[FFmpeg-trac] #7306(ffmpeg:new): Seeking problem: -ss as output parameter at a key frame of a mp4 and -c copy result in droping of video frames
FFmpeg
trac at avcodec.org
Fri Jul 6 16:59:29 EEST 2018
#7306: Seeking problem: -ss as output parameter at a key frame of a mp4 and -c
copy result in droping of video frames
---------------------------------+--------------------------------------
Reporter: duanyao | Type: defect
Status: new | Priority: normal
Component: ffmpeg | Version: git-master
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
---------------------------------+--------------------------------------
Summary of the bug:
How to reproduce:
{{{
% ffmpeg -report -y -i neck5.mp4 -ss 0 -t 1 -c copy neck5-1.mp4
Or
% ffmpeg -report -y -i neck5.mp4 -ss 2.36 -t 1 -c copy neck5-1.mp4
}}}
The 2 key frames of neck5.mp4 (5s length, 25fps) locate at 0s, 2.36s,
respectively.
Expected result: neck5-1.mp4 contains ~1s audio and video.
Actual result: neck5-1.mp4 contains only audio and no video.
To workaround this problem, I have to minus time of key frame by at least
2*pkt_duration_time, i.e. -0.08s:
{{{
% ffmpeg -report -y -i neck5.mp4 -ss -0.08 -t 1 -c copy neck5-1.mp4
Or
% ffmpeg -report -y -i neck5.mp4 -ss 2.28 -t 1 -c copy neck5-1.mp4
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/7306>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
More information about the FFmpeg-trac
mailing list