HEVC函数解析

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getUseAdaptiveQP()函数：在parseConfig()函数中，根据命令读入，由成员变量m_bUseAdaptiveQP保存，默认选项为false

("AdaptiveQP,-aq",  m_bUseAdaptiveQP,   false, "QP adaptation based on a psycho-visual model")

HEVC编码主要包括两个过程：模式选择和写码流，分别对应compress()和encode()。在模式选择时要统计bit信息，写码流时往bin文件中写入码流。这两种情况下都会调用EncEntropyEncoder这个类，而统计bit和写比特操作，是通过类的多态继承来实现的。
首先是两个主要的类：TEncEntropyIf和TEncEntropy，在TEncEntropy.hpp中定义类

/// entropy encoder pure classclass TEncEntropyIf{public:  virtual Void  resetEntropy          (const TComSlice *pSlice)                = 0;  virtual SliceType determineCabacInitIdx (const TComSlice *pSlice)                = 0;  virtual Void  setBitstream          ( TComBitIf* p )  = 0;  virtual Void  resetBits             ()                = 0;  virtual UInt  getNumberOfWrittenBits()                = 0;  virtual Void  codeVPS                 ( const TComVPS* pcVPS )                                      = 0;  virtual Void  codeSPS                 ( const TComSPS* pcSPS )                                      = 0;  virtual Void  codePPS                 ( const TComPPS* pcPPS )                                      = 0;  virtual Void  codeSliceHeader         ( TComSlice* pcSlice )                                  = 0;  virtual Void  codeTilesWPPEntryPoint  ( TComSlice* pSlice )     = 0;  virtual Void  codeTerminatingBit      ( UInt uilsLast )                                       = 0;  virtual Void  codeSliceFinish         ()                                                      = 0;  virtual Void  codeMVPIdx ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList ) = 0;public:  virtual Void codeCUTransquantBypassFlag( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeSkipFlag      ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeMergeFlag     ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeMergeIndex    ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeSplitFlag     ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth ) = 0;  virtual Void codePartSize      ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth ) = 0;  virtual Void codePredMode      ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeIPCMInfo      ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeTransformSubdivFlag( UInt uiSymbol, UInt uiCtx ) = 0;  virtual Void codeQtCbf         ( TComTU &rTu, const ComponentID compID, const Bool lowestLevel ) = 0;  virtual Void codeQtRootCbf     ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeQtCbfZero     ( TComTU &rTu, const ChannelType chType ) = 0;  virtual Void codeQtRootCbfZero ( ) = 0;  virtual Void codeIntraDirLumaAng( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool isMultiplePU ) = 0;  virtual Void codeIntraDirChroma( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeInterDir      ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeRefFrmIdx     ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList )      = 0;  virtual Void codeMvd           ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList )      = 0;  virtual Void codeCrossComponentPrediction( TComTU &rTu, ComponentID compID ) = 0;  virtual Void codeDeltaQP       ( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeChromaQpAdjustment( TComDataCU* pcCU, UInt uiAbsPartIdx ) = 0;  virtual Void codeCoeffNxN      ( TComTU &rTu, TCoeff* pcCoef, const ComponentID compID ) = 0;  virtual Void codeTransformSkipFlags ( TComTU &rTu, ComponentID component ) = 0;  virtual Void codeSAOBlkParam   (SAOBlkParam& saoBlkParam, const BitDepths &bitDepths, Bool* sliceEnabled, Bool leftMergeAvail, Bool aboveMergeAvail, Bool onlyEstMergeInfo = false)    =0;  virtual Void estBit               (estBitsSbacStruct* pcEstBitsSbac, Int width, Int height, ChannelType chType) = 0;  virtual Void codeExplicitRdpcmMode ( TComTU &rTu, const ComponentID compID ) = 0;  virtual ~TEncEntropyIf() {}};

