[Speex-dev] ARM7 decode resource requirements

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Wed Mar 29 14:15:45 PST 2006


> so the 100kbyte ROM value quoted by Tom in his earlier mail should reduce if
> I cut out all the encoder code? 

100 kB sounds a bit big, especially considering that all the codec
(including encoder and all bit-rates) fits in 64kB on my x86. I'm sure
you could make the decoder fit in less than 30 kB. Probably even less if
you use thumb instructions.

	Jean-Marc

> John
> 
> -----Original Message-----
> From: Jean-Marc Valin [mailto:Jean-Marc.Valin at USherbrooke.ca] 
> Sent: 28 March 2006 23:11
> To: Anderton, John
> Cc: 'speex-dev at xiph.org'
> Subject: Re: [Speex-dev] ARM7 decode resource requirements
> 
> > I'm looking in to using speex for an ARM7 based speech decode 
> > development (note we need the decode only). My hope is that we should 
> > be able to run the decoder (in wideband mode) real time on the ARM7
> > (40MHz) without any problems (the difficulty would be in the encode - 
> > but we plan to run that offline on a PC - so we should be OK). Can 
> > anyone confirm that this is the case please?
> 
> I think decoding wideband shouldn't be a problem, even on a slow ARM7.
> In the worst case, there are always some approximations possible (replacing
> the long FIR filter by an IIR).
> 
> > Also I'd like to get a handle on memory requirements, has anyone got 
> > any rough estimates of the ROM & RAM footprint of the decoder, built 
> > for the ARM7?
> 
> I've never measured that, but it shouldn't take too much space, especially
> if you disable all the code (and possibly codebooks) that aren't used.
> 
> > One last question, any estimates for how much of the decoder code is 
> > in floating point (number of lines of code)?
> 
> There's probably in the order of 5-15 lines of floating-point code left,
> most (all?) of which outside of loops. Should work in real-time even with
> float emulation.
> 
> 	Jean-Marc
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