Avidemux Forum

Avidemux => Main version 2.6 => Topic started by: jfx on September 21, 2012, 04:01:45 PM

Title: FPS is correct only when saving as MKV
Post by: jfx on September 21, 2012, 04:01:45 PM
The frame rate of the attached file is 50 fps. If the file is saved as MKV, the frame rate does not change. If it is saved as MP4v2, the frame rate changes to 46 fps.

https://rapidshare.com/files/846234364/fpstest.ts
Title: Re: FPS is correct only when saving as MKV
Post by: Jan Gruuthuse on September 21, 2012, 04:33:47 PM
VLC and Avidemux do: testmp4v2.mp4. MediaInfo Tells something else?
Title: Re: FPS is correct only when saving as MKV
Post by: mean on September 21, 2012, 04:52:46 PM
It is the average framerate for mp4, maximum/default for mkv
Title: Re: FPS is correct only when saving as MKV
Post by: jfx on September 21, 2012, 05:16:44 PM
Why is the average frame rate different from the original value? Is it possible to store normal frame rate in MP4?
Title: Re: FPS is correct only when saving as MKV
Post by: mean on September 21, 2012, 06:11:51 PM
For example if you have

*-*-*-*-
where - is a hole
you will have nominal framerate = 50
average=25

Perfectly legit file

Title: Re: FPS is correct only when saving as MKV
Post by: jfx on September 21, 2012, 06:42:24 PM
The file has no dropped frames. Even if there were any, the frame rate must not be affected. Dropped frames should change only the total time value.

If the MP4 file is saved as MKV, it also has the incorrect frame rate 46 fps.
Title: Re: FPS is correct only when saving as MKV
Post by: mean on September 21, 2012, 07:54:57 PM
I'll have a look, but it might be due to how libmp4v2 works
Title: Re: FPS is correct only when saving as MKV
Post by: jfx on November 03, 2012, 12:28:26 PM
If the file is converted to MP4 with FFmpeg, the resulting framerate is 50fps and total duration is 11.54s. Avidemux sets the duration to 12.27s which is incorrect.

The command line used to convert the file: ffmpeg.exe -i fpstest.ts -c copy fpstest.mp4