[x264-devel] x264 decoding is to slow on cell processor (PS3)

[Guillaume Poirier]

Hello,

Alex Izvorski wrote:
> On Wed, 2007-10-03 at 14:14 +0400, Dima Dima wrote:
>> I've been trying to play x264 video on my PS3 and results was awfull.
>> The question is: are there anybody who involved into porting x264
>> decoder to use the full advantage of cell processor (SIMD + spu's)?
> 
> Hello Dima,
> I have looked at what SIMD assembly on the Cell processor would look
> like.  It is somewhat not as good as you would think from looking at the
> processor specs.

That's exactly how I felt too.


>  I was looking at it from the perspective of porting
> x264 actually, since at the time (before quad Core2 Duo/Woodcrest
> processors) it looked very promising.  Now not so much, I'd rather have
> 2x4 Woodcrests than 8 SPU's any time.

Yep, coding a multi-threaded software is immensely easier on Symmetric
MultiProcessing machines (dual, quadricore x86 core) than on
Asymmetric multiprocessing machines (1PPU + 7SPU on Cell).


> There have been other people who are interested (Guillaume Poirier, you
> reading this? ;) but my sense is nothing will happen without someone
> contributing hardware and money.

An Strategist IBM offered people interested in optimizing code for the
Cell to offer PS3 machines. Except from the fact that I don't even own
a TV or HDCP monitor screen to which I can hook up the PS3, my
personal free time and personal interest don't allow me to spend time
on optimizing for PS3 even if I was given a PS3.

I'm afraid I could only reasonably spend time on it if I was paid to
do it. If anyone is interested in that solution (I somewhat doubt it),
I could have the company I work for do all the paperwork.

Guillaume