[FFmpeg-user] Why does fps == 1 for a webm videos?

Carl Eugen Hoyos cehoyos at ag.or.at
Thu Mar 21 14:34:03 CET 2013

Misha Penkov <misha.penkov <at> gmail.com> writes:

> ~/git/video-signature/gitignore/cz_clusters/0003$ ffmpeg -y
> -i 8szDFB30azA.webm -vcodec rawvideo -acodec none -s qcif test.yuv

> The problem is that test.yuv now contains many more frames that there
> really were in the webm file, with a majority of those frames being
> duplicates.  This is not what I want -- I want to extract all the frames
> from the webm file as they are, without any duplicates.

Use -vsync 0 to avoid the duplicates.

> If I play the resulting file (ffplay test.yuv -s qcif), it plays back
> approximately 30 times slower than the original file:

The default for yuv is 25fps, 1k would allow correct playback 
(but your hardware will not support it).

Generally, you cannot test fps or A/V sync with a yuv file.

It may help to find a solution for your problem (assuming you 
have one) if you describe your use case: I find it unlikely 
that your usecase is to output rawvideo files, or is it?

Carl Eugen

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