[FFmpeg-trac] #2108(undetermined:closed): empty frame add the end of the video
FFmpeg
trac at avcodec.org
Wed Jan 9 09:56:48 CET 2013
#2108: empty frame add the end of the video
-------------------------------------+-------------------------------------
Reporter: ben | Owner:
Type: defect | Status: closed
Priority: normal | Component:
Version: unspecified | undetermined
Keywords: h264 mov | Resolution: invalid
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
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Changes (by cehoyos):
* keywords: h264 => h264 mov
* status: new => closed
* resolution: => invalid
Comment:
Replying to [comment:8 ben]:
> I thought it was 2:85 because ffmpeg -i myinput.mp4 says:
> Duration: 00:00:02.85,
Afair, this is an informational value stored in the header of the file.
> start: 0.013333, bitrate: 1039 kb/s
>
> now I'm not sure what those two values means. and also why is 29.98 fps
getting changed to 30 fps after re-encoding?
> shouldn't it stay the same?
Without testing, I assume the original file is vfr (variable frame rate)
which is not supported by the FFmpeg mov muxer, it has to choose a
framerate.
Since no frames get dropped or duplicated (this would be visible in
ffmpeg's output), the framechoice seems to be ok. You can add -r
30000/1001 to your command line if you prefer. Also consider testing a
longer sample to see if frames will be dropped / duplicated with one of
the choices.
Please reopen if you encounter A/V desync (or similar problems), the fact
that the duration in the mov header does not exactly match the output file
is no bug imo.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2108#comment:9>
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