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Old 17th July 2019, 09:14   #1  |  Link
osgZach
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SVT-VP9 Framerate??

I've been playing with some compiled binaries my friend managed to find for me. But I'm having trouble with setting the proper FPS.

if I specify -fps-num 24000 -fps-denom 1001 it will output a file with 23.98 fps which ffmpeg does not like.

If I just tell it 24, ffmpeg will take it, but then the audio from the original source will be off by 1 second (source clip is 10 minutes, video file comes out to 9m59s)


Is it just not supported at this point, or is this some bug I have to wait for them to fix... Can I rescale the "FPS/duration" of the audio in ffmpeg as a compromise? What is the proper way to go about doing that?

edit:
Maybe a misunderstanding on my part. When I dump the input mkv file to YUV with ffmpeg it seems to want to assign it the 23.98 fps at that point.
I can't seem to get it to play nice in that regard

Last edited by osgZach; 18th July 2019 at 00:37.
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Old Yesterday, 23:01   #2  |  Link
benwaggoner
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Quote:
Originally Posted by osgZach View Post
I've been playing with some compiled binaries my friend managed to find for me. But I'm having trouble with setting the proper FPS.

if I specify -fps-num 24000 -fps-denom 1001 it will output a file with 23.98 fps which ffmpeg does not like.
How does ffmpeg not like it? Ffmpeg has had excellent support for fractional framerates for as long as I can remember.

Quote:
If I just tell it 24, ffmpeg will take it, but then the audio from the original source will be off by 1 second (source clip is 10 minutes, video file comes out to 9m59s)
Because you sped up the fps by 0.1%, and the video isn't. Any audio tool like Audition or Audacity can also resample your audio 0.1% faster; another way to fix your problem.

Quote:
Maybe a misunderstanding on my part. When I dump the input mkv file to YUV with ffmpeg it seems to want to assign it the 23.98 fps at that point.
I can't seem to get it to play nice in that regard
Did you specify the fps of the YUV? YUV doesn't have any metadata, so you need to manually specify fps along with a whole lot of other stuff. I much prefer .y4m for this, which is a yuv file but with metadata headers.
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