Question

情境：

我正在使用NAudio 1.5，我试图以I，格式PCM，8位，22050hz的IWaveProvider录制Sinus波，如下所示：

Private Sub record(ByVal waveForm As String, _
                   ByVal duration As Integer, _
                   ByVal frequency As Integer, _
                   ByVal amplitude As Integer, _
                   ByVal sampleRate As Integer)
    Dim wave As IWaveProvider = _
          Audio.SoundModulWaveFormProviderFactory.createWaveForm(waveForm, _
                frequency, amplitude, sampleRate)
    Dim memStream As New System.IO.MemoryStream()
    Dim writer As New WaveFileWriter(memStream, wave.WaveFormat)
    Dim numberOfBytes As Integer = writer.WaveFormat.AverageBytesPerSecond
    Dim buffer(numberOfBytes) As Byte
    Dim i As Integer
    Dim count As Integer
    For i = 1 To duration
        count = wave.Read(buffer, 0, numberOfBytes)
        writer.Write(buffer, 0, count)
    Next
    writer.Flush()
    Try
        Me.audioStream = New MemoryStream()
        memStream.WriteTo(Me.audioStream)
    Catch ex As Exception
        Trace.WriteLine(ex.Message)
    End Try
    writer.Close()
    recorded = True
End Sub

然后将内存流移交给正在解析整个wave文件的函数，并将其包含在声音列表中。

问题

上面提到的函数期望波数据的长度从字节位置42到45.不幸的是，它似乎总是为0.因此我不会有任何长度。

问题：

如何确保WaveFileWriter将此信息写入MemoryStream？或者它只在写入文件时才这样做？

也许有不同的方法达到同一目标？

更新

WaveFileWriter在直接写入文件时确实包含波形数据长度。

Answer 1

只有在您调用Close时，WaveFileWriter才会设置长度。所以移动writer.Close在你的Try块之前。此外，NAudio有一个名为IgnoreDisposeStream的辅助类，您可以使用它来防止MemoryStream在您需要之前被丢弃。

Dim writer As New WaveFileWriter(new IgnoreDisposeStream(memStream) ...

...
writer.Close()
Try
    Me.audioStream = New MemoryStream()
    memStream.WriteTo(Me.audioStream)
Catch ex As Exception
    Trace.WriteLine(ex.Message)
End Try

recorded = True

使用带WaveFileWriter的MemoryStream在PCM Wave文件中的数据长度

1 个答案: