/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include <assert.h>
#include <limits.h>
#include <stdio.h>

#include "aom/aom_encoder.h"
#include "aom_dsp/bitwriter_buffer.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_mem/aom_mem.h"
#include "aom_ports/mem_ops.h"
#include "aom_ports/system_state.h"
#include "aom_util/debug_util.h"

#if CONFIG_CLPF
#include "av1/common/clpf.h"
#endif
#if CONFIG_DERING
#include "av1/common/dering.h"
#endif  // CONFIG_DERING
#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"
#include "av1/common/seg_common.h"
#include "av1/common/tile_common.h"

#if CONFIG_ANS
#include "av1/encoder/buf_ans.h"
#endif  // CONFIG_ANS
#include "av1/encoder/bitstream.h"
#include "av1/encoder/cost.h"
#include "av1/encoder/encodemv.h"
#include "av1/encoder/mcomp.h"
#include "av1/encoder/segmentation.h"
#include "av1/encoder/subexp.h"
#include "av1/encoder/tokenize.h"

static const struct av1_token intra_mode_encodings[INTRA_MODES] = {
  { 0, 1 },  { 6, 3 },   { 28, 5 },  { 30, 5 }, { 58, 6 },
  { 59, 6 }, { 126, 7 }, { 127, 7 }, { 62, 6 }, { 2, 2 }
};
#if CONFIG_EXT_INTERP
static const struct av1_token switchable_interp_encodings[SWITCHABLE_FILTERS] =
    { { 0, 1 }, { 4, 3 }, { 6, 3 }, { 5, 3 }, { 7, 3 } };
#else
static const struct av1_token switchable_interp_encodings[SWITCHABLE_FILTERS] =
    { { 0, 1 }, { 2, 2 }, { 3, 2 } };
#endif  // CONFIG_EXT_INTERP
#if CONFIG_EXT_PARTITION_TYPES
static const struct av1_token ext_partition_encodings[EXT_PARTITION_TYPES] = {
  { 0, 1 },  { 4, 3 },  { 12, 4 }, { 7, 3 },
  { 10, 4 }, { 11, 4 }, { 26, 5 }, { 27, 5 }
};
#endif
static const struct av1_token partition_encodings[PARTITION_TYPES] = {
  { 0, 1 }, { 2, 2 }, { 6, 3 }, { 7, 3 }
};
#if !CONFIG_REF_MV
static const struct av1_token inter_mode_encodings[INTER_MODES] =
#if CONFIG_EXT_INTER
    { { 2, 2 }, { 6, 3 }, { 0, 1 }, { 14, 4 }, { 15, 4 } };
#else
    { { 2, 2 }, { 6, 3 }, { 0, 1 }, { 7, 3 } };
#endif  // CONFIG_EXT_INTER
#endif
#if CONFIG_EXT_INTER
static const struct av1_token
    inter_compound_mode_encodings[INTER_COMPOUND_MODES] = {
      { 2, 2 },  { 50, 6 }, { 51, 6 }, { 24, 5 }, { 52, 6 },
      { 53, 6 }, { 54, 6 }, { 55, 6 }, { 0, 1 },  { 7, 3 }
    };
#endif  // CONFIG_EXT_INTER
static const struct av1_token palette_size_encodings[] = {
  { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 30, 5 }, { 62, 6 }, { 63, 6 },
};
static const struct av1_token
    palette_color_encodings[PALETTE_MAX_SIZE - 1][PALETTE_MAX_SIZE] = {
      { { 0, 1 }, { 1, 1 } },                                  // 2 colors
      { { 0, 1 }, { 2, 2 }, { 3, 2 } },                        // 3 colors
      { { 0, 1 }, { 2, 2 }, { 6, 3 }, { 7, 3 } },              // 4 colors
      { { 0, 1 }, { 2, 2 }, { 6, 3 }, { 14, 4 }, { 15, 4 } },  // 5 colors
      { { 0, 1 },
        { 2, 2 },
        { 6, 3 },
        { 14, 4 },
        { 30, 5 },
        { 31, 5 } },  // 6 colors
      { { 0, 1 },
        { 2, 2 },
        { 6, 3 },
        { 14, 4 },
        { 30, 5 },
        { 62, 6 },
        { 63, 6 } },  // 7 colors
      { { 0, 1 },
        { 2, 2 },
        { 6, 3 },
        { 14, 4 },
        { 30, 5 },
        { 62, 6 },
        { 126, 7 },
        { 127, 7 } },  // 8 colors
    };

static const struct av1_token tx_size_encodings[TX_SIZES - 1][TX_SIZES] = {
  { { 0, 1 }, { 1, 1 } },                      // Max tx_size is 8X8
  { { 0, 1 }, { 2, 2 }, { 3, 2 } },            // Max tx_size is 16X16
  { { 0, 1 }, { 2, 2 }, { 6, 3 }, { 7, 3 } },  // Max tx_size is 32X32
};

static INLINE void write_uniform(aom_writer *w, int n, int v) {
  int l = get_unsigned_bits(n);
  int m = (1 << l) - n;
  if (l == 0) return;
  if (v < m) {
    aom_write_literal(w, v, l - 1);
  } else {
    aom_write_literal(w, m + ((v - m) >> 1), l - 1);
    aom_write_literal(w, (v - m) & 1, 1);
  }
}

#if CONFIG_EXT_TX
static struct av1_token ext_tx_inter_encodings[EXT_TX_SETS_INTER][TX_TYPES];
static struct av1_token ext_tx_intra_encodings[EXT_TX_SETS_INTRA][TX_TYPES];
#else
static struct av1_token ext_tx_encodings[TX_TYPES];
#endif  // CONFIG_EXT_TX
#if CONFIG_GLOBAL_MOTION
static struct av1_token global_motion_types_encodings[GLOBAL_MOTION_TYPES];
#endif  // CONFIG_GLOBAL_MOTION
#if CONFIG_EXT_INTRA
static struct av1_token intra_filter_encodings[INTRA_FILTERS];
#endif  // CONFIG_EXT_INTRA
#if CONFIG_EXT_INTER
static struct av1_token interintra_mode_encodings[INTERINTRA_MODES];
#endif  // CONFIG_EXT_INTER
#if CONFIG_OBMC || CONFIG_WARPED_MOTION
static struct av1_token motvar_encodings[MOTION_VARIATIONS];
#endif  // CONFIG_OBMC || CONFIG_WARPED_MOTION

