[FFmpeg-devel] speed regression in ffmpeg/mpeg2video

[vmrsss]

Hello.

	I am experiencing what looks like a substantial speed regression with  
mpeg2video, see the outputs below where the same command  line runs at  
220 fps with ffmpeg-r17815 and at 6 fps with ffmpeg-r17882.

The only strange thing i noticed is a number (say 100) of messages  
like this:

> {standard input}:2135:Alignment too large: 15. assumed.

when compiling swscale.c. Could this be a clue? The warnings only  
occur when compiling for 64bit (gcc -arch x86_64), and in fact for  
ffmpeg-r17882 compiled at 32bit there seems to be little speed  
regression, if anything at all. Also, for codecs other than mpeg2video  
the problem is either very small or non-existent.

Regards.

> ffmpeg17882 -i InFile.m2v -vcodec mpeg2video -f mpeg2video -b 4000k - 
> y OutFile.m2v -t 30
> FFmpeg version SVN-r17882, Copyright (c) 2000-2009 Fabrice Bellard,  
> et al.  configuration: --arch=x86_64 --cpu=core2 --cc=gcc-4.2 -arch  
> x86_64 --disable-shared --enable-nonfree --disable-ffserver -- 
> disable-gprof --disable-debug --enable-gpl --enable-libx264 --enable- 
> libxvid --enable-libdirac --enable-libschroedinger --enable-libfaac  
> --enable-libmp3lame --enable-pthreads --enable-postproc
>  libavutil     50. 0. 0 / 50. 0. 0
>  libavcodec    52.21. 0 / 52.21. 0
>  libavformat   52.31. 1 / 52.31. 1
>  libavdevice   52. 1. 0 / 52. 1. 0
>  libswscale     0. 7. 1 /  0. 7. 1
>  libpostproc   51. 2. 0 / 51. 2. 0
>  built on Mar  8 2009 20:40:11, gcc: 4.2.1 (Apple Inc. build 5566)
>
> Seems stream 0 codec frame rate differs from container frame rate:  
> 47.95 (48000/1001) -> 23.98 (24000/1001)
> Input #0, mpegvideo, from 'InFile.m2v':
>  Duration: 00:00:11.69, bitrate: 9800 kb/s
>    Stream #0.0: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR  
> 16:9], 9800 kb/s, 23.98 tbr, 1200k tbn, 47.95 tbc
> Output #0, mpeg2video, to 'OutFile.m2v':
>    Stream #0.0: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR  
> 16:9], q=2-31, 4000 kb/s, 90k tbn, 23.98 tbc
> Stream mapping:
>  Stream #0.0 -> #0.0
> Press [q] to stop encoding
> frame=  721 fps=  6 q=1.6 Lsize=    6652kB time=30.03  
> bitrate=1814.6kbits/s
> video:6652kB audio:0kB global headers:0kB muxing overhead 0.000000%


> ffmpeg17815 -i InFile.m2v -vcodec mpeg2video -f mpeg2video -b 4000k - 
> y OutFile.m2v -t 30
> FFmpeg version SVN-r17815, Copyright (c) 2000-2009 Fabrice Bellard,  
> et al.
>  configuration: --arch=x86_64 --cpu=core2 --cc=gcc-4.2 -arch x86_64  
> --disable-shared --enable-nonfree --disable-ffserver --disable-gprof  
> --disable-debug --enable-gpl --enable-libx264 --enable-libxvid -- 
> enable-libdirac --enable-libschroedinger --enable-libfaac --enable- 
> libmp3lame --enable-pthreads --enable-postproc
>  libavutil     49.15. 0 / 49.15. 0
>  libavcodec    52.20. 0 / 52.20. 0
>  libavformat   52.31. 0 / 52.31. 0
>  libavdevice   52. 1. 0 / 52. 1. 0
>  libswscale     0. 7. 1 /  0. 7. 1
>  libpostproc   51. 2. 0 / 51. 2. 0
>  built on Mar  4 2009 23:38:57, gcc: 4.2.1 (Apple Inc. build 5566)
>
> Seems stream 0 codec frame rate differs from container frame rate:  
> 47.95 (48000/1001) -> 23.98 (24000/1001)
> Input #0, mpegvideo, from 'InFile.m2v':
>  Duration: 00:00:11.69, bitrate: 9800 kb/s
>    Stream #0.0: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR  
> 16:9], 9800 kb/s, 23.98 tbr, 1200k tbn, 47.95 tbc
> Output #0, mpeg2video, to 'OutFile.m2v':
>    Stream #0.0: Video: mpeg2video, yuv420p, 720x576 [PAR 64:45 DAR  
> 16:9], q=2-31, 4000 kb/s, 90k tbn, 23.98 tbc
> Stream mapping:
>  Stream #0.0 -> #0.0
> Press [q] to stop encoding
> frame=  721 fps=220 q=1.6 Lsize=    6652kB time=30.03  
> bitrate=1814.6kbits/s
> video:6652kB audio:0kB global headers:0kB muxing overhead 0.000000%
>