Re: default output start & stop
Re: default output start & stop
- Subject: Re: default output start & stop
- From: papi <email@hidden>
- Date: Sun, 05 Jan 2003 15:32:33 -0800
There's a thread feeding the audio? I haven't worked with threads
myself
yet, but I haven't been able to find anything in the DefaultAudioOutput
sample app that says it's creating or calling a thread.
So, I hope this isn't off-topic, but if the theOutputUnit
is/contains/represents
a thread and the AudioOutputUnitStart() function starts playing it, how
does one stop it? Pressing my button that calls AudioOutputUnitStop()
just waits for the usleep() "timer" to expire.
Thanks again!
Scott
p.s. the render callback supplies a never-ending supply of PCM data
to the AU. Playback duration is currently (temporarily!) controlled
solely
by the length of time specified in usleep().
On Sunday, January 5, 2003, at 10:17 AM, David Duncan wrote:
On Sunday, January 5, 2003, at 12:55 PM, papi wrote:
New to core audio -- still pretty green at C++.
The DefaultAudioOutput example project's TestDefaultAU() function has
some
code that starts and stops a simple sine wave render. Can someone
explain
in further detail what exactly is happening here? (I've copied the
snippet below.)
Starting the audio unit here...
verify_noerr(AudioOutputUnitStart(theOutputUnit));
Sleeping the current thread for 5 seconds (the audio is played on a
separate thread) usleep() is a BSD call.
usleep (5 * 1000 * 1000); // sleep for 5 seconds
And stop the audio unit here...
verify_noerr(AudioOutputUnitStop(theOutputUnit));
That is literally all this code is doing. Now, the thread that is
feeding the audio may only play 5 seconds worth of sound regardless, I
have not looked at the source code for TestDefaultAU() so I don't
know. But if your looking for more clues, it would be more useful to
look at the render callback that is being installed on the output > unit.
--
Reality is what, when you stop believing in it, doesn't go away.
Failure is not an option. It is a privilege reserved for those who try.
David Duncan
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