[FFmpeg-devel] [PATCH] More H.264 decoding speed tweaks

Jason Garrett-Glaser darkshikari
Sat Jun 21 03:27:15 CEST 2008

> As you say you did test, please post your results and cpu type and compiler
> ver.
> If you tested on x86-64 i like to see the uint64_t changes tested on a x86-32,
> i will do that myself if noone else does. If you did test on x86-32 already
> then that half of the patch should be ok.

I've already tested 64-bit write-combining in x264 (and such write
combining is also used in other places in h264.c in ffmpeg); gcc does
not pessimize it.

> The other half partially reverts
>    r4971 | lorenm | 2006-02-10 07:55:25 +0100 (Fri, 10 Feb 2006) | 2 lines
>    h264: special case dc-only idct. ~1% faster overall
> Before i approve that i like to understand better what part of what patch
> improved speed for whom. r4971 did changes unrelated to dc-only idct its
> possible they where behind the speed improvents, this needs to be checked.
> And possibly your patch could be simplified by looking at
> r4971->r4970

Interesting--I will have to do more benchmarks since I'm reverting
Loren here ;)  Its possible the dc_add may be more useful for some MB
types than for others.

> please keep the {}  i prefer {} between if /else as they dont eat a line but
> make possible future patches clearer
> cosmetic, you should know iam picky about these in functional changes :)


Dark Shikari

More information about the ffmpeg-devel mailing list