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Re: InputCallback data request size
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Re: InputCallback data request size


  • Subject: Re: InputCallback data request size
  • From: William Stewart <email@hidden>
  • Date: Wed, 11 Oct 2006 17:28:23 -0700


On 11/10/2006, at 3:22 PM, Hari Seldon wrote:


I'm trying to improve the perf of my current CoreAudio usage. Right now I'm memcpy'ing data into the buffer provided by InputCallback (on an AUConverter). I'd like to change this to just provide a pointer to my internal buffer of data. The only problem I have with this is that the InputCallback parameter only takes a single buffer pointer, and I'm using a circular buffer. Currently InputCallback always asks for 2k worth of data, and I could use this number for my buffersize, but couldn't this number change?

Yes.


Is there a way to check how much data the InputCallback will ask for when the graph is created? Will this value ever change during execution, or will it remain the same during the life of the process?

No.

It depends on a couple of things:
- the amount of input asked for depends on how much output is being asked for.
- aufc type units (converter, varispeed, etc) can pull for more or less data than their output


So, you would want to look at the max frames setting of an AU (It should not ask you to provide more input than it can process). You then use this max frames to determine the max size of the input buffer you would be asked to fill

Bill


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      • From: Hari Seldon <email@hidden>
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