Function ParseIntra4x4Mode

codec/decoder/core/src/decode_slice.cpp:447–523

}

int32_t ParseIntra4x4Mode (PWelsDecoderContext pCtx, PWelsNeighAvail pNeighAvail, int8_t* pIntraPredMode,
                           PBitStringAux pBs,
                           PDqLayer pCurDqLayer) {
  int32_t iSampleAvail[5 * 6] = { 0 }; //initialize as 0
  int32_t iMbXy = pCurDqLayer->iMbXyIndex;
  int32_t iFinalMode, i;

  uint8_t uiNeighAvail = 0;
  uint32_t uiCode;
  int32_t iCode;
  pCtx->pMapNxNNeighToSampleFunc (pNeighAvail, iSampleAvail);
  uiNeighAvail = (iSampleAvail[6] << 2) | (iSampleAvail[0] << 1) | (iSampleAvail[1]);
  for (i = 0; i < 16; i++) {
    int32_t iPrevIntra4x4PredMode = 0;
    if (pCurDqLayer->sLayerInfo.pPps->bEntropyCodingModeFlag) {
      WELS_READ_VERIFY (ParseIntraPredModeLumaCabac (pCtx, iCode));
      iPrevIntra4x4PredMode = iCode;
    } else {
      WELS_READ_VERIFY (BsGetOneBit (pBs, &uiCode));
      iPrevIntra4x4PredMode = uiCode;
    }
    const int32_t kiPredMode = PredIntra4x4Mode (pIntraPredMode, i);

    int8_t iBestMode;
    if (pCurDqLayer->sLayerInfo.pPps->bEntropyCodingModeFlag) {
      if (iPrevIntra4x4PredMode == -1)
        iBestMode = kiPredMode;
      else
        iBestMode = iPrevIntra4x4PredMode + (iPrevIntra4x4PredMode >= kiPredMode);
    } else {
      if (iPrevIntra4x4PredMode) {
        iBestMode = kiPredMode;
      } else {
        WELS_READ_VERIFY (BsGetBits (pBs, 3, &uiCode));
        iBestMode = uiCode + ((int32_t) uiCode >= kiPredMode);
      }
    }

    iFinalMode = CheckIntraNxNPredMode (&iSampleAvail[0], &iBestMode, i, false);
    if (iFinalMode == GENERATE_ERROR_NO (ERR_LEVEL_MB_DATA, ERR_INVALID_INTRA4X4_MODE)) {
      return GENERATE_ERROR_NO (ERR_LEVEL_MB_DATA, ERR_INFO_INVALID_I4x4_PRED_MODE);
    }

    pCurDqLayer->pIntra4x4FinalMode[iMbXy][g_kuiScan4[i]] = iFinalMode;

    pIntraPredMode[g_kuiScan8[i]] = iBestMode;

    iSampleAvail[g_kuiCache30ScanIdx[i]] = 1;
  }
  ST32 (&pCurDqLayer->pIntraPredMode[iMbXy][0], LD32 (&pIntraPredMode[1 + 8 * 4]));
  pCurDqLayer->pIntraPredMode[iMbXy][4] = pIntraPredMode[4 + 8 * 1];
  pCurDqLayer->pIntraPredMode[iMbXy][5] = pIntraPredMode[4 + 8 * 2];
  pCurDqLayer->pIntraPredMode[iMbXy][6] = pIntraPredMode[4 + 8 * 3];

  if (pCtx->pSps->uiChromaFormatIdc == 0)//no need parse chroma
    return ERR_NONE;

  if (pCurDqLayer->sLayerInfo.pPps->bEntropyCodingModeFlag) {