void av1_encode_token_init(void) {
#if CONFIG_EXT_TX
  int s;
  for (s = 1; s < EXT_TX_SETS_INTER; ++s) {
    av1_tokens_from_tree(ext_tx_inter_encodings[s], av1_ext_tx_inter_tree[s]);
  }
  for (s = 1; s < EXT_TX_SETS_INTRA; ++s) {
    av1_tokens_from_tree(ext_tx_intra_encodings[s], av1_ext_tx_intra_tree[s]);
  }
#else
  av1_tokens_from_tree(ext_tx_encodings, av1_ext_tx_tree);
#endif  // CONFIG_EXT_TX
#if CONFIG_EXT_INTRA
  av1_tokens_from_tree(intra_filter_encodings, av1_intra_filter_tree);
#endif  // CONFIG_EXT_INTRA
#if CONFIG_EXT_INTER
  av1_tokens_from_tree(interintra_mode_encodings, av1_interintra_mode_tree);
#endif  // CONFIG_EXT_INTER
#if CONFIG_OBMC || CONFIG_WARPED_MOTION
  av1_tokens_from_tree(motvar_encodings, av1_motvar_tree);
#endif  // CONFIG_OBMC || CONFIG_WARPED_MOTION
#if CONFIG_GLOBAL_MOTION
  av1_tokens_from_tree(global_motion_types_encodings,
                       av1_global_motion_types_tree);
#endif  // CONFIG_GLOBAL_MOTION
}

static void write_intra_mode(aom_writer *w, PREDICTION_MODE mode,
                             const aom_prob *probs) {
  av1_write_token(w, av1_intra_mode_tree, probs, &intra_mode_encodings[mode]);
}

#if CONFIG_EXT_INTER
static void write_interintra_mode(aom_writer *w, INTERINTRA_MODE mode,
                                  const aom_prob *probs) {
  av1_write_token(w, av1_interintra_mode_tree, probs,
                  &interintra_mode_encodings[mode]);
}
#endif  // CONFIG_EXT_INTER

static void write_inter_mode(AV1_COMMON *cm, aom_writer *w,
                             PREDICTION_MODE mode,
#if CONFIG_REF_MV && CONFIG_EXT_INTER
                             int is_compound,
#endif  // CONFIG_REF_MV && CONFIG_EXT_INTER
                             const int16_t mode_ctx) {
#if CONFIG_REF_MV
  const int16_t newmv_ctx = mode_ctx & NEWMV_CTX_MASK;
  const aom_prob newmv_prob = cm->fc->newmv_prob[newmv_ctx];
#if CONFIG_EXT_INTER
  aom_write(w, mode != NEWMV && mode != NEWFROMNEARMV, newmv_prob);

  if (!is_compound && (mode == NEWMV || mode == NEWFROMNEARMV))
    aom_write(w, mode == NEWFROMNEARMV, cm->fc->new2mv_prob);

  if (mode != NEWMV && mode != NEWFROMNEARMV) {
#else
  aom_write(w, mode != NEWMV, newmv_prob);

  if (mode != NEWMV) {
#endif  // CONFIG_EXT_INTER
    const int16_t zeromv_ctx = (mode_ctx >> ZEROMV_OFFSET) & ZEROMV_CTX_MASK;
    const aom_prob zeromv_prob = cm->fc->zeromv_prob[zeromv_ctx];

    if (mode_ctx & (1 << ALL_ZERO_FLAG_OFFSET)) {
      assert(mode == ZEROMV);
      return;
    }

    aom_write(w, mode != ZEROMV, zeromv_prob);

    if (mode != ZEROMV) {
      int16_t refmv_ctx = (mode_ctx >> REFMV_OFFSET) & REFMV_CTX_MASK;
      aom_prob refmv_prob;

      if (mode_ctx & (1 << SKIP_NEARESTMV_OFFSET)) refmv_ctx = 6;
      if (mode_ctx & (1 << SKIP_NEARMV_OFFSET)) refmv_ctx = 7;
      if (mode_ctx & (1 << SKIP_NEARESTMV_SUB8X8_OFFSET)) refmv_ctx = 8;

      refmv_prob = cm->fc->refmv_prob[refmv_ctx];
      aom_write(w, mode != NEARESTMV, refmv_prob);
    }
  }
#else
  const aom_prob *const inter_probs = cm->fc->inter_mode_probs[mode_ctx];
  assert(is_inter_mode(mode));
  av1_write_token(w, av1_inter_mode_tree, inter_probs,
                  &inter_mode_encodings[INTER_OFFSET(mode)]);
#endif
}

#if CONFIG_REF_MV
static void write_drl_idx(const AV1_COMMON *cm, const MB_MODE_INFO *mbmi,
                          const MB_MODE_INFO_EXT *mbmi_ext, aom_writer *w) {
  uint8_t ref_frame_type = av1_ref_frame_type(mbmi->ref_frame);

  assert(mbmi->ref_mv_idx < 3);

  if (mbmi->mode == NEWMV) {
    int idx;
    for (idx = 0; idx < 2; ++idx) {
      if (mbmi_ext->ref_mv_count[ref_frame_type] > idx + 1) {
        uint8_t drl_ctx =
            av1_drl_ctx(mbmi_ext->ref_mv_stack[ref_frame_type], idx);
        aom_prob drl_prob = cm->fc->drl_prob[drl_ctx];

        aom_write(w, mbmi->ref_mv_idx != idx, drl_prob);
        if (mbmi->ref_mv_idx == idx) return;
      }
    }
    return;
  }

  if (mbmi->mode == NEARMV) {
    int idx;
    // TODO(jingning): Temporary solution to compensate the NEARESTMV offset.
    for (idx = 1; idx < 3; ++idx) {
      if (mbmi_ext->ref_mv_count[ref_frame_type] > idx + 1) {
        uint8_t drl_ctx =
            av1_drl_ctx(mbmi_ext->ref_mv_stack[ref_frame_type], idx);
        aom_prob drl_prob = cm->fc->drl_prob[drl_ctx];

        aom_write(w, mbmi->ref_mv_idx != (idx - 1), drl_prob);
        if (mbmi->ref_mv_idx == (idx - 1)) return;
      }
    }
    return;
  }
}
#endif

