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Re: Virtual audio device glitches
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Re: Virtual audio device glitches


  • Subject: Re: Virtual audio device glitches
  • From: Robert Bielik <email@hidden>
  • Date: Sat, 16 Oct 2010 09:49:44 +0200

Robert Bielik skrev 2010-10-15 09:01:
My architecture in short: A user mode application pulls data from the device via a IOUserClient API call with the same no of frames
that the engine is set to. I pass AudioTimeStamp.mHostTime in the call to provide timestamps derived from the output device
the UM app is sending audio to (i.e. I call takeTimeStamp in that API call). Thus, I feel that the timestamps should be pretty stable, and debugging the time diff during buffer wraps seems to confirm that.

Hmm.. not really. When I use the timeStamp generator, I don't get pops/clicks until I change the volume with the volume buttons on the MBP. So obviously the generation of the timestamp value is the key here. When I compared the timestamps from the API call with the delta of the generator, I get differences between -100000 and +100000 ticks. How can the timestamp given to my application IOProc differ so ? Isn't the timestamp in there derived from the output device ?

TIA
/Rob
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  • Follow-Ups:
    • Re: Virtual audio device glitches
      • From: Robert Bielik <email@hidden>
References: 
 >Virtual audio device glitches (From: Robert Bielik <email@hidden>)
 >Re: Virtual audio device glitches (From: Jeff Moore <email@hidden>)
 >Re: Virtual audio device glitches (From: Robert Bielik <email@hidden>)
 >Re: Virtual audio device glitches (From: Jeff Moore <email@hidden>)
 >Re: Virtual audio device glitches (From: Robert Bielik <email@hidden>)

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