/// <summary>
/// Decode DSP-ADPCM data.
/// </summary>
/// <param name="src">DSP-ADPCM source.</param>
/// <param name="dst">Destination array of samples.</param>
/// <param name="cxt">DSP-APCM context.</param>
/// <param name="samples">Number of samples.</param>
public static void Decode(byte[] src, ref Int16[] dst, ref DspAdpcmInfo cxt, UInt32 samples)
{
//Each DSP-APCM frame is 8 bytes long. It contains 1 header byte, and 7 sample bytes.
//Set initial values.
short hist1 = cxt.yn1;
short hist2 = cxt.yn2;
int dstIndex = 0;
int srcIndex = 0;
//Until all samples decoded.
while (dstIndex < samples)
{
//Get the header.
byte header = src[srcIndex++];
//Get scale and co-efficient index.
UInt16 scale = (UInt16)(1 << (header & 0xF));
byte coef_index = (byte)(header >> 4);
short coef1 = cxt.coefs[coef_index][0];
short coef2 = cxt.coefs[coef_index][1];
//7 sample bytes per frame.
for (UInt32 b = 0; b < 7; b++)
{
//Get byte.
byte byt = src[srcIndex++];
//2 samples per byte.
for (UInt32 s = 0; s < 2; s++)
{
sbyte adpcm_nibble = ((s == 0) ? GetHighNibble(byt) : GetLowNibble(byt));
short sample = Clamp16(((adpcm_nibble * scale) << 11) + 1024 + ((coef1 * hist1) + (coef2 * hist2)) >> 11);
hist2 = hist1;
hist1 = sample;
dst[dstIndex++] = sample;
if (dstIndex >= samples)
{
break;
}
}
if (dstIndex >= samples)
{
break;
}
}
}
}
/// <summary>
/// Encodes the samples.
/// </summary>
/// <returns>The samples.</returns>
/// <param name="samples">Samples.</param>
public static byte[] EncodeSamples(short[] samples, out DspAdpcmInfo info, uint loopStart)
{
//Encod data.
short[] coeffs = GcAdpcmCoefficients.CalculateCoefficients(samples);
byte[] dspAdpcm = GcAdpcmEncoder.Encode(samples, coeffs);
info = new DspAdpcmInfo();
info.coefs = new short[8][];
info.coefs[0] = new short[2];
info.coefs[1] = new short[2];
info.coefs[2] = new short[2];
info.coefs[3] = new short[2];
info.coefs[4] = new short[2];
info.coefs[5] = new short[2];
info.coefs[6] = new short[2];
info.coefs[7] = new short[2];
info.coefs[0][0] = coeffs[0];
info.coefs[0][1] = coeffs[1];
info.coefs[1][0] = coeffs[2];
info.coefs[1][1] = coeffs[3];
info.coefs[2][0] = coeffs[4];
info.coefs[2][1] = coeffs[5];
info.coefs[3][0] = coeffs[6];
info.coefs[3][1] = coeffs[7];
info.coefs[4][0] = coeffs[8];
info.coefs[4][1] = coeffs[9];
info.coefs[5][0] = coeffs[10];
info.coefs[5][1] = coeffs[11];
info.coefs[6][0] = coeffs[12];
info.coefs[6][1] = coeffs[13];
info.coefs[7][0] = coeffs[14];
info.coefs[7][1] = coeffs[15];
//Loop stuff.
if (loopStart > 0)
{
info.loop_yn1 = samples[loopStart - 1];
}
if (loopStart > 1)
{
info.loop_yn2 = samples[loopStart - 2];
}
return(dspAdpcm);
}
/// <summary>
/// Read data.
/// </summary>
/// <param name="br">The reader.</param>
public override void ReadData(BinaryDataReader br)
{
//Read data.
WaveFormat = (WaveFormatType)br.ReadUInt16();
NumChannels = br.ReadUInt16();
SampleRate = br.ReadUInt32();
br.ReadUInt32(); //Byte rate.
br.ReadUInt16(); //Block align.
BitsPerSample = br.ReadUInt16();
//Extra parameters.
if (WaveFormat == WaveFormatType.DSPADPCM)
{
//Read extra data.
br.ReadUInt16(); //Extra data.
br.ReadUInt16(); //Padding.
br.ReadUInt16(); //Unknown.
br.ReadUInt16(); //Padding.
DspAdpcmNumSamples = br.ReadUInt32();
//Foreach channel.
ChannelInfo = new List <DspAdpcmInfo>();
for (int i = 0; i < NumChannels; i++)
{
DspAdpcmInfo d = new DspAdpcmInfo();
d.coefs = new short[8][];
for (int j = 0; j < 8; j++)
{
d.coefs[j] = br.ReadInt16s(2);
}
br.ReadUInt16(); //Padding.
d.pred_scale = br.ReadUInt16();
d.yn1 = br.ReadInt16();
d.yn2 = br.ReadInt16();
d.loop_pred_scale = br.ReadUInt16();
d.loop_yn1 = br.ReadInt16();
d.loop_yn2 = br.ReadInt16();
ChannelInfo.Add(d);
}
//Read the last part.
br.ReadUInt16(); //Unknown.
}
}
