/// <summary>
/// Encode audio data.
/// </summary>
/// <returns>Encoded audio data.</returns>
public byte[] Encode()
{
byte[] data = new byte[Data.Length / 2 + (Data.Length % 2 != 0 ? 1 : 0)];
bool secondNibble = false;
int dataPtr = 0;
for (int i = 0; i < Data.Length; i++)
{
int config = GetBestConfig(Index, ConvertFloat(Data[i]) - Sample);
Sample = ImaAdpcmMath.ClampSample(Sample + (ImaAdpcmMath.StepTable[Index] / 8 + ImaAdpcmMath.StepTable[Index] / 4 * (config & 1) + ImaAdpcmMath.StepTable[Index] / 2 * (config >> 1 & 1) + ImaAdpcmMath.StepTable[Index] * (config >> 2 & 1)) * ((config >> 3 & 1) == 1 ? -1 : 1));
Index = ImaAdpcmMath.ClampIndex(this.Index + ImaAdpcmMath.IndexTable[config & 7]);
if (!secondNibble)
{
data[dataPtr] |= (byte)((config & 0xF) << 0);
}
else
{
data[dataPtr] |= (byte)((config & 0xF) << 4);
dataPtr++;
}
secondNibble = !secondNibble;
}
return(data);
}
/// <summary>
/// Get a sample from a nibble.
/// </summary>
/// <param name="nibble">Nibble to decode.</param>
/// <returns>Decoded sample.</returns>
private short GetSample(byte nibble)
{
Sample = ImaAdpcmMath.ClampSample(Sample + (ImaAdpcmMath.StepTable[Index] / 8 + ImaAdpcmMath.StepTable[Index] / 4 * ((int)nibble & 1) + ImaAdpcmMath.StepTable[Index] / 2 * ((int)nibble >> 1 & 1) + ImaAdpcmMath.StepTable[Index] * ((int)nibble >> 2 & 1)) * (((int)nibble >> 3 & 1) == 1 ? -1 : 1));
Index = ImaAdpcmMath.ClampIndex(Index + ImaAdpcmMath.IndexTable[(int)nibble & 7]);
return((short)Sample);
}
