为多个通道编写wav标头

Question

在wave file standard用Kinect录制音频数据之后，我编写了一个WriteWavHeader()方法，该方法适用于1个通道（PCM，采样率：16 kHz，位/样本：16）。问题是，当我尝试以立体声（nChannels = 2）录制时，似乎轨道的速度加倍！我有什么想法吗？

static void WriteWavHeader(Stream stream, int dataLength)
{
    using (var memStream = new MemoryStream(64))
    {
        int cbFormat = 16; //sizeof(WAVEFORMATEX)
        WAVEFORMATEX format = new WAVEFORMATEX()
        {
            //Subchunk1Size ==  16 for PCM.
            wFormatTag = 1,

            //NumChannels  :    Mono = 1, Stereo = 2, etc.
            nChannels = 2,

            //SampleRate       8000, 44100
            nSamplesPerSec = 16000,

            //ByteRate         == SampleRate * NumChannels * BitsPerSample/8
            nAvgBytesPerSec = 32000*2,

            //BlockAlign       == NumChannels * BitsPerSample/8
            nBlockAlign = 2*2,

            //BitsPerSample    8 bits = 8, 16 bits = 16, etc.
            wBitsPerSample = 16
        };

        using (var binarywriter = new BinaryWriter(memStream))
        {
            //RIFF header
            WriteString(memStream, "RIFF");
            binarywriter.Write(dataLength+8 + cbFormat+8 + 4); 
            WriteString(memStream, "WAVE");
            WriteString(memStream, "fmt ");
            binarywriter.Write(cbFormat);

            //WAVEFORMATEX
            binarywriter.Write(format.wFormatTag);
            binarywriter.Write(format.nChannels);
            binarywriter.Write(format.nSamplesPerSec);
            binarywriter.Write(format.nAvgBytesPerSec);
            binarywriter.Write(format.nBlockAlign);
            binarywriter.Write(format.wBitsPerSample);

            //data header
            WriteString(memStream, "data");

            binarywriter.Write(dataLength);
            memStream.WriteTo(stream);
        }
    }
}

录音方法：

public void RecordAudio()
{
    //Subchunk2Size    == NumSamples * NumChannels * BitsPerSample/8
    int recordingLength = 5 *16000* 2 *2;
    byte[] buffer = new byte[1024];

    using (FileStream _fileStream = new FileStream("c:\\kinectAudio.wav", FileMode.Create))
    {
        WriteWavHeader(_fileStream, recordingLength);
        int count, totalCount = 0;
        //Start capturing audio                               
        using (Stream audioStream = this.sensor.AudioSource.Start())
        {

            while ((count = audioStream.Read(buffer, 0, buffer.Length)) > 0 && totalCount < recordingLength)
            {
                _fileStream.Write(buffer, 0, count);
                totalCount += count;
            }
        }
         //write the real wav header
        long prePosition = _fileStream.Position;
        _fileStream.Seek(0, SeekOrigin.Begin);
        WriteWavHeader(_fileStream, totalCount);
        _fileStream.Seek(prePosition, SeekOrigin.Begin);
        _fileStream.Flush();         
    }
}