[CELT-dev] CELT grabbing 100KB of memory right off the top

Andrew Lentvorski bsder at allcaps.org
Mon Apr 18 22:54:24 PDT 2011

On 4/18/11 5:35 PM, Jean-Marc Valin wrote:
> Most likely because CELT actually up-samples to 48 kHz internally. Even
> if that wasn't the case, you wouldn't save much since most of the
> complexity is on frequencies below 12 kHz.

Well, its good to know that.  I'll probably pick up the extra sample if 
I can, then.  There's no point in throwing away a bunch of samples if 
it's just going to upsample, anyhow.

> Lowering the bit-rate would reduce complexity. Increasing the frame size
> *may* help as well. Lowering the "complexity setting"
> CELT_SET_COMPLEXITY should definitely help at the expense of lowering
> quality. I suggest trying complexity 4, which disables the pitch search
> for the prefilter.

I see no visible change moving from 5 to 4.  Even moving the whole way 
to 0 only gains about 10% (3.46ms per loop vs. 3.14ms per loop).

> ilog is an easy one. Most platforms have a hardware instruction to
> compute that, so just using it should make that 15% go away.

Yeah, that was straightforward to buy almost 10%.


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