[FFmpeg-devel] [PATCH] ffmpeg: redesign video resampling in case of mid-stream video size/format change

Stefano Sabatini stefano.sabatini-lala at poste.it
Mon Apr 25 00:26:05 CEST 2011


On date Saturday 2011-04-23 22:59:13 +0200, Michael Niedermayer encoded:
> On Sat, Apr 23, 2011 at 08:34:09PM +0200, Stefano Sabatini wrote:
> > On date Saturday 2011-04-23 19:56:37 +0200, Michael Niedermayer encoded:
> > > On Sat, Apr 23, 2011 at 12:34:03PM +0200, Stefano Sabatini wrote:
> > [...]
> > > > > compile without avfilter
> > > > > 
> > > > > then try
> > > > > ./ffmpeg -i 23.mpg -an -s 100x100 100.avi -s 200x200 200.avi
> > > > > 
> > > > > where 23.mpg is some file with a resolution change (here it was 200x200 -> 300x300)
> > > > 
> > > > Tested with and without CONFIG_AVFILTER, works fine.
> > > 
> > > did you look at the output videos?
> > > they didnt look fine here when played
> > 
> > Output size/format is set to the initial size/format, for the rest
> > they look fine to me. Do you have a specific sample to try?
> 
> --disable-libavfilter
> 
>  ./ffmpeg -t 2 -i ~/videos/matrixbench_mpeg2.mpg -s 100x100 100.mpg
>  ./ffmpeg -t 2 -i ~/videos/matrixbench_mpeg2.mpg -s 200x200 200.mpg
> cat 100.mpg  200.mpg >12.mpg
> ./ffmpeg  -i 12.mpg -s 150x150 150.mpg -s 300x300 300.mpg
> 
> and then watch the 150.mpg with ffplay
> 
> it will show only a croped part not the video scaled to 150x150
> 
> or try
> 
> ./ffmpeg  -i 12.mpg -s 300x300 300.mpg -s 150x150 150.mpg
> and watch 300.mpg it shows a small image and random mess in the rest
> of the frame

New approach, this is the neatest design I can find without
introducing filterchain re-configuration. It also fixes some problems
in the non-libavfilter code path.
-- 
FFmpeg = Formidable Fancy Majestic Prodigious Eager Game
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