[vorbis-dev] Optimisations

[Segher Boessenkool]

Jason Hecker wrote:
> 
> Looking through the archives I have seen talk of making CPU specific
> optimisations for Vorbis, a la MMX/3DNow!/SSE.  The feeling I gather is to
> wait until something is working well in C before committing to any kind of
> specific optimisation.  What if oft used and needed DSP functions were
> identified and standardised DSP functionality be written for Vorbis?  This
> would seperate the basically non-changing core signal processing functions
> (IIR, FIR and DCT/FFT) and allow them to be optimised with MMX and so on
> without fear of upsetting the other code that's in a state of flux at the
> moment.  Wouldn't this be nice?  ;)
> 
> If anyone is interested in heading down this path with me please let me know!

Sure I'm interested :-) For optimizing the current all-C version, I hand-unrolled
a lot of the critical loops; this will come in handy for doing a vector-op
version. Note, that the filters and fast transforms are not the most time-critical,
however.

Ciao,

Segher

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