Subject: Re: [linux-audio-dev] optimization / restrictions
From: Karl MacMillan (karlmac_AT_peabody.jhu.edu)
Date: Thu May 17 2001 - 23:50:09 EEST
On Thu, 17 May 2001, n++k wrote:
> [Steve Harris <S.W.Harris_AT_ecs.soton.ac.uk>]
> |
> | Known nominal 0db value (e.g. 1.0f)
> | Minimum sample rate (e.g. 44.1k's)
> | Guaranteed 2^n block size
>
> Somewhere (in a diskmag) I read Tammo Hinrichs (writing about
> his softsynth system)
>
> "A bad idea, however, is to make your buffer sizes a power of two.
> The times when ASM coders used AND operations to mask out the buffer
> offsets
> are over. Those one or two cycles for a compare operation don't
> hurt. So, there's no reason for using power-of-two bffer sizes
> except you may be used to it.
There are algorithms that are much more efficient when the block size is a
power of 2 - FFT being the most notable. I'm certain there are other
valid reasons to continue this practice.
Karl
> --
> n
> ++k
>
_____________________________________________________
| Karl W. MacMillan |
| Computer Music Department |
| Peabody Institute of the Johns Hopkins University |
| karlmac_AT_peabody.jhu.edu |
| mambo.peabody.jhu.edu/~karlmac |
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