av1/common/pred_common.c - aom - Git at Google

 /*
  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
  *
  * This source code is subject to the terms of the BSD 2 Clause License and
  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
  * was not distributed with this source code in the LICENSE file, you can
  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
  * Media Patent License 1.0 was not distributed with this source code in the
  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  */

 #include "av1/common/common.h"
 #include "av1/common/pred_common.h"
 #include "av1/common/reconinter.h"
 #include "av1/common/reconintra.h"
 #include "av1/common/seg_common.h"

 // Returns a context number for the given MB prediction signal
 static InterpFilter get_ref_filter_type(const MB_MODE_INFO *ref_mbmi,
                                         const MACROBLOCKD *xd, int dir,
                                         MV_REFERENCE_FRAME ref_frame) {
   (void)xd;

   return ((ref_mbmi->ref_frame[0] == ref_frame ||
            ref_mbmi->ref_frame[1] == ref_frame)
               ? av1_extract_interp_filter(ref_mbmi->interp_filters, dir & 0x01)
               : SWITCHABLE_FILTERS);
 }

 int av1_get_pred_context_switchable_interp(const MACROBLOCKD *xd, int dir) {
   const MB_MODE_INFO *const mbmi = xd->mi[0];
   const int ctx_offset =
       (mbmi->ref_frame[1] > INTRA_FRAME) * INTER_FILTER_COMP_OFFSET;
   assert(dir == 0 || dir == 1);
   const MV_REFERENCE_FRAME ref_frame = mbmi->ref_frame[0];
   // Note:
   // The mode info data structure has a one element border above and to the
   // left of the entries corresponding to real macroblocks.
   // The prediction flags in these dummy entries are initialized to 0.
   int filter_type_ctx = ctx_offset + (dir & 0x01) * INTER_FILTER_DIR_OFFSET;
   int left_type = SWITCHABLE_FILTERS;
   int above_type = SWITCHABLE_FILTERS;

   if (xd->left_available)
     left_type = get_ref_filter_type(xd->mi[-1], xd, dir, ref_frame);

   if (xd->up_available)
     above_type =
         get_ref_filter_type(xd->mi[-xd->mi_stride], xd, dir, ref_frame);

   if (left_type == above_type) {
     filter_type_ctx += left_type;
   } else if (left_type == SWITCHABLE_FILTERS) {
     assert(above_type != SWITCHABLE_FILTERS);
     filter_type_ctx += above_type;
   } else if (above_type == SWITCHABLE_FILTERS) {
     assert(left_type != SWITCHABLE_FILTERS);
     filter_type_ctx += left_type;
   } else {
     filter_type_ctx += SWITCHABLE_FILTERS;
   }

   return filter_type_ctx;
 }

 static void palette_add_to_cache(uint16_t *cache, int *n, uint16_t val) {
   // Do not add an already existing value
   if (*n > 0 && val == cache[*n - 1]) return;

   cache[(*n)++] = val;
 }

 int av1_get_palette_cache(const MACROBLOCKD *const xd, int plane,
                           uint16_t *cache) {
   const int row = -xd->mb_to_top_edge >> 3;
   // Do not refer to above SB row when on SB boundary.
   const MB_MODE_INFO *const above_mi =
       (row % (1 << MIN_SB_SIZE_LOG2)) ? xd->above_mbmi : NULL;
   const MB_MODE_INFO *const left_mi = xd->left_mbmi;
   int above_n = 0, left_n = 0;
   if (above_mi) above_n = above_mi->palette_mode_info.palette_size[plane != 0];
   if (left_mi) left_n = left_mi->palette_mode_info.palette_size[plane != 0];
   if (above_n == 0 && left_n == 0) return 0;
   int above_idx = plane * PALETTE_MAX_SIZE;
   int left_idx = plane * PALETTE_MAX_SIZE;
   int n = 0;
   const uint16_t *above_colors =
       above_mi ? above_mi->palette_mode_info.palette_colors : NULL;
   const uint16_t *left_colors =
       left_mi ? left_mi->palette_mode_info.palette_colors : NULL;
   // Merge the sorted lists of base colors from above and left to get
   // combined sorted color cache.
   while (above_n > 0 && left_n > 0) {
     uint16_t v_above = above_colors[above_idx];
     uint16_t v_left = left_colors[left_idx];
     if (v_left < v_above) {
       palette_add_to_cache(cache, &n, v_left);
       ++left_idx, --left_n;
     } else {
       palette_add_to_cache(cache, &n, v_above);
       ++above_idx, --above_n;
       if (v_left == v_above) ++left_idx, --left_n;
     }
   }
   while (above_n-- > 0) {
     uint16_t val = above_colors[above_idx++];
     palette_add_to_cache(cache, &n, val);
   }
   while (left_n-- > 0) {
     uint16_t val = left_colors[left_idx++];
     palette_add_to_cache(cache, &n, val);
   }
   assert(n <= 2 * PALETTE_MAX_SIZE);
   return n;
 }

