Re: [xine-devel] xine_fast_memcpy for PPC CPUs

[Michel L. <wa...@zo...>]

On Sat, Feb 16, 2002 at 04:35:07PM -0000, James Courtier-Dutton wrote:
> I did not ask him if he had an altivec capable CPU.

One other thing to check for is hardware yuv2rgb support. If you dont
get that running, its a *huge* performance impact.

g3 should probably not skip too many frames if you can use xv output.

> Like above, I have not checked these. I don't have a PPC platform, so is
> there any log message which will tell the user if it is using the altivec
> routines.

For debugging I'd recommend to run the plain mpeg2dec package. It's
not useable as a player, but it tells you quick wether the problem is
in libmpeg2 or elsewhere.

> Maybe we will need a specific ATI version of libmpeg2 much like the
> dxr3 has one.

In the long term, I'd like to introduct some functionality to record
some per-macroblock information (mainly motion vectors and qscale) in
an array from within libmpeg2. This would allow people to implement
error concealment outside of libmpeg2. Also in the case of
hardware-allelerated operations, you could use null routines for IDCT
and/or MC and just use the information logged in these arrays to
program the hardware.

This is only a long-term project though. Before that I'd like to
switch libmpeg2 to a saner API.

Cheers,

-- 
Michel "Walken" LESPINASSE
Is this the best that god can do ? Then I'm not impressed.