[Asterisk-Dev] IBM/SGI implementations

[Steve Kann]

On Nov 22, 2004, at 7:22 PM, Tracy R Reed wrote:

> On Mon, Nov 22, 2004 at 01:56:12PM -0500, Steve Kann spake thusly:
>> I think a great "trick" to do DSP operations like codecs on cheap
>> hardware is to use the power of the GPU.  This is something that 
>> Mark's
>> been talking about in the past.
>
> Are we even using MMX/SIMD yet? Seems like that would make more sense
> before going in for a GPU.

Depends on the codec.  Depends even more on the options you use when 
you compile.

The GSM library * uses has MMX support, if you define K6OPT (bad name, 
but it's just MMX, no K6-specific stuff).
Speex can use SSE if you compile it that way.  It gets you about 20% if 
I remember my tests.
The iLBC stuff doesn't have any such optimizations: it's pretty 
non-optimized code.

uLaw/aLaw doesn't need any of that, they're table lookups for decode, 
and a few more instructions for encode.  However, I would like to add 
PLC support to these codecs, which to do well, requires a little DSP 
work.

-SteveK