 // The mode info data structure has a one element border above and to the
 // left of the entries corresponding to real macroblocks.
 // The prediction flags in these dummy entries are initialized to 0.
 // 0 - inter/inter, inter/--, --/inter, --/--
 // 1 - intra/inter, inter/intra
 // 2 - intra/--, --/intra
 // 3 - intra/intra
 int av1_get_intra_inter_context(const MACROBLOCKD *xd) {
   const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
   const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
   const int has_above = xd->up_available;
   const int has_left = xd->left_available;

   if (has_above && has_left) {  // both edges available
     const int above_intra = !is_inter_block(above_mbmi);
     const int left_intra = !is_inter_block(left_mbmi);
     return left_intra && above_intra ? 3 : left_intra || above_intra;
   } else if (has_above || has_left) {  // one edge available
     return 2 * !is_inter_block(has_above ? above_mbmi : left_mbmi);
   } else {
     return 0;
   }
 }

 #define CHECK_BACKWARD_REFS(ref_frame) \
   (((ref_frame) >= BWDREF_FRAME) && ((ref_frame) <= ALTREF_FRAME))
 #define IS_BACKWARD_REF_FRAME(ref_frame) CHECK_BACKWARD_REFS(ref_frame)

 int av1_get_reference_mode_context(const MACROBLOCKD *xd) {
   int ctx;
   const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
   const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
   const int has_above = xd->up_available;
   const int has_left = xd->left_available;

   // Note:
   // The mode info data structure has a one element border above and to the
   // left of the entries corresponding to real macroblocks.
   // The prediction flags in these dummy entries are initialized to 0.
   if (has_above && has_left) {  // both edges available
     if (!has_second_ref(above_mbmi) && !has_second_ref(left_mbmi))
       // neither edge uses comp pred (0/1)
       ctx = IS_BACKWARD_REF_FRAME(above_mbmi->ref_frame[0]) ^
             IS_BACKWARD_REF_FRAME(left_mbmi->ref_frame[0]);
     else if (!has_second_ref(above_mbmi))
       // one of two edges uses comp pred (2/3)
       ctx = 2 + (IS_BACKWARD_REF_FRAME(above_mbmi->ref_frame[0]) ||
                  !is_inter_block(above_mbmi));
     else if (!has_second_ref(left_mbmi))
       // one of two edges uses comp pred (2/3)
       ctx = 2 + (IS_BACKWARD_REF_FRAME(left_mbmi->ref_frame[0]) ||
                  !is_inter_block(left_mbmi));
     else  // both edges use comp pred (4)
       ctx = 4;
   } else if (has_above || has_left) {  // one edge available
     const MB_MODE_INFO *edge_mbmi = has_above ? above_mbmi : left_mbmi;

     if (!has_second_ref(edge_mbmi))
       // edge does not use comp pred (0/1)
       ctx = IS_BACKWARD_REF_FRAME(edge_mbmi->ref_frame[0]);
     else
       // edge uses comp pred (3)
       ctx = 3;
   } else {  // no edges available (1)
     ctx = 1;
   }
   assert(ctx >= 0 && ctx < COMP_INTER_CONTEXTS);
   return ctx;
 }

 int av1_get_comp_reference_type_context(const MACROBLOCKD *xd) {
   int pred_context;
   const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
   const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
   const int above_in_image = xd->up_available;
   const int left_in_image = xd->left_available;

   if (above_in_image && left_in_image) {  // both edges available
     const int above_intra = !is_inter_block(above_mbmi);
     const int left_intra = !is_inter_block(left_mbmi);

     if (above_intra && left_intra) {  // intra/intra
       pred_context = 2;
     } else if (above_intra || left_intra) {  // intra/inter
       const MB_MODE_INFO *inter_mbmi = above_intra ? left_mbmi : above_mbmi;

       if (!has_second_ref(inter_mbmi))  // single pred
         pred_context = 2;
       else  // comp pred
         pred_context = 1 + 2 * has_uni_comp_refs(inter_mbmi);
     } else {  // inter/inter
       const int a_sg = !has_second_ref(above_mbmi);
       const int l_sg = !has_second_ref(left_mbmi);
       const MV_REFERENCE_FRAME frfa = above_mbmi->ref_frame[0];
       const MV_REFERENCE_FRAME frfl = left_mbmi->ref_frame[0];

       if (a_sg && l_sg) {  // single/single
         pred_context = 1 + 2 * (!(IS_BACKWARD_REF_FRAME(frfa) ^
                                   IS_BACKWARD_REF_FRAME(frfl)));
       } else if (l_sg || a_sg) {  // single/comp
         const int uni_rfc =
             a_sg ? has_uni_comp_refs(left_mbmi) : has_uni_comp_refs(above_mbmi);

