private sbyte DecodeSign(ContextVector contextVector, int x, int y)
{
contextVector.GetSignCodingContextLabelAndXorBit(out int contextLabel, out int xorBit);
var cx = GetContext(contextLabel);
var d = EntropyCoder.DecodeNextBit(cx);
var signBit = d ^ xorBit;
var sign = (sbyte)((signBit == 0) ? 1 : -1);
UpdateNeighbourContextVectors(x, y, sign);
return(sign);
}
private void RunSignificancePassOnCoefficient(int x, int y, bool includeZeroContext)
{
var coefficient = CoefficientArray[GetCoefficientIndex(x, y)];
if (coefficient.Sign == 0)
{
var contextLabel = coefficient.ContextVector.GetSignificanceCodingContextLabel(CodeBlock.Subband.SubbandType);
if ((contextLabel != 0) || includeZeroContext)
{
var cx = GetContext(contextLabel);
if (EntropyCoder.DecodeNextBit(cx) == 1)
{
var sign = DecodeSign(coefficient.ContextVector, x, y);
coefficient.ApplySignificance(sign, CurrentCodingPass.BitPlane);
}
else
{
coefficient.ApplySignificance(0, CurrentCodingPass.BitPlane);
}
}
}
}
