[FFmpeg-devel] [RFC] faster vp3 unpack_vlc

[Mike Melanson]

Reimar D?ffinger wrote:
> 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
> 
> original:
> 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.

Go ahead with the patch, then. Also, please remove the START/STOP_TIMERs 
sprinkled throughout (as a separate patch, of course).

-- 
	-Mike Melanson