         if (!uni_rfc)  // comp bidir
           pred_context = 1;
         else  // comp unidir
           pred_context = 3 + (!(IS_BACKWARD_REF_FRAME(frfa) ^
                                 IS_BACKWARD_REF_FRAME(frfl)));
       } else {  // comp/comp
         const int a_uni_rfc = has_uni_comp_refs(above_mbmi);
         const int l_uni_rfc = has_uni_comp_refs(left_mbmi);

         if (!a_uni_rfc && !l_uni_rfc)  // bidir/bidir
           pred_context = 0;
         else if (!a_uni_rfc || !l_uni_rfc)  // unidir/bidir
           pred_context = 2;
         else  // unidir/unidir
           pred_context =
               3 + (!((frfa == BWDREF_FRAME) ^ (frfl == BWDREF_FRAME)));
       }
     }
   } else if (above_in_image || left_in_image) {  // one edge available
     const MB_MODE_INFO *edge_mbmi = above_in_image ? above_mbmi : left_mbmi;

     if (!is_inter_block(edge_mbmi)) {  // intra
       pred_context = 2;
     } else {                           // inter
       if (!has_second_ref(edge_mbmi))  // single pred
         pred_context = 2;
       else  // comp pred
         pred_context = 4 * has_uni_comp_refs(edge_mbmi);
     }
   } else {  // no edges available
     pred_context = 2;
   }

   assert(pred_context >= 0 && pred_context < COMP_REF_TYPE_CONTEXTS);
   return pred_context;
 }

 // Returns a context number for the given MB prediction signal
 //
 // Signal the uni-directional compound reference frame pair as either
 // (BWDREF, ALTREF), or (LAST, LAST2) / (LAST, LAST3) / (LAST, GOLDEN),
 // conditioning on the pair is known as uni-directional.
 //
 // 3 contexts: Voting is used to compare the count of forward references with
 //             that of backward references from the spatial neighbors.
 int av1_get_pred_context_uni_comp_ref_p(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of forward references (L, L2, L3, or G)
   const int frf_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME] +
                         ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];
   // Count of backward references (B or A)
   const int brf_count = ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME] +
                         ref_counts[ALTREF_FRAME];

   const int pred_context =
       (frf_count == brf_count) ? 1 : ((frf_count < brf_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
   return pred_context;
 }

 // Returns a context number for the given MB prediction signal
 //
 // Signal the uni-directional compound reference frame pair as
 // either (LAST, LAST2), or (LAST, LAST3) / (LAST, GOLDEN),
 // conditioning on the pair is known as one of the above three.
 //
 // 3 contexts: Voting is used to compare the count of LAST2_FRAME with the
 //             total count of LAST3/GOLDEN from the spatial neighbors.
 int av1_get_pred_context_uni_comp_ref_p1(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of LAST2
   const int last2_count = ref_counts[LAST2_FRAME];
   // Count of LAST3 or GOLDEN
   const int last3_or_gld_count =
       ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];

   const int pred_context = (last2_count == last3_or_gld_count)
                                ? 1
                                : ((last2_count < last3_or_gld_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
   return pred_context;
 }

 // Returns a context number for the given MB prediction signal
 //
 // Signal the uni-directional compound reference frame pair as
 // either (LAST, LAST3) or (LAST, GOLDEN),
 // conditioning on the pair is known as one of the above two.
 //
 // 3 contexts: Voting is used to compare the count of LAST3_FRAME with the
 //             total count of GOLDEN_FRAME from the spatial neighbors.
 int av1_get_pred_context_uni_comp_ref_p2(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of LAST3
   const int last3_count = ref_counts[LAST3_FRAME];
   // Count of GOLDEN
   const int gld_count = ref_counts[GOLDEN_FRAME];

   const int pred_context =
       (last3_count == gld_count) ? 1 : ((last3_count < gld_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
   return pred_context;
 }

 // == Common context functions for both comp and single ref ==
 //
 // Obtain contexts to signal a reference frame to be either LAST/LAST2 or
 // LAST3/GOLDEN.
 static int get_pred_context_ll2_or_l3gld(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of LAST + LAST2
   const int last_last2_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME];
   // Count of LAST3 + GOLDEN
   const int last3_gld_count =
       ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];

   const int pred_context = (last_last2_count == last3_gld_count)
                                ? 1
                                : ((last_last2_count < last3_gld_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // Obtain contexts to signal a reference frame to be either LAST or LAST2.
 static int get_pred_context_last_or_last2(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of LAST
   const int last_count = ref_counts[LAST_FRAME];
   // Count of LAST2
   const int last2_count = ref_counts[LAST2_FRAME];

   const int pred_context =
       (last_count == last2_count) ? 1 : ((last_count < last2_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // Obtain contexts to signal a reference frame to be either LAST3 or GOLDEN.
 static int get_pred_context_last3_or_gld(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of LAST3
   const int last3_count = ref_counts[LAST3_FRAME];
   // Count of GOLDEN
   const int gld_count = ref_counts[GOLDEN_FRAME];

