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我試圖設置一個高通濾波器，但AUGraphStart給我-10863，當我嘗試。我根本找不到多少文件。這裏是我設置過濾器的意圖：爲CoreAudio設置效果音頻單元
- (void)initializeAUGraph{
AUNode outputNode;
AUNode mixerNode;
AUNode effectNode;
NewAUGraph(&mGraph);
// Create AudioComponentDescriptions for the AUs we want in the graph
// mixer component
AudioComponentDescription mixer_desc;
mixer_desc.componentType = kAudioUnitType_Mixer;
mixer_desc.componentSubType = kAudioUnitSubType_AU3DMixerEmbedded;
mixer_desc.componentFlags = 0;
mixer_desc.componentFlagsMask = 0;
mixer_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// output component
AudioComponentDescription output_desc;
output_desc.componentType = kAudioUnitType_Output;
output_desc.componentSubType = kAudioUnitSubType_RemoteIO;
output_desc.componentFlags = 0;
output_desc.componentFlagsMask = 0;
output_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
//effect component
AudioComponentDescription effect_desc;
effect_desc.componentType = kAudioUnitType_Effect;
effect_desc.componentSubType = kAudioUnitSubType_HighPassFilter;
effect_desc.componentFlags = 0;
effect_desc.componentFlagsMask = 0;
effect_desc.componentManufacturer = kAudioUnitManufacturer_Apple;
// Add nodes to the graph to hold our AudioUnits
AUGraphAddNode(mGraph, &output_desc, &outputNode);
AUGraphAddNode(mGraph, &mixer_desc, &mixerNode);
AUGraphAddNode(mGraph, &effect_desc, &effectNode);
// Connect the nodes
AUGraphConnectNodeInput(mGraph, mixerNode, 0, effectNode, 0);
AUGraphConnectNodeInput(mGraph, effectNode, 0, outputNode, 0);
//Open Graph
AUGraphOpen(mGraph);
// Get a link to the mixer AU
AUGraphNodeInfo(mGraph, mixerNode, NULL, &mMixer);
// Get a link to the effect AU
AUGraphNodeInfo(mGraph, effectNode, NULL, &mEffect);
//Setup buses
size_t numbuses = track_count;
UInt32 size = sizeof(numbuses);
AudioUnitSetProperty(mMixer, kAudioUnitProperty_ElementCount, kAudioUnitScope_Input, 0, &numbuses, size);
//Setup Stream Format Data
AudioStreamBasicDescription desc;
size = sizeof(desc);
// Setup Stream Format
desc.mSampleRate = kGraphSampleRate;
desc.mFormatID = kAudioFormatLinearPCM;
desc.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
desc.mBitsPerChannel = sizeof(AudioSampleType) * 8; // AudioSampleType == 16 bit signed ints
desc.mChannelsPerFrame = 1;
desc.mFramesPerPacket = 1;
desc.mBytesPerFrame = sizeof(AudioSampleType);
desc.mBytesPerPacket = desc.mBytesPerFrame;
// Loop through and setup a callback for each source you want to send to the mixer.
for (int i = 0; i < numbuses; ++i) {
// Setup render callback struct
AURenderCallbackStruct renderCallbackStruct;
renderCallbackStruct.inputProc = &renderInput;
renderCallbackStruct.inputProcRefCon = self;
// Connect the callback to the mixer input channel
AUGraphSetNodeInputCallback(mGraph, mixerNode, i, &renderCallbackStruct);
// Apply Stream Data
AudioUnitSetProperty(mMixer, kAudioUnitProperty_StreamFormat,kAudioUnitScope_Input,i,&desc,size);
AudioUnitSetParameter(mMixer, k3DMixerParam_Distance, kAudioUnitScope_Input, i, rand() % 6, 0);
rotation[i] = rand() % 360;
rotation_speed[i] = rand() % 5;
AudioUnitSetParameter(mMixer, k3DMixerParam_Azimuth, kAudioUnitScope_Input, i, rotation[i], 0);
AudioUnitSetParameter(mMixer, k3DMixerParam_Elevation, kAudioUnitScope_Input, i, 30, 0);
}
// Reset stream fromat data to 0
memset (&desc, 0, sizeof (desc));
// Setup output stream format
desc.mSampleRate = kGraphSampleRate;
// Apply Stream Data to Output
AudioUnitSetProperty(mEffect,kAudioUnitProperty_StreamFormat,kAudioUnitScope_Input,0,&desc,size);
AudioUnitSetProperty(mEffect,kAudioUnitProperty_StreamFormat,kAudioUnitScope_Output,0,&desc,size);
AudioUnitSetProperty(mMixer,kAudioUnitProperty_StreamFormat,kAudioUnitScope_Output,0,&desc,size);
//All done so initialise
AUGraphInitialize(mGraph);
}
它可以工作，當我刪除高通濾波器。我如何獲得過濾器的工作？
謝謝。
PS：3D立面應該什麼都不做？
我已經得到了這個10863錯誤之前。「kAudioUnitErr_CannotDoInCurrentContext」http://developer.apple.com/library/mac/#documentation/AudioUnit/Reference/AUComponentServicesReference/Reference/reference.html。我還沒有找到詳細的解釋，但 – dubbeat