Mixer AudioUnit to RemoteIO AudioUnit - ios

Question

I have an AudioUnit with correspondent Callback working properly, But now, I need to send it to a RemoteIO, cause i'm implementing some framework who needs an RemoteIO AudioUnit to work.
THen... I need the same output i'm getting with this audiounit mixer but with another audiounit with type kAudioUnitSubType_RemoteIO.
Please, help!
EDIT ...
This is the code I'm trying...
EDIT 2- iOUnitDescription Added
AudioComponentDescription iOUnitDescription;
iOUnitDescription.componentType = kAudioUnitType_Output;
iOUnitDescription.componentSubType = kAudioUnitSubType_RemoteIO;
iOUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
iOUnitDescription.componentFlags = 0;
iOUnitDescription.componentFlagsMask = 0;
AudioComponent foundIoUnitReference = AudioComponentFindNext (
NULL,
&iOUnitDescription
);
AudioComponentInstanceNew (
foundIoUnitReference,
&audioUnit
);
result = AudioUnitSetProperty (
audioUnit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input,
guitarBus,
&stereoStreamFormat,
sizeof (stereoStreamFormat)
);
if (noErr != result) {[self printErrorMessage: #"AudioUnitSetProperty (set mixer unit guitar input bus stream format)" withStatus: result];return;}
result = AudioUnitSetProperty (
audioUnit,
kAudioUnitProperty_SampleRate,
kAudioUnitScope_Output,
0,
&graphSampleRate,
sizeof (graphSampleRate)
);
if (noErr != result) {[self printErrorMessage: #"AudioUnitSetProperty (set AUDIOUNIT unit output stream format)" withStatus: result]; return;}
AudioUnitElement mixerUnitOutputBus = 0;
AudioUnitElement ioUnitOutputElement = 0;
AudioUnitConnection mixerOutToIoUnitIn;
mixerOutToIoUnitIn.sourceAudioUnit = mixerUnit;
mixerOutToIoUnitIn.sourceOutputNumber = mixerUnitOutputBus;
mixerOutToIoUnitIn.destInputNumber = ioUnitOutputElement;
AudioUnitSetProperty (
audioUnit, // connection destination
kAudioUnitProperty_MakeConnection, // property key
kAudioUnitScope_Input, // destination scope
ioUnitOutputElement, // destination element
&mixerOutToIoUnitIn, // connection definition
sizeof (mixerOutToIoUnitIn)
);

Answer 1

I really need more info. From the above, i see you have a mixer somewhere, a guitarBus which presumably is your input (and seemingly a stream). What is the definition of &iOUnitDescription. More importantly, where are you hooking your renderCallback to, what are you doing in the callback and what does the framework expect?
Typically, when i need to process Audio, I build my own graph; I make this it's own class for better portability. This should be a good starting point for you
Here is how I implement such a solution.
// header file
#interface MDMixerGraph : NSObject{
AUGraph graph;
AudioUnit mixerUnit;
AudioUnit inputUnit;
AudioUnit rioUnit;
}
-(void) setupAUGraph;
#end
// implementation
#implementation MDMixerGraph
// exception Helper
void MDThrowOnError(OSStatus status){
if (status != noErr) {
#throw [NSException exceptionWithName:#"MDMixerException"
reason:[NSString stringWithFormat:#"Status Error %d).", (int)status]
userInfo:nil];
}
}
// helper method for setting up graph nodes
OSStatus MDAdAUGraphdNode(OSType inComponentType, OSType inComponentSubType, AUGraph inGraph, AUNode *outNode)
{
AudioComponentDescription desc;
desc.componentType = inComponentType;
desc.componentSubType = inComponentSubType;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
return AUGraphAddNode(inGraph, &desc, outNode);
}
// setup method to init and start AUGraph
-(void) setupAUGraph{
//Create the Graph
MDThrowOnError(NewAUGraph(&graph));
// setup AU Units
// Add Audio Units (Nodes) to the graph
AUNode inputNode, rioNode, mixerNode;
//Input Node -- this may need to be a different type to accept your Stream (not enough info above)
MDThrowOnError(MDAdAUGraphdNode(kAudioUnitType_Output, kAudioUnitSubType_RemoteIO, graph, &inputUnit));
//Remote IO Node - your output node
MDThrowOnError(MDAdAUGraphdNode(kAudioUnitType_Output, kAudioUnitSubType_RemoteIO, graph, &rioNode));
//mixerNode - Depending on output and input change the mixer sub-type here
// you can configure additional nodes depending on your needs for inputs and outputs
MDThrowOnError(MDAdAUGraphdNode(kAudioUnitType_Mixer, kAudioUnitSubType_AU3DMixerEmbedded, graph, &mixerNode));
// open graph
MDThrowOnError(AUGraphOpen(graph));
// we need a ref to the Audio Units so lets grab all of them here
MDThrowOnError(AUGraphNodeInfo(graph, inputNode, NULL, &inputUnit));
MDThrowOnError(AUGraphNodeInfo(graph, rioNode, NULL, &rioUnit));
MDThrowOnError(AUGraphNodeInfo(graph, mixerNode, NULL, &mixerUnit));
// setup the connections here, input to output of the graph.
/// the graph looks like inputNode->mixerNode->rioNode
MDThrowOnError(AUGraphConnectNodeInput(graph, inputNode, 0, mixerNode, 0));
MDThrowOnError(AUGraphConnectNodeInput(graph, mixerNode, 0, rioNode, 0));
// Init the graph
MDThrowOnError(AUGraphInitialize(graph));
//do any other setup here for your stream
// Finally, Start the graph
MDThrowOnError(AUGraphStart(graph));
}
In your View Controller extension you simply;
// define the MDMixerGraph Class
// #property (nonatomic) MDMixerGraph *mixer;
And in the implementation
self.mixer = [[MDMixerGraph alloc]init];
[self.mixer setupAUGraph];
And you have reference to the rioUnit to pass to your framework (self.mixer.rioUnit); Without knowing more about your requirements connection/processing this is the best i can do for you.
Cheers!