Entropy context related cleanups.

Adding set_skip_context() function used from both encoder and decoder.

Change-Id: Ia22cfad3211a00a63eb294f64f857b78f4aa9b85

vp9/common/vp9_alloccommon.c

@@ -145,11 +145,8 @@ int vp9_alloc_frame_buffers(VP9_COMMON *oci, int width, int height) {
 
   // 2 contexts per 'mi unit', so that we have one context per 4x4 txfm
   // block where mi unit size is 8x8.
-# if CONFIG_ALPHA
-  oci->above_context[0] = vpx_calloc(sizeof(ENTROPY_CONTEXT) * 8 * mi_cols, 1);
-#else
-  oci->above_context[0] = vpx_calloc(sizeof(ENTROPY_CONTEXT) * 6 * mi_cols, 1);
-#endif
+  oci->above_context[0] = vpx_calloc(sizeof(ENTROPY_CONTEXT) * MAX_MB_PLANE *
+                                         (2 * mi_cols), 1);
   if (!oci->above_context[0])
     goto fail;
 

vp9/common/vp9_entropy.h

@@ -156,17 +156,16 @@ extern DECLARE_ALIGNED(16, int16_t,
 void vp9_coef_tree_initialize(void);
 void vp9_adapt_coef_probs(struct VP9Common *);
 
-static INLINE void vp9_reset_sb_tokens_context(MACROBLOCKD* const xd,
-                                               BLOCK_SIZE_TYPE bsize) {
-  /* Clear entropy contexts */
+static INLINE void reset_skip_context(MACROBLOCKD *xd, BLOCK_SIZE_TYPE bsize) {
   const int bw = 1 << b_width_log2(bsize);
   const int bh = 1 << b_height_log2(bsize);
   int i;
   for (i = 0; i < MAX_MB_PLANE; i++) {
-    vpx_memset(xd->plane[i].above_context, 0,
-               sizeof(ENTROPY_CONTEXT) * bw >> xd->plane[i].subsampling_x);
-    vpx_memset(xd->plane[i].left_context, 0,
-               sizeof(ENTROPY_CONTEXT) * bh >> xd->plane[i].subsampling_y);
+    struct macroblockd_plane *const pd = &xd->plane[i];
+    vpx_memset(pd->above_context, 0,
+               sizeof(ENTROPY_CONTEXT) * (bw >> pd->subsampling_x));
+    vpx_memset(pd->left_context, 0,
+               sizeof(ENTROPY_CONTEXT) * (bh >> pd->subsampling_y));
   }
 }
 

vp9/common/vp9_onyxc_int.h

@@ -236,6 +236,18 @@ static int mi_cols_aligned_to_sb(int n_mis) {
   return ALIGN_POWER_OF_TWO(n_mis, LOG2_MI_BLOCK_SIZE);
 }
 
+static INLINE void set_skip_context(VP9_COMMON *cm, MACROBLOCKD *xd,
+                                    int mi_row, int mi_col) {
+  const int above_idx = mi_col * 2;
+  const int left_idx = (mi_row * 2) & 15;
+  int i;
+  for (i = 0; i < MAX_MB_PLANE; i++) {
+    struct macroblockd_plane *const pd = &xd->plane[i];
+    pd->above_context = cm->above_context[i] + (above_idx >> pd->subsampling_x);
+    pd->left_context = cm->left_context[i] + (left_idx >> pd->subsampling_y);
+  }
+}
+
 static INLINE void set_partition_seg_context(VP9_COMMON *cm, MACROBLOCKD *xd,
                                              int mi_row, int mi_col) {
   xd->above_seg_context = cm->above_seg_context + mi_col;

vp9/decoder/vp9_decodframe.c

@@ -167,7 +167,7 @@ static int decode_tokens(VP9D_COMP *pbi, BLOCK_SIZE_TYPE bsize, vp9_reader *r) {
   MACROBLOCKD *const xd = &pbi->mb;
 
   if (xd->mode_info_context->mbmi.mb_skip_coeff) {
-    vp9_reset_sb_tokens_context(xd, bsize);
+      reset_skip_context(xd, bsize);
     return -1;
   } else {
     if (xd->seg.enabled)
@@ -185,7 +185,6 @@ static void set_offsets(VP9D_COMP *pbi, BLOCK_SIZE_TYPE bsize,
   const int bh = 1 << mi_height_log2(bsize);
   const int bw = 1 << mi_width_log2(bsize);
   const int mi_idx = mi_row * cm->mode_info_stride + mi_col;
-  int i;
 
   xd->mode_info_context = cm->mi + mi_idx;
   xd->mode_info_context->mbmi.sb_type = bsize;
@@ -193,14 +192,8 @@ static void set_offsets(VP9D_COMP *pbi, BLOCK_SIZE_TYPE bsize,
   // cannot be used.
   xd->prev_mode_info_context = cm->prev_mi ? cm->prev_mi + mi_idx : NULL;
 
-  for (i = 0; i < MAX_MB_PLANE; i++) {
-    struct macroblockd_plane *pd = &xd->plane[i];
-    pd->above_context = cm->above_context[i] +
-                            (mi_col * 2 >> pd->subsampling_x);
-    pd->left_context = cm->left_context[i] +
-                           (((mi_row * 2) & 15) >> pd->subsampling_y);
-  }
 
+  set_skip_context(cm, xd, mi_row, mi_col);
   set_partition_seg_context(cm, xd, mi_row, mi_col);
 
   // Distance of Mb to the various image edges. These are specified to 8th pel
@@ -675,7 +668,7 @@ static const uint8_t *decode_tiles(VP9D_COMP *pbi, const uint8_t *data) {
   // Note: this memset assumes above_context[0], [1] and [2]
   // are allocated as part of the same buffer.
   vpx_memset(pc->above_context[0], 0,
-             sizeof(ENTROPY_CONTEXT) * 2 * MAX_MB_PLANE * aligned_mi_cols);
+             sizeof(ENTROPY_CONTEXT) * MAX_MB_PLANE * (2 * aligned_mi_cols));
 
   vpx_memset(pc->above_seg_context, 0,
              sizeof(PARTITION_CONTEXT) * aligned_mi_cols);

vp9/encoder/vp9_encodeframe.c

@@ -480,17 +480,8 @@ static void set_offsets(VP9_COMP *cpi, int mi_row, int mi_col,
   const int mb_col = mi_col >> 1;
   const int idx_map = mb_row * cm->mb_cols + mb_col;
   const struct segmentation *const seg = &xd->seg;
-  int i;
 
-  // entropy context structures
-  for (i = 0; i < MAX_MB_PLANE; i++) {
-    xd->plane[i].above_context = cm->above_context[i]
-        + (mi_col * 2 >> xd->plane[i].subsampling_x);
-    xd->plane[i].left_context = cm->left_context[i]
-        + (((mi_row * 2) & 15) >> xd->plane[i].subsampling_y);
-  }
-
-  // partition contexts
+  set_skip_context(cm, xd, mi_row, mi_col);
   set_partition_seg_context(cm, xd, mi_row, mi_col);
 
   // Activity map pointer
@@ -2630,7 +2621,7 @@ static void encode_superblock(VP9_COMP *cpi, TOKENEXTRA **t, int output_enabled,
     mbmi->mb_skip_coeff = 1;
     if (output_enabled)
       cm->counts.mbskip[mb_skip_context][1]++;
-    vp9_reset_sb_tokens_context(xd, MAX(bsize, BLOCK_8X8));
+    reset_skip_context(xd, MAX(bsize, BLOCK_8X8));
   }
 
   // copy skip flag on all mb_mode_info contexts in this SB

vp9/encoder/vp9_tokenize.c

@@ -282,7 +282,7 @@ void vp9_tokenize_sb(VP9_COMP *cpi, TOKENEXTRA **t, int dry_run,
   if (mbmi->mb_skip_coeff) {
     if (!dry_run)
       cm->counts.mbskip[mb_skip_context][1] += skip_inc;
-    vp9_reset_sb_tokens_context(xd, bsize);
+    reset_skip_context(xd, bsize);
     if (dry_run)
       *t = t_backup;
     return;