UmaViewer/Assets/Scripts/Audio/WAV.cs

public class WAV
{

    // convert two bytes to one float in the range -1 to 1
    static float bytesToFloat(byte firstByte, byte secondByte)
    {
        // convert two bytes to one short (little endian)
        short s = (short)((secondByte << 8) | firstByte);
        // convert to range from -1 to (just below) 1
        return s / 32768.0F;
    }

    static int bytesToInt(byte[] bytes, int offset = 0)
    {
        int value = 0;
        for (int i = 0; i < 4; i++)
        {
            value |= ((int)bytes[offset + i]) << (i * 8);
        }
        return value;
    }
    // properties
    public float[] LeftChannel { get; internal set; }
    public float[] RightChannel { get; internal set; }
    public float[] StereoChannel { get; internal set; }
    public int ChannelCount { get; internal set; }
    public int SampleCount { get; internal set; }
    public int Frequency { get; internal set; }

    public WAV(byte[] wav)
    {

        // Determine if mono or stereo
        ChannelCount = wav[22];     // Forget byte 23 as 99.999% of WAVs are 1 or 2 channels

        // Get the frequency
        Frequency = bytesToInt(wav, 24);

        // Get past all the other sub chunks to get to the data subchunk:
        int pos = 12;   // First Subchunk ID from 12 to 16

        // Keep iterating until we find the data chunk (i.e. 64 61 74 61 ...... (i.e. 100 97 116 97 in decimal))
        while (!(wav[pos] == 100 && wav[pos + 1] == 97 && wav[pos + 2] == 116 && wav[pos + 3] == 97))
        {
            pos += 4;
            int chunkSize = wav[pos] + wav[pos + 1] * 256 + wav[pos + 2] * 65536 + wav[pos + 3] * 16777216;
            pos += 4 + chunkSize;
        }
        pos += 8;

        // Pos is now positioned to start of actual sound data.
        SampleCount = (wav.Length - pos) / 2;     // 2 bytes per sample (16 bit sound mono)
        if (ChannelCount == 2) SampleCount /= 2;        // 4 bytes per sample (16 bit stereo)

        // Allocate memory (right will be null if only mono sound)
        LeftChannel = new float[SampleCount];
        if (ChannelCount == 2) RightChannel = new float[SampleCount];
        else RightChannel = null;

        // Write to double array/s:
        int i = 0;
        while (pos < wav.Length)
        {
            LeftChannel[i] = bytesToFloat(wav[pos], wav[pos + 1]);
            pos += 2;
            if (ChannelCount == 2)
            {
                RightChannel[i] = bytesToFloat(wav[pos], wav[pos + 1]);
                pos += 2;
            }
            i++;
        }

        //Merge left and right channels for stereo sound
        if (ChannelCount == 2)
        {
            StereoChannel = new float[SampleCount * 2];
            //Current position in our left and right channels
            int channelPos = 0;
            //After we've changed two values for our Stereochannel, we want to increase our channelPos
            short posChange = 0;

            for (int index = 0; index < (SampleCount * 2); index++)
            {

                if (index % 2 == 0)
                {
                    StereoChannel[index] = LeftChannel[channelPos];
                    posChange++;
                }
                else
                {
                    StereoChannel[index] = RightChannel[channelPos];
                    posChange++;
                }
                //Two values have been changed, so update our channelPos
                if (posChange % 2 == 0)
                {
                    if (channelPos < SampleCount)
                    {
                        channelPos++;
                        //Reset the counter for next iterations
                        posChange = 0;
                    }
                }
            }
        }
        else
        {
            StereoChannel = null;
        }
    }

    public override string ToString()
    {
        return string.Format("[WAV: LeftChannel={0}, RightChannel={1}, ChannelCount={2}, SampleCount={3}, Frequency={4}]", LeftChannel, RightChannel, ChannelCount, SampleCount, Frequency);
    }
}