[FFmpeg-user] strange h264 framerate diagnostics

[belcampo]

> Hi,
> 
> Here, even with explicit "-r 25" (shouldn't be needed, as source
> is 25fps) and following sample cmdline:
> 
> $ ffmpeg -i test.mov -vcodec libx264 -vpre normal \
> -acodec libfaac -ac 1 -ar 22050 -ac 1 -ab 40k -r 25 -y test.mp4
What does ffmpeg -i test.mov tell you.
Maybe it's interlaced 50fps that plays at 25fps.
> 
> a check gives codec frame rate differs from container frame rate!
> 
> $ ffmpeg -i test.mp4
> FFmpeg version SVN-r17657, Copyright (c) 2000-2009 Fabrice Bellard, et al.
>   configuration: --enable-gpl --enable-nonfree --disable-network --disable-ffserver --disable-vhook --disable-ffplay --enable-shared --enable-pthreads --enable-postproc --enable-swscale --enable-libfaad --enable-libfaac --enable-libx264 --enable-libxvid --enable-libmp3lame --extra-cflags=-I/sw/include --extra-libs=-L/sw/lib
>   libavutil     49.15. 0 / 49.15. 0
>   libavcodec    52.20. 0 / 52.20. 0
>   libavformat   52.30. 1 / 52.30. 1
>   libavdevice   52. 1. 0 / 52. 1. 0
>   libswscale     0. 7. 1 /  0. 7. 1
>   libpostproc   51. 2. 0 / 51. 2. 0
>   built on Feb 28 2009 15:04:37, gcc: 4.0.1 (Apple Inc. build 5490)
> 
> Seems stream 0 codec frame rate differs from container frame rate: 25.00 (25/1) -> 12.50 (25/2)
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test.mp4':
>   Duration: 00:04:22.04, start: 0.000000, bitrate: 243 kb/s
>     Stream #0.0(eng): Video: h264, yuv420p, 720x576, 12.50 tbr, 25 tbn, 25 tbc
>     Stream #0.1(eng): Audio: aac, 22050 Hz, mono, s16
> At least one output file must be specified
> 
> QuickTime reports 25 fps. And the movie plays fine.
> 
> I just would like to know what's going on.