音频队列录制错误：AudioQueueNew中的AudioConverterNew返回“FMT？”

Question

aqData = AQRecorderState()
    aqData.mDataFormat.mFormatID             = kAudioFormatMPEG4AAC
    aqData.mDataFormat.mSampleRate           = 16000.0
    aqData.mDataFormat.mChannelsPerFrame     = 1
    aqData.mDataFormat.mBitsPerChannel       = 16
    aqData.mDataFormat.mBytesPerPacket       = aqData.mDataFormat.mChannelsPerFrame * UInt32(sizeof(UInt16))
    aqData.mDataFormat.mBytesPerFrame        = aqData.mDataFormat.mChannelsPerFrame * UInt32(sizeof(UInt16))
    aqData.mDataFormat.mFramesPerPacket      = 1
    aqData.mDataFormat.mFormatFlags          = kLinearPCMFormatFlagIsFloat | kLinearPCMFormatFlagIsBigEndian
    aqData.mQueue                            = AudioQueueRef()
    fileType                                 = kAudioFileM4AType

    // create new input for audio queue
    AudioQueueNewInput(&aqData.mDataFormat, handleInputBuffer, &aqData, nil, kCFRunLoopCommonModes, 0, &aqData.mQueue)
    var dataFormatSize:UInt32 = UInt32(sizeof(aqData.mDataFormat.dynamicType))
    AudioQueueGetProperty(aqData.mQueue, kAudioQueueProperty_StreamDescription, &aqData.mDataFormat, &dataFormatSize)

    // create file to store audio
    let data = recordUrl.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
    let audioFileURL: CFURLRef = CFURLCreateFromFileSystemRepresentation(nil, UnsafePointer(data.bytes), data.length, false)
    AudioFileCreateWithURL(audioFileURL, fileType, &aqData.mDataFormat, AudioFileFlags.EraseFile, &aqData.mAudioFile)

    // set magic cookie for file if needed
    setMegicCookieForFile(aqData.mQueue, inFile: aqData.mAudioFile)

    // derive buffer size
    deriveBufferSize(aqData.mQueue, ASBDescription: &aqData.mDataFormat, seconds: kBufferLengthInSecond, outbufferSize: &aqData.bufferByteSize)

    // allocate and enqueue each buffer
    for i in 0..<Record.kNumberBuffers {
        AudioQueueAllocateBuffer(aqData.mQueue, aqData.bufferByteSize, &aqData.mBuffers[i])
        AudioQueueEnqueueBuffer(aqData.mQueue, aqData.mBuffers[i], 0, nil)
    }

代码在行处产生错误

AudioQueueNewInput(&aqData.mDataFormat, handleInputBuffer, &aqData, nil, kCFRunLoopCommonModes, 0, &aqData.mQueue)

而错误消息是

AudioConverterNew from AudioQueueNew returned 'fmt?'

IO：1 ch,44100 Hz,Float32客户机：1 ch,44100 Hz,“AAC”(0x00000003)16位/通道，2字节/包，1帧/包，2字节/帧

我尝试过不同的音频格式设置，但似乎没有一个修复这个错误。有人能帮忙吗？

Answer 1

从CoreAudioTypes.h头文件中，我们收集到以下内容：

kAudioFormatMPEG4AAC MPEG-4低复杂度AAC音频对象，没有标志。

aqData.mDataFormat.mBitsPerChannel       = 0
aqData.mDataFormat.mBytesPerPacket       = 0
aqData.mDataFormat.mBytesPerFrame        = 0
aqData.mDataFormat.mFramesPerPacket      = 1024
aqData.mDataFormat.mFormatFlags          = 0