[FFmpeg-devel] [RFC] faster vp3 unpack_vlc

Reimar Döffinger Reimar.Doeffinger
Sun Jun 8 10:15:58 CEST 2008

On Sat, Jun 07, 2008 at 11:31:40PM -0700, Mike Melanson wrote:
> Reimar D?ffinger wrote:
> > Well, I am no good at proper benchmarks, but with above file,
> > mplayer -nosound -benchmark -vo xv big_buck_bunny_1080p_stereo.ogg -demuxer lavf -frames 400
> > takes 26 seconds to decode with original code and 22 after the change.
> The theory is sound. I tried to benchmark it with START_TIMER but it 
> didn't report anything. I wonder if that facility is still supposed to work?

Yes, but you need to add -v 2 to the command-line. And yes I find it a
pain, too, because I can never remember the right option.

Some example values, again for above video (testing other videos
as well probably would be a good idea though).

Commandline: ffmpeg -v 2 -i big_buck_bunny_1080p_stereo.ogg -f avi -an /dev/null

2349923 dezicycles in unpack_vlcs, 2037 runs, 11 skips
3077961 dezicycles in unpack_vlcs, 4085 runs, 11 skips
3359234 dezicycles in unpack_vlcs, 8181 runs, 11 skips

with patch:
1127070 dezicycles in unpack_vlcs, 2036 runs, 12 skips
1445002 dezicycles in unpack_vlcs, 4068 runs, 28 skips
1635682 dezicycles in unpack_vlcs, 8145 runs, 47 skips

i.e. nearly double speed, and this is with my CPU pinned to the lowest
available frequency.

Reimar D?ffinger

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