   const int pred_context =
       (last3_count == gld_count) ? 1 : ((last3_count < gld_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // Obtain contexts to signal a reference frame be either BWDREF/ALTREF2, or
 // ALTREF.
 static int get_pred_context_brfarf2_or_arf(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Counts of BWDREF, ALTREF2, or ALTREF frames (B, A2, or A)
   const int brfarf2_count =
       ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME];
   const int arf_count = ref_counts[ALTREF_FRAME];

   const int pred_context =
       (brfarf2_count == arf_count) ? 1 : ((brfarf2_count < arf_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // Obtain contexts to signal a reference frame be either BWDREF or ALTREF2.
 static int get_pred_context_brf_or_arf2(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of BWDREF frames (B)
   const int brf_count = ref_counts[BWDREF_FRAME];
   // Count of ALTREF2 frames (A2)
   const int arf2_count = ref_counts[ALTREF2_FRAME];

   const int pred_context =
       (brf_count == arf2_count) ? 1 : ((brf_count < arf2_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // == Context functions for comp ref ==
 //
 // Returns a context number for the given MB prediction signal
 // Signal the first reference frame for a compound mode be either
 // GOLDEN/LAST3, or LAST/LAST2.
 int av1_get_pred_context_comp_ref_p(const MACROBLOCKD *xd) {
   return get_pred_context_ll2_or_l3gld(xd);
 }

 // Returns a context number for the given MB prediction signal
 // Signal the first reference frame for a compound mode be LAST,
 // conditioning on that it is known either LAST/LAST2.
 int av1_get_pred_context_comp_ref_p1(const MACROBLOCKD *xd) {
   return get_pred_context_last_or_last2(xd);
 }

 // Returns a context number for the given MB prediction signal
 // Signal the first reference frame for a compound mode be GOLDEN,
 // conditioning on that it is known either GOLDEN or LAST3.
 int av1_get_pred_context_comp_ref_p2(const MACROBLOCKD *xd) {
   return get_pred_context_last3_or_gld(xd);
 }

 // Signal the 2nd reference frame for a compound mode be either
 // ALTREF, or ALTREF2/BWDREF.
 int av1_get_pred_context_comp_bwdref_p(const MACROBLOCKD *xd) {
   return get_pred_context_brfarf2_or_arf(xd);
 }

 // Signal the 2nd reference frame for a compound mode be either
 // ALTREF2 or BWDREF.
 int av1_get_pred_context_comp_bwdref_p1(const MACROBLOCKD *xd) {
   return get_pred_context_brf_or_arf2(xd);
 }

 // == Context functions for single ref ==
 //
 // For the bit to signal whether the single reference is a forward reference
 // frame or a backward reference frame.
 int av1_get_pred_context_single_ref_p1(const MACROBLOCKD *xd) {
   const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

   // Count of forward reference frames
   const int fwd_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME] +
                         ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];
   // Count of backward reference frames
   const int bwd_count = ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME] +
                         ref_counts[ALTREF_FRAME];

   const int pred_context =
       (fwd_count == bwd_count) ? 1 : ((fwd_count < bwd_count) ? 0 : 2);

   assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
   return pred_context;
 }

 // For the bit to signal whether the single reference is ALTREF_FRAME or
 // non-ALTREF backward reference frame, knowing that it shall be either of
 // these 2 choices.
 int av1_get_pred_context_single_ref_p2(const MACROBLOCKD *xd) {
   return get_pred_context_brfarf2_or_arf(xd);
 }

 // For the bit to signal whether the single reference is LAST3/GOLDEN or
 // LAST2/LAST, knowing that it shall be either of these 2 choices.
 int av1_get_pred_context_single_ref_p3(const MACROBLOCKD *xd) {
   return get_pred_context_ll2_or_l3gld(xd);
 }

 // For the bit to signal whether the single reference is LAST2_FRAME or
 // LAST_FRAME, knowing that it shall be either of these 2 choices.
 int av1_get_pred_context_single_ref_p4(const MACROBLOCKD *xd) {
   return get_pred_context_last_or_last2(xd);
 }

 // For the bit to signal whether the single reference is GOLDEN_FRAME or
 // LAST3_FRAME, knowing that it shall be either of these 2 choices.
 int av1_get_pred_context_single_ref_p5(const MACROBLOCKD *xd) {
   return get_pred_context_last3_or_gld(xd);
 }

 // For the bit to signal whether the single reference is ALTREF2_FRAME or
 // BWDREF_FRAME, knowing that it shall be either of these 2 choices.
 int av1_get_pred_context_single_ref_p6(const MACROBLOCKD *xd) {
   return get_pred_context_brf_or_arf2(xd);
 }
	/*
	* Copyright (c) 2016, Alliance for Open Media. All rights reserved
	*
	* This source code is subject to the terms of the BSD 2 Clause License and
	* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
	* was not distributed with this source code in the LICENSE file, you can
	* obtain it at www.aomedia.org/license/software. If the Alliance for Open
	* Media Patent License 1.0 was not distributed with this source code in the
	* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
	*/

