Re: "Native" sample format
Re: "Native" sample format
- Subject: Re: "Native" sample format
- From: Jens Bauer <email@hidden>
- Date: Thu, 11 Dec 2003 00:35:00 +0100
Hi James and Jeff,
Thanks for the information on the native sample format.
I've been thinking about it, and yes, it'd probably be best, if I use a
float, rather than integers, imagining that I mix a few 0.33333 values
into one sample value. When doing that as integer, it'd probably be
much more precise using floats. =)
On Wednesday, Dec 10, 2003, at 21:12 Europe/Copenhagen, Jeff Moore
wrote:
The canonical sample format is 32 bit float. We chose that because it
strikes the right balance between memory bulk (only take a third more
space than the original 24 bit sample) and computational speed
(floating point headroom management and Altivec acceleration speed
things along quite nicley).
On Wednesday, Dec 10, 2003, at 20:41 Europe/Copenhagen, James Coker
wrote:
The native format is 32-bit floating point, but you can always
move to double-precision when necessary (filter coefficients).
Of course, you'll take a big performance hit for that, unless
you're running on a G5....
On Wednesday, December 10, 2003, at 06:37 AM, Jens Bauer wrote:
What's the native format of a sample ?
-Is it a 32bit signed integer ?
I'm asking this question, because I'd like to write my code, so
CoreAudio doesn't have to convert my data, before feeding them to the
soundcard.
I've been thinking about using floats, but since that floats are only
32bit, they're getting unprecise (but ofcourse, as long as I need 24
bits only, I don't know whether the data are actually ruined).
I'd prefer doubles, so I'm sure that I won't get that problem.
Unfortunately, there's no such format, so is the most precise format
32-bit ?
I know that most people can't hear these differences, but if I'm
going to sample some data for other purposes than sound, it could be
quite neat to have them as exact as possible, however, I'm also going
to write sound applications. ;)
Love,
Jens
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