How can I save a music network stream to a mp3 file?

Question

How can I save a stream (arriving as byte[] samples and encoded as PCM) to an mp3 file using NAudio? I've already heard about the new Naudio Lame encoder, but didn't really understand it.

I've already searched through the web but didn't really find something helpful.

What I have right now to play the stream:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using NAudio;

namespace PLAYER
{
    class NAudioPlayer : Player
    {
        NAudio.Wave.BufferedWaveProvider buf;
        NAudio.Wave.IWavePlayer player;
        int times = 0;

        public int EnqueueSamples(int channels, int rate, byte[] samples, int frames)
        {
            if (buf == null)
            {
                buf = new NAudio.Wave.BufferedWaveProvider(new   NAudio.Wave.WaveFormat(rate, channels));
                NAudio.Wave.WaveOut dso = new NAudio.Wave.WaveOut();
                dso.Init(buffer);
                dso.Play();
                player = dso;
            }
            int space = buf.BufferLength - buf.BufferedBytes;
            if (space > samples.Length)
            {
                if (times == 0)
                times = (times + 1) % 100;
                buf.AddSamples(samples, 0, samples.Length);
                return frames;
            }
            return 0;
        }
        public void Reset()
        {
            if (buffer != null) buffer.ClearBuffer();
        }
}

Do you may help me and provide me a code snippet? Or just tell me where I can find useful snippet?

Answer 1

You can use LameMP3FileWriter from NAudio.Lame to do the encoding by treating it as a Stream and writing samples to it.

Here's an off-the-cuff example:

    LameMP3FileWriter mp3writer = null;
    WaveFormat mp3format = null;

    public void StartMP3Encoding(string filename, WaveFormat format)
    {
        if (mp3writer != null)
            StopMP3Encoding();

        mp3format = format;
        mp3writer = new LameMP3FileWriter(filename, format, 128);
    }

    public void StopMP3Encoding()
    {
        if (mp3writer != null)
        {
            mp3writer.Dispose();
            mp3writer = null;
        }
    }

    public int EnqueueSamples(int channels, int rate, byte[] samples, int frames)
    {
        if (mp3writer != null && mp3format.Channels == channels)
            mp3writer.Write(samples, 0, samples.Length);

        return frames;
    }

When you want to start recording the MP3 file call StartMP3Encoding with the file name to record to and the format of the data. When done, call StopMP3Encoding to close the encoder. In between, write your incoming samples as and when they arrive.

The LAME encoder isn't time-precious so you can dribble data to it as slow as you like or blast it with data as quickly as it will take it.

There are a few limitations in the combinations of input sample rate and output bitrate imposed by the LAME encoder, but it handles a fair variations on standard values.