audio - CSCore-将立体声转换为环绕声

我必须解码立体声mp4文件并将L和R通道映射到5.1 or 7.1 surround。另外，我必须提供一种特定的输出格式:16bit pcm 44.1kHz。
将音频源转换为44100Hz 16bit没问题。唯一的问题是通道混合。
我有以下代码:

const string filename = @"stereo.mp3";
IWaveSource waveSource = CodecFactory.Instance.GetCodec(filename)
    .AppendSource(x => new CSCore.Streams.CachedSoundSource(x))
    .ChangeSampleRate(44100) //44.1kHz
    .ToSampleSource()
    .ToWaveSource(16); //16bit

此处的官方项目页面:http://cscore.codeplex.com/告诉我可以进行 channel 混合。我找到了CSCore.DSP.ChannelMatrix类，但是很难弄清楚如何使用它。
也许有人可以帮助我？

最佳答案

完全正确，您必须使用CSCore.DSP.ChannelMatrix类。
我为您创建了一个小示例并添加了一些评论。应该几乎可以自我解释:

static void Main(string[] args)
{
    const string filename = @"stereo.mp3";

    /*
     * First of all you need a channel matrix that fits your needs.
     * There are many ways to get one...:
     */

    //Simply use one of the predefined...
    ChannelMatrix channelMatrix = ChannelMatrix.StereoToSevenDotOneSurround;

    //or

    //use some kind of factory to get one
    channelMatrix = ChannelMatrix.GetMatrix(
        ChannelMasks.StereoMask,
        ChannelMasks.SevenDotOneMask);

    //or

    //or create your own one (the matrix below equals the two above but of course you can use custom values)
    //the rows represent your input channels (the stereo signal) and the columns your output channels.
    //specify with a value from 0-1 how much percentage of the L (row index 0) or the R (row index 1) channel
    //you want to apply to the specific column (the columns are getting mapped to the output channel mask
    // -> the SevenDotOneMask ordered by the values of the certain flags inside of the channel mask).
    channelMatrix = new ChannelMatrix(
        ChannelMasks.StereoMask,
        ChannelMasks.SevenDotOneMask);
    channelMatrix.SetMatrix(
        new[,]
        {
            {0.222f, 0f, 0.157f, 0.022f, 0.189f, 0.116f, 0.203f, 0.090f},
            {0f, 0.222f, 0.157f, 0.022f, 0.116f, 0.189f, 0.090f, 0.203f}
        });

    IWaveSource waveSource = CodecFactory.Instance.GetCodec(filename)
        .AppendSource(x => new CSCore.Streams.CachedSoundSource(x))
        .ChangeSampleRate(44100) //44.1kHz
        .AppendSource(x => new DmoChannelResampler(x, channelMatrix)) //append a channelresampler with the channelmatrix
        .ToSampleSource()
        .ToWaveSource(16); //16bit

    ...
}

我强烈建议您使用预定义的 channel 矩阵。
当然，如果需要一些自定义值，请像上面的示例一样定义自己的值。

顺便说一句。您还可以实时更改 channel 矩阵:
只需对channelMatrix进行更改，然后调用CommitChannelMatrixChanges(当然，您必须存储DmoChannelResampler实例->使用out parameter方法的AppendSource进行此操作)。

关于audio - CSCore-将立体声转换为环绕声，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/30742321/