[FFmpeg-trac] #1607(avformat:new): av_seek_frame() without AVSEEK_FLAG_ANY on mpg files returns success without seeking to a keyframe
FFmpeg
trac at avcodec.org
Tue Aug 7 10:38:13 CEST 2012
#1607: av_seek_frame() without AVSEEK_FLAG_ANY on mpg files returns success
without seeking to a keyframe
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Reporter: mbradshaw | Owner:
Type: defect | Status: new
Priority: normal | Component: avformat
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by cehoyos):
Replying to [comment:5 mbradshaw]:
> Replying to [comment:4 cehoyos]:
> > Replying to [comment:3 DonMoir]:
> > > mpeg2video failing sample file (6 MB):
> > >
> > > http://sms.pangolin.com/temp/mpeg2video_seek_to_non_keyframe.mpg
> > I failed to extract a non-keyframe out of this sample with ffmpeg.
> > If it is possible, please provide the command together with complete,
uncut console output.
> Can you describe how you were able to extract only keyframes out of this
sample?
$ ffmpeg -ss 1 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 2 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 3 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 4 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 5 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 6 -i mpeg2video_seek_to_non_keyframe.mpg out.png
$ ffmpeg -ss 7 -i mpeg2video_seek_to_non_keyframe.mpg out.png
> The problem isn't that you get a junk frame out (the decoder makes sure
you don't).
I wonder what this sentence means: There are many samples that return gray
frames for above command line (including some sample that you pointed to).
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1607#comment:10>
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