decodemv.c

/*
 * 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 <assert.h>

#include "av1/common/common.h"
#include "av1/common/entropy.h"
#include "av1/common/entropymode.h"
#include "av1/common/entropymv.h"
#include "av1/common/mvref_common.h"
#include "av1/common/pred_common.h"
#include "av1/common/reconinter.h"
#if CONFIG_EXT_INTRA
#include "av1/common/reconintra.h"
#endif  // CONFIG_EXT_INTRA
#include "av1/common/seg_common.h"
#include "av1/common/warped_motion.h"

#include "av1/decoder/decodeframe.h"
#include "av1/decoder/decodemv.h"

#include "aom_dsp/aom_dsp_common.h"

#if CONFIG_CFL
#include "av1/common/cfl.h"
#endif

#define ACCT_STR __func__

#define DEC_MISMATCH_DEBUG 0

static PREDICTION_MODE read_intra_mode(aom_reader *r, aom_cdf_prob *cdf) {
  return (PREDICTION_MODE)aom_read_symbol(r, cdf, INTRA_MODES, ACCT_STR);
}

static void read_cdef(AV1_COMMON *cm, aom_reader *r, MB_MODE_INFO *const mbmi,
                      int mi_col, int mi_row) {
  if (cm->all_lossless) return;

  const int m = ~((1 << (6 - MI_SIZE_LOG2)) - 1);
  if (!(mi_col & (cm->mib_size - 1)) &&
      !(mi_row & (cm->mib_size - 1))) {  // Top left?
#if CONFIG_EXT_PARTITION
    cm->cdef_preset[0] = cm->cdef_preset[1] = cm->cdef_preset[2] =
        cm->cdef_preset[3] = -1;
#else
    cm->cdef_preset = -1;
#endif
  }
// Read CDEF param at first a non-skip coding block
#if CONFIG_EXT_PARTITION
  const int mask = 1 << (6 - MI_SIZE_LOG2);
  const int index = cm->sb_size == BLOCK_128X128
                        ? !!(mi_col & mask) + 2 * !!(mi_row & mask)
                        : 0;
  cm->mi_grid_visible[(mi_row & m) * cm->mi_stride + (mi_col & m)]
      ->mbmi.cdef_strength = cm->cdef_preset[index] =
      cm->cdef_preset[index] == -1 && !mbmi->skip
          ? aom_read_literal(r, cm->cdef_bits, ACCT_STR)
          : cm->cdef_preset[index];
#else
  cm->mi_grid_visible[(mi_row & m) * cm->mi_stride + (mi_col & m)]
      ->mbmi.cdef_strength = cm->cdef_preset =
      cm->cdef_preset == -1 && !mbmi->skip
          ? aom_read_literal(r, cm->cdef_bits, ACCT_STR)
          : cm->cdef_preset;
#endif
}

static int read_delta_qindex(AV1_COMMON *cm, MACROBLOCKD *xd, aom_reader *r,
                             MB_MODE_INFO *const mbmi, int mi_col, int mi_row) {
  FRAME_COUNTS *counts = xd->counts;
  int sign, abs, reduced_delta_qindex = 0;
  BLOCK_SIZE bsize = mbmi->sb_type;
  const int b_col = mi_col & (cm->mib_size - 1);
  const int b_row = mi_row & (cm->mib_size - 1);
  const int read_delta_q_flag = (b_col == 0 && b_row == 0);
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  (void)cm;

  if ((bsize != cm->sb_size || mbmi->skip == 0) && read_delta_q_flag) {
    abs = aom_read_symbol(r, ec_ctx->delta_q_cdf, DELTA_Q_PROBS + 1, ACCT_STR);
    const int smallval = (abs < DELTA_Q_SMALL);
    if (counts) {
      for (int i = 0; i < abs; ++i) counts->delta_q[i][1]++;
      if (smallval) counts->delta_q[abs][0]++;
    }

    if (!smallval) {
      const int rem_bits = aom_read_literal(r, 3, ACCT_STR) + 1;
      const int thr = (1 << rem_bits) + 1;
      abs = aom_read_literal(r, rem_bits, ACCT_STR) + thr;
    }

    if (abs) {
      sign = aom_read_bit(r, ACCT_STR);
    } else {
      sign = 1;
    }

    reduced_delta_qindex = sign ? -abs : abs;
  }
  return reduced_delta_qindex;
}
#if CONFIG_EXT_DELTA_Q
static int read_delta_lflevel(AV1_COMMON *cm, MACROBLOCKD *xd, aom_reader *r,
#if CONFIG_LOOPFILTER_LEVEL
                              int lf_id,
#endif
                              MB_MODE_INFO *const mbmi, int mi_col,
                              int mi_row) {
  FRAME_COUNTS *counts = xd->counts;
  int sign, abs, reduced_delta_lflevel = 0;
  BLOCK_SIZE bsize = mbmi->sb_type;
  const int b_col = mi_col & (cm->mib_size - 1);
  const int b_row = mi_row & (cm->mib_size - 1);
  const int read_delta_lf_flag = (b_col == 0 && b_row == 0);
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  (void)cm;

