core-audio - 能够在模拟器上播放立体声类型音频，但不能在使用示例 RemoteIO/AudioUnit 应用程序的设备上播放

Question

在这个示例应用程序中，我能够加载立体声数据文件并使用模拟器播放它。但它在设备上不起作用。我尝试使用声音编辑器并将立体声剪辑转换为单声道并更改描述符设置，它只适用于单声道。我很难找出原因，我猜这与我的描述符配置问题有关。

此示例应用程序位于https://github.com/peter7777usa/TestAudio

播放功能

static OSStatus playbackCallback(void *inRefCon,
                                 AudioUnitRenderActionFlags *ioActionFlags,
                                 const AudioTimeStamp *inTimeStamp,
                                 UInt32 inBusNumber,
                                 UInt32 inNumberFrames,
                                 AudioBufferList *ioData) {
    // Notes: ioData contains buffers (may be more than one!)
    // Fill them up as much as you can. Remember to set the size value in each buffer to match how
    // much data is in the buffer.
    NSLog(@"muffers %d", ioData->mNumberBuffers);
    UInt32 size = 2048;
    if (iosAudio->incomingCircularBuffer.fillCount>size){
        NSLog(@"Playing %d", iosAudio->incomingCircularBuffer.fillCount);
        iosAudio.pkgtotal -=2;
        int32_t availableBytes;
        SInt16 *databuffer = TPCircularBufferTail(&iosAudio->incomingCircularBuffer, &availableBytes);
        memcpy(ioData->mBuffers[0].mData, databuffer, size);
        ioData->mBuffers[0].mDataByteSize = size; // indicate how much data we wrote in the buffer
        TPCircularBufferConsume(&iosAudio->incomingCircularBuffer, size);
    }else{
    }

    return noErr;
}

音频流描述

// Describe format
AudioStreamBasicDescription audioFormat;
bzero(&audioFormat, sizeof(AudioStreamBasicDescription));
UInt32 channelCount = 2;
UInt32 sampleSize = sizeof(UInt16);
audioFormat.mSampleRate         = 44100.00;
audioFormat.mFormatID           = kAudioFormatLinearPCM;
audioFormat.mFormatFlags        = kAudioFormatFlagsCanonical;;
audioFormat.mFramesPerPacket    = 1;
audioFormat.mChannelsPerFrame   = channelCount;
audioFormat.mBitsPerChannel     = sampleSize * 8;
audioFormat.mBytesPerPacket     = sampleSize * channelCount;
audioFormat.mBytesPerFrame      = sampleSize * channelCount;

// Apply format
status = AudioUnitSetProperty(audioUnit,
                              kAudioUnitProperty_StreamFormat,
                              kAudioUnitScope_Output,
                              kInputBus,
                              &audioFormat,
                              sizeof(audioFormat));