private void GetCodedBlockPattern()
{
_codedBlockPattern = new CodedBlockPattern(_mbStateA.CodedBlockPattern, _mbStateB.CodedBlockPattern);
for (uint binIdx = 0; binIdx < 4; binIdx++)
{
uint ctxIdx = 73 + (_codedBlockPattern.GetCtxIdxInc(binIdx) ^ 3);
if (_arithmeticDecoder.DecodeDecision(ctxIdx) == 1)
{
_codedBlockPattern.SetCodedBlockPatternBit(binIdx);
}
}
if (_sequenceState.IsChromaSubsampling)
{
uint ctxIdxBinIdx4 = 77 + _codedBlockPattern.GetCtxIdxInc(4);
if (_arithmeticDecoder.DecodeDecision(ctxIdxBinIdx4) == 1)
{
uint ctxIdxBinIdx5 = 77 + (4 + _codedBlockPattern.GetCtxIdxInc(5));
_codedBlockPattern.SetCodedBlockPatternBit(4U + _arithmeticDecoder.DecodeDecision(ctxIdxBinIdx5));
}
}
}
private void MacroBlockLayer()
{
IMacroblockType macroBlockType = GetMacroblockType();
#if DEBUG
H264Debug.WriteLine("{0}: mb_type={1}", CurrentMbIndex, macroBlockType);
#endif
if (macroBlockType.IsIPcm)
{
_reader.GetPcmSamples();
InitializeCabac();
_currMbState = MacroblockState.Pcm;
}
else
{
bool transform8X8ModeFlagSet = false;
if (macroBlockType.NumMbPart == 4)
{
// Note: Only inter-coded blocks can have mb parts, in particular,
// we are not currently decoding an intra-coded block!
SubMacroBlockPrediction();
if (HasSubMbPartSizeLessThan8X8())
{
transform8X8ModeFlagSet = true; // Transform 8x8 mode is not possible!
}
}
else
{
if (_pictureState.Transform8X8ModeFlag && macroBlockType.IsI_NxN)
{
GetTransformSize8X8Flag();
transform8X8ModeFlagSet = true;
}
MacroBlockPrediction(macroBlockType);
}
if (macroBlockType.IsIntra16X16)
{
_codedBlockPattern = new CodedBlockPattern(macroBlockType.CodedBlockPattern);
}
else
{
GetCodedBlockPattern();
if (_pictureState.Transform8X8ModeFlag && !transform8X8ModeFlagSet &&
_codedBlockPattern.IsLumaResidualPresent &&
(!macroBlockType.IsDirect || _sequenceState.Direct8X8InferenceFlag))
{
GetTransformSize8X8Flag();
}
}
_currMbState.CodedBlockPattern = _codedBlockPattern.Bits;
if (_codedBlockPattern.IsResidualPresent || macroBlockType.IsIntra16X16)
{
GetMbQpDelta(); // mb_qp_delta
Residual(macroBlockType, 0, 15);
}
}
}
