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

Rich Felker dalias at aerifal.cx
Sun Feb 18 08:36:54 CET 2007

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.

Well we can start by throwing out loop filter by assuming people who
care about performance will just turn it off, no? :) How much does
that eliminate?


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