Re: Opinions sought: AudioUnit Rendering
Re: Opinions sought: AudioUnit Rendering
- Subject: Re: Opinions sought: AudioUnit Rendering
- From: Doug Wyatt <email@hidden>
- Date: Wed, 6 Mar 2002 06:57:32 -0800
This is a very promising idea -- we could have AudioToolbox export two
globals:
extern const Float32 *kAudioToolbox_SilentBuffer;
extern const UInt32 kAudioToolbox_SilentBufferNumberSamples; // number of
samples in kAudioToolbox_SilentBuffer
and AudioUnits' RenderSlice methods would be free to compare incoming
AudioBuffer.mData's against it, and set outgoing mData's to it (as long
as they were outputting fewer than
kAudioToolbox_SilentBufferNumberSamples). Totally backward-compatible,
a minimal API addition, and allows a good optimization.
Thanks!
Doug
On Tuesday, March 5, 2002, at 10:14 , James McCartney wrote:
In SuperCollider v1 I had this case and I don't know if it can be
applied to
AudioUnits, but I passed a pointer to a globally known constant buffer
of
zeroes. Dumb units can just process this as a normal buffer of zeroes.
Others can be smart and check if the pointer is the buffer-of-zeroes
pointer
and if so, ignore it.
This trick relies on a number of things: buffers are a constant size,
units
only read inputs and do not mix into them in place (so that it remains a
buffer of zeroes).
(strange, I did not receive the original post and had to go to the
archives
to read it.. maybe I just got happy with the 'D' key in Pine without
looking..)
--
Doug Wyatt
work: email@hidden (CoreAudio)
personal: email@hidden
http://www.sonosphere.com
"Premature optimization is the root of all evil."
-- Knuth
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