Skip non-reference position chroma uv intra mode coding

Skip coding the intra mode for chroma component for sub8x8 blocks
that are not in the reference position.

Change-Id: Ic3daab2668ab41c3b743664faf195e34124ead33

av1/decoder/decodemv.c

@@ -910,7 +910,13 @@ static void read_intra_frame_mode_info(AV1_COMMON *const cm,
   }
 #endif
 
+#if CONFIG_CB4X4
+  if (bsize >= BLOCK_8X8 || is_chroma_reference(mi_row, mi_col))
+    mbmi->uv_mode = read_intra_mode_uv(cm, xd, r, mbmi->mode);
+#else
   mbmi->uv_mode = read_intra_mode_uv(cm, xd, r, mbmi->mode);
+#endif
+
 #if CONFIG_EXT_INTRA
   read_intra_angle_info(cm, xd, r);
 #endif  // CONFIG_EXT_INTRA
@@ -1195,9 +1201,9 @@ static INLINE void read_mb_interp_filter(AV1_COMMON *const cm,
 #endif  // CONFIG_DUAL_FILTER
 }
 
-static void read_intra_block_mode_info(AV1_COMMON *const cm,
-                                       MACROBLOCKD *const xd, MODE_INFO *mi,
-                                       aom_reader *r) {
+static void read_intra_block_mode_info(AV1_COMMON *const cm, const int mi_row,
+                                       const int mi_col, MACROBLOCKD *const xd,
+                                       MODE_INFO *mi, aom_reader *r) {
   MB_MODE_INFO *const mbmi = &mi->mbmi;
   const BLOCK_SIZE bsize = mi->mbmi.sb_type;
   int i;
@@ -1230,7 +1236,15 @@ static void read_intra_block_mode_info(AV1_COMMON *const cm,
   }
 #endif
 
+#if CONFIG_CB4X4
+  if (bsize >= BLOCK_8X8 || is_chroma_reference(mi_row, mi_col))
+    mbmi->uv_mode = read_intra_mode_uv(cm, xd, r, mbmi->mode);
+#else
   mbmi->uv_mode = read_intra_mode_uv(cm, xd, r, mbmi->mode);
+  (void)mi_row;
+  (void)mi_col;
+#endif
+
 #if CONFIG_EXT_INTRA
   read_intra_angle_info(cm, xd, r);
 #endif  // CONFIG_EXT_INTRA
@@ -2105,7 +2119,7 @@ static void read_inter_frame_mode_info(AV1Decoder *const pbi,
                                mi, mi_row, mi_col, r);
 #endif  // CONFIG_MOTION_VAR && CONFIG_SUPERTX
   else
-    read_intra_block_mode_info(cm, xd, mi, r);
+    read_intra_block_mode_info(cm, mi_row, mi_col, xd, mi, r);
 
   read_tx_type(cm, xd, mbmi,
 #if CONFIG_SUPERTX

av1/encoder/bitstream.c

@@ -1362,6 +1362,7 @@ static void write_tx_type(const AV1_COMMON *const cm, const MACROBLOCKD *xd,
 }
 
 static void pack_inter_mode_mvs(AV1_COMP *cpi, const MODE_INFO *mi,
+                                const int mi_row, const int mi_col,
 #if CONFIG_SUPERTX
                                 int supertx_enabled,
 #endif
@@ -1421,8 +1422,6 @@ static void pack_inter_mode_mvs(AV1_COMP *cpi, const MODE_INFO *mi,
 #endif  // CONFIG_SUPERTX
 #if CONFIG_DELTA_Q
   if (cm->delta_q_present_flag) {
-    int mi_row = (-xd->mb_to_top_edge) >> (MI_SIZE_LOG2 + 3);
-    int mi_col = (-xd->mb_to_left_edge) >> (MI_SIZE_LOG2 + 3);
     int super_block_upper_left =
         ((mi_row & MAX_MIB_MASK) == 0) && ((mi_col & MAX_MIB_MASK) == 0);
     if ((bsize != BLOCK_64X64 || skip == 0) && super_block_upper_left) {
@@ -1505,8 +1504,13 @@ static void pack_inter_mode_mvs(AV1_COMP *cpi, const MODE_INFO *mi,
 #if CONFIG_EC_MULTISYMBOL
     aom_write_symbol(w, av1_intra_mode_ind[mbmi->uv_mode],
                      ec_ctx->uv_mode_cdf[mode], INTRA_MODES);
+#else
+#if CONFIG_CB4X4
+    if (bsize >= BLOCK_8X8 || is_chroma_reference(mi_row, mi_col))
+      write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mode]);
 #else
     write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mode]);
+#endif  // CONFIG_CB4X4
 #endif
 #if CONFIG_EXT_INTRA
     write_intra_angle_info(cm, xd, w);
@@ -1766,11 +1770,13 @@ static void pack_inter_mode_mvs(AV1_COMP *cpi, const MODE_INFO *mi,
 }
 
