x265中checkIntra()分析(版本2.8)

 一. 函数调用关系图：

 二.函数具体实现流程：

三.  源码注释分析： 

/*
 =======Analysed by :      yangxin
 =======Date:              2018.9
 =======Function:          checkIntra(),实现full RD search of intra modes
 =======参数：             intraMode：存放帧内模式数据;cuGeom：CU的几何结构;partSize：运动分区,帧内只有2Nx2N和NxN
*/
void Search::checkIntra(Mode& intraMode, const CUGeom& cuGeom, PartSize partSize)
{
    CUData& cu = intraMode.cu;

    cu.setPartSizeSubParts(partSize);//--设置运动分区的子块位置
    cu.setPredModeSubParts(MODE_INTRA);//--设置预测模式子块为为帧内模式

    uint32_t tuDepthRange[2];
    cu.getIntraTUQtDepthRange(tuDepthRange, 0);//--TU的深度范围确定

    intraMode.initCosts();//--初始化cost

	//***==== a=a+b,亮度失真，遍历所有角度模式，RDO search of luma intra modes; result is fully encoded luma. luma distortion is returned
    intraMode.lumaDistortion += estIntraPredQT(intraMode, cuGeom, tuDepthRange);
    if (m_csp != X265_CSP_I400)//--不是4:0:0的颜色空间
    {
        intraMode.chromaDistortion += estIntraPredChromaQT(intraMode, cuGeom);//--色度失真
        intraMode.distortion += intraMode.lumaDistortion + intraMode.chromaDistortion;//--总失真=亮度失真+色度失真
    }
    else//--4:0:0
        intraMode.distortion += intraMode.lumaDistortion;//--

    cu.m_distortion[0] = intraMode.distortion;

	/*=======熵编码部分==============================*/
    m_entropyCoder.resetBits();//--熵编码复位清理
    if (m_slice->m_pps->bTransquantBypassEnabled)
        m_entropyCoder.codeCUTransquantBypassFlag(cu.m_tqBypass[0]);

    int skipFlagBits = 0;
    if (!m_slice->isIntra())
    {
        m_entropyCoder.codeSkipFlag(cu, 0);
        skipFlagBits = m_entropyCoder.getNumberOfWrittenBits();
        m_entropyCoder.codePredMode(cu.m_predMode[0]);
    }

    m_entropyCoder.codePartSize(cu, 0, cuGeom.depth);//--编码运动分区
    m_entropyCoder.codePredInfo(cu, 0);//--encode intra prediction mode.
    intraMode.mvBits = m_entropyCoder.getNumberOfWrittenBits() - skipFlagBits;

    bool bCodeDQP = m_slice->m_pps->bUseDQP;
    m_entropyCoder.codeCoeff(cu, 0, bCodeDQP, tuDepthRange);
    m_entropyCoder.store(intraMode.contexts);
    intraMode.totalBits = m_entropyCoder.getNumberOfWrittenBits(); //--总bit
    intraMode.coeffBits = intraMode.totalBits - intraMode.mvBits - skipFlagBits; //--DCT系数bit
    const Yuv* fencYuv = intraMode.fencYuv;

    if (m_rdCost.m_psyRd)//--心理视觉上的rd
		 //==return the difference in energy between the source block and the recon block
        intraMode.psyEnergy = m_rdCost.psyCost(cuGeom.log2CUSize - 2, fencYuv->m_buf[0], fencYuv->m_size, intraMode.reconYuv.m_buf[0], intraMode.reconYuv.m_size);
    else if(m_rdCost.m_ssimRd)//--客观rd
		//==原与重建的失真计算,Calculate dc and ac normalization factor
        intraMode.ssimEnergy = m_quant.ssimDistortion(cu, fencYuv->m_buf[0], fencYuv->m_size, intraMode.reconYuv.m_buf[0], intraMode.reconYuv.m_size, cuGeom.log2CUSize, TEXT_LUMA, 0);

	 //==Sum of Square Error (pixel, pixel) fenc alignment not assumed 平方误差之和
    intraMode.resEnergy = primitives.cu[cuGeom.log2CUSize - 2].sse_pp(intraMode.fencYuv->m_buf[0], intraMode.fencYuv->m_size, intraMode.predYuv.m_buf[0], intraMode.predYuv.m_size);

    updateModeCost(intraMode);//--更新模式cost值
    checkDQP(intraMode, cuGeom);//---update CBF flags and QP values to be internally consistent 
}