[MPlayer-dev-eng] Re: Re: PATCH [0/12] CoreAVCDecoder support

Dominik 'Rathann' Mierzejewski dominik at rangers.eu.org
Mon Feb 19 12:19:42 CET 2007


On Sunday, 18 February 2007 at 14:17, Michael Niedermayer wrote:
> Hi
> 
> On Sat, Feb 17, 2007 at 10:27:42PM -0700, Loren Merritt wrote:
> > On Sat, 17 Feb 2007, Rich Felker wrote:
> > >On Sun, Feb 18, 2007 at 01:42:02AM +0100, Michael Niedermayer wrote:
> > >
> > >>this wont happen and it shouldnt, its the compilers job, this is not
> > >>2 pages of code its more like 200 pages of c code ...
> > >
> > >bleh.. :(
> > >is there any sane way to isolate the parts that are actually the most
> > >performance-intensive and only write them in asm? or is h264 just THAT
> > >idiotic that it has 200 pages of performance-intensive code do to
> > >massive overcomplexity?
> > 
> > If we define "performance-intensive" to be anything that runs 
> > per-macroblock, then that makes up 5488 of the 8653 lines in h264.c
> > (not counting anything in dsputil since that has already been asmed).
> > Of course not all of that is used on every video, e.g. a bunch of code is 
> > separate for cabac and cavlc. But all of it needs to be considered for 
> > optimization if we want all videos to be faster.
> > It can't be narrowed too much farther, since a significant fraction of the 
> > cpu-time is spent in code that runs only once per macroblock.
> 
> so my 200 page guess is pretty close 200*25=5000
> 
> 5000 lines of code is a pretty large amount no matter if its to be asm
> optimized or some more highlevel optimizations, maybe we could do some
> contest where the winner gets a real 10l cola (and all the fame of being
> the best) so
> 
> the winner could be selected by simply benchmarking
> there could be 2 classes (P4 and athlon maybe so 2 winners)

Maybe include AMD64 (in 64bit mode) as a third class here?

Regards,
R.

-- 
MPlayer developer and RPMs maintainer: http://mplayerhq.hu http://rpm.livna.org
There should be a science of discontent. People need hard times and
oppression to develop psychic muscles.
	-- from "Collected Sayings of Muad'Dib" by the Princess Irulan



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