[Speex-dev] Blackfin port on Visual DSP, Michael Shatz ?

Stéphane Lesage stephane.lesage at ateis-international.com
Tue Oct 16 09:43:24 PDT 2007


I'm using the Speex codec on my Blackfin-based board,
and plain-C performance is pretty poor.

Decoder is OK (something 25 MIPS for wide-band).
But Encoder is not (wide-band quality 8, complexity 1):
- 162 MIPS with Analog-Devices lib
- 128 MIPS with 1.2beta2 (faster but not working)

I don't worry that much, as it's not the optimized version, and everything
is running in SDRAM.

Can you give me some advice on what I should try to put into internal SRAM ?
Critical code ? Input samples ? Code-books ?
Can we pre-allocate internal buffers heavily used by the encoder ?

I'm also trying to compile Speex with asm optimizations.
But it's targetted for GCC...

I went through the archives, and found some entry-points to port
asm-constraints to the VDSP compiler.
But I'm facing the problem of 'dynamic' labels for loops.

I don't know if Michael Shatz has completed the port...
If you're reading this. Would you share your files ?

Jean-Marc, I don't want to come back on the debate,
but I think you should include the VDSP architecture.

(there is also a problem with variables named "bank"
which is a compiler keyword...)

Best regards.

Stéphane Lesage
ATEIS International 

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