Re: AUGraph with built-in input failing to set device (OSX)

Subject: Re: AUGraph with built-in input failing to set device (OSX)
From: Tim Kemp <email@hidden>
Date: Thu, 06 Dec 2012 16:13:40 -0500

The code sample you provided is actually the old way of doing it -- it uses a now-deprecated call (AudioHardwareGetProperty).

You're quite right, sorry. Thanks for the pastie link, that's much easier to read. I have run it and I can reproduce your problem on my machine.

Are you trying to do what I assumed - that is, collect input from the default input device? This here from Chris Adamson's website (companion to his excellent Learning Core Audio book) is a fully working version of that, using an AUGraph. Note that he's using Audio Component Services to find the input component, create an AU instance of it and configure it fully before it's added to the graph: http://www.informit.com/store/learning-core-audio-a-hands-on-guide-to-audio-programming-9780321636843 (click Downloads tab. You want the Chapter 8 sample.)

Hope that helps.

On 6 Dec 2012, at 15:17, John Nastos wrote:

Tim et al,

The code sample you provided is actually the old way of doing it -- it uses a now-deprecated call (AudioHardwareGetProperty).

The way that I'm getting the default device ID works fine, assuming I get a reference to the AudioUnit using `AudioComponentInstanceNew` -- however, it does not work when using `AUGraphNodeInfo`

Is it not possible to use the default input in an AUGraph like this?

Here's the code again on pastie if it makes it easier to read: http://pastie.org/5490322

Note that this (not using an AUGraph) works fine: http://pastie.org/5490326

- John Nastos
On Thu, Dec 6, 2012 at 11:22 AM, Tim Kemp <email@hidden> wrote:
A -10851 error means "Invalid Property Value" (see here: https://developer.apple.com/library/mac/#documentation/AudioUnit/Reference/AUComponentServicesReference/Reference/reference.html)
You've set something it doesn't like.

Take a look at this:
OSStatus SetDefaultInputDeviceAsCurrent(){
    UInt32 size;
    OSStatus err =noErr;
    size = sizeof(AudioDeviceID);

    AudioDeviceID inputDevice;
    err = AudioHardwareGetProperty(kAudioHardwarePropertyDefaultInputDevice,
                                                  &size,
                                                  &inputDevice);

    if (err)
        return err;

    err =AudioUnitSetProperty(InputUnit,
                         kAudioOutputUnitProperty_CurrentDevice,
                         kAudioUnitScope_Global,
                         0,
                         &inputDevice,
                         sizeof(inputDevice));

   return err;

}
From http://developer.apple.com/library/mac/#technotes/tn2091/_index.html which is an article describing exactly what you want to do (using the HALOutput object to collect input.)

On 4 Dec 2012, at 04:56, John Nastos wrote:

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	>Re: AUGraph with built-in input failing to set device (OSX) (From: Tim Kemp <email@hidden>)
	>Re: AUGraph with built-in input failing to set device (OSX) (From: John Nastos <email@hidden>)

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