	#include "av1/common/common.h"
	#include "av1/common/pred_common.h"
	#include "av1/common/reconinter.h"
	#include "av1/common/reconintra.h"
	#include "av1/common/seg_common.h"

	// Returns a context number for the given MB prediction signal
	static InterpFilter get_ref_filter_type(const MB_MODE_INFO *ref_mbmi,
	const MACROBLOCKD *xd, int dir,
	MV_REFERENCE_FRAME ref_frame) {
	(void)xd;

	return ((ref_mbmi->ref_frame[0] == ref_frame \|\|
	ref_mbmi->ref_frame[1] == ref_frame)
	? av1_extract_interp_filter(ref_mbmi->interp_filters, dir & 0x01)
	: SWITCHABLE_FILTERS);
	}

	int av1_get_pred_context_switchable_interp(const MACROBLOCKD *xd, int dir) {
	const MB_MODE_INFO *const mbmi = xd->mi[0];
	const int ctx_offset =
	(mbmi->ref_frame[1] > INTRA_FRAME) * INTER_FILTER_COMP_OFFSET;
	assert(dir == 0 \|\| dir == 1);
	const MV_REFERENCE_FRAME ref_frame = mbmi->ref_frame[0];
	// Note:
	// The mode info data structure has a one element border above and to the
	// left of the entries corresponding to real macroblocks.
	// The prediction flags in these dummy entries are initialized to 0.
	int filter_type_ctx = ctx_offset + (dir & 0x01) * INTER_FILTER_DIR_OFFSET;
	int left_type = SWITCHABLE_FILTERS;
	int above_type = SWITCHABLE_FILTERS;

	if (xd->left_available)
	left_type = get_ref_filter_type(xd->mi[-1], xd, dir, ref_frame);

	if (xd->up_available)
	above_type =
	get_ref_filter_type(xd->mi[-xd->mi_stride], xd, dir, ref_frame);

	if (left_type == above_type) {
	filter_type_ctx += left_type;
	} else if (left_type == SWITCHABLE_FILTERS) {
	assert(above_type != SWITCHABLE_FILTERS);
	filter_type_ctx += above_type;
	} else if (above_type == SWITCHABLE_FILTERS) {
	assert(left_type != SWITCHABLE_FILTERS);
	filter_type_ctx += left_type;
	} else {
	filter_type_ctx += SWITCHABLE_FILTERS;
	}

	return filter_type_ctx;
	}

	static void palette_add_to_cache(uint16_t cache, int n, uint16_t val) {
	// Do not add an already existing value
	if (n > 0 && val == cache[n - 1]) return;

	cache[(*n)++] = val;
	}

	int av1_get_palette_cache(const MACROBLOCKD *const xd, int plane,
	uint16_t *cache) {
	const int row = -xd->mb_to_top_edge >> 3;
	// Do not refer to above SB row when on SB boundary.
	const MB_MODE_INFO *const above_mi =
	(row % (1 << MIN_SB_SIZE_LOG2)) ? xd->above_mbmi : NULL;
	const MB_MODE_INFO *const left_mi = xd->left_mbmi;
	int above_n = 0, left_n = 0;
	if (above_mi) above_n = above_mi->palette_mode_info.palette_size[plane != 0];
	if (left_mi) left_n = left_mi->palette_mode_info.palette_size[plane != 0];
	if (above_n == 0 && left_n == 0) return 0;
	int above_idx = plane * PALETTE_MAX_SIZE;
	int left_idx = plane * PALETTE_MAX_SIZE;
	int n = 0;
	const uint16_t *above_colors =
	above_mi ? above_mi->palette_mode_info.palette_colors : NULL;
	const uint16_t *left_colors =
	left_mi ? left_mi->palette_mode_info.palette_colors : NULL;
	// Merge the sorted lists of base colors from above and left to get
	// combined sorted color cache.
	while (above_n > 0 && left_n > 0) {
	uint16_t v_above = above_colors[above_idx];
	uint16_t v_left = left_colors[left_idx];
	if (v_left < v_above) {
	palette_add_to_cache(cache, &n, v_left);
	++left_idx, --left_n;
	} else {
	palette_add_to_cache(cache, &n, v_above);
	++above_idx, --above_n;
	if (v_left == v_above) ++left_idx, --left_n;
	}
	}
	while (above_n-- > 0) {
	uint16_t val = above_colors[above_idx++];
	palette_add_to_cache(cache, &n, val);
	}
	while (left_n-- > 0) {
	uint16_t val = left_colors[left_idx++];
	palette_add_to_cache(cache, &n, val);
	}
	assert(n <= 2 * PALETTE_MAX_SIZE);
	return n;
	}

