private void GetMotionVector(MotionField motionField, MacroblockPartition mbPart)
{
#if DEBUG
int dmvx = 0, dmvy = 0;
#endif
if (_arithmeticDecoder.DecodeDecision(40 + motionField.GetCtxIdxInc(_currMbAddr, mbPart, 0)) == 1)
{
uint dx = GetAbsMotionVectorComponent(40); // dx coordinate?
motionField.UpdateComponent(_currMbAddr, mbPart, 0, dx);
#if DEBUG
dmvx = (_arithmeticDecoder.DecodeBypass() == 1) ? -(int)dx : (int)dx; // sign?
#else
_arithmeticDecoder.DecodeBypass(); // sign
#endif
}
if (_arithmeticDecoder.DecodeDecision(47 + motionField.GetCtxIdxInc(_currMbAddr, mbPart, 1)) == 1)
{
uint dy = GetAbsMotionVectorComponent(47); // dy coordinate?
motionField.UpdateComponent(_currMbAddr, mbPart, 1, dy);
#if DEBUG
dmvy = (_arithmeticDecoder.DecodeBypass() == 1) ? -(int)dy : (int)dy; // sign?
#else
_arithmeticDecoder.DecodeBypass(); // sign
#endif
}
#if DEBUG
H264Debug.WriteLine(" dmv={0},{1}", dmvx, dmvy);
#endif
}
// 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));
}
public void UpdateComponent(uint mbAddr, MacroblockPartition mbPart, uint compIdx, uint absValue)
{
var byteValue = (byte)Math.Min(absValue, 127);
foreach (uint subBlkIdx in mbPart.MbPartSubBlks)
{
_motionVectors[mbAddr, subBlkIdx, compIdx] = byteValue;
}
}
