News:

--

Main Menu

FPS is correct only when saving as MKV

Started by jfx, September 21, 2012, 04:01:45 PM

Previous topic - Next topic

jfx

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

Jan Gruuthuse

#1
VLC and Avidemux do: testmp4v2.mp4. MediaInfo Tells something else?

mean

It is the average framerate for mp4, maximum/default for mkv

jfx

Why is the average frame rate different from the original value? Is it possible to store normal frame rate in MP4?

mean

For example if you have

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

Perfectly legit file


jfx

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.

mean

I'll have a look, but it might be due to how libmp4v2 works

jfx

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