#if CONFIG_EXT_INTER
static void write_inter_compound_mode(AV1_COMMON *cm, aom_writer *w,
                                      PREDICTION_MODE mode,
                                      const int16_t mode_ctx) {
  const aom_prob *const inter_compound_probs =
      cm->fc->inter_compound_mode_probs[mode_ctx];

  assert(is_inter_compound_mode(mode));
  av1_write_token(w, av1_inter_compound_mode_tree, inter_compound_probs,
                  &inter_compound_mode_encodings[INTER_COMPOUND_OFFSET(mode)]);
}
#endif  // CONFIG_EXT_INTER

static void encode_unsigned_max(struct aom_write_bit_buffer *wb, int data,
                                int max) {
  aom_wb_write_literal(wb, data, get_unsigned_bits(max));
}

static void prob_diff_update(const aom_tree_index *tree,
                             aom_prob probs[/*n - 1*/],
                             const unsigned int counts[/*n - 1*/], int n,
                             aom_writer *w) {
  int i;
  unsigned int branch_ct[32][2];

  // Assuming max number of probabilities <= 32
  assert(n <= 32);

  av1_tree_probs_from_distribution(tree, branch_ct, counts);
  for (i = 0; i < n - 1; ++i)
    av1_cond_prob_diff_update(w, &probs[i], branch_ct[i]);
}

static int prob_diff_update_savings(const aom_tree_index *tree,
                                    aom_prob probs[/*n - 1*/],
                                    const unsigned int counts[/*n - 1*/],
                                    int n) {
  int i;
  unsigned int branch_ct[32][2];
  int savings = 0;

  // Assuming max number of probabilities <= 32
  assert(n <= 32);
  av1_tree_probs_from_distribution(tree, branch_ct, counts);
  for (i = 0; i < n - 1; ++i) {
    savings += av1_cond_prob_diff_update_savings(&probs[i], branch_ct[i]);
  }
  return savings;
}

#if CONFIG_VAR_TX
static void write_tx_size_vartx(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                                const MB_MODE_INFO *mbmi, TX_SIZE tx_size,
                                int blk_row, int blk_col, aom_writer *w) {
  const int tx_row = blk_row >> 1;
  const int tx_col = blk_col >> 1;
  int max_blocks_high = num_4x4_blocks_high_lookup[mbmi->sb_type];
  int max_blocks_wide = num_4x4_blocks_wide_lookup[mbmi->sb_type];
  int ctx = txfm_partition_context(xd->above_txfm_context + tx_col,
                                   xd->left_txfm_context + tx_row, tx_size);

  if (xd->mb_to_bottom_edge < 0) max_blocks_high += xd->mb_to_bottom_edge >> 5;
  if (xd->mb_to_right_edge < 0) max_blocks_wide += xd->mb_to_right_edge >> 5;

  if (blk_row >= max_blocks_high || blk_col >= max_blocks_wide) return;

  if (tx_size == mbmi->inter_tx_size[tx_row][tx_col]) {
    aom_write(w, 0, cm->fc->txfm_partition_prob[ctx]);
    txfm_partition_update(xd->above_txfm_context + tx_col,
                          xd->left_txfm_context + tx_row, tx_size);
  } else {
    const BLOCK_SIZE bsize = txsize_to_bsize[tx_size];
    int bsl = b_width_log2_lookup[bsize];
    int i;
    aom_write(w, 1, cm->fc->txfm_partition_prob[ctx]);

    if (tx_size == TX_8X8) {
      txfm_partition_update(xd->above_txfm_context + tx_col,
                            xd->left_txfm_context + tx_row, TX_4X4);
      return;
    }

    assert(bsl > 0);
    --bsl;
    for (i = 0; i < 4; ++i) {
      int offsetr = blk_row + ((i >> 1) << bsl);
      int offsetc = blk_col + ((i & 0x01) << bsl);
      write_tx_size_vartx(cm, xd, mbmi, tx_size - 1, offsetr, offsetc, w);
    }
  }
}

static void update_txfm_partition_probs(AV1_COMMON *cm, aom_writer *w,
                                        FRAME_COUNTS *counts) {
  int k;
  for (k = 0; k < TXFM_PARTITION_CONTEXTS; ++k)
    av1_cond_prob_diff_update(w, &cm->fc->txfm_partition_prob[k],
                              counts->txfm_partition[k]);
}
#endif

static void write_selected_tx_size(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                                   aom_writer *w) {
  const MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
  const BLOCK_SIZE bsize = mbmi->sb_type;
  // For sub8x8 blocks the tx_size symbol does not need to be sent
  if (bsize >= BLOCK_8X8) {
    const TX_SIZE tx_size = mbmi->tx_size;
    const int is_inter = is_inter_block(mbmi);
    const int tx_size_ctx = get_tx_size_context(xd);
    const int tx_size_cat = is_inter ? inter_tx_size_cat_lookup[bsize]
                                     : intra_tx_size_cat_lookup[bsize];
    const TX_SIZE coded_tx_size = txsize_sqr_up_map[tx_size];

#if CONFIG_EXT_TX && CONFIG_RECT_TX
    assert(IMPLIES(is_rect_tx(tx_size), is_rect_tx_allowed(mbmi)));
    assert(
        IMPLIES(is_rect_tx(tx_size), tx_size == max_txsize_rect_lookup[bsize]));
#endif  // CONFIG_EXT_TX && CONFIG_RECT_TX

    av1_write_token(w, av1_tx_size_tree[tx_size_cat],
                    cm->fc->tx_size_probs[tx_size_cat][tx_size_ctx],
                    &tx_size_encodings[tx_size_cat][coded_tx_size]);
  }
}

#if CONFIG_REF_MV
static void update_inter_mode_probs(AV1_COMMON *cm, aom_writer *w,
                                    FRAME_COUNTS *counts) {
  int i;
  for (i = 0; i < NEWMV_MODE_CONTEXTS; ++i)
    av1_cond_prob_diff_update(w, &cm->fc->newmv_prob[i], counts->newmv_mode[i]);
  for (i = 0; i < ZEROMV_MODE_CONTEXTS; ++i)
    av1_cond_prob_diff_update(w, &cm->fc->zeromv_prob[i],
                              counts->zeromv_mode[i]);
  for (i = 0; i < REFMV_MODE_CONTEXTS; ++i)
    av1_cond_prob_diff_update(w, &cm->fc->refmv_prob[i], counts->refmv_mode[i]);
  for (i = 0; i < DRL_MODE_CONTEXTS; ++i)
    av1_cond_prob_diff_update(w, &cm->fc->drl_prob[i], counts->drl_mode[i]);
#if CONFIG_EXT_INTER
  av1_cond_prob_diff_update(w, &cm->fc->new2mv_prob, counts->new2mv_mode);
#endif  // CONFIG_EXT_INTER
}
#endif

