将 2 通道以上音频转换为单声道

Question

我正在使用下一个代码将立体声转换为单声道：

using (var waveFileReader = new WaveFileReader(sourceStream))
{
    var outFormat = new WaveFormat(waveFileReader.WaveFormat.SampleRate, 1);
    using (var resampler = new MediaFoundationResampler(waveFileReader, outFormat))
    {
        var stream = new MemoryStream();
        WaveFileWriter.WriteWavFileToStream(stream, resampler);

        var format = WaveFormat.CreateIeeeFloatWaveFormat(waveFileReader.WaveFormat.SampleRate, 1);
        var writer = new LameMP3FileWriter(stream, format, 32);

        writer.Flush();
        byte[] channelBytes = stream.ToArray();
        writer.Dispose();

        File.WriteAllBytes(outputFile, channelBytes);
    }
}

我想知道是否可以将 2 个以上通道（我有 8 个通道音频）音频转换为单声道音频？

更新状态： 好的，看起来我更改了代码，现在它可以将任何通道转换为单声道：

using (var waveFileReader = new WaveFileReader(sourceFile))
{
    var outFormat = new WaveFormat(44100, 1);
    using (var resampler = new MediaFoundationResampler(waveFileReader, outFormat))
    {
        var stream = new MemoryStream();
        WaveFileWriter.WriteWavFileToStream(stream, resampler);

        var format = WaveFormat.CreateIeeeFloatWaveFormat(outFormat.SampleRate, 1);
        var writer = new LameMP3FileWriter(stream, format, 32);

        writer.Flush();
        byte[] channelBytes = stream.ToArray();
        writer.Dispose();

        File.WriteAllBytes(outputFile, channelBytes);
    }
}

但现在的问题是重采样器降低了音量。我该如何修复它？我需要那个音量来保持相同的响度。

Answer 1

好吧，看来我找到了问题的答案：

using (var waveFileReader = new WaveFileReader(sourceFile))
{
    var outFormat = new WaveFormat(44100, 1);
    using (var resampler = new MediaFoundationResampler(waveFileReader, outFormat))
    {
        VolumeWaveProvider16 vol = new VolumeWaveProvider16(resampler)
        {
            Volume = 2f
        };
        var stream = new MemoryStream();
        WaveFileWriter.WriteWavFileToStream(stream, vol);

        var format = WaveFormat.CreateIeeeFloatWaveFormat(outFormat.SampleRate, 1);
        var writer = new LameMP3FileWriter(stream, format, 32);

        writer.Flush();
        byte[] channelBytes = stream.ToArray();
        writer.Dispose();

        File.WriteAllBytes(outputFile, channelBytes);
    }
}