TEncEntropyIf是一个由纯虚函数定义的抽象类，其成员函数被申明为纯虚函数，具体的函数功能实现留待派生类中定义。

/// entropy encoder classclass TEncEntropy{public:  Void    setEntropyCoder           ( TEncEntropyIf* e );  Void    setBitstream              ( TComBitIf* p )          { m_pcEntropyCoderIf->setBitstream(p);  }  Void    resetBits                 ()                        { m_pcEntropyCoderIf->resetBits();      }  UInt    getNumberOfWrittenBits    ()                        { return m_pcEntropyCoderIf->getNumberOfWrittenBits(); }  Void    resetEntropy              (const TComSlice *pSlice) { m_pcEntropyCoderIf->resetEntropy(pSlice);  }  SliceType determineCabacInitIdx   (const TComSlice *pSlice) { return m_pcEntropyCoderIf->determineCabacInitIdx(pSlice); }  Void    encodeSliceHeader         ( TComSlice* pcSlice );  Void    encodeTilesWPPEntryPoint( TComSlice* pSlice );  Void    encodeTerminatingBit      ( UInt uiIsLast );  Void    encodeSliceFinish         ();  TEncEntropyIf*      m_pcEntropyCoderIf;public:  Void encodeVPS               ( const TComVPS* pcVPS);  // SPS  Void encodeSPS               ( const TComSPS* pcSPS );  Void encodePPS               ( const TComPPS* pcPPS );  Void encodeSplitFlag         ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth, Bool bRD = false );  Void encodeCUTransquantBypassFlag( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodeSkipFlag          ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodePUWise       ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void encodeInterDirPU   ( TComDataCU* pcSubCU, UInt uiAbsPartIdx  );  Void encodeRefFrmIdxPU  ( TComDataCU* pcSubCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void encodeMvdPU        ( TComDataCU* pcSubCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void encodeMVPIdxPU     ( TComDataCU* pcSubCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void encodeMergeFlag    ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void encodeMergeIndex   ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodePredMode          ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodePartSize          ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth, Bool bRD = false );  Void encodeIPCMInfo          ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodePredInfo          ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void encodeIntraDirModeLuma  ( TComDataCU* pcCU, UInt absPartIdx, Bool isMultiplePU = false );  Void encodeIntraDirModeChroma( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void encodeTransformSubdivFlag( UInt uiSymbol, UInt uiCtx );  Void encodeQtCbf             ( TComTU &rTu, const ComponentID compID, const Bool lowestLevel );  Void encodeQtCbfZero         ( TComTU &rTu, const ChannelType chType );  Void encodeQtRootCbfZero     ( );  Void encodeQtRootCbf         ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void encodeQP                ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodeChromaQpAdjustment ( TComDataCU* pcCU, UInt uiAbsPartIdx, Bool bRD = false );  Void encodeCrossComponentPrediction( TComTU &rTu, ComponentID compID );private:  Void xEncodeTransform        ( Bool& bCodeDQP, Bool& codeChromaQpAdj, TComTU &rTu );public:  Void encodeCoeff             ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth, Bool& bCodeDQP, Bool& codeChromaQpAdj );  Void encodeCoeffNxN         ( TComTU &rTu, TCoeff* pcCoef, const ComponentID compID );  Void estimateBit             ( estBitsSbacStruct* pcEstBitsSbac, Int width, Int height, ChannelType chType );  Void encodeSAOBlkParam(SAOBlkParam& saoBlkParam, const BitDepths &bitDepths, Bool* sliceEnabled, Bool leftMergeAvail, Bool aboveMergeAvail){m_pcEntropyCoderIf->codeSAOBlkParam(saoBlkParam, bitDepths, sliceEnabled, leftMergeAvail, aboveMergeAvail, false);}  static Int countNonZeroCoeffs( TCoeff* pcCoef, UInt uiSize );};// END CLASS DEFINITION TEncEntropy

TEncEntropy是具体类，也是在代码中经常见到的，常作为GOPEncoder,SliceEncoder等类的成员变量：m_pcEntropyCoder
该类包含唯一的一个成员变量，指向的抽象类的指针：m_pcEntropyCoderIf

TEncEntropyIf*      m_pcEntropyCoderIf;

这个成员变量通过set()函数被赋值

Void TEncEntropy::setEntropyCoder ( TEncEntropyIf* e ){  m_pcEntropyCoderIf = e;}

同时TEncEntropy的其他进行encode函数，也都是由m_pcEntropyCoderIf来实现，例如

Void TEncEntropy::encodeSliceHeader ( TComSlice* pcSlice ){  m_pcEntropyCoderIf->codeSliceHeader( pcSlice );  return;

这样关系一下子就明朗了：首先由派生类的指针或引用作为参数传递给setEntropyCoder函数，这样m_pcEntropyCoderIf成员变代表了不同的派生子类，然后具体的encode任务由不同的派生类来完成，程序对外只有唯一的一个TEncEntropy的函数定义的接口。
那么，继承了TEncEntropyIf的子类有哪些呢？
派生子类TEncCavlc