#if CONFIG_EXT_INTER
static void update_inter_compound_mode_probs(AV1_COMMON *cm, aom_writer *w) {
  const int savings_thresh = av1_cost_one(GROUP_DIFF_UPDATE_PROB) -
                             av1_cost_zero(GROUP_DIFF_UPDATE_PROB);
  int i;
  int savings = 0;
  int do_update = 0;
  for (i = 0; i < INTER_MODE_CONTEXTS; ++i) {
    savings += prob_diff_update_savings(
        av1_inter_compound_mode_tree, cm->fc->inter_compound_mode_probs[i],
        cm->counts.inter_compound_mode[i], INTER_COMPOUND_MODES);
  }
  do_update = savings > savings_thresh;
  aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
  if (do_update) {
    for (i = 0; i < INTER_MODE_CONTEXTS; ++i) {
      prob_diff_update(
          av1_inter_compound_mode_tree, cm->fc->inter_compound_mode_probs[i],
          cm->counts.inter_compound_mode[i], INTER_COMPOUND_MODES, w);
    }
  }
}
#endif  // CONFIG_EXT_INTER

static int write_skip(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                      int segment_id, const MODE_INFO *mi, aom_writer *w) {
  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_SKIP)) {
    return 1;
  } else {
    const int skip = mi->mbmi.skip;
    aom_write(w, skip, av1_get_skip_prob(cm, xd));
    return skip;
  }
}

static void update_skip_probs(AV1_COMMON *cm, aom_writer *w,
                              FRAME_COUNTS *counts) {
  int k;

  for (k = 0; k < SKIP_CONTEXTS; ++k)
    av1_cond_prob_diff_update(w, &cm->fc->skip_probs[k], counts->skip[k]);
}

static void update_switchable_interp_probs(AV1_COMMON *cm, aom_writer *w,
                                           FRAME_COUNTS *counts) {
  int j;
  for (j = 0; j < SWITCHABLE_FILTER_CONTEXTS; ++j)
    prob_diff_update(av1_switchable_interp_tree,
                     cm->fc->switchable_interp_prob[j],
                     counts->switchable_interp[j], SWITCHABLE_FILTERS, w);
}

#if CONFIG_EXT_TX
static void update_ext_tx_probs(AV1_COMMON *cm, aom_writer *w) {
  const int savings_thresh = av1_cost_one(GROUP_DIFF_UPDATE_PROB) -
                             av1_cost_zero(GROUP_DIFF_UPDATE_PROB);
  int i, j;
  int s;
  for (s = 1; s < EXT_TX_SETS_INTER; ++s) {
    int savings = 0;
    int do_update = 0;
    for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
      if (!use_inter_ext_tx_for_txsize[s][i]) continue;
      savings += prob_diff_update_savings(
          av1_ext_tx_inter_tree[s], cm->fc->inter_ext_tx_prob[s][i],
          cm->counts.inter_ext_tx[s][i], num_ext_tx_set_inter[s]);
    }
    do_update = savings > savings_thresh;
    aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
    if (do_update) {
      for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
        if (!use_inter_ext_tx_for_txsize[s][i]) continue;
        prob_diff_update(
            av1_ext_tx_inter_tree[s], cm->fc->inter_ext_tx_prob[s][i],
            cm->counts.inter_ext_tx[s][i], num_ext_tx_set_inter[s], w);
      }
    }
  }

  for (s = 1; s < EXT_TX_SETS_INTRA; ++s) {
    int savings = 0;
    int do_update = 0;
    for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
      if (!use_intra_ext_tx_for_txsize[s][i]) continue;
      for (j = 0; j < INTRA_MODES; ++j)
        savings += prob_diff_update_savings(
            av1_ext_tx_intra_tree[s], cm->fc->intra_ext_tx_prob[s][i][j],
            cm->counts.intra_ext_tx[s][i][j], num_ext_tx_set_intra[s]);
    }
    do_update = savings > savings_thresh;
    aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
    if (do_update) {
      for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
        if (!use_intra_ext_tx_for_txsize[s][i]) continue;
        for (j = 0; j < INTRA_MODES; ++j)
          prob_diff_update(
              av1_ext_tx_intra_tree[s], cm->fc->intra_ext_tx_prob[s][i][j],
              cm->counts.intra_ext_tx[s][i][j], num_ext_tx_set_intra[s], w);
      }
    }
  }
}

#else

static void update_ext_tx_probs(AV1_COMMON *cm, aom_writer *w) {
  const int savings_thresh = av1_cost_one(GROUP_DIFF_UPDATE_PROB) -
                             av1_cost_zero(GROUP_DIFF_UPDATE_PROB);
  int i, j;

  int savings = 0;
  int do_update = 0;
  for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
    for (j = 0; j < TX_TYPES; ++j)
      savings += prob_diff_update_savings(
          av1_ext_tx_tree, cm->fc->intra_ext_tx_prob[i][j],
          cm->counts.intra_ext_tx[i][j], TX_TYPES);
  }
  do_update = savings > savings_thresh;
  aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
  if (do_update) {
    for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
      for (j = 0; j < TX_TYPES; ++j)
        prob_diff_update(av1_ext_tx_tree, cm->fc->intra_ext_tx_prob[i][j],
                         cm->counts.intra_ext_tx[i][j], TX_TYPES, w);
    }
  }
  savings = 0;
  for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
    savings +=
        prob_diff_update_savings(av1_ext_tx_tree, cm->fc->inter_ext_tx_prob[i],
                                 cm->counts.inter_ext_tx[i], TX_TYPES);
  }
  do_update = savings > savings_thresh;
  aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
  if (do_update) {
    for (i = TX_4X4; i < EXT_TX_SIZES; ++i) {
      prob_diff_update(av1_ext_tx_tree, cm->fc->inter_ext_tx_prob[i],
                       cm->counts.inter_ext_tx[i], TX_TYPES, w);
    }
  }
}
#endif  // CONFIG_EXT_TX

static void pack_palette_tokens(aom_writer *w, const TOKENEXTRA **tp, int n,
                                int num) {
  int i;
  const TOKENEXTRA *p = *tp;

  for (i = 0; i < num; ++i) {
    av1_write_token(w, av1_palette_color_tree[n - 2], p->context_tree,
                    &palette_color_encodings[n - 2][p->token]);
    ++p;
  }

