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Re: VariSpeed and Timestamps
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Re: VariSpeed and Timestamps


  • Subject: Re: VariSpeed and Timestamps
  • From: Doug Wyatt <email@hidden>
  • Date: Wed, 17 Nov 2004 11:49:26 -0800

On Nov 17, 2004, at 7:47, Ethan Funk wrote:
If I call AudioUnitRender to get a sample buffer from a VariSpeed audio unit, passing it my local sample time stamp, what time stamp will the VariSpeed AU pass along to it's render call back when it pull on the next unit in the chain (a ring buffer in my case)? Will it just pass along my time stamp? Does it used my time stamp multiplied/divided by the rate convertion scalar? Does it have it's own internal input sample counter that it uses?

It has its own internal sample counter ...

I am having trouble where the resuling audio sounds modulated by a square wave at around the render period rate which makes me suspect the the time stamps are skipping through ring buffer when the VariSpeed filter pulls on it.

To check up on the varispeed, I would log the timestamps it pulls you for, e.g.:


pull 1:
	It pulls you at time 1000 for 500 samples.
pull 2:
	is the timestamp 1500? if not, error
	time 1500, 499 samples
pull 3:
	is the timestamp 1999? if not, error

If the timestamps aren't correct, let us know ... if they are, then check your code further ...

Doug

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  • Follow-Ups:
    • Re: VariSpeed and Timestamps
      • From: Ethan Funk <email@hidden>
References: 
 >VariSpeed and Timestamps (From: Ethan Funk <email@hidden>)

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