c# - Convert short[] to Stream which can be played as Audio

Question

so what I have is a short[] array which represents the raw data of a WAV file. This means it doesn't include any header or footer information which is usually included. In order to play this audio, I need to convert it to a stream of some sort, unfortunately the data in this short[] array is Int16 and many of the values exceed 255, therefore cannot be converted to bytes and cannot be converted to a stream. Does anyone have any idea how I would be able to play this audio data?

Answer 1

You can convert the short array back to a byte array:

short[] sampleData = ...
byte[] byteArray = new byte[sampleData.Length*2];
Buffer.BlockCopy(sampleData , 0, byteArray, 0, byteArray.Length);

Then you can create a wave stream using the WaveMemoryStream class below - for that you will need to know the wave format of your sample data. This stream can then i.e be saved as a WAV file or played back by SoundPlayer.

public class WaveMemoryStream : Stream
{
    public override bool CanSeek { get { return false; } }
    public override bool CanWrite { get { return false; } }
    public override bool CanRead { get { return true; } }
    public override long Length { get { return _waveStream.Length; } }
    public override long Position { get { return _waveStream.Position; } set { _waveStream.Position = value; } }

    private MemoryStream _waveStream;

    public WaveMemoryStream(byte[] sampleData, int audioSampleRate, ushort audioBitsPerSample, ushort audioChannels)
    {
        _waveStream = new MemoryStream();
        WriteHeader(_waveStream, sampleData.Length, audioSampleRate, audioBitsPerSample, audioChannels);
        WriteSamples(_waveStream, sampleData);
        _waveStream.Position = 0;
    }

    public void WriteHeader(Stream stream, int length, int audioSampleRate, ushort audioBitsPerSample, ushort audioChannels)
    {
        BinaryWriter bw = new BinaryWriter(stream);

        bw.Write(new char[4] { 'R', 'I', 'F', 'F' });
        int fileSize = 36 + length;
        bw.Write(fileSize);
        bw.Write(new char[8] { 'W', 'A', 'V', 'E', 'f', 'm', 't', ' ' });
        bw.Write((int)16);
        bw.Write((short)1);
        bw.Write((short)audioChannels);
        bw.Write(audioSampleRate);
        bw.Write((int)(audioSampleRate * ((audioBitsPerSample * audioChannels) / 8)));
        bw.Write((short)((audioBitsPerSample * audioChannels) / 8));
        bw.Write((short)audioBitsPerSample);

        bw.Write(new char[4] { 'd', 'a', 't', 'a' });
        bw.Write(length);
    }

    public void WriteSamples(Stream stream, byte[] sampleData)
    {
        BinaryWriter bw = new BinaryWriter(stream);
        bw.Write(sampleData, 0, sampleData.Length);
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        return _waveStream.Read(buffer, offset, count);
    }

    public virtual void WriteTo(Stream stream)
    {
        int bytesRead = 0;
        byte[] buffer = new byte[8192];

        do
        {
            bytesRead = Read(buffer, 0, buffer.Length);
            stream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0);

        stream.Flush();
    }

    public override void Flush()
    {
        _waveStream.Flush();
    }

    public override long Seek(long offset, SeekOrigin origin)
    {
        return _waveStream.Seek(offset, origin);
    }

    public override void SetLength(long value)
    {
        throw new NotImplementedException();
    }
    public override void Write(byte[] buffer, int offset, int count)
    {
        throw new NotImplementedException();
    }
}