  *tp = p;
}

#if CONFIG_SUPERTX
static void update_supertx_probs(AV1_COMMON *cm, aom_writer *w) {
  const int savings_thresh = av1_cost_one(GROUP_DIFF_UPDATE_PROB) -
                             av1_cost_zero(GROUP_DIFF_UPDATE_PROB);
  int i, j;
  int savings = 0;
  int do_update = 0;
  for (i = 0; i < PARTITION_SUPERTX_CONTEXTS; ++i) {
    for (j = 1; j < TX_SIZES; ++j) {
      savings += av1_cond_prob_diff_update_savings(&cm->fc->supertx_prob[i][j],
                                                   cm->counts.supertx[i][j]);
    }
  }
  do_update = savings > savings_thresh;
  aom_write(w, do_update, GROUP_DIFF_UPDATE_PROB);
  if (do_update) {
    for (i = 0; i < PARTITION_SUPERTX_CONTEXTS; ++i) {
      for (j = 1; j < TX_SIZES; ++j) {
        av1_cond_prob_diff_update(w, &cm->fc->supertx_prob[i][j],
                                  cm->counts.supertx[i][j]);
      }
    }
  }
}
#endif  // CONFIG_SUPERTX

#if !CONFIG_ANS
static void pack_mb_tokens(aom_writer *w, const TOKENEXTRA **tp,
                           const TOKENEXTRA *const stop,
                           aom_bit_depth_t bit_depth, const TX_SIZE tx) {
  const TOKENEXTRA *p = *tp;
#if CONFIG_VAR_TX
  int count = 0;
  const int seg_eob = get_tx2d_size(tx);
#endif

  while (p < stop && p->token != EOSB_TOKEN) {
    const int t = p->token;
    const struct av1_token *const a = &av1_coef_encodings[t];
    int v = a->value;
    int n = a->len;
#if CONFIG_AOM_HIGHBITDEPTH
    const av1_extra_bit *b;
    if (bit_depth == AOM_BITS_12)
      b = &av1_extra_bits_high12[t];
    else if (bit_depth == AOM_BITS_10)
      b = &av1_extra_bits_high10[t];
    else
      b = &av1_extra_bits[t];
#else
    const av1_extra_bit *const b = &av1_extra_bits[t];
    (void)bit_depth;
#endif  // CONFIG_AOM_HIGHBITDEPTH

    /* skip one or two nodes */
    if (p->skip_eob_node)
      n -= p->skip_eob_node;
    else
      aom_write(w, t != EOB_TOKEN, p->context_tree[0]);

    if (t != EOB_TOKEN) {
      aom_write(w, t != ZERO_TOKEN, p->context_tree[1]);

      if (t != ZERO_TOKEN) {
        aom_write(w, t != ONE_TOKEN, p->context_tree[2]);

        if (t != ONE_TOKEN) {
          int len = UNCONSTRAINED_NODES - p->skip_eob_node;
          av1_write_tree(w, av1_coef_con_tree,
                         av1_pareto8_full[p->context_tree[PIVOT_NODE] - 1], v,
                         n - len, 0);
        }
      }
    }

    if (b->base_val) {
      const int e = p->extra, l = b->len;
      int skip_bits = (b->base_val == CAT6_MIN_VAL)
                          ? TX_SIZES - 1 - txsize_sqr_up_map[tx]
                          : 0;

      if (l) {
        const unsigned char *pb = b->prob;
        int v = e >> 1;
        int n = l; /* number of bits in v, assumed nonzero */
        int i = 0;

        do {
          const int bb = (v >> --n) & 1;
          if (skip_bits) {
            skip_bits--;
            assert(!bb);
          } else {
            aom_write(w, bb, pb[i >> 1]);
          }
          i = b->tree[i + bb];
        } while (n);
      }

      aom_write_bit(w, e & 1);
    }
    ++p;

#if CONFIG_VAR_TX
    ++count;
    if (t == EOB_TOKEN || count == seg_eob) break;
#endif
  }

  *tp = p;
}
#else
// This function serializes the tokens in forward order using a buffered ans
// coder.
static void pack_mb_tokens(struct BufAnsCoder *ans, const TOKENEXTRA **tp,
                           const TOKENEXTRA *const stop,
                           aom_bit_depth_t bit_depth, const TX_SIZE tx) {
  const TOKENEXTRA *p = *tp;
#if CONFIG_VAR_TX
  int count = 0;
  const int seg_eob = 16 << (tx << 1);
#endif  // CONFIG_VAR_TX

  while (p < stop && p->token != EOSB_TOKEN) {
    const int t = p->token;
#if CONFIG_AOM_HIGHBITDEPTH
    const av1_extra_bit *b;
    if (bit_depth == AOM_BITS_12)
      b = &av1_extra_bits_high12[t];
    else if (bit_depth == AOM_BITS_10)
      b = &av1_extra_bits_high10[t];
    else
      b = &av1_extra_bits[t];
#else
    const av1_extra_bit *const b = &av1_extra_bits[t];
    (void)bit_depth;
#endif  // CONFIG_AOM_HIGHBITDEPTH

    /* skip one or two nodes */
    if (!p->skip_eob_node)
      buf_uabs_write(ans, t != EOB_TOKEN, p->context_tree[0]);

    if (t != EOB_TOKEN) {
      struct rans_sym s;
      const rans_dec_lut *token_cdf = p->token_cdf;
      assert(token_cdf);
      s.cum_prob = (*token_cdf)[t - ZERO_TOKEN];
      s.prob = (*token_cdf)[t - ZERO_TOKEN + 1] - s.cum_prob;
      buf_rans_write(ans, &s);

      if (b->base_val) {
        const int e = p->extra, l = b->len;
        int skip_bits = (b->base_val == CAT6_MIN_VAL)
                            ? TX_SIZES - 1 - txsize_sqr_up_map[tx]
                            : 0;

        if (l) {
          const unsigned char *pb = b->prob;
          int v = e >> 1;
          int n = l; /* number of bits in v, assumed nonzero */
          int i = 0;

          do {
            const int bb = (v >> --n) & 1;
            if (skip_bits) {
              skip_bits--;
              assert(!bb);
            } else {
              buf_uabs_write(ans, bb, pb[i >> 1]);
            }
            i = b->tree[i + bb];
          } while (n);
        }

        buf_uabs_write(ans, e & 1, 128);
      }
    }
    ++p;

#if CONFIG_VAR_TX
    ++count;
    if (t == EOB_TOKEN || count == seg_eob) break;
#endif  // CONFIG_VAR_TX
  }

