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 GetMbTypeI()
{
const uint ctxOffset = 3;
if (_arithmeticDecoder.DecodeDecision(ctxOffset + _mbFlags.GetMbTypeCtxIdxInc()) == 0)
{
return(MacroblockType.GetMbTypeI(0));
}
_mbFlags.SetMbTypeNotZero();
return(GetMbTypeIntra(ctxOffset, MbTypeIntraCtxIdxIncIntraSlice));
}
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));
}
private IMacroblockType GetMbTypeIntra(uint ctxOffset, uint[] binIdxCtxIdxInc)
{
if (_arithmeticDecoder.DecodeTerminate() == 1)
{
return(MacroblockType.GetMbTypeI(25)); // I_PCM
}
// First decision determines 'CodedBlockPatternLuma' (0 for '0', 1 for '15')
uint mbType = (12U * _arithmeticDecoder.DecodeDecision(ctxOffset + binIdxCtxIdxInc[2]));
// Next 1-2 bits determine 'CodedBlockPatternChroma' (0, 1 or 2)
if (_arithmeticDecoder.DecodeDecision(ctxOffset + binIdxCtxIdxInc[3]) == 1)
{
mbType += (1 + (uint)_arithmeticDecoder.DecodeDecision(ctxOffset + binIdxCtxIdxInc[4])) << 2;
}
// Final 2 bits determine the 'intra_chroma_pred_mode'
mbType |= (uint)_arithmeticDecoder.DecodeDecision(ctxOffset + binIdxCtxIdxInc[5]) << 1;
mbType |= _arithmeticDecoder.DecodeDecision(ctxOffset + binIdxCtxIdxInc[6]);
return(MacroblockType.GetMbTypeI(mbType + 1));
}
private IMacroblockType GetMbTypeP()
{
// Note: The 'MbTypeNotZero' flag is not used in P-slices!
// Table 9-37 – Binarization for macroblock types in P, SP, and B slices
const uint ctxOffsetPrefix = 14;
if (_arithmeticDecoder.DecodeDecision(ctxOffsetPrefix) == 0)
{
// 9.3.3.1.2 Assignment process of ctxIdxInc using prior decoded bin values
uint b1 = _arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + 1);
uint b2 = _arithmeticDecoder.DecodeDecision(ctxOffsetPrefix + (b1 + 2));
return(MacroblockType.GetMbTypeP((b1 << 1) ^ (3 * b2)));
}
const uint ctxOffsetSuffix = 17;
if (_arithmeticDecoder.DecodeDecision(ctxOffsetSuffix) == 0)
{
return(MacroblockType.GetMbTypeI(0));
}
return(GetMbTypeIntra(ctxOffsetSuffix, MbTypeIntraCtxIdxIncInterSlice));
}
protected YuvFrameBuffer outputFrameBuffer; // encoded frame
#endregion Fields
#region Constructors
protected AbstractEncodingMode(Macroblock macroblock, MacroblockType mbType)
{
this.macroblock = macroblock;
this.mbType = mbType;
}
