[FFmpeg-user] h264 frame rate detection

Jan Pohanka xhpohanka at gmail.com
Fri Apr 13 09:00:18 CEST 2012


> I assume there is a problem with the framerate in (some)
> raw h264 videos.
> But since ffplay is not the primary application,
> please test ffmpeg:
> ffmpeg -i test.264 -c:v copy -y test.avi
> ffmpeg -i test.avi -qscale 2 outavi.avi
> ffmpeg -i test.264 -c:v copy -y test.mkv
> ffmpeg -i test.mkv -qscale 2 outmkv.avi
>
> It should be possible to test the resulting outavi.avi
> and outmkv.avi with multiple players.
>

I have tested your recomendations. Both files (outavi and outmkv now  
recoded to mpeg4) are played on wrong 2.5 fps in all players (ffplay,  
mplayer, vlc, ...)
ffplay info about streams:
outavi.avi
  Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46), yuv420p,  
1600x1200 [SAR 1:1 DAR 4:3], 5 tbr, 5 tbn, 5 tbc
outmkv.avi
  Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46), yuv420p,  
1600x1200 [SAR 1:1 DAR 4:3], 2.50 tbr, 2.50 tbn, 5 tbc

What seems really weird to me is the fact, that the raw video is played  
correctly by ffplay even when it says it is 2.5.

Does there exist any (free) tool which is able to show a header of a raw  
h264 stream? I set the fps to 5 (which is the rate I get the images from  
cmos sensor) by setting VUI params num_units_in_tick = 1000 and time_scale  
= 5000.

best regards
Jan


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