混合器AudioUnit到RemoteIO AudioUnit

Question

我有一个具有相应回调功能的AudioUnit，但是现在我需要将它发送到一个RemoteIO，因为我正在实现一些需要RemoteIO AudioUnit才能工作的框架。

THen...我需要相同的输出，我得到了这个音频混频器，但与另一个声音类型的kAudioUnitSubType_RemoteIO。

求你了救命！

编辑..。这就是我正在尝试的密码..。编辑2- iOUnitDescription添加

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

我真的需要更多的信息。从上面，我看到您有一个混合器，一个guitarBus，它可能是您的输入(似乎是一个流)。什么是定义&iOUnitDescription。更重要的是，您在哪里连接您的renderCallback，您在回调中做什么，以及框架期望的是什么？

通常，当我需要处理音频时，我构建了我自己的图形；为了更好的移植性，我把它变成了自己的类。这对你来说应该是个好的起点

以下是我如何实现这样一个解决方案。

 // 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));

}

在您的视图控制器扩展，您只是简单；

  // define the MDMixerGraph Class
  // @property (nonatomic) MDMixerGraph *mixer;

以及在实施中

  self.mixer = [[MDMixerGraph alloc]init];
 [self.mixer setupAUGraph];

您可以引用rioUnit传递给您的框架(self.mixer.rioUnit)；在不了解更多需求、连接/处理的情况下，这是我能为您做的最好的事情。

干杯!