  *tp = p;
}
#endif  // !CONFIG_ANS

#if CONFIG_VAR_TX
static void pack_txb_tokens(aom_writer *w, const TOKENEXTRA **tp,
                            const TOKENEXTRA *const tok_end, MACROBLOCKD *xd,
                            MB_MODE_INFO *mbmi, int plane,
                            BLOCK_SIZE plane_bsize, aom_bit_depth_t bit_depth,
                            int block, int blk_row, int blk_col,
                            TX_SIZE tx_size) {
  const struct macroblockd_plane *const pd = &xd->plane[plane];
  const BLOCK_SIZE bsize = txsize_to_bsize[tx_size];
  const int tx_row = blk_row >> (1 - pd->subsampling_y);
  const int tx_col = blk_col >> (1 - pd->subsampling_x);
  TX_SIZE plane_tx_size;
  int max_blocks_high = num_4x4_blocks_high_lookup[plane_bsize];
  int max_blocks_wide = num_4x4_blocks_wide_lookup[plane_bsize];

  if (xd->mb_to_bottom_edge < 0)
    max_blocks_high += xd->mb_to_bottom_edge >> (5 + pd->subsampling_y);
  if (xd->mb_to_right_edge < 0)
    max_blocks_wide += xd->mb_to_right_edge >> (5 + pd->subsampling_x);

  if (blk_row >= max_blocks_high || blk_col >= max_blocks_wide) return;

  plane_tx_size = plane ? get_uv_tx_size_impl(
                              mbmi->inter_tx_size[tx_row][tx_col], bsize, 0, 0)
                        : mbmi->inter_tx_size[tx_row][tx_col];

  if (tx_size == plane_tx_size) {
    pack_mb_tokens(w, tp, tok_end, bit_depth, tx_size);
  } else {
    int bsl = b_width_log2_lookup[bsize];
    int i;

    assert(bsl > 0);
    --bsl;

    for (i = 0; i < 4; ++i) {
      const int offsetr = blk_row + ((i >> 1) << bsl);
      const int offsetc = blk_col + ((i & 0x01) << bsl);
      int step = num_4x4_blocks_txsize_lookup[tx_size - 1];

      if (offsetr >= max_blocks_high || offsetc >= max_blocks_wide) continue;

      pack_txb_tokens(w, tp, tok_end, xd, mbmi, plane, plane_bsize, bit_depth,
                      block + i * step, offsetr, offsetc, tx_size - 1);
    }
  }
}
#endif

static void write_segment_id(aom_writer *w, const struct segmentation *seg,
                             const struct segmentation_probs *segp,
                             int segment_id) {
  if (seg->enabled && seg->update_map)
    av1_write_tree(w, av1_segment_tree, segp->tree_probs, segment_id, 3, 0);
}

// This function encodes the reference frame
static void write_ref_frames(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                             aom_writer *w) {
  const MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
  const int is_compound = has_second_ref(mbmi);
  const int segment_id = mbmi->segment_id;

  // If segment level coding of this signal is disabled...
  // or the segment allows multiple reference frame options
  if (segfeature_active(&cm->seg, segment_id, SEG_LVL_REF_FRAME)) {
    assert(!is_compound);
    assert(mbmi->ref_frame[0] ==
           get_segdata(&cm->seg, segment_id, SEG_LVL_REF_FRAME));
  } else {
    // does the feature use compound prediction or not
    // (if not specified at the frame/segment level)
    if (cm->reference_mode == REFERENCE_MODE_SELECT) {
      aom_write(w, is_compound, av1_get_reference_mode_prob(cm, xd));
    } else {
      assert((!is_compound) == (cm->reference_mode == SINGLE_REFERENCE));
    }

    if (is_compound) {
#if CONFIG_EXT_REFS
      const int bit = (mbmi->ref_frame[0] == GOLDEN_FRAME ||
                       mbmi->ref_frame[0] == LAST3_FRAME);
      const int bit_bwd = mbmi->ref_frame[1] == ALTREF_FRAME;
#else  // CONFIG_EXT_REFS
      const int bit = mbmi->ref_frame[0] == GOLDEN_FRAME;
#endif  // CONFIG_EXT_REFS

      aom_write(w, bit, av1_get_pred_prob_comp_ref_p(cm, xd));

#if CONFIG_EXT_REFS
      if (!bit) {
        const int bit1 = mbmi->ref_frame[0] == LAST_FRAME;
        aom_write(w, bit1, av1_get_pred_prob_comp_ref_p1(cm, xd));
      } else {
        const int bit2 = mbmi->ref_frame[0] == GOLDEN_FRAME;
        aom_write(w, bit2, av1_get_pred_prob_comp_ref_p2(cm, xd));
      }
      aom_write(w, bit_bwd, av1_get_pred_prob_comp_bwdref_p(cm, xd));
#endif  // CONFIG_EXT_REFS
    } else {
#if CONFIG_EXT_REFS
      const int bit0 = (mbmi->ref_frame[0] == ALTREF_FRAME ||
                        mbmi->ref_frame[0] == BWDREF_FRAME);
      aom_write(w, bit0, av1_get_pred_prob_single_ref_p1(cm, xd));

      if (bit0) {
        const int bit1 = mbmi->ref_frame[0] == ALTREF_FRAME;
        aom_write(w, bit1, av1_get_pred_prob_single_ref_p2(cm, xd));
      } else {
        const int bit2 = (mbmi->ref_frame[0] == LAST3_FRAME ||
                          mbmi->ref_frame[0] == GOLDEN_FRAME);
        aom_write(w, bit2, av1_get_pred_prob_single_ref_p3(cm, xd));

        if (!bit2) {
          const int bit3 = mbmi->ref_frame[0] != LAST_FRAME;
          aom_write(w, bit3, av1_get_pred_prob_single_ref_p4(cm, xd));
        } else {
          const int bit4 = mbmi->ref_frame[0] != LAST3_FRAME;
          aom_write(w, bit4, av1_get_pred_prob_single_ref_p5(cm, xd));
        }
      }
#else   // CONFIG_EXT_REFS
      const int bit0 = mbmi->ref_frame[0] != LAST_FRAME;
      aom_write(w, bit0, av1_get_pred_prob_single_ref_p1(cm, xd));

      if (bit0) {
        const int bit1 = mbmi->ref_frame[0] != GOLDEN_FRAME;
        aom_write(w, bit1, av1_get_pred_prob_single_ref_p2(cm, xd));
      }
#endif  // CONFIG_EXT_REFS
    }
  }
}

#if CONFIG_EXT_INTRA
static void write_ext_intra_mode_info(const AV1_COMMON *const cm,
                                      const MB_MODE_INFO *const mbmi,
                                      aom_writer *w) {
#if !ALLOW_FILTER_INTRA_MODES
  return;
#endif
  if (mbmi->mode == DC_PRED && mbmi->palette_mode_info.palette_size[0] == 0) {
    aom_write(w, mbmi->ext_intra_mode_info.use_ext_intra_mode[0],
              cm->fc->ext_intra_probs[0]);
    if (mbmi->ext_intra_mode_info.use_ext_intra_mode[0]) {
      EXT_INTRA_MODE mode = mbmi->ext_intra_mode_info.ext_intra_mode[0];
      write_uniform(w, FILTER_INTRA_MODES, mode);
    }
  }

  if (mbmi->uv_mode == DC_PRED &&
      mbmi->palette_mode_info.palette_size[1] == 0) {
    aom_write(w, mbmi->ext_intra_mode_info.use_ext_intra_mode[1],
              cm->fc->ext_intra_probs[1]);
    if (mbmi->ext_intra_mode_info.use_ext_intra_mode[1]) {
      EXT_INTRA_MODE mode = mbmi->ext_intra_mode_info.ext_intra_mode[1];
      write_uniform(w, FILTER_INTRA_MODES, mode);
    }
  }
}

static void write_intra_angle_info(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                                   aom_writer *w) {
  const MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
  const BLOCK_SIZE bsize = mbmi->sb_type;
  const int intra_filter_ctx = av1_get_pred_context_intra_interp(xd);
  int p_angle;

  if (bsize < BLOCK_8X8) return;

  if (mbmi->mode != DC_PRED && mbmi->mode != TM_PRED) {
    write_uniform(w, 2 * MAX_ANGLE_DELTAS + 1,
                  MAX_ANGLE_DELTAS + mbmi->angle_delta[0]);
    p_angle = mode_to_angle_map[mbmi->mode] + mbmi->angle_delta[0] * ANGLE_STEP;
    if (av1_is_intra_filter_switchable(p_angle)) {
      av1_write_token(w, av1_intra_filter_tree,
                      cm->fc->intra_filter_probs[intra_filter_ctx],
                      &intra_filter_encodings[mbmi->intra_filter]);
    }
  }

  if (mbmi->uv_mode != DC_PRED && mbmi->uv_mode != TM_PRED) {
    write_uniform(w, 2 * MAX_ANGLE_DELTAS + 1,
                  MAX_ANGLE_DELTAS + mbmi->angle_delta[1]);
  }
}
#endif  // CONFIG_EXT_INTRA

static void write_switchable_interp_filter(AV1_COMP *cpi, const MACROBLOCKD *xd,
                                           aom_writer *w) {
  AV1_COMMON *const cm = &cpi->common;
  const MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
#if CONFIG_DUAL_FILTER
  int dir;
#endif
  if (cm->interp_filter == SWITCHABLE) {
#if CONFIG_EXT_INTERP
#if CONFIG_DUAL_FILTER
    if (!av1_is_interp_needed(xd)) {
      assert(mbmi->interp_filter[0] == EIGHTTAP_REGULAR);
      return;
    }
#else
    if (!av1_is_interp_needed(xd)) {
#if CONFIG_DUAL_FILTER
      assert(mbmi->interp_filter[0] == EIGHTTAP_REGULAR);
      assert(mbmi->interp_filter[1] == EIGHTTAP_REGULAR);
#else
      assert(mbmi->interp_filter == EIGHTTAP_REGULAR);
#endif
      return;
    }
#endif  // CONFIG_DUAL_FILTER
#endif  // CONFIG_EXT_INTERP
#if CONFIG_DUAL_FILTER
    for (dir = 0; dir < 2; ++dir) {
      if (has_subpel_mv_component(xd->mi[0], xd, dir) ||
          (mbmi->ref_frame[1] > INTRA_FRAME &&
           has_subpel_mv_component(xd->mi[0], xd, dir + 2))) {
        const int ctx = av1_get_pred_context_switchable_interp(xd, dir);
        av1_write_token(w, av1_switchable_interp_tree,
                        cm->fc->switchable_interp_prob[ctx],
                        &switchable_interp_encodings[mbmi->interp_filter[dir]]);
        ++cpi->interp_filter_selected[0][mbmi->interp_filter[dir]];
      }
    }
#else
    {
      const int ctx = av1_get_pred_context_switchable_interp(xd);
      av1_write_token(w, av1_switchable_interp_tree,
                      cm->fc->switchable_interp_prob[ctx],
                      &switchable_interp_encodings[mbmi->interp_filter]);
      ++cpi->interp_filter_selected[0][mbmi->interp_filter];
    }
#endif
  }
}

static void write_palette_mode_info(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                                    const MODE_INFO *const mi, aom_writer *w) {
  const 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;
  const PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;
  int palette_ctx = 0;
  int n, i;

  if (mbmi->mode == DC_PRED) {
    n = pmi->palette_size[0];
    if (above_mi)
      palette_ctx += (above_mi->mbmi.palette_mode_info.palette_size[0] > 0);
    if (left_mi)
      palette_ctx += (left_mi->mbmi.palette_mode_info.palette_size[0] > 0);
    aom_write(w, n > 0,
              av1_default_palette_y_mode_prob[bsize - BLOCK_8X8][palette_ctx]);
    if (n > 0) {
      av1_write_token(w, av1_palette_size_tree,
                      av1_default_palette_y_size_prob[bsize - BLOCK_8X8],
                      &palette_size_encodings[n - 2]);
      for (i = 0; i < n; ++i)
        aom_write_literal(w, pmi->palette_colors[i], cm->bit_depth);
      write_uniform(w, n, pmi->palette_first_color_idx[0]);
    }
  }

  if (mbmi->uv_mode == DC_PRED) {
    n = pmi->palette_size[1];
    aom_write(w, n > 0,
              av1_default_palette_uv_mode_prob[pmi->palette_size[0] > 0]);
    if (n > 0) {
      av1_write_token(w, av1_palette_size_tree,
                      av1_default_palette_uv_size_prob[bsize - BLOCK_8X8],
                      &palette_size_encodings[n - 2]);
      for (i = 0; i < n; ++i) {
        aom_write_literal(w, pmi->palette_colors[PALETTE_MAX_SIZE + i],
                          cm->bit_depth);
        aom_write_literal(w, pmi->palette_colors[2 * PALETTE_MAX_SIZE + i],
                          cm->bit_depth);
      }
      write_uniform(w, n, pmi->palette_first_color_idx[1]);
    }
  }
}

static void pack_inter_mode_mvs(AV1_COMP *cpi, const MODE_INFO *mi,
#if CONFIG_SUPERTX
                                int supertx_enabled,
#endif
                                aom_writer *w) {
  AV1_COMMON *const cm = &cpi->common;
#if !CONFIG_REF_MV
  const nmv_context *nmvc = &cm->fc->nmvc;
#endif
  const MACROBLOCK *x = &cpi->td.mb;
  const MACROBLOCKD *xd = &x->e_mbd;
  const struct segmentation *const seg = &cm->seg;
  const struct segmentation_probs *const segp = &cm->fc->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;
  const int segment_id = mbmi->segment_id;
  const BLOCK_SIZE bsize = mbmi->sb_type;
  const int allow_hp = cm->allow_high_precision_mv;
  const int is_inter = is_inter_block(mbmi);
  const int is_compound = has_second_ref(mbmi);
  int skip, ref;

  if (seg->update_map) {
    if (seg->temporal_update) {
      const int pred_flag = mbmi->seg_id_predicted;
      aom_prob pred_prob = av1_get_pred_prob_seg_id(segp, xd);
      aom_write(w, pred_flag, pred_prob);
      if (!pred_flag) write_segment_id(w, seg, segp, segment_id);
    } else {
      write_segment_id(w, seg, segp, segment_id);
    }
  }

