NEW_MULTISYMBOL: Adapt skip binary symbol.

Perform symbol-by-symbol adaptation for the skip syntax
element and remove updates from the compressed header.

Change-Id: Ic42f60e19c56db52dd51b3784fd305c7e6b595c7

av1/common/entropy.c

@@ -5677,6 +5677,10 @@ void av1_average_tile_intra_cdfs(FRAME_CONTEXT *fc, FRAME_CONTEXT *ec_ctxs[],
 #if CONFIG_EXT_INTRA && CONFIG_INTRA_INTERP
   AVERAGE_TILE_CDFS(intra_filter_cdf)
 #endif  // CONFIG_EXT_INTRA && CONFIG_INTRA_INTERP
+
+#if CONFIG_NEW_MULTISYMBOL
+  AVERAGE_TILE_CDFS(skip_cdfs)
+#endif
 }
 
 void av1_average_tile_inter_cdfs(AV1_COMMON *cm, FRAME_CONTEXT *fc,

av1/common/entropymode.c

@@ -1775,6 +1775,13 @@ static const aom_prob default_txfm_partition_probs[TXFM_PARTITION_CONTEXTS] = {
 #endif
 
 static const aom_prob default_skip_probs[SKIP_CONTEXTS] = { 192, 128, 64 };
+#if CONFIG_NEW_MULTISYMBOL
+static const aom_cdf_prob default_skip_cdfs[SKIP_CONTEXTS][CDF_SIZE(2)] = {
+  { AOM_ICDF(24576), AOM_ICDF(32768), 0 },
+  { AOM_ICDF(16384), AOM_ICDF(32768), 0 },
+  { AOM_ICDF(8192), AOM_ICDF(32768), 0 }
+};
+#endif
 
 #if CONFIG_DUAL_FILTER
 #if USE_EXTRA_FILTER
@@ -4547,6 +4554,9 @@ static void init_mode_probs(FRAME_CONTEXT *fc) {
   av1_copy(fc->partition_cdf, default_partition_cdf);
   av1_copy(fc->intra_ext_tx_cdf, default_intra_ext_tx_cdf);
   av1_copy(fc->inter_ext_tx_cdf, default_inter_ext_tx_cdf);
+#if CONFIG_NEW_MULTISYMBOL
+  av1_copy(fc->skip_cdfs, default_skip_cdfs);
+#endif
 #if CONFIG_EXT_INTRA && CONFIG_INTRA_INTERP
   av1_copy(fc->intra_filter_cdf, default_intra_filter_cdf);
 #endif  // CONFIG_EXT_INTRA && CONFIG_INTRA_INTERP

av1/common/entropymode.h

@@ -226,6 +226,9 @@ typedef struct frame_contexts {
   aom_prob txfm_partition_prob[TXFM_PARTITION_CONTEXTS];
 #endif
   aom_prob skip_probs[SKIP_CONTEXTS];
+#if CONFIG_NEW_MULTISYMBOL
+  aom_cdf_prob skip_cdfs[SKIP_CONTEXTS][CDF_SIZE(2)];
+#endif
   nmv_context nmvc[NMV_CONTEXTS];
 #if CONFIG_INTRABC
   nmv_context ndvc;

av1/decoder/decodeframe.c

@@ -2302,7 +2302,16 @@ static int read_skip(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,
     return 1;
   } else {
     const int ctx = av1_get_skip_context(xd);
+#if CONFIG_NEW_MULTISYMBOL
+#if CONFIG_EC_ADAPT
+    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+#else
+    FRAME_CONTEXT *ec_ctx = cm->fc;
+#endif
+    const int skip = aom_read_symbol(r, ec_ctx->skip_cdfs[ctx], 2, ACCT_STR);
+#else
     const int skip = aom_read(r, cm->fc->skip_probs[ctx], ACCT_STR);
+#endif
     FRAME_COUNTS *counts = xd->counts;
     if (counts) ++counts->skip[ctx][skip];
     return skip;
@@ -4931,7 +4940,7 @@ static int read_compressed_header(AV1Decoder *pbi, const uint8_t *data,
 #endif
   FRAME_CONTEXT *const fc = cm->fc;
   aom_reader r;
-  int k, i;
+  int i;
 #if !CONFIG_EC_ADAPT || \
     (CONFIG_MOTION_VAR || CONFIG_WARPED_MOTION || CONFIG_EXT_INTER)
   int j;
@@ -4973,11 +4982,13 @@ static int read_compressed_header(AV1Decoder *pbi, const uint8_t *data,
 #endif  // CONFIG_LV_MAP
 
