-trac mailing list
[email protected]
http://ffmpeg.org/mailman/listinfo/ffmpeg-trac