  if ((bsize != cm->sb_size || mbmi->skip == 0) && read_delta_lf_flag) {
#if CONFIG_LOOPFILTER_LEVEL
    if (cm->delta_lf_multi) {
      assert(lf_id >= 0 && lf_id < FRAME_LF_COUNT);
      abs = aom_read_symbol(r, ec_ctx->delta_lf_multi_cdf[lf_id],
                            DELTA_LF_PROBS + 1, ACCT_STR);
    } else {
      abs = aom_read_symbol(r, ec_ctx->delta_lf_cdf, DELTA_LF_PROBS + 1,
                            ACCT_STR);
    }
#else
    abs =
        aom_read_symbol(r, ec_ctx->delta_lf_cdf, DELTA_LF_PROBS + 1, ACCT_STR);
#endif  // CONFIG_LOOPFILTER_LEVEL
    const int smallval = (abs < DELTA_LF_SMALL);
    if (counts) {
#if CONFIG_LOOPFILTER_LEVEL
      if (cm->delta_lf_multi) {
        for (int i = 0; i < abs; ++i) counts->delta_lf_multi[lf_id][i][1]++;
        if (smallval) counts->delta_lf_multi[lf_id][abs][0]++;
      } else {
        for (int i = 0; i < abs; ++i) counts->delta_lf[i][1]++;
        if (smallval) counts->delta_lf[abs][0]++;
      }
#else
      for (int i = 0; i < abs; ++i) counts->delta_lf[i][1]++;
      if (smallval) counts->delta_lf[abs][0]++;
#endif  // CONFIG_LOOPFILTER_LEVEL
    }
    if (!smallval) {
      const int rem_bits = aom_read_literal(r, 3, ACCT_STR) + 1;
      const int thr = (1 << rem_bits) + 1;
      abs = aom_read_literal(r, rem_bits, ACCT_STR) + thr;
    }

    if (abs) {
      sign = aom_read_bit(r, ACCT_STR);
    } else {
      sign = 1;
    }

    reduced_delta_lflevel = sign ? -abs : abs;
  }
  return reduced_delta_lflevel;
}
#endif

static UV_PREDICTION_MODE read_intra_mode_uv(FRAME_CONTEXT *ec_ctx,
                                             aom_reader *r,
                                             PREDICTION_MODE y_mode) {
  const UV_PREDICTION_MODE uv_mode =
#if CONFIG_CFL
      aom_read_symbol(r, ec_ctx->uv_mode_cdf[y_mode], UV_INTRA_MODES, ACCT_STR);
#else
      read_intra_mode(r, ec_ctx->uv_mode_cdf[y_mode]);
#endif  // CONFIG_CFL
  return uv_mode;
}

#if CONFIG_CFL
static int read_cfl_alphas(FRAME_CONTEXT *const ec_ctx, aom_reader *r,
                           int *signs_out) {
  const int joint_sign =
      aom_read_symbol(r, ec_ctx->cfl_sign_cdf, CFL_JOINT_SIGNS, "cfl:signs");
  int idx = 0;
  // Magnitudes are only coded for nonzero values
  if (CFL_SIGN_U(joint_sign) != CFL_SIGN_ZERO) {
    aom_cdf_prob *cdf_u = ec_ctx->cfl_alpha_cdf[CFL_CONTEXT_U(joint_sign)];
    idx = aom_read_symbol(r, cdf_u, CFL_ALPHABET_SIZE, "cfl:alpha_u")
          << CFL_ALPHABET_SIZE_LOG2;
  }
  if (CFL_SIGN_V(joint_sign) != CFL_SIGN_ZERO) {
    aom_cdf_prob *cdf_v = ec_ctx->cfl_alpha_cdf[CFL_CONTEXT_V(joint_sign)];
    idx += aom_read_symbol(r, cdf_v, CFL_ALPHABET_SIZE, "cfl:alpha_v");
  }
  *signs_out = joint_sign;
  return idx;
}
#endif

static INTERINTRA_MODE read_interintra_mode(MACROBLOCKD *xd, aom_reader *r,
                                            int size_group) {
  const INTERINTRA_MODE ii_mode = (INTERINTRA_MODE)aom_read_symbol(
      r, xd->tile_ctx->interintra_mode_cdf[size_group], INTERINTRA_MODES,
      ACCT_STR);
  FRAME_COUNTS *counts = xd->counts;
  if (counts) ++counts->interintra_mode[size_group][ii_mode];
  return ii_mode;
}

static PREDICTION_MODE read_inter_mode(FRAME_CONTEXT *ec_ctx, MACROBLOCKD *xd,
                                       aom_reader *r, int16_t ctx) {
  FRAME_COUNTS *counts = xd->counts;
  int16_t mode_ctx = ctx & NEWMV_CTX_MASK;
  int is_newmv, is_zeromv, is_refmv;
  is_newmv = aom_read_symbol(r, ec_ctx->newmv_cdf[mode_ctx], 2, ACCT_STR) == 0;
  if (is_newmv) {
    if (counts) ++counts->newmv_mode[mode_ctx][0];
    return NEWMV;
  }
  if (counts) ++counts->newmv_mode[mode_ctx][1];
  if (ctx & (1 << ALL_ZERO_FLAG_OFFSET)) return GLOBALMV;
  mode_ctx = (ctx >> GLOBALMV_OFFSET) & GLOBALMV_CTX_MASK;
  is_zeromv =
      aom_read_symbol(r, ec_ctx->zeromv_cdf[mode_ctx], 2, ACCT_STR) == 0;
  if (is_zeromv) {
    if (counts) ++counts->zeromv_mode[mode_ctx][0];
    return GLOBALMV;
  }
  if (counts) ++counts->zeromv_mode[mode_ctx][1];
  mode_ctx = (ctx >> REFMV_OFFSET) & REFMV_CTX_MASK;
  if (ctx & (1 << SKIP_NEARESTMV_OFFSET)) mode_ctx = 6;
  if (ctx & (1 << SKIP_NEARMV_OFFSET)) mode_ctx = 7;
  if (ctx & (1 << SKIP_NEARESTMV_SUB8X8_OFFSET)) mode_ctx = 8;
  is_refmv = aom_read_symbol(r, ec_ctx->refmv_cdf[mode_ctx], 2, ACCT_STR) == 0;
  if (is_refmv) {
    if (counts) ++counts->refmv_mode[mode_ctx][0];
    return NEARESTMV;
  } else {
    if (counts) ++counts->refmv_mode[mode_ctx][1];
    return NEARMV;
  }
}

static void read_drl_idx(FRAME_CONTEXT *ec_ctx, MACROBLOCKD *xd,
                         MB_MODE_INFO *mbmi, aom_reader *r) {
  uint8_t ref_frame_type = av1_ref_frame_type(mbmi->ref_frame);
  mbmi->ref_mv_idx = 0;
  if (mbmi->mode == NEWMV || mbmi->mode == NEW_NEWMV) {
    for (int idx = 0; idx < 2; ++idx) {
      if (xd->ref_mv_count[ref_frame_type] > idx + 1 || CONFIG_OPT_REF_MV) {
        uint8_t drl_ctx = av1_drl_ctx(xd->ref_mv_stack[ref_frame_type], idx);
        int drl_idx = aom_read_symbol(r, ec_ctx->drl_cdf[drl_ctx], 2, ACCT_STR);
        mbmi->ref_mv_idx = idx + drl_idx;
        if (xd->counts) ++xd->counts->drl_mode[drl_ctx][drl_idx];
        if (!drl_idx) return;
      }
    }
  }
  if (have_nearmv_in_inter_mode(mbmi->mode)) {
    // Offset the NEARESTMV mode.
    // TODO(jingning): Unify the two syntax decoding loops after the NEARESTMV
    // mode is factored in.
    for (int idx = 1; idx < 3; ++idx) {
      if (xd->ref_mv_count[ref_frame_type] > idx + 1 || CONFIG_OPT_REF_MV) {
        uint8_t drl_ctx = av1_drl_ctx(xd->ref_mv_stack[ref_frame_type], idx);
        int drl_idx = aom_read_symbol(r, ec_ctx->drl_cdf[drl_ctx], 2, ACCT_STR);
        mbmi->ref_mv_idx = idx + drl_idx - 1;
        if (xd->counts) ++xd->counts->drl_mode[drl_ctx][drl_idx];
        if (!drl_idx) return;
      }
    }
  }
}

#if CONFIG_EXT_WARPED_MOTION
static MOTION_MODE read_motion_mode(MACROBLOCKD *xd, MODE_INFO *mi,
                                    aom_reader *r, int best) {
#else
static MOTION_MODE read_motion_mode(MACROBLOCKD *xd, MODE_INFO *mi,
                                    aom_reader *r) {
#endif  // CONFIG_EXT_WARPED_MOTION
  MB_MODE_INFO *mbmi = &mi->mbmi;

#if CONFIG_EXT_SKIP
  if (mbmi->skip_mode) return SIMPLE_TRANSLATION;
#endif  // CONFIG_EXT_SKIP

  const MOTION_MODE last_motion_mode_allowed =
      motion_mode_allowed(xd->global_motion, xd, mi);
  int motion_mode;
  FRAME_COUNTS *counts = xd->counts;

  if (last_motion_mode_allowed == SIMPLE_TRANSLATION) return SIMPLE_TRANSLATION;

  if (last_motion_mode_allowed == OBMC_CAUSAL) {
    motion_mode =
        aom_read_symbol(r, xd->tile_ctx->obmc_cdf[mbmi->sb_type], 2, ACCT_STR);
    if (counts) ++counts->obmc[mbmi->sb_type][motion_mode];
    return (MOTION_MODE)(SIMPLE_TRANSLATION + motion_mode);
  } else {
#if CONFIG_EXT_WARPED_MOTION
    int wm_ctx = 0;
    if (best != -1) {
      wm_ctx = 1;
      if (mbmi->mode == NEARESTMV) wm_ctx = 2;
    }

    motion_mode =
        aom_read_symbol(r, xd->tile_ctx->motion_mode_cdf[wm_ctx][mbmi->sb_type],
                        MOTION_MODES, ACCT_STR);
    if (counts) ++counts->motion_mode[wm_ctx][mbmi->sb_type][motion_mode];
#else
    motion_mode =
        aom_read_symbol(r, xd->tile_ctx->motion_mode_cdf[mbmi->sb_type],
                        MOTION_MODES, ACCT_STR);
    if (counts) ++counts->motion_mode[mbmi->sb_type][motion_mode];
#endif  // CONFIG_EXT_WARPED_MOTION

    return (MOTION_MODE)(SIMPLE_TRANSLATION + motion_mode);
  }
}

static PREDICTION_MODE read_inter_compound_mode(AV1_COMMON *cm, MACROBLOCKD *xd,
                                                aom_reader *r, int16_t ctx) {
  (void)cm;
  const int mode =
      aom_read_symbol(r, xd->tile_ctx->inter_compound_mode_cdf[ctx],
                      INTER_COMPOUND_MODES, ACCT_STR);
  FRAME_COUNTS *counts = xd->counts;
  if (counts) ++counts->inter_compound_mode[ctx][mode];
  assert(is_inter_compound_mode(NEAREST_NEARESTMV + mode));
  return NEAREST_NEARESTMV + mode;
}

#if CONFIG_SPATIAL_SEGMENTATION
static int neg_deinterleave(int diff, int ref, int max) {
  if (!ref) return diff;
  if (ref >= (max - 1)) return max - diff - 1;
  if (2 * ref < max) {
    if (diff <= 2 * ref) {
      if (diff & 1)
        return ref + ((diff + 1) >> 1);
      else
        return ref - (diff >> 1);
    }
    return diff;
  } else {
    if (diff <= 2 * (max - ref - 1)) {
      if (diff & 1)
        return ref + ((diff + 1) >> 1);
      else
        return ref - (diff >> 1);
    }
    return max - (diff + 1);
  }
}

static int read_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                           int mi_row, int mi_col, aom_reader *r, int skip) {
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  struct segmentation_probs *const segp = &ec_ctx->seg;
  int prev_ul = 0; /* Top left segment_id */
  int prev_l = 0;  /* Current left segment_id */
  int prev_u = 0;  /* Current top segment_id */

  MODE_INFO *const mi = cm->mi + mi_row * cm->mi_stride + mi_col;
  int tinfo = mi->mbmi.boundary_info;
  int above = (!(tinfo & TILE_ABOVE_BOUNDARY)) && ((mi_row - 1) >= 0);
  int left = (!(tinfo & TILE_LEFT_BOUNDARY)) && ((mi_col - 1) >= 0);

  if (above && left)
    prev_ul = get_segment_id(cm, cm->current_frame_seg_map, BLOCK_4X4,
                             mi_row - 1, mi_col - 1);

  if (above)
    prev_u = get_segment_id(cm, cm->current_frame_seg_map, BLOCK_4X4,
                            mi_row - 1, mi_col - 0);

  if (left)
    prev_l = get_segment_id(cm, cm->current_frame_seg_map, BLOCK_4X4,
                            mi_row - 0, mi_col - 1);

  int cdf_num = pick_spatial_seg_cdf(prev_ul, prev_u, prev_l);
  int pred = pick_spatial_seg_pred(prev_ul, prev_u, prev_l);

  if (skip) return pred;

  aom_cdf_prob *pred_cdf = segp->spatial_pred_seg_cdf[cdf_num];
  int coded_id = aom_read_symbol(r, pred_cdf, 8, ACCT_STR);

  int segment_id = neg_deinterleave(coded_id, pred, cm->last_active_segid + 1);

  assert(segment_id >= 0 && segment_id <= cm->last_active_segid);

  return segment_id;
}
#else
static int read_segment_id(aom_reader *r, struct segmentation_probs *segp) {
  return aom_read_symbol(r, segp->tree_cdf, MAX_SEGMENTS, ACCT_STR);
}
#endif

static void read_tx_size_vartx(AV1_COMMON *cm, MACROBLOCKD *xd,
                               MB_MODE_INFO *mbmi, FRAME_COUNTS *counts,
                               TX_SIZE tx_size, int depth, int blk_row,
                               int blk_col, aom_reader *r) {
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  (void)cm;
  int is_split = 0;
  const int tx_row = blk_row >> 1;
  const int tx_col = blk_col >> 1;
  const int max_blocks_high = max_block_high(xd, mbmi->sb_type, 0);
  const int max_blocks_wide = max_block_wide(xd, mbmi->sb_type, 0);
  int ctx = txfm_partition_context(xd->above_txfm_context + blk_col,
                                   xd->left_txfm_context + blk_row,
                                   mbmi->sb_type, tx_size);
  TX_SIZE(*const inter_tx_size)
  [MAX_MIB_SIZE] =
      (TX_SIZE(*)[MAX_MIB_SIZE]) & mbmi->inter_tx_size[tx_row][tx_col];
  if (blk_row >= max_blocks_high || blk_col >= max_blocks_wide) return;
  assert(tx_size > TX_4X4);

  if (depth == MAX_VARTX_DEPTH) {
    int idx, idy;
    inter_tx_size[0][0] = tx_size;
    for (idy = 0; idy < AOMMAX(1, tx_size_high_unit[tx_size] / 2); ++idy)
      for (idx = 0; idx < AOMMAX(1, tx_size_wide_unit[tx_size] / 2); ++idx)
        inter_tx_size[idy][idx] = tx_size;
    mbmi->tx_size = tx_size;
    mbmi->min_tx_size = AOMMIN(mbmi->min_tx_size, get_min_tx_size(tx_size));
    txfm_partition_update(xd->above_txfm_context + blk_col,
                          xd->left_txfm_context + blk_row, tx_size, tx_size);
    return;
  }

  is_split = aom_read_symbol(r, ec_ctx->txfm_partition_cdf[ctx], 2, ACCT_STR);

  if (is_split) {
    const TX_SIZE sub_txs = sub_tx_size_map[1][tx_size];
    const int bsw = tx_size_wide_unit[sub_txs];
    const int bsh = tx_size_high_unit[sub_txs];

    if (counts) ++counts->txfm_partition[ctx][1];

    if (sub_txs == TX_4X4) {
      int idx, idy;
      inter_tx_size[0][0] = sub_txs;
      for (idy = 0; idy < AOMMAX(1, tx_size_high_unit[tx_size] / 2); ++idy)
        for (idx = 0; idx < AOMMAX(1, tx_size_wide_unit[tx_size] / 2); ++idx)
          inter_tx_size[idy][idx] = inter_tx_size[0][0];
      mbmi->tx_size = sub_txs;
      mbmi->min_tx_size = get_min_tx_size(mbmi->tx_size);
      txfm_partition_update(xd->above_txfm_context + blk_col,
                            xd->left_txfm_context + blk_row, sub_txs, tx_size);
      return;
    }

    assert(bsw > 0 && bsh > 0);
    for (int row = 0; row < tx_size_high_unit[tx_size]; row += bsh) {
      for (int col = 0; col < tx_size_wide_unit[tx_size]; col += bsw) {
        int offsetr = blk_row + row;
        int offsetc = blk_col + col;
        read_tx_size_vartx(cm, xd, mbmi, counts, sub_txs, depth + 1, offsetr,
                           offsetc, r);
      }
    }
  } else {
    int idx, idy;
    inter_tx_size[0][0] = tx_size;
    for (idy = 0; idy < AOMMAX(1, tx_size_high_unit[tx_size] / 2); ++idy)
      for (idx = 0; idx < AOMMAX(1, tx_size_wide_unit[tx_size] / 2); ++idx)
        inter_tx_size[idy][idx] = tx_size;
    mbmi->tx_size = tx_size;
    mbmi->min_tx_size = AOMMIN(mbmi->min_tx_size, get_min_tx_size(tx_size));
    if (counts) ++counts->txfm_partition[ctx][0];
    txfm_partition_update(xd->above_txfm_context + blk_col,
                          xd->left_txfm_context + blk_row, tx_size, tx_size);
  }
}

static TX_SIZE read_selected_tx_size(AV1_COMMON *cm, MACROBLOCKD *xd,
                                     int is_inter, aom_reader *r) {
  // TODO(debargha): Clean up the logic here. This function should only
  // be called for intra.
  const BLOCK_SIZE bsize = xd->mi[0]->mbmi.sb_type;
  const int32_t tx_size_cat = bsize_to_tx_size_cat(bsize, is_inter);
  const int max_depths = bsize_to_max_depth(bsize, 0);
  const int ctx = get_tx_size_context(xd);
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  (void)cm;

  const int depth = aom_read_symbol(r, ec_ctx->tx_size_cdf[tx_size_cat][ctx],
                                    max_depths + 1, ACCT_STR);
  assert(depth >= 0 && depth <= max_depths);
  const TX_SIZE tx_size = depth_to_tx_size(depth, bsize, 0);
  return tx_size;
}

static TX_SIZE read_tx_size(AV1_COMMON *cm, MACROBLOCKD *xd, int is_inter,
                            int allow_select_inter, aom_reader *r) {
  const TX_MODE tx_mode = cm->tx_mode;
  const BLOCK_SIZE bsize = xd->mi[0]->mbmi.sb_type;
  if (xd->lossless[xd->mi[0]->mbmi.segment_id]) return TX_4X4;

  if (block_signals_txsize(bsize)) {
    if ((!is_inter || allow_select_inter) && tx_mode == TX_MODE_SELECT) {
      const TX_SIZE coded_tx_size = read_selected_tx_size(cm, xd, is_inter, r);
      return coded_tx_size;
    } else {
      return tx_size_from_tx_mode(bsize, tx_mode, is_inter);
    }
  } else {
    assert(IMPLIES(tx_mode == ONLY_4X4, bsize == BLOCK_4X4));
    return get_max_rect_tx_size(bsize, is_inter);
  }
}

static int dec_get_segment_id(const AV1_COMMON *cm, const uint8_t *segment_ids,
                              int mi_offset, int x_mis, int y_mis) {
  int segment_id = INT_MAX;

  for (int y = 0; y < y_mis; y++)
    for (int x = 0; x < x_mis; x++)
      segment_id =
          AOMMIN(segment_id, segment_ids[mi_offset + y * cm->mi_cols + x]);

  assert(segment_id >= 0 && segment_id < MAX_SEGMENTS);
  return segment_id;
}

static void set_segment_id(AV1_COMMON *cm, int mi_offset, int x_mis, int y_mis,
                           int segment_id) {
  assert(segment_id >= 0 && segment_id < MAX_SEGMENTS);

  for (int y = 0; y < y_mis; y++)
    for (int x = 0; x < x_mis; x++)
      cm->current_frame_seg_map[mi_offset + y * cm->mi_cols + x] = segment_id;
}

static int read_intra_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                                 MB_MODE_INFO *const mbmi, int mi_row,
                                 int mi_col, int bsize, int preskip,
                                 aom_reader *r) {
  struct segmentation *const seg = &cm->seg;
  const int mi_offset = mi_row * cm->mi_cols + mi_col;
  const int bw = mi_size_wide[bsize];
  const int bh = mi_size_high[bsize];
  const int x_mis = AOMMIN(cm->mi_cols - mi_col, bw);
  const int y_mis = AOMMIN(cm->mi_rows - mi_row, bh);

  if (!seg->enabled) return 0;  // Default for disabled segmentation

  assert(seg->update_map && !seg->temporal_update);

#if CONFIG_SPATIAL_SEGMENTATION
  if (preskip) {
    if (!cm->preskip_segid) return 0;
  } else {
    if (cm->preskip_segid) return mbmi->segment_id;
  }
  const int segment_id =
      read_segment_id(cm, xd, mi_row, mi_col, r, preskip ? 0 : mbmi->skip);
#else
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  (void)preskip;
  (void)mbmi;
  const int segment_id = read_segment_id(r, &ec_ctx->seg);
#endif
  FRAME_COUNTS *counts = xd->counts;
  if (counts) ++counts->seg.tree_total[segment_id];
  set_segment_id(cm, mi_offset, x_mis, y_mis, segment_id);
  return segment_id;
}

static void copy_segment_id(const AV1_COMMON *cm,
                            const uint8_t *last_segment_ids,
                            uint8_t *current_segment_ids, int mi_offset,
                            int x_mis, int y_mis) {
  for (int y = 0; y < y_mis; y++)
    for (int x = 0; x < x_mis; x++)
      current_segment_ids[mi_offset + y * cm->mi_cols + x] =
          last_segment_ids ? last_segment_ids[mi_offset + y * cm->mi_cols + x]
                           : 0;
}

static int read_inter_segment_id(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                                 int mi_row, int mi_col, int preskip,
                                 aom_reader *r) {
  struct segmentation *const seg = &cm->seg;
  FRAME_COUNTS *counts = xd->counts;
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  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;
  const int bw = mi_size_wide[mbmi->sb_type];
  const int bh = mi_size_high[mbmi->sb_type];

  // TODO(slavarnway): move x_mis, y_mis into xd ?????
  const int x_mis = AOMMIN(cm->mi_cols - mi_col, bw);
  const int y_mis = AOMMIN(cm->mi_rows - mi_row, bh);

  if (!seg->enabled) return 0;  // Default for disabled segmentation

  predicted_segment_id = cm->last_frame_seg_map
                             ? dec_get_segment_id(cm, cm->last_frame_seg_map,
                                                  mi_offset, x_mis, y_mis)
                             : 0;

  if (!seg->update_map) {
    copy_segment_id(cm, cm->last_frame_seg_map, cm->current_frame_seg_map,
                    mi_offset, x_mis, y_mis);
    return predicted_segment_id;
  }

#if CONFIG_SPATIAL_SEGMENTATION
  if (preskip) {
    if (!cm->preskip_segid) return 0;
  } else {
    if (cm->preskip_segid) return mbmi->segment_id;
    if (mbmi->skip) {
      if (seg->temporal_update) {
        const int ctx = av1_get_pred_context_seg_id(xd);
        mbmi->seg_id_predicted = 0;
        if (counts) ++counts->seg.pred[ctx][mbmi->seg_id_predicted];
      }
      segment_id = read_segment_id(cm, xd, mi_row, mi_col, r, 0);
      if (counts) ++counts->seg.tree_total[segment_id];
      set_segment_id(cm, mi_offset, x_mis, y_mis, segment_id);
      return segment_id;
    }
  }
#endif
  (void)preskip;
  if (seg->temporal_update) {
    const int ctx = av1_get_pred_context_seg_id(xd);
    aom_cdf_prob *pred_cdf = segp->pred_cdf[ctx];
    mbmi->seg_id_predicted = aom_read_symbol(r, pred_cdf, 2, ACCT_STR);
    if (counts) ++counts->seg.pred[ctx][mbmi->seg_id_predicted];
    if (mbmi->seg_id_predicted) {
      segment_id = predicted_segment_id;
    } else {
#if CONFIG_SPATIAL_SEGMENTATION
      segment_id = read_segment_id(cm, xd, mi_row, mi_col, r, 0);
#else
      segment_id = read_segment_id(r, segp);
#endif
      if (counts) ++counts->seg.tree_mispred[segment_id];
    }
  } else {
#if CONFIG_SPATIAL_SEGMENTATION
    segment_id = read_segment_id(cm, xd, mi_row, mi_col, r, 0);
#else
    segment_id = read_segment_id(r, segp);
#endif
    if (counts) ++counts->seg.tree_total[segment_id];
  }
  set_segment_id(cm, mi_offset, x_mis, y_mis, segment_id);
  return segment_id;
}

#if CONFIG_EXT_SKIP
static int read_skip_mode(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,
                          aom_reader *r) {
  if (!cm->skip_mode_flag) return 0;

  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP)) {
    // TODO(zoeliu): To revisit the handling of this scenario.
    return 0;
  }

  if (!is_comp_ref_allowed(xd->mi[0]->mbmi.sb_type)) return 0;

  const int ctx = av1_get_skip_mode_context(xd);
  FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
  const int skip_mode =
      aom_read_symbol(r, ec_ctx->skip_mode_cdfs[ctx], 2, ACCT_STR);
  FRAME_COUNTS *counts = xd->counts;
  if (counts) ++counts->skip_mode[ctx][skip_mode];

  return skip_mode;
}
#endif  // CONFIG_EXT_SKIP

static int read_skip(AV1_COMMON *cm, const MACROBLOCKD *xd, int segment_id,
                     aom_reader *r) {
  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP)) {
    return 1;
  } else {
    const int ctx = av1_get_skip_context(xd);
    FRAME_CONTEXT *ec_ctx = xd->tile_ctx;
    const int skip = aom_read_symbol(r, ec_ctx->skip_cdfs[ctx], 2, ACCT_STR);
    FRAME_COUNTS *counts = xd->counts;
    if (counts) ++counts->skip[ctx][skip];
    return skip;
  }
}