 #if CONFIG_DELTA_Q
-static void write_mb_modes_kf(AV1_COMMON *cm, MACROBLOCKD *xd,
-                              MODE_INFO **mi_8x8, aom_writer *w) {
+static void write_mb_modes_kf(AV1_COMMON *cm, MACROBLOCKD *xd, const int mi_row,
+                              const int mi_col, MODE_INFO **mi_8x8,
+                              aom_writer *w) {
   int skip;
 #else
 static void write_mb_modes_kf(AV1_COMMON *cm, const MACROBLOCKD *xd,
+                              const int mi_row, const int mi_col,
                               MODE_INFO **mi_8x8, aom_writer *w) {
 #endif
   const struct segmentation *const seg = &cm->seg;
@@ -1797,8 +1803,6 @@ static void write_mb_modes_kf(AV1_COMMON *cm, const MACROBLOCKD *xd,
 #if CONFIG_DELTA_Q
   skip = write_skip(cm, xd, mbmi->segment_id, mi, w);
   if (cm->delta_q_present_flag) {
-    int mi_row = (-xd->mb_to_top_edge) >> 6;
-    int mi_col = (-xd->mb_to_left_edge) >> 6;
     int super_block_upper_left = ((mi_row & 7) == 0) && ((mi_col & 7) == 0);
     if ((bsize != BLOCK_64X64 || skip == 0) && super_block_upper_left) {
       int reduced_delta_qindex =
@@ -1855,8 +1859,13 @@ static void write_mb_modes_kf(AV1_COMMON *cm, const MACROBLOCKD *xd,
 #if CONFIG_EC_MULTISYMBOL
   aom_write_symbol(w, av1_intra_mode_ind[mbmi->uv_mode],
                    ec_ctx->uv_mode_cdf[mbmi->mode], INTRA_MODES);
+#else
+#if CONFIG_CB4X4
+  if (bsize >= BLOCK_8X8 || is_chroma_reference(mi_row, mi_col))
+    write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mbmi->mode]);
 #else
   write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mbmi->mode]);
+#endif  // CONFIG_CB4X4
 #endif
 #if CONFIG_EXT_INTRA
   write_intra_angle_info(cm, xd, w);
@@ -1972,7 +1981,7 @@ static void write_mbmi_b(AV1_COMP *cpi, const TileInfo *const tile,
 #endif
 
   if (frame_is_intra_only(cm)) {
-    write_mb_modes_kf(cm, xd, xd->mi, w);
+    write_mb_modes_kf(cm, xd, mi_row, mi_col, xd->mi, w);
   } else {
 #if CONFIG_VAR_TX
     xd->above_txfm_context = cm->above_txfm_context + mi_col;
@@ -2009,7 +2018,7 @@ static void write_mbmi_b(AV1_COMP *cpi, const TileInfo *const tile,
              m->mbmi.ref_frame[0], m->mbmi.ref_frame[1]);
     }
 #endif  // 0
-    pack_inter_mode_mvs(cpi, m,
+    pack_inter_mode_mvs(cpi, m, mi_row, mi_col,
 #if CONFIG_SUPERTX
                         supertx_enabled,
 #endif

av1/encoder/encodeframe.c

@@ -5406,7 +5406,8 @@ void av1_encode_frame(AV1_COMP *cpi) {
 
 static void sum_intra_stats(FRAME_COUNTS *counts, const MODE_INFO *mi,
                             const MODE_INFO *above_mi, const MODE_INFO *left_mi,
-                            const int intraonly) {
+                            const int intraonly, const int mi_row,
+                            const int mi_col) {
   const PREDICTION_MODE y_mode = mi->mbmi.mode;
   const PREDICTION_MODE uv_mode = mi->mbmi.uv_mode;
   const BLOCK_SIZE bsize = mi->mbmi.sb_type;
@@ -5438,6 +5439,12 @@ static void sum_intra_stats(FRAME_COUNTS *counts, const MODE_INFO *mi,
     }
   }
 
+#if CONFIG_CB4X4
+  if (bsize < BLOCK_8X8 && !is_chroma_reference(mi_row, mi_col)) return;
+#else
+  (void)mi_row;
+  (void)mi_col;
+#endif
   ++counts->uv_mode[y_mode][uv_mode];
 }
 
@@ -5603,7 +5610,7 @@ static void encode_superblock(const AV1_COMP *const cpi, ThreadData *td,
                                    mi_row, mi_col);
     if (!dry_run)
       sum_intra_stats(td->counts, mi, xd->above_mi, xd->left_mi,
-                      frame_is_intra_only(cm));
+                      frame_is_intra_only(cm), mi_row, mi_col);
 
     // TODO(huisu): move this into sum_intra_stats().
     if (!dry_run && (bsize >= BLOCK_8X8 || unify_bsize)) {

av1/encoder/rdopt.c

@@ -10091,8 +10091,15 @@ void av1_rd_pick_inter_mode_sb(const AV1_COMP *cpi, TileDataEnc *tile_data,
       }
 #endif  // CONFIG_FILTER_INTRA
 
+#if CONFIG_CB4X4
+      rate2 = rate_y + intra_mode_cost[mbmi->mode];
+      if (!x->skip_chroma_rd)
+        rate2 += rate_uv + cpi->intra_uv_mode_cost[mbmi->mode][mbmi->uv_mode];
+#else
       rate2 = rate_y + intra_mode_cost[mbmi->mode] + rate_uv +
               cpi->intra_uv_mode_cost[mbmi->mode][mbmi->uv_mode];
+#endif
+
 #if CONFIG_PALETTE
       if (cpi->common.allow_screen_content_tools && mbmi->mode == DC_PRED)
         rate2 += av1_cost_bit(