[Vorbis-dev] low-memory vorbis decoding

[David Etherton]

Some more information about the SPU's: (all public)

 

-          Unified scalar/vector register file (128 x 128bits)

-          Otherwise very similar to PPC Altivec

-          Fast DMA engine can access anything in main memory at behest
of SPU.

 

Tremor would not be ideal, this is a floating-point machine, but it is
sensitive to memory footprint.

 

-Dave

 

________________________________

From: vorbis-dev-bounces at xiph.org [mailto:vorbis-dev-bounces at xiph.org]
On Behalf Of Ethan Fenn
Sent: Thursday, March 08, 2007 10:34 AM
To: vorbis-dev at xiph.org
Subject: [Vorbis-dev] low-memory vorbis decoding

 

Hi all,

 

Does anyone have any experience porting libvorbis to platforms with
small total memory sizes?  Specifically, I'm trying to figure out if
it's feasible to run Ogg Vorbis decoding on one of the PlayStation 3's
SPU's -- secondary processors with only 256kb of local memory.  It looks
like out of the box the memory footprint of libvorbis is roughly:

 

~130k code

~60k static data

~160k heap

 

So clearly there's some work to be done.  I have some ideas of things to
try... speed isn't a huge issue so I could eliminate some of the lookup
tables (e.g. for mdct and windowing), and I could try to tease apart the
analysis/synthesis code, as it looks like a lot of code on the analysis
side is needlessly being linked in.

 

But, before I dive into that I was wondering if anyone has any
experience with this sort of thing and could give me some idea of how
much work it's likely to be.

 

Thanks,

-Ethan

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