Question

AudioComponentDescription defaultOutputDescription;
defaultOutputDescription.componentType = kAudioUnitType_Output;
defaultOutputDescription.componentSubType = kAudioUnitSubType_RemoteIO;
defaultOutputDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
defaultOutputDescription.componentFlags = 0;
defaultOutputDescription.componentFlagsMask = 0;

// Get the default playback output unit
AudioComponent defaultOutput = AudioComponentFindNext(NULL, &defaultOutputDescription);
NSAssert(defaultOutput, @"Can't find default output");

// Create a new unit based on this that we'll use for output
OSErr err = AudioComponentInstanceNew(defaultOutput, &toneUnit);
NSAssert1(toneUnit, @"Error creating unit: %hd", err);


// Set our tone rendering function on the unit
AURenderCallbackStruct input;
input.inputProc = RenderTone;
input.inputProcRefCon = self;
err = AudioUnitSetProperty(toneUnit, 
    kAudioUnitProperty_SetRenderCallback, 
    kAudioUnitScope_Input,
    0, 
    &input, 
    sizeof(input));

NSAssert1(err == noErr, @"Error setting callback: %hd", err);

// Set the format to 32 bit, single channel, floating point, linear PCM
const int four_bytes_per_float = 4;
const int eight_bits_per_byte = 8;
AudioStreamBasicDescription streamFormat;
streamFormat.mSampleRate = sampleRate;
streamFormat.mFormatID = kAudioFormatLinearPCM;
streamFormat.mFormatFlags =
    kAudioFormatFlagsNativeFloatPacked | kAudioFormatFlagIsNonInterleaved;
streamFormat.mBytesPerPacket = four_bytes_per_float;
streamFormat.mFramesPerPacket = 1;  
streamFormat.mBytesPerFrame = four_bytes_per_float;     
streamFormat.mChannelsPerFrame = 1; 
streamFormat.mBitsPerChannel = four_bytes_per_float * eight_bits_per_byte;

err = AudioUnitSetProperty (toneUnit,
      kAudioUnitProperty_StreamFormat,
      kAudioUnitScope_Input,
      0,
      &streamFormat,
      sizeof(AudioStreamBasicDescription));

现在我正在使用AudioUnit回调函数在不同的频率和振幅下创建声音，现在我希望声音在耳朵之间移动，就像我们使用AVAudioPlayer的pan属性一样。为此，我尝试使用kMultiChannelMixerParam_Pan属性 AudioUnitSetParameter（toneUnit，kMultiChannelMixerParam_Pan，kAudioUnitScope_Output，0，sender.value，0）但它不适合我。

Answer 1

在调音台上设置摇摄值不能吗？ kMultiChannelMixerParam_Pan您还可以添加kAudioUnitType_Panner。

Answer 2

我使用了以下代码。

 AudioUnitSetParameter(<mixerUnit>,
                          kMultiChannelMixerParam_Pan,
                          kAudioUnitScope_Input,
                          0,
                          <panValue>,
                          0);

音频单元类型：kAudioUnitType_Mixer

子类型：kAudioUnitSubType_MultiChannelMixer

Answer 3

我发现在总线0上设置声像直到混音器音频单元初始化后才能工作。在此之前设置总线0上的音量，并且在此之前设置总线1上的音调。我不知道为什么。如果重要的话我在iOS上

如何使用AudioUnit一次只在一只耳朵中播放声音，即一次左右声音

3 个答案: