[LMCS] Import LMCS chroma functions from VTM13.0

src/encoder_state-bitstream.c

@@ -1124,7 +1124,7 @@ static void kvz_encoder_state_write_bitstream_picture_header(
 
       if (encoder->chroma_format != KVZ_CSP_400)
       {
-        WRITE_U(stream, 0, 1, "ph_chroma_residual_scale_flag"); // ToDo: LMCS Enable chroma scaling
+        WRITE_U(stream, state->tile->frame->lmcs_aps->m_sliceReshapeInfo.enableChromaAdj, 1, "ph_chroma_residual_scale_flag");
       }
     }
   }

src/reshape.c

@@ -1363,12 +1363,11 @@ static void code_lmcs_aps(encoder_state_t* const state, lmcs_aps* aps)
       WRITE_U(stream, signCW, 1, "lmcs_delta_sign_cw_flag[ i ]");
     }
   }
-  // ToDo: LMCS Chroma scaling
-  /*  
-  int deltaCRS = aps->chromaPresentFlag ? aps->m_sliceReshapeInfo.chrResScalingOffset : 0;
+  
+  int deltaCRS = state->encoder_control->chroma_format != KVZ_CSP_400 ? aps->m_sliceReshapeInfo.chrResScalingOffset : 0;
   int signCRS = (deltaCRS < 0) ? 1 : 0;
   int absCRS = (deltaCRS < 0) ? (-deltaCRS) : deltaCRS;
-  if (pcAPS->chromaPresentFlag)
+  if (state->encoder_control->chroma_format != KVZ_CSP_400)
   {
     WRITE_U(stream, absCRS, 3, "lmcs_delta_abs_crs");
   }
@@ -1376,7 +1375,6 @@ static void code_lmcs_aps(encoder_state_t* const state, lmcs_aps* aps)
   {
     WRITE_U(stream, signCRS, 1, "lmcs_delta_sign_crs_flag");
   }  
-  */
 }
 
 
@@ -1396,7 +1394,7 @@ void kvz_encode_lmcs_adaptive_parameter_set(encoder_state_t* const state)
 
    WRITE_U(stream, (int)1/*LMCS_APS*/, 3, "aps_params_type");
    WRITE_U(stream, 0, 5, "adaptation_parameter_set_id");
-   WRITE_U(stream, 0/*state->encoder_control->chroma_format != KVZ_CSP_400*/, 1, "aps_chroma_present_flag");
+   WRITE_U(stream, state->encoder_control->chroma_format != KVZ_CSP_400, 1, "aps_chroma_present_flag");
 
    code_lmcs_aps(state, state->tile->frame->lmcs_aps);
 
@@ -1405,3 +1403,115 @@ void kvz_encode_lmcs_adaptive_parameter_set(encoder_state_t* const state)
     
   }
 }
+
+
+/** find inx of PWL for inverse mapping
+* \param average luma pred of TU
+* \return idx of PWL for inverse mapping
+* From VTM 13.0
+*/
+static int getPWLIdxInv(lmcs_aps* aps, int lumaVal)
+{
+  int idxS = 0;
+  for (idxS = aps->m_sliceReshapeInfo.reshaperModelMinBinIdx; (idxS <= aps->m_sliceReshapeInfo.reshaperModelMaxBinIdx); idxS++)
+  {
+    if (lumaVal < aps->m_reshapePivot[idxS + 1])     break;
+  }
+  return MIN(idxS, PIC_CODE_CW_BINS - 1);
+}
+
+/** compute chroma residuce scale for TU
+* \param average luma pred of TU
+* \return chroma residue scale
+* From VTM 13.0
+*/
+static int calculate_lmcs_chroma_adj(lmcs_aps* aps, kvz_pixel avgLuma)
+{
+  int iAdj = aps->m_chromaAdjHelpLUT[getPWLIdxInv(aps, avgLuma)];
+  return iAdj;
+}
+
+/** compute chroma residuce scale for TU
+* \param average luma pred of TU
+* \return chroma residue scale
+* From VTM 13.0
+*/
+int kvz_calculate_lmcs_chroma_adj_vpdu_nei(encoder_state_t* const state, lmcs_aps* aps, int x, int y, cu_info_t* cur_cu, lcu_t* lcu)
+{
+  int xPos = x;
+  int yPos = y;
+
+  int x_local = SUB_SCU(x);
+  int y_local = SUB_SCU(y);
+
+  int ctuSize = LCU_WIDTH;
+  int numNeighbor = MIN(64, ctuSize);
+  int numNeighborLog = kvz_math_floor_log2(numNeighbor);
+
+  xPos = xPos / 64 * 64;
+  yPos = yPos / 64 * 64;
+  
+  assert(LCU_WIDTH >= 64);
+  /*
+  // ToDo: Optimize the calculations by storing already calculated results
+  if (isVPDUprocessed(xPos, yPos))
+  {
+    return getChromaScale();
+  }
+  else*/
+  {
+    //setVPDULoc(xPos, yPos);
+    
+    // ToDo: Handle dualtree
+
+    bool left_cu = (x > 0);
+    bool above_cu = (y > 0);
+    
+   
+    int strideY = state->tile->frame->rec_lmcs->stride;
+    int chromaScale = (1 << CSCALE_FP_PREC);
+    int lumaValue = -1;
+
+    kvz_pixel* recSrc0 = &state->tile->frame->rec_lmcs->y[x+y*strideY];
+
+    const uint32_t picH = state->tile->frame->height;
+    const uint32_t picW = state->tile->frame->width;
+    const kvz_pixel valueDC = 1 << (KVZ_BIT_DEPTH - 1);
+    int32_t recLuma = 0;
+    int pelnum = 0;
+    if (left_cu)
+    {
+      for (int i = 0; i < numNeighbor; i++)
+      {
+        int k = (yPos + i) >= picH ? (picH - yPos - 1) : i;
+        recLuma += recSrc0[-1 + k * strideY];
+        pelnum++;
+      }
+    }
+    if (above_cu)
+    {
+      for (int i = 0; i < numNeighbor; i++)
+      {
+        int k = (xPos + i) >= picW ? (picW - xPos - 1) : i;
+        recLuma += recSrc0[-strideY + k];
+        pelnum++;
+      }
+    }
+    if (pelnum == numNeighbor)
+    {
+      lumaValue = (recLuma + (1 << (numNeighborLog - 1))) >> numNeighborLog;
+    }
+    else if (pelnum == (numNeighbor << 1))
+    {
+      lumaValue = (recLuma + (1 << numNeighborLog)) >> (numNeighborLog + 1);
+    }
+    else
+    {
+      assert(pelnum == 0);
+      lumaValue = valueDC;
+    }
+    chromaScale = calculate_lmcs_chroma_adj(aps,lumaValue);    
+    aps->m_chromaScale = chromaScale;
+    return chromaScale;
+  }
+}