#if CONFIG_PALETTE_DELTA_ENCODING
// Merge the sorted list of cached colors(cached_colors[0...n_cached_colors-1])
// and the sorted list of transmitted colors(colors[n_cached_colors...n-1]) into
// one single sorted list(colors[...]).
static void merge_colors(uint16_t *colors, uint16_t *cached_colors,
                         int n_colors, int n_cached_colors) {
  if (n_cached_colors == 0) return;
  int cache_idx = 0, trans_idx = n_cached_colors;
  for (int i = 0; i < n_colors; ++i) {
    if (cache_idx < n_cached_colors &&
        (trans_idx >= n_colors ||
         cached_colors[cache_idx] <= colors[trans_idx])) {
      colors[i] = cached_colors[cache_idx++];
    } else {
      assert(trans_idx < n_colors);
      colors[i] = colors[trans_idx++];
    }
  }
}

static void read_palette_colors_y(MACROBLOCKD *const xd, int bit_depth,
                                  PALETTE_MODE_INFO *const pmi, aom_reader *r) {
  uint16_t color_cache[2 * PALETTE_MAX_SIZE];
  uint16_t cached_colors[PALETTE_MAX_SIZE];
  const int n_cache = av1_get_palette_cache(xd, 0, color_cache);
  const int n = pmi->palette_size[0];
  int idx = 0;
  for (int i = 0; i < n_cache && idx < n; ++i)
    if (aom_read_bit(r, ACCT_STR)) cached_colors[idx++] = color_cache[i];
  if (idx < n) {
    const int n_cached_colors = idx;
    pmi->palette_colors[idx++] = aom_read_literal(r, bit_depth, ACCT_STR);
    if (idx < n) {
      const int min_bits = bit_depth - 3;
      int bits = min_bits + aom_read_literal(r, 2, ACCT_STR);
      int range = (1 << bit_depth) - pmi->palette_colors[idx - 1] - 1;
      for (; idx < n; ++idx) {
        assert(range >= 0);
        const int delta = aom_read_literal(r, bits, ACCT_STR) + 1;
        pmi->palette_colors[idx] = clamp(pmi->palette_colors[idx - 1] + delta,
                                         0, (1 << bit_depth) - 1);
        range -= (pmi->palette_colors[idx] - pmi->palette_colors[idx - 1]);
        bits = AOMMIN(bits, av1_ceil_log2(range));
      }
    }
    merge_colors(pmi->palette_colors, cached_colors, n, n_cached_colors);
  } else {
    memcpy(pmi->palette_colors, cached_colors, n * sizeof(cached_colors[0]));
  }
}

static void read_palette_colors_uv(MACROBLOCKD *const xd, int bit_depth,
                                   PALETTE_MODE_INFO *const pmi,
                                   aom_reader *r) {
  const int n = pmi->palette_size[1];
  // U channel colors.
  uint16_t color_cache[2 * PALETTE_MAX_SIZE];
  uint16_t cached_colors[PALETTE_MAX_SIZE];
  const int n_cache = av1_get_palette_cache(xd, 1, color_cache);
  int idx = 0;
  for (int i = 0; i < n_cache && idx < n; ++i)
    if (aom_read_bit(r, ACCT_STR)) cached_colors[idx++] = color_cache[i];
  if (idx < n) {
    const int n_cached_colors = idx;
    idx += PALETTE_MAX_SIZE;
    pmi->palette_colors[idx++] = aom_read_literal(r, bit_depth, ACCT_STR);
    if (idx < PALETTE_MAX_SIZE + n) {
      const int min_bits = bit_depth - 3;
      int bits = min_bits + aom_read_literal(r, 2, ACCT_STR);
      int range = (1 << bit_depth) - pmi->palette_colors[idx - 1];
      for (; idx < PALETTE_MAX_SIZE + n; ++idx) {
        assert(range >= 0);
        const int delta = aom_read_literal(r, bits, ACCT_STR);
        pmi->palette_colors[idx] = clamp(pmi->palette_colors[idx - 1] + delta,
                                         0, (1 << bit_depth) - 1);
        range -= (pmi->palette_colors[idx] - pmi->palette_colors[idx - 1]);
        bits = AOMMIN(bits, av1_ceil_log2(range));
      }
    }
    merge_colors(pmi->palette_colors + PALETTE_MAX_SIZE, cached_colors, n,
                 n_cached_colors);
  } else {
    memcpy(pmi->palette_colors + PALETTE_MAX_SIZE, cached_colors,
           n * sizeof(cached_colors[0]));
  }

