Sync sub8x8 chroma component decoding process

Process sub8x8 chroma component decoding in the unit of 4x4 block.

Change-Id: I02e149f6076cdb5942b8a0a0b9ac2d833b1a7e49

av1/common/onyxc_int.h

@@ -584,6 +584,9 @@ static INLINE void set_plane_n4(MACROBLOCKD *const xd, int bw, int bh) {
 
     xd->plane[i].width = (bw * MI_SIZE) >> xd->plane[i].subsampling_x;
     xd->plane[i].height = (bh * MI_SIZE) >> xd->plane[i].subsampling_y;
+
+    xd->plane[i].width = AOMMAX(xd->plane[i].width, 4);
+    xd->plane[i].height = AOMMAX(xd->plane[i].height, 4);
   }
 }
 

av1/common/reconinter.c

@@ -1085,6 +1085,11 @@ static void build_inter_predictors_for_planes(MACROBLOCKD *xd, BLOCK_SIZE bsize,
     const int bw = pd->width;
     const int bh = pd->height;
 
+#if CONFIG_CB4X4
+    if (bsize < BLOCK_8X8 && plane && !is_chroma_reference(mi_row, mi_col))
+      continue;
+#endif
+
     if (xd->mi[0]->mbmi.sb_type < BLOCK_8X8 && !unify_bsize) {
       const PARTITION_TYPE bp = bsize - xd->mi[0]->mbmi.sb_type;
       const int have_vsplit = bp != PARTITION_HORZ;

av1/decoder/decodeframe.c

@@ -1659,7 +1659,8 @@ static void decode_token_and_recon_block(AV1Decoder *const pbi,
       const int stepr = tx_size_high_unit[tx_size];
       const int stepc = tx_size_wide_unit[tx_size];
 #if CONFIG_CB4X4
-      const BLOCK_SIZE plane_bsize = get_plane_block_size(bsize, pd);
+      const BLOCK_SIZE plane_bsize =
+          AOMMAX(BLOCK_4X4, get_plane_block_size(bsize, pd));
 #else
       const BLOCK_SIZE plane_bsize =
           get_plane_block_size(AOMMAX(BLOCK_8X8, bsize), pd);
@@ -1668,6 +1669,11 @@ static void decode_token_and_recon_block(AV1Decoder *const pbi,
       const int max_blocks_wide = max_block_wide(xd, plane_bsize, plane);
       const int max_blocks_high = max_block_high(xd, plane_bsize, plane);
 
+#if CONFIG_CB4X4
+      if (bsize < BLOCK_8X8 && plane && !is_chroma_reference(mi_row, mi_col))
+        continue;
+#endif
+
       for (row = 0; row < max_blocks_high; row += stepr)
         for (col = 0; col < max_blocks_wide; col += stepc)
           predict_and_reconstruct_intra_block(cm, xd, r, mbmi, plane, row, col,
@@ -1738,7 +1744,8 @@ static void decode_token_and_recon_block(AV1Decoder *const pbi,
       for (plane = 0; plane < MAX_MB_PLANE; ++plane) {
         const struct macroblockd_plane *const pd = &xd->plane[plane];
 #if CONFIG_CB4X4
-        const BLOCK_SIZE plane_bsize = get_plane_block_size(bsize, pd);
+        const BLOCK_SIZE plane_bsize =
+            AOMMAX(BLOCK_4X4, get_plane_block_size(bsize, pd));
 #else
         const BLOCK_SIZE plane_bsize =
             get_plane_block_size(AOMMAX(BLOCK_8X8, bsize), pd);
@@ -1746,6 +1753,12 @@ static void decode_token_and_recon_block(AV1Decoder *const pbi,
         const int max_blocks_wide = max_block_wide(xd, plane_bsize, plane);
         const int max_blocks_high = max_block_high(xd, plane_bsize, plane);
         int row, col;
+
+#if CONFIG_CB4X4
+        if (bsize < BLOCK_8X8 && plane && !is_chroma_reference(mi_row, mi_col))
+          continue;
+#endif
+
 #if CONFIG_VAR_TX
         const TX_SIZE max_tx_size = max_txsize_rect_lookup[plane_bsize];
         const int bh_var_tx = tx_size_high_unit[max_tx_size];

av1/encoder/bitstream.c

@@ -2151,6 +2151,15 @@ static void write_tokens_b(AV1_COMP *cpi, const TileInfo *const tile,
     assert(*tok < tok_end);
     for (plane = 0; plane < MAX_MB_PLANE; ++plane) {
       MB_MODE_INFO *mbmi = &m->mbmi;
+
+#if CONFIG_CB4X4
+      if (mbmi->sb_type < BLOCK_8X8 && plane &&
+          !is_chroma_reference(mi_row, mi_col)) {
+        (*tok)++;
+        continue;
+      }
+#endif
+
 #if CONFIG_VAR_TX
       const struct macroblockd_plane *const pd = &xd->plane[plane];
       BLOCK_SIZE bsize = mbmi->sb_type;

av1/encoder/tokenize.c

@@ -816,6 +816,16 @@ void av1_tokenize_sb(const AV1_COMP *cpi, ThreadData *td, TOKENEXTRA **t,
 
     td->counts->skip[ctx][0] += skip_inc;
     for (plane = 0; plane < MAX_MB_PLANE; ++plane) {
+#if CONFIG_CB4X4
+      if (bsize < BLOCK_8X8 && plane && !is_chroma_reference(mi_row, mi_col)) {
+        (*t)->token = EOSB_TOKEN;
+        (*t)++;
+        continue;
+      }
+#else
+      (void)mi_row;
+      (void)mi_col;
+#endif
       av1_foreach_transformed_block_in_plane(xd, bsize, plane, tokenize_b,
                                              &arg);
       (*t)->token = EOSB_TOKEN;