	// The mode info data structure has a one element border above and to the
	// left of the entries corresponding to real macroblocks.
	// The prediction flags in these dummy entries are initialized to 0.
	// 0 - inter/inter, inter/--, --/inter, --/--
	// 1 - intra/inter, inter/intra
	// 2 - intra/--, --/intra
	// 3 - intra/intra
	int av1_get_intra_inter_context(const MACROBLOCKD *xd) {
	const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
	const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
	const int has_above = xd->up_available;
	const int has_left = xd->left_available;

	if (has_above && has_left) { // both edges available
	const int above_intra = !is_inter_block(above_mbmi);
	const int left_intra = !is_inter_block(left_mbmi);
	return left_intra && above_intra ? 3 : left_intra \|\| above_intra;
	} else if (has_above \|\| has_left) { // one edge available
	return 2 * !is_inter_block(has_above ? above_mbmi : left_mbmi);
	} else {
	return 0;
	}
	}

	#define CHECK_BACKWARD_REFS(ref_frame) \
	(((ref_frame) >= BWDREF_FRAME) && ((ref_frame) <= ALTREF_FRAME))
	#define IS_BACKWARD_REF_FRAME(ref_frame) CHECK_BACKWARD_REFS(ref_frame)

	int av1_get_reference_mode_context(const MACROBLOCKD *xd) {
	int ctx;
	const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
	const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
	const int has_above = xd->up_available;
	const int has_left = xd->left_available;

	// Note:
	// The mode info data structure has a one element border above and to the
	// left of the entries corresponding to real macroblocks.
	// The prediction flags in these dummy entries are initialized to 0.
	if (has_above && has_left) { // both edges available
	if (!has_second_ref(above_mbmi) && !has_second_ref(left_mbmi))
	// neither edge uses comp pred (0/1)
	ctx = IS_BACKWARD_REF_FRAME(above_mbmi->ref_frame[0]) ^
	IS_BACKWARD_REF_FRAME(left_mbmi->ref_frame[0]);
	else if (!has_second_ref(above_mbmi))
	// one of two edges uses comp pred (2/3)
	ctx = 2 + (IS_BACKWARD_REF_FRAME(above_mbmi->ref_frame[0]) \|\|
	!is_inter_block(above_mbmi));
	else if (!has_second_ref(left_mbmi))
	// one of two edges uses comp pred (2/3)
	ctx = 2 + (IS_BACKWARD_REF_FRAME(left_mbmi->ref_frame[0]) \|\|
	!is_inter_block(left_mbmi));
	else // both edges use comp pred (4)
	ctx = 4;
	} else if (has_above \|\| has_left) { // one edge available
	const MB_MODE_INFO *edge_mbmi = has_above ? above_mbmi : left_mbmi;

	if (!has_second_ref(edge_mbmi))
	// edge does not use comp pred (0/1)
	ctx = IS_BACKWARD_REF_FRAME(edge_mbmi->ref_frame[0]);
	else
	// edge uses comp pred (3)
	ctx = 3;
	} else { // no edges available (1)
	ctx = 1;
	}
	assert(ctx >= 0 && ctx < COMP_INTER_CONTEXTS);
	return ctx;
	}

	int av1_get_comp_reference_type_context(const MACROBLOCKD *xd) {
	int pred_context;
	const MB_MODE_INFO *const above_mbmi = xd->above_mbmi;
	const MB_MODE_INFO *const left_mbmi = xd->left_mbmi;
	const int above_in_image = xd->up_available;
	const int left_in_image = xd->left_available;

	if (above_in_image && left_in_image) { // both edges available
	const int above_intra = !is_inter_block(above_mbmi);
	const int left_intra = !is_inter_block(left_mbmi);

	if (above_intra && left_intra) { // intra/intra
	pred_context = 2;
	} else if (above_intra \|\| left_intra) { // intra/inter
	const MB_MODE_INFO *inter_mbmi = above_intra ? left_mbmi : above_mbmi;

	if (!has_second_ref(inter_mbmi)) // single pred
	pred_context = 2;
	else // comp pred
	pred_context = 1 + 2 * has_uni_comp_refs(inter_mbmi);
	} else { // inter/inter
	const int a_sg = !has_second_ref(above_mbmi);
	const int l_sg = !has_second_ref(left_mbmi);
	const MV_REFERENCE_FRAME frfa = above_mbmi->ref_frame[0];
	const MV_REFERENCE_FRAME frfl = left_mbmi->ref_frame[0];

	if (a_sg && l_sg) { // single/single
	pred_context = 1 + 2 * (!(IS_BACKWARD_REF_FRAME(frfa) ^
	IS_BACKWARD_REF_FRAME(frfl)));
	} else if (l_sg \|\| a_sg) { // single/comp
	const int uni_rfc =
	a_sg ? has_uni_comp_refs(left_mbmi) : has_uni_comp_refs(above_mbmi);

