static extern int AUGraphSetNodeInputCallback(IntPtr inUnit, Int32 inDestNode, UInt32 inDestInputNumber, AudioUnit.AURenderCallbackStrct inInputCallback);
void prepareAUGraph()
{
// Creating audio graph instance
_auGraph = AUGraph.CreateInstance();
// Adding Remote IO node to AUGraph
AudioComponentDescription cd = new AudioComponentDescription()
{
componentType = AudioComponentDescription.AudioComponentType.kAudioUnitType_Output,
componentSubType = AudioComponentDescription.AudioComponentSubType.kAudioUnitSubType_RemoteIO,
componentManufacturer = AudioComponentDescription.AudioComponentManufacturerType.kAudioUnitManufacturer_Apple,
componentFlags = 0,
componentFlagsMask = 0
};
int remoteIONode = _auGraph.AddNode(cd);
// Preparing AudioComponentDescrption of MultiChannelMixer
cd.componentType = AudioComponentDescription.AudioComponentType.kAudioUnitType_Mixer;
cd.componentSubType = AudioComponentDescription.AudioComponentSubType.kAudioUnitSubType_MultiChannelMixer;
int multiChannelMixerNode = _auGraph.AddNode(cd);
// Setting callback method as the case of Audio Unit
for (int i = 0; i < _waveDef.Length; i++)
{
var callbackStruct = new AudioUnit.AURenderCallbackStrct();
callbackStruct.inputProc = device_renderCallback; // setting callback function
callbackStruct.inputProcRefCon = GCHandle.ToIntPtr(_handle); // a pointer that passed to the renderCallback (IntPtr inRefCon)
_auGraph.AUGraphSetNodeInputCallback(
multiChannelMixerNode,
(uint)i, // bus number
callbackStruct);
}
var remoteIOAudioUnit = _auGraph.GetNodeInfo(remoteIONode);
var multiChannelMixerAudioUnit = _auGraph.GetNodeInfo(multiChannelMixerNode);
// Getting an AudioUnit canonical description
var audioFormat = AudioUnitUtils.AUCanonicalASBD(44100.0, 2);
// applying the audio format to each audio units
remoteIOAudioUnit.SetAudioFormat(audioFormat, AudioUnit.AudioUnitScopeType.kAudioUnitScope_Input, 0);
multiChannelMixerAudioUnit.SetAudioFormat(audioFormat, AudioUnit.AudioUnitScopeType.kAudioUnitScope_Input, 0);
// connecting multiChannelMixerNode(bus:0) to remoteIONode(bus:0)
_auGraph.ConnnectNodeInput(
multiChannelMixerNode,
0, // output bus
remoteIONode,
0 // input bus
);
// graph initialization
_auGraph.Initialize();
}
public void AUGraphSetNodeInputCallback(int inDestNode, uint inDestInputNumber, AudioUnit.AURenderCallbackStrct inInputCallback)
{
int err = AUGraphSetNodeInputCallback(_auGraph,
inDestNode, inDestInputNumber, inInputCallback);
if (err != 0)
{
throw new ArgumentException(String.Format("Error code:", err));
}
}
