Use tile context not frame context for segment_id coding.

BUG=aomedia:629

Change-Id: I929e6e1db8491092f3e165d0990f9e10920fb2d3

av1/decoder/decodemv.c

@@ -624,7 +624,12 @@ static int read_intra_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                                  aom_reader *r) {
   struct segmentation *const seg = &cm->seg;
   FRAME_COUNTS *counts = xd->counts;
-  struct segmentation_probs *const segp = &cm->fc->seg;
+#if CONFIG_EC_ADAPT
+  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+#else
+  FRAME_CONTEXT *ec_ctx = cm->fc;
+#endif
+  struct segmentation_probs *const segp = &ec_ctx->seg;
   int segment_id;
 
   if (!seg->enabled) return 0;  // Default for disabled segmentation
@@ -654,7 +659,13 @@ static int read_inter_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                                  int mi_row, int mi_col, aom_reader *r) {
   struct segmentation *const seg = &cm->seg;
   FRAME_COUNTS *counts = xd->counts;
-  struct segmentation_probs *const segp = &cm->fc->seg;
+#if CONFIG_EC_ADAPT
+  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+#else
+  FRAME_CONTEXT *ec_ctx = cm->fc;
+#endif
+  struct segmentation_probs *const segp = &ec_ctx->seg;
+
   MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
   int predicted_segment_id, segment_id;
   const int mi_offset = mi_row * cm->mi_cols + mi_col;

av1/encoder/bitstream.c

@@ -1942,7 +1942,7 @@ static void pack_inter_mode_mvs(AV1_COMP *cpi, const int mi_row,
   const MODE_INFO *mi = xd->mi[0];
 
   const struct segmentation *const seg = &cm->seg;
-  struct segmentation_probs *const segp = &cm->fc->seg;
+  struct segmentation_probs *const segp = &ec_ctx->seg;
   const MB_MODE_INFO *const mbmi = &mi->mbmi;
   const MB_MODE_INFO_EXT *const mbmi_ext = x->mbmi_ext;
   const PREDICTION_MODE mode = mbmi->mode;
@@ -2384,8 +2384,13 @@ static void write_mb_modes_kf(AV1_COMMON *cm,
 #endif  // CONFIG_INTRABC
                               const int mi_row, const int mi_col,
                               aom_writer *w) {
+#if CONFIG_EC_ADAPT
+  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+#else
+  FRAME_CONTEXT *ec_ctx = cm->fc;
+#endif
   const struct segmentation *const seg = &cm->seg;
-  struct segmentation_probs *const segp = &cm->fc->seg;
+  struct segmentation_probs *const segp = &ec_ctx->seg;
   const MODE_INFO *const mi = xd->mi[0];
   const MODE_INFO *const above_mi = xd->above_mi;
   const MODE_INFO *const left_mi = xd->left_mi;
@@ -2399,12 +2404,6 @@ static void write_mb_modes_kf(AV1_COMMON *cm,
   (void)mi_row;
   (void)mi_col;
 
-#if CONFIG_EC_ADAPT
-  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
-#else
-  FRAME_CONTEXT *ec_ctx = cm->fc;
-#endif
-
   if (seg->update_map) write_segment_id(w, seg, segp, mbmi->segment_id);
 
 #if CONFIG_DELTA_Q