// 9.3.3.1.1.7 Derivation process of ctxIdxInc for the syntax elements mvd_l0 and mvd_l1
public uint GetCtxIdxInc(uint mbAddr, MacroblockPartition mbPart, uint compIdx)
{
uint absMvdCompA;
if (mbPart.SubMbPartIdxA < 16)
{
absMvdCompA = _motionVectors[mbAddr, mbPart.SubMbPartIdxA, compIdx];
}
else
{
uint mbAddrA = _sliceState.GetMbAddrA(mbAddr);
absMvdCompA = (mbAddrA == uint.MaxValue) ? 0U : _motionVectors[mbAddrA, (mbPart.SubMbPartIdxA & 15), compIdx];
}
uint absMvdCompB;
if (mbPart.SubMbPartIdxB < 16)
{
absMvdCompB = _motionVectors[mbAddr, mbPart.SubMbPartIdxB, compIdx];
}
else
{
uint mbAddrB = _sliceState.GetMbAddrB(mbAddr);
absMvdCompB = (mbAddrB == uint.MaxValue) ? 0U : _motionVectors[mbAddrB, (mbPart.SubMbPartIdxB & 15), compIdx];
}
uint absMvdComp = (absMvdCompA + absMvdCompB);
return((absMvdComp < 3) ? 0U : ((absMvdComp > 32) ? 2U : 1U));
}
/// <summary>
/// Retrieves the TotalCoeff of the subblock left of the provided one (one column left)
/// </summary>
private int GetLeftNumberCoeff(uint mbIndex, uint subBlockIndex)
{
if (!_subBlockPartition.IsLeftMostSubBlock(subBlockIndex))
{
return(_totalCoeffs[mbIndex, _subBlockPartition.GetSubBlockIndexLeft(subBlockIndex)]);
}
uint mbAddrA = _sliceState.GetMbAddrA(mbIndex);
if (mbAddrA == uint.MaxValue)
{
return(TotalCoeffUnavailable); // 'TotalCoeff' information not available!
}
return(_totalCoeffs[mbAddrA, _subBlockPartition.GetSubBlockIndexLeft(subBlockIndex)]);
}
public void Parse()
{
InitializeCabac();
_currMbAddr = _sliceState.FirstMacroBlockInSlice * (MbAffFrameFlag ? 2U : 1U);
MbFieldDecodingFlag = _sliceState.FieldPicFlag; // The default for non-MBAFF frames
bool moreDataFlag = true;
bool prevMbSkipped = false;
while (_readerState.Valid && moreDataFlag)
{
_currMbState = new MacroblockState();
_mbQpDeltaNotZero = 0;
// Load macroblock states for block A (left) and B (top)
_mbStateA = GetMacroblockState(_sliceState.GetMbAddrA(_currMbAddr));
_mbStateB = GetMacroblockState(_sliceState.GetMbAddrB(_currMbAddr));
_mbFlags = new MacroblockFlags(_mbStateA.Flags, _mbStateB.Flags);
bool mbSkipFlag = false;
if (!_sliceState.IntraCoded)
{
mbSkipFlag = GetMbSkipFlag(); // mb_skip_flag
}
if (!mbSkipFlag)
{
_mbFlags.SetCodedBlockFlag();
if (MbAffFrameFlag && (IsFirstMacroblockInPair() || prevMbSkipped))
{
MbFieldDecodingFlag = GetMbFieldDecodingFlag(); // is field macro block
}
MacroBlockLayer();
}
if (MbFieldDecodingFlag && (!MbAffFrameFlag || IsLastMacroblockInPair()))
{
_mbFlags.SetFieldDecodingMode();
}
_currMbState.Flags = _mbFlags.Bits;
_macroblockStates[_currMbAddr] = _currMbState;
_prevMbQpDeltaNotZero = _mbQpDeltaNotZero;
if (!_sliceState.IntraCoded)
{
prevMbSkipped = mbSkipFlag;
}
if (!MbAffFrameFlag || IsLastMacroblockInPair())
{
moreDataFlag = !GetEndOfSliceFlag();
}
if (moreDataFlag)
{
NextMbAddress();
}
}
#if DEBUG
H264Debug.WriteLine(" - Terminated ({4}) at {0} of {1} ({2}), nextBits(16)={3}",
_reader.Position, _reader.Length, _currMbAddr, ToBitString(_reader.ShowBits(16), 16),
_sliceState.SliceType.ToString());
#endif
}