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我正在編寫一個Mac OS X應用程序，通過帶回聲消除的麥克風捕獲一些音頻。我正在創建一個類型爲VoiceProcessingIO的AudioUnit。我想輸出音頻作爲帶符號整數線性PCM。但是，當我指出我希望輸出採樣格式記錄爲SignedInteger時，我得到一個「不支持的格式」錯誤。配置Mac OS X AudioUnit以提供SignedInteger示例
如何配置AudioUnit以有符號整數格式輸出數據？以下是我現在如何配置它。如果我嘗試kAudioFormatFlagIsSignedInteger更換kAudioFormatFlagIsFloat，然後我得到一個錯誤:(
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
AudioComponent comp = AudioComponentFindNext(NULL, &desc);
OSStatus status = AudioComponentInstanceNew(comp, &_audioUnit);
...
const int sampleSize = 2;
const int eight_bits_per_byte = 8;
AudioStreamBasicDescription streamFormat;
streamFormat.mSampleRate = 16000;
streamFormat.mFormatID = kAudioFormatLinearPCM;
streamFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
streamFormat.mBytesPerPacket = sampleSize;
streamFormat.mFramesPerPacket = 1;
streamFormat.mBytesPerFrame = sampleSize;
streamFormat.mChannelsPerFrame = 1;
streamFormat.mBitsPerChannel = sampleSize * eight_bits_per_byte;
status = AudioUnitSetProperty(_audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &streamFormat, sizeof(streamFormat));
//狀態= UnsupportedFormatError