处理NAudio中mp3内存流的WaveFormat设置

Question

I'm trying to set up the WaveStream so that it uses the same format as the mp3 data passed in. I get the format by reading a frame, but when I try to actually create the new conversion stream using the new format I get an "AcmNotPossible calling AcmStreamOpen" exception.

Here's where I'm trying to set the new format:

Mp3Frame f = Mp3Frame.LoadFromStream(ms);
WaveFormat targetFormat = new Mp3WaveFormat(f.SampleRate, f.ChannelMode == ChannelMode.Mono ? 1 : 2, f.FrameLength, f.BitRate);
WaveFormatConversionStream conversionStream;
try
{
    using (WaveStream blockAlignedStream =
        new BlockAlignReductionStream(conversionStream = new WaveFormatConversionStream(targetFormat,
                new Mp3FileReader(ms))))
    {
        using (WaveOut waveOut = new WaveOut(WaveCallbackInfo.FunctionCallback()))
        {
            waveOut.Init(blockAlignedStream);
            waveOut.Play();

I'm not sure if I even need to convert anything if I set up the wave stream to match the format of the mp3 data.

NOTE: I tried using WaveFormatStream.CreatePcmStream but I was getting 'static/white noise' for some mp3's. They appeared to be 16bit 44,100 stereo, but were being labeled as Version 1, Layer 1, as opposed to version 1, layer 3 which plays back correctly.

Answer 1

This code sample seems to have come from a long time back. You don;t need the BlockAlignReductionStream or the WaveFormatConversionStream , and you should stay away from function callbacks in WaveOut . This should be sufficient to play from a memory stream:

var reader = new Mp3FileReader(ms)
var waveOut = new WaveOutEvent();
waveOut.Init(reader);
waveOut.Play();