private void ResidualBlockCavlc(int startIdx, int endIdx, int maxNumCoeff, CoeffToken coeffToken)
{
int suffixLength = ((coeffToken.TotalCoeff > 10) && (coeffToken.TrailingOnes < 3)) ? 1 : 0;
#if DEBUG
H264Debug.Write(" - levels=");
if (coeffToken.TrailingOnes > 0)
{
uint signs = _reader.GetBits(coeffToken.TrailingOnes); // (n) x trailing_ones_sign_flag
for (int i = 0; i < coeffToken.TrailingOnes; i++)
{
H264Debug.Write((((signs & (1 << (coeffToken.TrailingOnes - 1 - i))) == 0) ? "1," : "-1,"));
}
}
#else
_reader.GetBits(coeffToken.TrailingOnes); // (n) x trailing_ones_sign_flag
#endif
for (int i = coeffToken.TrailingOnes; i < coeffToken.TotalCoeff; i++)
{
int levelCode = GetCoefficientLevelCode(suffixLength);
// The first non-zero coefficient after 'trailing ones' must be larger than 1,
// unless the maximum count of trailing ones, i.e. 3, was reached.
// This will further reduce the amount of bits required to represent a
// coefficient level.
if ((i == coeffToken.TrailingOnes) && (i /*trailing ones*/ < 3))
{
levelCode += 2; // 2 instead of 1, because the lowest bit is the sign bit!
}
#if DEBUG
H264Debug.Write("{0},", ((levelCode % 2) == 0) ? ((levelCode + 2) >> 1) : ((-levelCode - 1) >> 1));
#endif
// Automatically adjust the suffix length if high coefficients levels are
// encountered, to reduce the number of bits required to represent subsequent
// high coefficient levels.
if (suffixLength == 0)
{
suffixLength = 1;
}
if (suffixLength < 6)
{
int absLevelMinusOne = (levelCode >> 1);
if (absLevelMinusOne >= (3 << (suffixLength - 1)))
{
suffixLength++;
}
}
}
#if DEBUG
H264Debug.WriteLine();
#endif
if (coeffToken.TotalCoeff < (endIdx - startIdx + 1))
{
int zerosLeft = GetTotalZeros(coeffToken.TotalCoeff, maxNumCoeff); // total_zeros
#if DEBUG
H264Debug.WriteLine(" - total_zeros={0}", zerosLeft);
H264Debug.WriteLine("ShowBits(32) = {0:x8} at {1:x8}", _reader.ShowBits(32), _reader.Position);
H264Debug.Write(" - run_before=");
#endif
for (int i = 0; i < (coeffToken.TotalCoeff - 1) && (zerosLeft > 0); i++)
{
#if DEBUG
int runBefore = _reader.GetVlc(RunBeforeTable[Math.Min(zerosLeft, 7)]);
zerosLeft -= runBefore; // run_before
H264Debug.Write("{0},", runBefore);
#else
zerosLeft -= _reader.GetVlc(RunBeforeTable[Math.Min(zerosLeft, 7)]); // run_before
#endif
}
#if DEBUG
H264Debug.WriteLine();
#endif
}
}