	if (!uni_rfc) // comp bidir
	pred_context = 1;
	else // comp unidir
	pred_context = 3 + (!(IS_BACKWARD_REF_FRAME(frfa) ^
	IS_BACKWARD_REF_FRAME(frfl)));
	} else { // comp/comp
	const int a_uni_rfc = has_uni_comp_refs(above_mbmi);
	const int l_uni_rfc = has_uni_comp_refs(left_mbmi);

	if (!a_uni_rfc && !l_uni_rfc) // bidir/bidir
	pred_context = 0;
	else if (!a_uni_rfc \|\| !l_uni_rfc) // unidir/bidir
	pred_context = 2;
	else // unidir/unidir
	pred_context =
	3 + (!((frfa == BWDREF_FRAME) ^ (frfl == BWDREF_FRAME)));
	}
	}
	} else if (above_in_image \|\| left_in_image) { // one edge available
	const MB_MODE_INFO *edge_mbmi = above_in_image ? above_mbmi : left_mbmi;

	if (!is_inter_block(edge_mbmi)) { // intra
	pred_context = 2;
	} else { // inter
	if (!has_second_ref(edge_mbmi)) // single pred
	pred_context = 2;
	else // comp pred
	pred_context = 4 * has_uni_comp_refs(edge_mbmi);
	}
	} else { // no edges available
	pred_context = 2;
	}

	assert(pred_context >= 0 && pred_context < COMP_REF_TYPE_CONTEXTS);
	return pred_context;
	}

	// Returns a context number for the given MB prediction signal
	//
	// Signal the uni-directional compound reference frame pair as either
	// (BWDREF, ALTREF), or (LAST, LAST2) / (LAST, LAST3) / (LAST, GOLDEN),
	// conditioning on the pair is known as uni-directional.
	//
	// 3 contexts: Voting is used to compare the count of forward references with
	// that of backward references from the spatial neighbors.
	int av1_get_pred_context_uni_comp_ref_p(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of forward references (L, L2, L3, or G)
	const int frf_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME] +
	ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];
	// Count of backward references (B or A)
	const int brf_count = ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME] +
	ref_counts[ALTREF_FRAME];

	const int pred_context =
	(frf_count == brf_count) ? 1 : ((frf_count < brf_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
	return pred_context;
	}

	// Returns a context number for the given MB prediction signal
	//
	// Signal the uni-directional compound reference frame pair as
	// either (LAST, LAST2), or (LAST, LAST3) / (LAST, GOLDEN),
	// conditioning on the pair is known as one of the above three.
	//
	// 3 contexts: Voting is used to compare the count of LAST2_FRAME with the
	// total count of LAST3/GOLDEN from the spatial neighbors.
	int av1_get_pred_context_uni_comp_ref_p1(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of LAST2
	const int last2_count = ref_counts[LAST2_FRAME];
	// Count of LAST3 or GOLDEN
	const int last3_or_gld_count =
	ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];

	const int pred_context = (last2_count == last3_or_gld_count)
	? 1
	: ((last2_count < last3_or_gld_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
	return pred_context;
	}

	// Returns a context number for the given MB prediction signal
	//
	// Signal the uni-directional compound reference frame pair as
	// either (LAST, LAST3) or (LAST, GOLDEN),
	// conditioning on the pair is known as one of the above two.
	//
	// 3 contexts: Voting is used to compare the count of LAST3_FRAME with the
	// total count of GOLDEN_FRAME from the spatial neighbors.
	int av1_get_pred_context_uni_comp_ref_p2(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of LAST3
	const int last3_count = ref_counts[LAST3_FRAME];
	// Count of GOLDEN
	const int gld_count = ref_counts[GOLDEN_FRAME];

	const int pred_context =
	(last3_count == gld_count) ? 1 : ((last3_count < gld_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < UNI_COMP_REF_CONTEXTS);
	return pred_context;
	}

	// == Common context functions for both comp and single ref ==
	//
	// Obtain contexts to signal a reference frame to be either LAST/LAST2 or
	// LAST3/GOLDEN.
	static int get_pred_context_ll2_or_l3gld(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of LAST + LAST2
	const int last_last2_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME];
	// Count of LAST3 + GOLDEN
	const int last3_gld_count =
	ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];

	const int pred_context = (last_last2_count == last3_gld_count)
	? 1
	: ((last_last2_count < last3_gld_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// Obtain contexts to signal a reference frame to be either LAST or LAST2.
	static int get_pred_context_last_or_last2(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of LAST
	const int last_count = ref_counts[LAST_FRAME];
	// Count of LAST2
	const int last2_count = ref_counts[LAST2_FRAME];

	const int pred_context =
	(last_count == last2_count) ? 1 : ((last_count < last2_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// Obtain contexts to signal a reference frame to be either LAST3 or GOLDEN.
	static int get_pred_context_last3_or_gld(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of LAST3
	const int last3_count = ref_counts[LAST3_FRAME];
	// Count of GOLDEN
	const int gld_count = ref_counts[GOLDEN_FRAME];

