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Re: playing audio files separated by specified time intervals
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Re: playing audio files separated by specified time intervals


  • Subject: Re: playing audio files separated by specified time intervals
  • From: Brian Willoughby <email@hidden>
  • Date: Mon, 22 Dec 2008 02:17:49 -0800

The display doesn't really need to be that accurate, and you can catch every major audio application on the market showing slight variations in display performance, so I wouldn't let that bother you. You can use CoreAudio to determine the output device latency so that you can predict the amount of time it takes between delivering the start of your audio file and when someone will hear it, so that will help accuracy.

Tahome beat me to answering your question about audio accuracy. The key is that you're always delivering audio, including the silence between the sounds, so you have precise sample-accuracy at all times.

Brian Willoughby
Sound Consulting


On Dec 22, 2008, at 00:51, Maissam Barkeshli wrote:
I'm still a little bit confused though about how this specifically should work. Say I want to do something simple: play a single audio file once per second and simultaneously update a visual counter on the GUI.


Right now I'm looking at starting a CoreAudioClock, running a loop and continuously polling the clock to see whether a second has passed since the last time. Once at least one second has passed, then play the file and update the display. The problem with this is that even though CoreAudioClock is very accurate, the program itself sometimes might actually take an extra fraction of a second if the computer is busy with other applications.
But people still develop rock-solid metronome applications, with displays and everything. How do they do it? The only thing I can think of about making this work is that somehow I need to be using a thread that has extremely high priority, so that the operating system focuses on this particular program.


Perhaps I have settle with not being able to get the display to be perfectly accurate, but with your suggestion I can get the audio to be accurate?

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References: 
 >playing audio files separated by specified time intervals (From: Maissam Barkeshli <email@hidden>)
 >Re: playing audio files separated by specified time intervals (From: Brian Willoughby <email@hidden>)
 >Re: playing audio files separated by specified time intervals (From: Maissam Barkeshli <email@hidden>)

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