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Re: USB Audio streaming start
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Re: USB Audio streaming start


  • Subject: Re: USB Audio streaming start
  • From: Vyacheslav Matyushin <email@hidden>
  • Date: Fri, 21 Oct 2011 08:42:18 -0700 (PDT)

Thanks, Daniel.

One more thing which I can't get is safety offset.
How do I calculate it?

One tip I found is:
Sample offset is a feature designed for audio devices based on block I/O. Consider an output device as an example. If the audio device transfers data in a 32-sample block transaction, it must have at
least 32 samples available when the audio engine wakes up. Otherwise, the engine won’t be able to queue up a block transfer, and will end up slipping a cycle, potentially resulting in a glitch. To solve this problem, you can specify a sample offset to guarantee that the higher levels stay a certain distance ahead of the I/O head.

So does it really depend on the size of buffers I queue?
If I queue some number of buffers each holding say 8 ms of data, should my safety offset be (number_of_samples_in_1ms * 8)?
I guess it's too much..

Thanks,
Vyacheslav.
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  • Follow-Ups:
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      • From: Daniel Mack <email@hidden>
References: 
 >USB Audio streaming start (From: Vyacheslav Matyushin <email@hidden>)
 >Re: USB Audio streaming start (From: Daniel Mack <email@hidden>)
 >Re: USB Audio streaming start (From: Daniel Mack <email@hidden>)
 >Re: USB Audio streaming start (From: Vyacheslav Matyushin <email@hidden>)
 >Re: USB Audio streaming start (From: Daniel Mack <email@hidden>)

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