[mythtv-users] PS3 keys

[Raymond Wagner]

On 1/19/2011 15:17, Richard Morton wrote:
> And according to the wikipedia article the PS3 has only a geforce 7x00
> series graphics chip, so you couldnt offload to that for playback with
> vdpau.
>
> "Based on NV47 Chip (Nvidia GeForce 7800 Architecture)"
>
> http://en.wikipedia.org/wiki/RSX_'Reality_Synthesizer'
>
> So it would have to be a highly parallel software video decoder
> written for the SPEs.

Correct.  You can't just install the nVidia drivers and call it a day.  
I have no idea if the PS3 has a separate decoding engine, but with no 
documentation on it, implementing use of it would be a more difficult 
prospect than writing a new video decoder from scratch.

That leaves the SPEs.  While the SPEs have gobs of raw potential, they 
are an architecture designed for one limited purpose, and are vastly 
different than the x86 or even PPC chips most people are used to using.  
If anything, they are somewhat close in function to the SIMD units found 
in SSE, 3dNow, and Altivec.  As mentioned several times, access to the 
SPEs has been available since the PS3 was first released over four years 
ago, and removing the hypervisor does not change anything.

There was a project spu-medialib 
(http://wiki.ps2dev.org/ps3:spu-medialib) intended to write such a video 
decoder using the SPEs, but the furthest they ever got was scaling and 
colorspace conversion, effectively Xv.  While certainly nothing to laugh 
at, video scaling is relatively easy, and just requires sufficiently 
optimized code to fit within the performance envelope of your hardware.  
Its a far far cry from actually decoding video.  The project made a good 
start, but never seemed to progress any further beyond that.

Sure, we have a negative attitude, and aren't thinking happy thoughts, 
but history hasn't given us any reason to behave otherwise.  The PS3 was 
interesting as a Linux platform four years ago.  Today, it's just 
another piece of old hardware that can be cheaply replaced with 
something better.