	const int pred_context =
	(last3_count == gld_count) ? 1 : ((last3_count < gld_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// Obtain contexts to signal a reference frame be either BWDREF/ALTREF2, or
	// ALTREF.
	static int get_pred_context_brfarf2_or_arf(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Counts of BWDREF, ALTREF2, or ALTREF frames (B, A2, or A)
	const int brfarf2_count =
	ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME];
	const int arf_count = ref_counts[ALTREF_FRAME];

	const int pred_context =
	(brfarf2_count == arf_count) ? 1 : ((brfarf2_count < arf_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// Obtain contexts to signal a reference frame be either BWDREF or ALTREF2.
	static int get_pred_context_brf_or_arf2(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of BWDREF frames (B)
	const int brf_count = ref_counts[BWDREF_FRAME];
	// Count of ALTREF2 frames (A2)
	const int arf2_count = ref_counts[ALTREF2_FRAME];

	const int pred_context =
	(brf_count == arf2_count) ? 1 : ((brf_count < arf2_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// == Context functions for comp ref ==
	//
	// Returns a context number for the given MB prediction signal
	// Signal the first reference frame for a compound mode be either
	// GOLDEN/LAST3, or LAST/LAST2.
	int av1_get_pred_context_comp_ref_p(const MACROBLOCKD *xd) {
	return get_pred_context_ll2_or_l3gld(xd);
	}

	// Returns a context number for the given MB prediction signal
	// Signal the first reference frame for a compound mode be LAST,
	// conditioning on that it is known either LAST/LAST2.
	int av1_get_pred_context_comp_ref_p1(const MACROBLOCKD *xd) {
	return get_pred_context_last_or_last2(xd);
	}

	// Returns a context number for the given MB prediction signal
	// Signal the first reference frame for a compound mode be GOLDEN,
	// conditioning on that it is known either GOLDEN or LAST3.
	int av1_get_pred_context_comp_ref_p2(const MACROBLOCKD *xd) {
	return get_pred_context_last3_or_gld(xd);
	}

	// Signal the 2nd reference frame for a compound mode be either
	// ALTREF, or ALTREF2/BWDREF.
	int av1_get_pred_context_comp_bwdref_p(const MACROBLOCKD *xd) {
	return get_pred_context_brfarf2_or_arf(xd);
	}

	// Signal the 2nd reference frame for a compound mode be either
	// ALTREF2 or BWDREF.
	int av1_get_pred_context_comp_bwdref_p1(const MACROBLOCKD *xd) {
	return get_pred_context_brf_or_arf2(xd);
	}

	// == Context functions for single ref ==
	//
	// For the bit to signal whether the single reference is a forward reference
	// frame or a backward reference frame.
	int av1_get_pred_context_single_ref_p1(const MACROBLOCKD *xd) {
	const uint8_t *const ref_counts = &xd->neighbors_ref_counts[0];

	// Count of forward reference frames
	const int fwd_count = ref_counts[LAST_FRAME] + ref_counts[LAST2_FRAME] +
	ref_counts[LAST3_FRAME] + ref_counts[GOLDEN_FRAME];
	// Count of backward reference frames
	const int bwd_count = ref_counts[BWDREF_FRAME] + ref_counts[ALTREF2_FRAME] +
	ref_counts[ALTREF_FRAME];

	const int pred_context =
	(fwd_count == bwd_count) ? 1 : ((fwd_count < bwd_count) ? 0 : 2);

	assert(pred_context >= 0 && pred_context < REF_CONTEXTS);
	return pred_context;
	}

	// For the bit to signal whether the single reference is ALTREF_FRAME or
	// non-ALTREF backward reference frame, knowing that it shall be either of
	// these 2 choices.
	int av1_get_pred_context_single_ref_p2(const MACROBLOCKD *xd) {
	return get_pred_context_brfarf2_or_arf(xd);
	}

	// For the bit to signal whether the single reference is LAST3/GOLDEN or
	// LAST2/LAST, knowing that it shall be either of these 2 choices.
	int av1_get_pred_context_single_ref_p3(const MACROBLOCKD *xd) {
	return get_pred_context_ll2_or_l3gld(xd);
	}

	// For the bit to signal whether the single reference is LAST2_FRAME or
	// LAST_FRAME, knowing that it shall be either of these 2 choices.
	int av1_get_pred_context_single_ref_p4(const MACROBLOCKD *xd) {
	return get_pred_context_last_or_last2(xd);
	}

	// For the bit to signal whether the single reference is GOLDEN_FRAME or
	// LAST3_FRAME, knowing that it shall be either of these 2 choices.
	int av1_get_pred_context_single_ref_p5(const MACROBLOCKD *xd) {
	return get_pred_context_last3_or_gld(xd);
	}

	// For the bit to signal whether the single reference is ALTREF2_FRAME or
	// BWDREF_FRAME, knowing that it shall be either of these 2 choices.
	int av1_get_pred_context_single_ref_p6(const MACROBLOCKD *xd) {
	return get_pred_context_brf_or_arf2(xd);
	}