[Speex-dev] Speex memory usage?

Ghost Wolf ghostdewolf at gmail.com
Sat Feb 2 04:48:36 PST 2008


Thank you for making it super clear to me that it wouldn't work. My goal 
is to make a simple pinhole based speex player kit (pinhole circuit 
board that is) to sell and of course donate some of the profit to 
speex/xiph.

I love speex but it would be great if the recommended system 
requirements would be viewable on the site. I'm guessing that it can be 
difficult because of the changes in code and assembly optimisation but 
if you only post the recommended and add that minimal can be less and 
that is changing over time then the page doesn't need to be updated as 
often.

and Jean-Marc, I am grateful for really explaining why my idea wouldn't 
work. I am a beginner with visions but don't have the skill to realise 
it yet, so please bear with me.

Jean-Marc Valin skrev:
>> ok, that is not good for my plans...
>> Is there any thing in the the 8kB of RAM that is always the same (lookup
>> table etc.) or did you already think of that?
> 
> I told you the RAM requirements. The lookup tables are already counted
> as ROM. Basically, just one decoded frame already takes 320 bytes. Add
> the excitation memory and you've already blown the budget.
> 
>> I'm curios since the
>> ATmega168 got 16kB of Flash that is as fast as the RAM (I think the chip
>> is made so it limits its maximum speed to the slowest memory, flash. it
>> also has some EEPROM besides the SRAM).
> 
> It's not clear the code size + lookups would fit in the flash anyway.
> 
>> Ps. ATmega spec:
>> FLASH: 16kB
>> EEPROM: 512B
>> SRAM: 1kB
>> SPEED: 0-20MHz
> 
> Too slow.
> 
>> Architecture: 8-bit RISC, no FPU.
> 
> All the code assumes you have a 16x16 multiplier and a 32-bit
> accumulator. Emulating that on an 8-bit chip would be far too costly.
> 
>> Site: http://www.atmel.com/dyn/products/product_card.asp?part_id=3303
> 
> Given your requirements, the only thing that might work for you is one
> of the ADPCM variants.
> 
> 	Jean-Marc
> 


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