NAudio WaveIn.DataAvailable 事件：分离通道

Posted 2023-02-25

【中文标题】NAudio WaveIn.DataAvailable 事件：分离通道

【英文标题】：NAudio WaveIn.DataAvailable Event: Separating Channels

【发布时间】：2013-11-18 22:01:03

【问题描述】：

假设一个立体声 WaveIn 的样本通过 WaveIn.DataAvailable (ByVal sender As Object, ByVal e As WaveInEventArgs) 事件被截获。如何从e.Buffer 中提取特定通道（即右/左）的样本？

【参考方案1】：

样本交错存储。因此，如果您正在录制 16 位样本，前两个字节是左声道样本，后两个字节是右声道样本，然后是另一个左声道样本，依此类推。

【参考方案2】：

3 年后回复，以防其他人试图从 WaveIn 读取左右声道。我将Microphone Demo，特别是FormMicrophone.cs 改编为以下内容：

 private void cbDevices_SelectedIndexChanged(object sender, EventArgs e)
    
        wvin?.Dispose();
        wvin = new NAudio.Wave.WaveInEvent();
        wvin.DeviceNumber = cbDevices.SelectedIndex;
        
        //Changed this line to have 2 instead of 1 channel
        wvin.WaveFormat = new NAudio.Wave.WaveFormat(rate: SAMPLE_RATE, bits: 16, channels: 2);
        wvin.DataAvailable += OnDataAvailable;
        wvin.BufferMilliseconds = 20;
        wvin.StartRecording();
    

    double[] lastBuffer;
    double[] lastBufferRight;
    private void OnDataAvailable(object sender, NAudio.Wave.WaveInEventArgs args)
    
        int bytesPerSample = wvin.WaveFormat.BitsPerSample / 8;
        int samplesRecorded = args.BytesRecorded / bytesPerSample;
        if (lastBuffer is null || lastBuffer.Length != samplesRecorded)
        
            lastBuffer = new double[samplesRecorded/2];
            lastBufferRight = new double[samplesRecorded/2];
        

        int indexBuffer = 0;
        for (int indexSample = 0; indexSample < samplesRecorded; indexSample+=2)
        
            lastBuffer[indexBuffer] = BitConverter.ToInt16(args.Buffer, indexSample * bytesPerSample);             
            lastBufferRight[indexBuffer] = BitConverter.ToInt16(args.Buffer, (indexSample+1) * bytesPerSample);
            ++indexBuffer;
        
    

如果你想试试这个tone generator 非常适合检查左右通道上的单个正弦波