  // V channel colors.
  if (aom_read_bit(r, ACCT_STR)) {  // Delta encoding.
    const int min_bits_v = bit_depth - 4;
    const int max_val = 1 << bit_depth;
    int bits = min_bits_v + aom_read_literal(r, 2, ACCT_STR);
    pmi->palette_colors[2 * PALETTE_MAX_SIZE] =
        aom_read_literal(r, bit_depth, ACCT_STR);
    for (int i = 1; i < n; ++i) {
      int delta = aom_read_literal(r, bits, ACCT_STR);
      if (delta && aom_read_bit(r, ACCT_STR)) delta = -delta;
      int val = (int)pmi->palette_colors[2 * PALETTE_MAX_SIZE + i - 1] + delta;
      if (val < 0) val += max_val;
      if (val >= max_val) val -= max_val;
      pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] = val;
    }
  } else {
    for (int i = 0; i < n; ++i) {
      pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] =
          aom_read_literal(r, bit_depth, ACCT_STR);
    }
  }
}
#endif  // CONFIG_PALETTE_DELTA_ENCODING

static void read_palette_mode_info(AV1_COMMON *const cm, MACROBLOCKD *const xd,
                                   aom_reader *r) {
  MODE_INFO *const mi = xd->mi[0];
  MB_MODE_INFO *const mbmi = &mi->mbmi;
  const MODE_INFO *const above_mi = xd->above_mi;
  const MODE_INFO *const left_mi = xd->left_mi;
  const BLOCK_SIZE bsize = mbmi->sb_type;
  assert(av1_allow_palette(cm->allow_screen_content_tools, bsize));
  PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;
  const int block_palette_idx = bsize - BLOCK_8X8;

  if (mbmi->mode == DC_PRED) {
    int palette_y_mode_ctx = 0;
    if (above_mi) {
      palette_y_mode_ctx +=
          (above_mi->mbmi.palette_mode_info.palette_size[0] > 0);
    }
    if (left_mi) {
      palette_y_mode_ctx +=
          (left_mi->mbmi.palette_mode_info.palette_size[0] > 0);
    }
    const int modev = aom_read_symbol(
        r,
        xd->tile_ctx->palette_y_mode_cdf[block_palette_idx][palette_y_mode_ctx],
        2, ACCT_STR);
    if (modev) {
      pmi->palette_size[0] =
          aom_read_symbol(r,
                          xd->tile_ctx->palette_y_size_cdf[block_palette_idx],
                          PALETTE_SIZES, ACCT_STR) +
          2;
#if CONFIG_PALETTE_DELTA_ENCODING
      read_palette_colors_y(xd, cm->bit_depth, pmi, r);
#else
      for (int i = 0; i < pmi->palette_size[0]; ++i)
        pmi->palette_colors[i] = aom_read_literal(r, cm->bit_depth, ACCT_STR);
#endif  // CONFIG_PALETTE_DELTA_ENCODING
    }
  }
  if (mbmi->uv_mode == UV_DC_PRED) {
    const int palette_uv_mode_ctx = (pmi->palette_size[0] > 0);
    const int modev = aom_read_symbol(
        r, xd->tile_ctx->palette_uv_mode_cdf[palette_uv_mode_ctx], 2, ACCT_STR);
    if (modev) {
      pmi->palette_size[1] =
          aom_read_symbol(r,
                          xd->tile_ctx->palette_uv_size_cdf[block_palette_idx],
                          PALETTE_SIZES, ACCT_STR) +
          2;
#if CONFIG_PALETTE_DELTA_ENCODING
      read_palette_colors_uv(xd, cm->bit_depth, pmi, r);
#else
      for (int i = 0; i < pmi->palette_size[1]; ++i) {
        pmi->palette_colors[PALETTE_MAX_SIZE + i] =
            aom_read_literal(r, cm->bit_depth, ACCT_STR);
        pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] =
            aom_read_literal(r, cm->bit_depth, ACCT_STR);
      }
#endif  // CONFIG_PALETTE_DELTA_ENCODING
    }
  }
}

#if CONFIG_FILTER_INTRA
static void read_filter_intra_mode_info(MACROBLOCKD *const xd, aom_reader *r) {
  MODE_INFO *const mi = xd->mi[0];
  MB_MODE_INFO *const mbmi = &mi->mbmi;
  FILTER_INTRA_MODE_INFO *filter_intra_mode_info =
      &mbmi->filter_intra_mode_info;

  if (mbmi->mode == DC_PRED && mbmi->palette_mode_info.palette_size[0] == 0 &&
      av1_filter_intra_allowed_txsize(mbmi->tx_size)) {
    filter_intra_mode_info->use_filter_intra_mode[0] = aom_read_symbol(
        r, xd->tile_ctx->filter_intra_cdfs[mbmi->tx_size], 2, ACCT_STR);
    if (filter_intra_mode_info->use_filter_intra_mode[0]) {
      filter_intra_mode_info->filter_intra_mode[0] =
          aom_read_symbol(r, xd->tile_ctx->filter_intra_mode_cdf[0],
                          FILTER_INTRA_MODES, ACCT_STR);
    }
  }
}
#endif  // CONFIG_FILTER_INTRA

#if CONFIG_EXT_INTRA
#if CONFIG_EXT_INTRA_MOD
static int read_angle_delta(aom_reader *r, aom_cdf_prob *cdf) {
  const int sym = aom_read_symbol(r, cdf, 2 * MAX_ANGLE_DELTA + 1, ACCT_STR);
  return sym - MAX_ANGLE_DELTA;
}
#endif  // CONFIG_EXT_INTRA_MOD

static void read_intra_angle_info(MACROBLOCKD *const xd, aom_reader *r) {
  MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
  const BLOCK_SIZE bsize = mbmi->sb_type;
#if CONFIG_EXT_INTRA_MOD
  FRAME_CONTEXT *const ec_ctx = xd->tile_ctx;
#endif  // CONFIG_EXT_INTRA_MOD

  mbmi->angle_delta[0] = 0;
  mbmi->angle_delta[1] = 0;
  if (!av1_use_angle_delta(bsize)) return;