public void InitializeAUGraph ()
{
Debug.Print ("Initialize");
LoadFiles ();
graph = new AUGraph ();
// create two AudioComponentDescriptions for the AUs we want in the graph
// output unit
var outputNode = graph.AddNode (AudioComponentDescription.CreateOutput (AudioTypeOutput.Remote));
// mixer node
var mixerNode = graph.AddNode (AudioComponentDescription.CreateMixer (AudioTypeMixer.MultiChannel));
// connect a node's output to a node's input
if (graph.ConnnectNodeInput (mixerNode, 0, outputNode, 0) != AUGraphError.OK)
throw new ApplicationException ();
// open the graph AudioUnits are open but not initialized (no resource allocation occurs here)
if (graph.TryOpen () != 0)
throw new ApplicationException ();
mixer = graph.GetNodeInfo (mixerNode);
// set bus count
const uint numbuses = 2;
Debug.Print ("Set input bus count {0}", numbuses);
if (mixer.SetElementCount (AudioUnitScopeType.Input, numbuses) != AudioUnitStatus.OK)
throw new ApplicationException ();
AudioStreamBasicDescription desc;
for (uint i = 0; i < numbuses; ++i) {
// setup render callback
if (graph.SetNodeInputCallback (mixerNode, i, HandleRenderDelegate) != AUGraphError.OK)
throw new ApplicationException ();
// set input stream format to what we want
desc = mixer.GetAudioFormat (AudioUnitScopeType.Input, i);
//desc.ChangeNumberChannels(2, false);
desc.SampleRate = GraphSampleRate;
mixer.SetAudioFormat (desc, AudioUnitScopeType.Input, i);
}
// set output stream format to what we want
desc = mixer.GetAudioFormat (AudioUnitScopeType.Output);
//desc.ChangeNumberChannels(2, false);
desc.SampleRate = GraphSampleRate;
mixer.SetAudioFormat (desc, AudioUnitScopeType.Output);
// now that we've set everything up we can initialize the graph, this will also validate the connections
if (graph.Initialize () != AUGraphError.OK)
throw new ApplicationException ();
}
