x265源码解析：参考帧管理

x265源码解析：NAL Unit Type
x265源码解析：参考帧管理
x265源码解析：编码结构

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//! 准备rps
void DPB::computeRPS(int curPoc, bool isRAP, RPS * rps, unsigned int maxDecPicBuffer)
{
    unsigned int poci = 0, numNeg = 0, numPos = 0;

    Frame* iterPic = m_picList.first();

    while (iterPic && (poci < maxDecPicBuffer - 1))     ///< iterate decode picture buf
    {
        if ((iterPic->m_poc != curPoc) && iterPic->m_encData->m_bHasReferences)
        {
            if ((m_lastIDR >= curPoc) || (m_lastIDR <= iterPic->m_poc))
            {
                    rps->poc[poci] = iterPic->m_poc;
                    rps->deltaPOC[poci] = rps->poc[poci] - curPoc;          ///< used to construct StBefor StAfter
                    (rps->deltaPOC[poci] < 0) ? numNeg++ : numPos++;
                    rps->bUsed[poci] = !isRAP;                              ///< 参：nal unit type
                    poci++;
            }
        }
        iterPic = iterPic->m_next;
    }

    rps->numberOfPictures = poci;
    rps->numberOfPositivePictures = numPos;
    rps->numberOfNegativePictures = numNeg;

    rps->sortDeltaPOC();
}

//! 构建参考帧列表
void Slice::setRefPicList(PicList& picList)
{
    //! I帧
    if (m_sliceType == I_SLICE)
    {
        memset(m_refFrameList, 0, sizeof(m_refFrameList));
        memset(m_refReconPicList, 0, sizeof(m_refReconPicList));
        memset(m_refPOCList, 0, sizeof(m_refPOCList));
        m_numRefIdx[1] = m_numRefIdx[0] = 0;
        return;
    }

    Frame* refPic = NULL;
    Frame* refPicSetStCurr0[MAX_NUM_REF]; 
    Frame* refPicSetStCurr1[MAX_NUM_REF];
    Frame* refPicSetLtCurr[MAX_NUM_REF];
    int numPocStCurr0 = 0;
    int numPocStCurr1 = 0;
    int numPocLtCurr = 0;
    int i;
    
    //! 构建Ref Short-Term Before
    for (i = 0; i < m_rps.numberOfNegativePictures; i++)
    {
        if (m_rps.bUsed[i])
        {
            refPic = picList.getPOC(m_poc + m_rps.deltaPOC[i]);
            refPicSetStCurr0[numPocStCurr0] = refPic;
            numPocStCurr0++;
        }
    }
    //! 构建Ref Short-Term After
    for (; i < m_rps.numberOfNegativePictures + m_rps.numberOfPositivePictures; i++)
    {
        if (m_rps.bUsed[i])
        {
            refPic = picList.getPOC(m_poc + m_rps.deltaPOC[i]);
            refPicSetStCurr1[numPocStCurr1] = refPic;
            numPocStCurr1++;
        }
    }

    X265_CHECK(m_rps.numberOfPictures == m_rps.numberOfNegativePictures + m_rps.numberOfPositivePictures,
               "unexpected picture in RPS\n");

    // ref_pic_list_init
    Frame* rpsCurrList0[MAX_NUM_REF + 1];       ///< L0
    Frame* rpsCurrList1[MAX_NUM_REF + 1];       ///< L1
    int numPocTotalCurr = numPocStCurr0 + numPocStCurr1 + numPocLtCurr;
	
    //! 构建L0 
    int cIdx = 0;
    for (i = 0; i < numPocStCurr0; i++, cIdx++)
        rpsCurrList0[cIdx] = refPicSetStCurr0[i];

    for (i = 0; i < numPocStCurr1; i++, cIdx++)
        rpsCurrList0[cIdx] = refPicSetStCurr1[i];

    for (i = 0; i < numPocLtCurr; i++, cIdx++)
        rpsCurrList0[cIdx] = refPicSetLtCurr[i];

    X265_CHECK(cIdx == numPocTotalCurr, "RPS index check fail\n");

    //! 构建L1
    if (m_sliceType == B_SLICE)
    {
        cIdx = 0;
        for (i = 0; i < numPocStCurr1; i++, cIdx++)
            rpsCurrList1[cIdx] = refPicSetStCurr1[i];

        for (i = 0; i < numPocStCurr0; i++, cIdx++)
            rpsCurrList1[cIdx] = refPicSetStCurr0[i];

        for (i = 0; i < numPocLtCurr; i++, cIdx++)
            rpsCurrList1[cIdx] = refPicSetLtCurr[i];

        X265_CHECK(cIdx == numPocTotalCurr, "RPS index check fail\n");
    }

    for (int rIdx = 0; rIdx < m_numRefIdx[0]; rIdx++)
    {
        cIdx = rIdx % numPocTotalCurr;
        X265_CHECK(cIdx >= 0 && cIdx < numPocTotalCurr, "RPS index check fail\n");
        m_refFrameList[0][rIdx] = rpsCurrList0[cIdx];
    }

    if (m_sliceType != B_SLICE)
    {
        m_numRefIdx[1] = 0;
        memset(m_refFrameList[1], 0, sizeof(m_refFrameList[1]));
    }
    else
    {
        for (int rIdx = 0; rIdx < m_numRefIdx[1]; rIdx++)
        {
            cIdx = rIdx % numPocTotalCurr;
            X265_CHECK(cIdx >= 0 && cIdx < numPocTotalCurr, "RPS index check fail\n");
            m_refFrameList[1][rIdx] = rpsCurrList1[cIdx];
        }
    }

    //! 构建ref POC list
    for (int dir = 0; dir < 2; dir++)
        for (int numRefIdx = 0; numRefIdx < m_numRefIdx[dir]; numRefIdx++)
            m_refPOCList[dir][numRefIdx] = m_refFrameList[dir][numRefIdx]->m_poc;
}