Implemented band SAO reconstruction

src/sao.c

@@ -52,6 +52,28 @@ static const unsigned g_sao_eo_idx_to_eo_category[] = { 1, 2, 0, 3, 4 };
 // Mapping relationships between a, b and c to eo_idx.
 #define EO_IDX(a, b, c) (2 + SIGN3((c) - (a)) + SIGN3((c) - (b)))
 
+
+/**
+ * \brief calculate an array of intensity correlations for each intensity value
+ */
+void calc_sao_offset_array(const sao_info *sao, int *offset)
+{
+  int val;
+  int values = (1<<g_bitdepth);
+  int shift = g_bitdepth-5;
+
+  // Loop through all intensity values and construct an offset array
+  for (val = 0; val < values; val++) {
+    int cur_band = val>>shift;
+    if(cur_band >= sao->band_position && cur_band < sao->band_position+4) {
+      offset[val] = CLIP(0, values-1,val+sao->offsets[cur_band-sao->band_position+1]);
+    } else {
+      offset[val] = val;
+    }
+  }
+}
+
+
 /**
  * \param orig_data  Original pixel data. 64x64 for luma, 32x32 for chroma.
  * \param rec_data  Reconstructed pixel data. 64x64 for luma, 32x32 for chroma.
@@ -73,7 +95,11 @@ int calc_sao_band_offsets(int sao_bands[2][32], int offsets[4], int *band_positi
   // Calculate distortion for each band using N*h^2 - 2*h*E
   for (band = 0; band < 32; band++) {
     best_dist = INT_MAX;
-    offset = sao_bands[1][band]?sao_bands[0][band]/sao_bands[1][band]:0;
+    offset = 0;
+    if (sao_bands[1][band] != 0) {
+      offset = (sao_bands[0][band] + (sao_bands[1][band] >> 1)) / sao_bands[1][band];
+      offset = CLIP(-SAO_ABS_OFFSET_MAX, SAO_ABS_OFFSET_MAX, offset);
+    }
     dist[band] = offset==0?0:INT_MAX;
     temp_offsets[band] = 0;    
     while(offset != 0) {
@@ -168,6 +194,16 @@ void sao_reconstruct_color(const pixel *rec_data, pixel *new_rec_data, const sao
   vector2d b_ofs = g_sao_edge_offsets[sao->eo_class][1];
   // Arrays orig_data and rec_data are quarter size for chroma.
 
+
+  if(sao->type == SAO_TYPE_BAND) {
+    int offsets[1<<BIT_DEPTH];
+    calc_sao_offset_array(sao, offsets);
+    for (y = 0; y < block_height; ++y) {
+      for (x = 0; x < block_width; ++x) {
+        new_rec_data[y * new_stride + x] = offsets[rec_data[y * stride + x]];        
+      }
+    }
+  } else {
     // Don't sample the edge pixels because this function doesn't have access to
     // their neighbours.
     for (y = 0; y < block_height; ++y) {
@@ -185,6 +221,39 @@ void sao_reconstruct_color(const pixel *rec_data, pixel *new_rec_data, const sao
       }
     }
   }
+}
+
+/**
+ * \brief Calculate dimensions of the buffer used by sao reconstruction.
+
+ * \param pic  Picture.
+ * \param sao  Sao parameters.
+ * \param rec  Top-left corner of the LCU
+ */
+void sao_calc_band_block_dims(const picture *pic, color_index color_i, 
+                         const sao_info *sao, vector2d *rec, 
+                         vector2d *block)
+{
+  const int is_chroma = (color_i != COLOR_Y ? 1 : 0);
+  int width = pic->width >> is_chroma;
+  int height = pic->height >> is_chroma;
+  int block_width = LCU_WIDTH >> is_chroma;
+
+
+  // Handle right and bottom, taking care of non-LCU sized CUs.
+  if (rec->y + block_width >= height) {
+    if (rec->y + block_width >= height) {
+      block->y = height - rec->y;
+    }
+  }
+  if (rec->x + block_width >= width) {
+    if (rec->x + block_width > width) {
+      block->x = width - rec->x;
+    }
+  }
+
+  rec->x = 0; rec->y = 0;
+}
 
 /**
  * \brief Calculate dimensions of the buffer used by sao reconstruction.
@@ -217,7 +286,7 @@ void sao_reconstruct_color(const pixel *rec_data, pixel *new_rec_data, const sao
  * \param sao  Sao parameters.
  * \param rec  Top-left corner of the LCU, modified to be top-left corner of 
  */
-void sao_calc_block_dims(const picture *pic, color_index color_i, 
+void sao_calc_edge_block_dims(const picture *pic, color_index color_i, 
                          const sao_info *sao, vector2d *rec, 
                          vector2d *tl, vector2d *br, vector2d *block)
 {
@@ -299,7 +368,14 @@ void sao_reconstruct(picture *pic, const pixel *old_rec,
   ofs.y = y_ctb * lcu_stride;
   block.x = lcu_stride;
   block.y = lcu_stride;
-  sao_calc_block_dims(pic, color_i, sao, &ofs, &tl, &br, &block);
+  if (sao->type == SAO_TYPE_BAND) {    
+    tl.x = 0; tl.y = 0;
+    br.x = 0; br.y = 0;
+    sao_calc_band_block_dims(pic, color_i, sao,&ofs, &block);
+  }
+  else {
+    sao_calc_edge_block_dims(pic, color_i, sao, &ofs, &tl, &br, &block);
+  }
 
   // Data to tmp buffer.
   picture_blit_pixels(&old_lcu_rec[ofs.y * pic_stride + ofs.x],