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Re: IOProc limitations
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Re: IOProc limitations


  • Subject: Re: IOProc limitations
  • From: James McCartney <email@hidden>
  • Date: Wed, 30 May 2001 17:54:05 -0500

on 5/24/01 3:10 PM, Matt J. Ingalls at email@hidden wrote:

> hi there,
>
> im getting a bunch of EXC_BAD_ACCESS errors whenever i try using various
> foundation kit methods inside the AudioDeviceIOProc - is this a bad thing
> to do?
> what can/[not] you do inside the ioproc?

More questions along this line:

Does OSX/CoreAudio do priority inversion to bump my thread up if I'm holding
a mutex to change some data structure like for instance an in-memory sound
file header?

I tried to fill my audio outside of the callback by synchronizing with a
condition. It worked, but dragging windows would cause dropouts. Filling the
buffer inside the callback does not cause dropouts.

Can this scheme be done correctly by setting up priorities or something
else?

The idea is that I would like to have a { getcommand; processcommand } loop
that runs indefinitely processing commands where filling an audio buffer is
just like any other command. This lets the same thread operate whether the
audio is turned on or not. Thus it could switch from processing audio in
real time to some other task.

If that kind of scheme is not possible then I have to exit one thread and
start processing commands in the audio loop and if audio is turned on then
go back to a thread again.



--- james mccartney email@hidden <http://www.audiosynth.com>
SuperCollider - a real time synthesis programming language for the PowerMac.
<ftp://www.audiosynth.com/pub/updates/SC2.2.10.sea.hqx>


  • Follow-Ups:
    • Re: IOProc limitations
      • From: James McCartney <email@hidden>
References: 
 >IOProc limitations (From: "Matt J. Ingalls" <email@hidden>)

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