private IMacroblockType GetMacroBlockType()
{
//Table 7-10,7-11,..
switch (_sliceState.SliceType)
{
case SliceType.I:
uint mbTypeI = _reader.GetExpGolombCoded(25);
return(MacroblockType.GetMbTypeI(mbTypeI));
case SliceType.Si:
uint mbTypeSi = _reader.GetExpGolombCoded(26);
return(MacroblockType.GetMbTypeSi(mbTypeSi));
case SliceType.P:
case SliceType.Sp:
uint mbTypeP = _reader.GetExpGolombCoded(30);
return(MacroblockType.GetMbTypeP(mbTypeP));
case SliceType.B:
uint mbTypeB = _reader.GetExpGolombCoded(48);
return(MacroblockType.GetMbTypeB(mbTypeB));
}
throw new InvalidOperationException("Current type not set");
}
private IMacroblockType GetMbTypeB()
{
const uint ctxOffsetPrefix = 27;
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + _mbFlags.GetMbTypeCtxIdxInc()) == 0)
{
return(MacroblockType.GetMbTypeB(0));
}
_mbFlags.SetMbTypeNotZero();
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 3) == 0)
{
return(MacroblockType.GetMbTypeB(1U + _arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5)));
}
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 4) == 0)
{
return(MacroblockType.GetMbTypeB(3U + GetFixedLength((ctxOffsetPrefix + 5), 3)));
}
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5) == 0)
{
return(MacroblockType.GetMbTypeB(12U + GetFixedLength((ctxOffsetPrefix + 5), 3)));
}
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5) == 1)
{
return(MacroblockType.GetMbTypeB(11U + (11U * _arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5))));
}
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5) == 0)
{
return(MacroblockType.GetMbTypeB(20U + _arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 5)));
}
const uint ctxOffsetSuffix = 32;
if (_arithmeticDecoder.DecodeDecision(ctxOffsetSuffix) == 0)
{
return(MacroblockType.GetMbTypeI(0));
}
return(GetMbTypeIntra(ctxOffsetSuffix, MbTypeIntraCtxIdxIncInterSlice));
}