 #if CONFIG_VAR_TX
-  for (k = 0; k < TXFM_PARTITION_CONTEXTS; ++k)
-    av1_diff_update_prob(&r, &fc->txfm_partition_prob[k], ACCT_STR);
+  for (i = 0; i < TXFM_PARTITION_CONTEXTS; ++i)
+    av1_diff_update_prob(&r, &fc->txfm_partition_prob[i], ACCT_STR);
 #endif  // CONFIG_VAR_TX
-  for (k = 0; k < SKIP_CONTEXTS; ++k)
-    av1_diff_update_prob(&r, &fc->skip_probs[k], ACCT_STR);
+#if !CONFIG_NEW_MULTISYMBOL
+  for (i = 0; i < SKIP_CONTEXTS; ++i)
+    av1_diff_update_prob(&r, &fc->skip_probs[i], ACCT_STR);
+#endif
 
 #if CONFIG_DELTA_Q && !CONFIG_EC_ADAPT
 #if CONFIG_EXT_DELTA_Q
@@ -4998,11 +5009,11 @@ static int read_compressed_header(AV1Decoder *pbi, const uint8_t *data,
 #if !CONFIG_EC_ADAPT
   if (cm->seg.enabled && cm->seg.update_map) {
     if (cm->seg.temporal_update) {
-      for (k = 0; k < PREDICTION_PROBS; k++)
-        av1_diff_update_prob(&r, &cm->fc->seg.pred_probs[k], ACCT_STR);
+      for (i = 0; i < PREDICTION_PROBS; i++)
+        av1_diff_update_prob(&r, &cm->fc->seg.pred_probs[i], ACCT_STR);
     }
-    for (k = 0; k < MAX_SEGMENTS - 1; k++)
-      av1_diff_update_prob(&r, &cm->fc->seg.tree_probs[k], ACCT_STR);
+    for (i = 0; i < MAX_SEGMENTS - 1; i++)
+      av1_diff_update_prob(&r, &cm->fc->seg.tree_probs[i], ACCT_STR);
   }
 
   for (j = 0; j < INTRA_MODES; j++) {
@@ -5041,6 +5052,7 @@ static int read_compressed_header(AV1Decoder *pbi, const uint8_t *data,
     av1_copy(cm->kf_y_prob, av1_kf_y_mode_prob);
     av1_copy(cm->fc->kf_y_cdf, av1_kf_y_mode_cdf);
 #if !CONFIG_EC_ADAPT
+    int k;
     for (k = 0; k < INTRA_MODES; k++)
       for (j = 0; j < INTRA_MODES; j++)
         for (i = 0; i < INTRA_MODES - 1; ++i)

av1/decoder/decodemv.c

@@ -613,7 +613,12 @@ static int read_skip(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,
     return 1;
   } else {
     const int ctx = av1_get_skip_context(xd);
+#if CONFIG_NEW_MULTISYMBOL
+    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+    const int skip = aom_read_symbol(r, ec_ctx->skip_cdfs[ctx], 2, ACCT_STR);
+#else
     const int skip = aom_read(r, cm->fc->skip_probs[ctx], ACCT_STR);
+#endif
     FRAME_COUNTS *counts = xd->counts;
     if (counts) ++counts->skip[ctx][skip];
     return skip;

av1/encoder/bitstream.c

@@ -548,7 +548,13 @@ static int write_skip(const AV1_COMMON *cm, const MACROBLOCKD *xd,
     return 1;
   } else {
     const int skip = mi->mbmi.skip;
+#if CONFIG_NEW_MULTISYMBOL
+    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
+    const int ctx = av1_get_skip_context(xd);
+    aom_write_symbol(w, skip, ec_ctx->skip_cdfs[ctx], 2);
+#else
     aom_write(w, skip, av1_get_skip_prob(cm, xd));
+#endif
     return skip;
   }
 }
@@ -675,6 +681,7 @@ static void update_delta_lf_probs(AV1_COMMON *cm, aom_writer *w,
 #endif  // CONFIG_EXT_DELTA_Q
 #endif  // CONFIG_DELTA_Q
 
+#if !CONFIG_NEW_MULTISYMBOL
 static void update_skip_probs(AV1_COMMON *cm, aom_writer *w,
                               FRAME_COUNTS *counts) {
   int k;
@@ -688,6 +695,7 @@ static void update_skip_probs(AV1_COMMON *cm, aom_writer *w,
                               probwt);
   }
 }
+#endif
 
 #if !CONFIG_EC_ADAPT
 static void update_switchable_interp_probs(AV1_COMMON *cm, aom_writer *w,
@@ -4845,7 +4853,9 @@ static uint32_t write_compressed_header(AV1_COMP *cpi, uint8_t *data) {
   update_txfm_partition_probs(cm, header_bc, counts, probwt);
 #endif
 
+#if !CONFIG_NEW_MULTISYMBOL
   update_skip_probs(cm, header_bc, counts);
+#endif
 #if !CONFIG_EC_ADAPT && CONFIG_DELTA_Q
   update_delta_q_probs(cm, header_bc, counts);
 #if CONFIG_EXT_DELTA_Q