Re: 3D Audio Unit + Sample Conversion + Performance Hit
Re: 3D Audio Unit + Sample Conversion + Performance Hit
- Subject: Re: 3D Audio Unit + Sample Conversion + Performance Hit
- From: Bill Stewart <email@hidden>
- Date: Fri, 18 Oct 2002 18:50:33 -0700
You should use the AUConverter unit - the kAudioUnitID_PolyphaseSRC unit is
basically deprecated and subsumed by the converter unit.
The converter unit uses an AudioConverter and uses the input and output
formats to determine what conversion needs to be applied. You can set the
type of SRC to use through a property on this unit.
The Polyphase is a pretty reasonable quality converter, but its not cheap -
so if you're concerned about CPU usage I'd leave this alone (the default SRC
for this is the MediumQuality converter, which is reasonable and cheaper)
If you have a look through the AudioFile code in the SDK you'll see some
direct usage of an AudioConverter if that helps...
Bill
on 18/10/02 6:12 PM, Brian Barnes wrote:
>
The 3D Audio Mixer gives a pretty major performance hit -- I'm still
>
going to use it since it's a bit better than my quicky routines, but
>
the hit is noticable (about 5-10% at lower fps).
>
>
Next up: I do pitch by changing how I feed the data in the input. I
>
want to try out the conversion module and see how speed is on that.
>
>
I'm pretty sure I hook up kAudioUnitID_PolyphaseSRC audio unit, but how
>
do I change how it works? Do I setup the stream format on both the
>
input and output?
>
>
[>] Brian
>
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