[FFmpeg-devel] [PATCH][RFC] variable frame sizes

Baptiste Coudurier baptiste.coudurier
Thu May 21 09:05:26 CEST 2009


Hi,

Eric Buehl wrote:
> [...]
> 
> This appears to expose another bug:
> 
> $ ffmpeg -i a.mov -s 200x200 b.mpg
> 
> $ ffmpeg -i a.mov -s 400x400 c.mpg
> 
> $ ffmpeg -i b.mpg d.mpg -newvideo -i c.mpg
> FFmpeg version SVN-r18769, Copyright (c) 2000-2009 Fabrice Bellard, et al.
>   configuration: --enable-pthreads --enable-libfaac --enable-libx264
> --enable-decoders --enable-gpl --enable-libfaad --enable-nonfree
>   libavutil     50. 3. 0 / 50. 3. 0
>   libavcodec    52.28. 0 / 52.28. 0
>   libavformat   52.32. 0 / 52.32. 0
>   libavdevice   52. 2. 0 / 52. 2. 0
>   libswscale     0. 7. 1 /  0. 7. 1
>   built on May  7 2009 12:24:33, gcc: 4.3.2 20081105 (Red Hat 4.3.2-7)
> Input #0, mpeg, from 'b.mpg':
>   Duration: 00:00:12.05, start: 0.500000, bitrate: 236 kb/s
>     Stream #0.0[0x1e0]: Video: mpeg1video, yuv420p, 200x200 [PAR 49:33 DAR
> 49:33], 104857 kb/s, 23.98 tbr, 90k tbn, 23.98 tbc
> Input #1, mpeg, from 'c.mpg':
>   Duration: 00:00:12.09, start: 0.500000, bitrate: 329 kb/s
>     Stream #1.0[0x1e0]: Video: mpeg1video, yuv420p, 400x400 [PAR 49:33 DAR
> 49:33], 104857 kb/s, 23.98 tbr, 90k tbn, 23.98 tbc
> Output #0, mpeg, to 'd.mpg':
>     Stream #0.0: Video: mpeg1video, yuv420p, 200x200 [PAR 49:33 DAR 49:33],
> q=2-31, 200 kb/s, 90k tbn, 23.98 tbc
>     Stream #0.1: Video: mpeg1video, yuv420p, 200x200 [PAR 49:33 DAR 49:33],
> q=2-31, 200 kb/s, 90k tbn, 23.98 tbc
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #1.0 -> #0.1
> 
> 
> Notice that both output streams are now listed as 200x200 while no
> resampling was requested.

Yes, that's a know behaviour.

> So I tied again using something else to mux the video streams:
> 
> $ ffmpeg -i a.mov -s 200x200 b.mp4
> 
> $ ffmpeg -i a.mov -s 400x400 c.mp4
> 
> $ MP4Box -add b.mp4 -add c.mp4 d.mp4
> Saving to d.mp4: 0.500 secs Interleaving

You can achieve this using ffmpeg:

ffmpeg -i <file> -i <file> <outfile>.mp4 -newvideo

[...]

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
FFmpeg maintainer                                  http://www.ffmpeg.org



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