/// CAVLC encoder classclass TEncCavlc : public SyntaxElementWriter, public TEncEntropyIf{public:  TEncCavlc();  virtual ~TEncCavlc();protected:  Void codeShortTermRefPicSet              ( const TComReferencePictureSet* pcRPS, Bool calledFromSliceHeader, Int idx );  Bool findMatchingLTRP ( TComSlice* pcSlice, UInt *ltrpsIndex, Int ltrpPOC, Bool usedFlag );public:  Void  resetEntropy          (const TComSlice *pSlice);  SliceType determineCabacInitIdx  (const TComSlice* /*pSlice*/) { assert(0); return I_SLICE; };  Void  setBitstream          ( TComBitIf* p )  { m_pcBitIf = p;  }  Void  resetBits             ()                { m_pcBitIf->resetBits(); }  UInt  getNumberOfWrittenBits()                { return  m_pcBitIf->getNumberOfWrittenBits();  }  Void  codeVPS                 ( const TComVPS* pcVPS );  Void  codeVUI                 ( const TComVUI *pcVUI, const TComSPS* pcSPS );  Void  codeSPS                 ( const TComSPS* pcSPS );  Void  codePPS                 ( const TComPPS* pcPPS );  Void  codeSliceHeader         ( TComSlice* pcSlice );  Void  codePTL                 ( const TComPTL* pcPTL, Bool profilePresentFlag, Int maxNumSubLayersMinus1);  Void  codeProfileTier         ( const ProfileTierLevel* ptl, const Bool bIsSubLayer );  Void  codeHrdParameters       ( const TComHRD *hrd, Bool commonInfPresentFlag, UInt maxNumSubLayersMinus1 );  Void  codeTilesWPPEntryPoint( TComSlice* pSlice );  Void  codeTerminatingBit      ( UInt uilsLast );  Void  codeSliceFinish         ();  Void codeMVPIdx ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void codeSAOBlkParam(SAOBlkParam& /*saoBlkParam*/, const BitDepths& /*bitDepths*/, Bool* /*sliceEnabled*/, Bool /*leftMergeAvail*/, Bool /*aboveMergeAvail*/, Bool /*onlyEstMergeInfo*/ = false){printf("only supported in CABAC"); assert(0); exit(-1);}  Void codeCUTransquantBypassFlag( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeSkipFlag      ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeMergeFlag     ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeMergeIndex    ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeAlfCtrlFlag   ( ComponentID /*component*/, UInt /*code*/ ) {printf("Not supported\n"); assert(0);}  Void codeInterModeFlag( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth, UInt uiEncMode );  Void codeSplitFlag     ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth );  Void codePartSize      ( TComDataCU* pcCU, UInt uiAbsPartIdx, UInt uiDepth );  Void codePredMode      ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeIPCMInfo      ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeTransformSubdivFlag( UInt uiSymbol, UInt uiCtx );  Void codeQtCbf         ( TComTU &rTu, const ComponentID compID, const Bool lowestLevel );  Void codeQtRootCbf     ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeQtCbfZero     ( TComTU &rTu, const ChannelType chType );  Void codeQtRootCbfZero ( );  Void codeIntraDirLumaAng( TComDataCU* pcCU, UInt absPartIdx, Bool isMultiple);  Void codeIntraDirChroma( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeInterDir      ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeRefFrmIdx     ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void codeMvd           ( TComDataCU* pcCU, UInt uiAbsPartIdx, RefPicList eRefList );  Void codeCrossComponentPrediction( TComTU &rTu, ComponentID compID );  Void codeDeltaQP       ( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeChromaQpAdjustment( TComDataCU* pcCU, UInt uiAbsPartIdx );  Void codeCoeffNxN      ( TComTU &rTu, TCoeff* pcCoef, const ComponentID compID );  Void codeTransformSkipFlags ( TComTU &rTu, ComponentID component );  Void estBit            ( estBitsSbacStruct* pcEstBitsSbac, Int width, Int height, ChannelType chType );  Void xCodePredWeightTable          ( TComSlice* pcSlice );  Void codeScalingList  ( const TComScalingList &scalingList );  Void xCodeScalingList ( const TComScalingList* scalingList, UInt sizeId, UInt listId);  Void codeExplicitRdpcmMode( TComTU &rTu, const ComponentID compID );};

TEncCavlc是写码流的子类，同时还多继承了父类syntaxElementWritter。TEncCavlc执行code()操作的基本单元，都是调用父类syntaxElementWriter的下面几个函数

#define WRITE_CODE( value, length, name)     xWriteCode ( value, length )#define WRITE_UVLC( value,         name)     xWriteUvlc ( value )#define WRITE_SVLC( value,         name)     xWriteSvlc ( value )#define WRITE_FLAG( value,         name)     xWriteFlag ( value )

class SyntaxElementWriter{protected:  TComBitIf*    m_pcBitIf;  SyntaxElementWriter()  :m_pcBitIf(NULL)  {};  virtual ~SyntaxElementWriter() {};  Void  setBitstream          ( TComBitIf* p )  { m_pcBitIf = p;  }  Void  xWriteCode            ( UInt uiCode, UInt uiLength );  Void  xWriteUvlc            ( UInt uiCode );  Void  xWriteSvlc            ( Int  iCode   );  Void  xWriteFlag            ( UInt uiCode );#if ENC_DEC_TRACE  Void  xWriteCodeTr          ( UInt value, UInt  length, const TChar *pSymbolName);  Void  xWriteUvlcTr          ( UInt value,               const TChar *pSymbolName);  Void  xWriteSvlcTr          ( Int  value,               const TChar *pSymbolName);  Void  xWriteFlagTr          ( UInt value,               const TChar *pSymbolName);#endif  Void xWriteRbspTrailingBits();  UInt  xConvertToUInt        ( Int iValue ) {  return ( iValue <= 0) ? -iValue<<1 : (iValue<<1)-1; }};

Void SyntaxElementWriter::xWriteCode     ( UInt uiCode, UInt uiLength ){  assert ( uiLength > 0 );  m_pcBitIf->write( uiCode, uiLength );}

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