[Speex-dev] Speex memory usage?

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Fri Feb 1 20:31:21 PST 2008

> 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.


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