#if CONFIG_SUPERTX
  if (supertx_enabled)
    skip = mbmi->skip;
  else
    skip = write_skip(cm, xd, segment_id, mi, w);
#else
  skip = write_skip(cm, xd, segment_id, mi, w);
#endif  // CONFIG_SUPERTX

#if CONFIG_SUPERTX
  if (!supertx_enabled)
#endif  // CONFIG_SUPERTX
    if (!segfeature_active(seg, segment_id, SEG_LVL_REF_FRAME))
      aom_write(w, is_inter, av1_get_intra_inter_prob(cm, xd));

  if (bsize >= BLOCK_8X8 && cm->tx_mode == TX_MODE_SELECT &&
#if CONFIG_SUPERTX
      !supertx_enabled &&
#endif  // CONFIG_SUPERTX
      !(is_inter && skip) && !xd->lossless[segment_id]) {
#if CONFIG_VAR_TX
    if (is_inter) {  // This implies skip flag is 0.
      const TX_SIZE max_tx_size = max_txsize_lookup[bsize];
      const int txb_size = txsize_to_bsize[max_tx_size];
      const int bs = num_4x4_blocks_wide_lookup[txb_size];
      const int width = num_4x4_blocks_wide_lookup[bsize];
      const int height = num_4x4_blocks_high_lookup[bsize];
      int idx, idy;
      for (idy = 0; idy < height; idy += bs)
        for (idx = 0; idx < width; idx += bs)
          write_tx_size_vartx(cm, xd, mbmi, max_tx_size, idy, idx, w);
    } else {
      set_txfm_ctxs(mbmi->tx_size, xd->n8_w, xd->n8_h, xd);
      write_selected_tx_size(cm, xd, w);
    }
  } else {
    set_txfm_ctxs(mbmi->tx_size, xd->n8_w, xd->n8_h, xd);
#else
    write_selected_tx_size(cm, xd, w);
#endif
  }

  if (!is_inter) {
    if (bsize >= BLOCK_8X8) {
      write_intra_mode(w, mode, cm->fc->y_mode_prob[size_group_lookup[bsize]]);
    } else {
      int idx, idy;
      const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
      const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
      for (idy = 0; idy < 2; idy += num_4x4_h) {
        for (idx = 0; idx < 2; idx += num_4x4_w) {
          const PREDICTION_MODE b_mode = mi->bmi[idy * 2 + idx].as_mode;
          write_intra_mode(w, b_mode, cm->fc->y_mode_prob[0]);
        }
      }
    }
    write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mode]);
#if CONFIG_EXT_INTRA
    write_intra_angle_info(cm, xd, w);
#endif  // CONFIG_EXT_INTRA
    if (bsize >= BLOCK_8X8 && cm->allow_screen_content_tools)
      write_palette_mode_info(cm, xd, mi, w);
#if CONFIG_EXT_INTRA
    if (bsize >= BLOCK_8X8) write_ext_intra_mode_info(cm, mbmi, w);
#endif  // CONFIG_EXT_INTRA
  } else {
    int16_t mode_ctx = mbmi_ext->mode_context[mbmi->ref_frame[0]];
    write_ref_frames(cm, xd, w);

#if CONFIG_REF_MV
#if CONFIG_EXT_INTER
    if (is_compound)
      mode_ctx = mbmi_ext->compound_mode_context[mbmi->ref_frame[0]];
    else
#endif  // CONFIG_EXT_INTER
      mode_ctx = av1_mode_context_analyzer(mbmi_ext->mode_context,
                                           mbmi->ref_frame, bsize, -1);
#endif

    // If segment skip is not enabled code the mode.
    if (!segfeature_active(seg, segment_id, SEG_LVL_SKIP)) {
      if (bsize >= BLOCK_8X8) {
#if CONFIG_EXT_INTER
        if (is_inter_compound_mode(mode))
          write_inter_compound_mode(cm, w, mode, mode_ctx);
        else if (is_inter_singleref_mode(mode))
#endif  // CONFIG_EXT_INTER
          write_inter_mode(cm, w, mode,
#if CONFIG_REF_MV && CONFIG_EXT_INTER
                           is_compound,
#endif  // CONFIG_REF_MV && CONFIG_EXT_INTER
                           mode_ctx);

#if CONFIG_REF_MV
        if (mode == NEARMV || mode == NEWMV)
          write_drl_idx(cm, mbmi, mbmi_ext, w);
#endif
      }
    }

#if !CONFIG_EXT_INTERP && !CONFIG_DUAL_FILTER
    write_switchable_interp_filter(cpi, xd, w);
#endif  // !CONFIG_EXT_INTERP

    if (bsize < BLOCK_8X8) {
      const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
      const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
      int idx, idy;
      for (idy = 0; idy < 2; idy += num_4x4_h) {
        for (idx = 0; idx < 2; idx += num_4x4_w) {
          const int j = idy * 2 + idx;
          const PREDICTION_MODE b_mode = mi->bmi[j].as_mode;
#if CONFIG_REF_MV
#if CONFIG_EXT_INTER
          if (!is_compound)
#endif  // CONFIG_EXT_INTER
            mode_ctx = av1_mode_context_analyzer(mbmi_ext->mode_context,
                                                 mbmi->ref_frame, bsize, j);
#endif
#if CONFIG_EXT_INTER
          if (is_inter_compound_mode(b_mode))
            write_inter_compound_mode(cm, w, b_mode, mode_ctx);
          else if (is_inter_singleref_mode(b_mode))
#endif  // CONFIG_EXT_INTER
            write_inter_mode(cm, w, b_mode,
#if CONFIG_REF_MV && CONFIG_EXT_INTER
                             has_second_ref(mbmi),
#endif  // CONFIG_REF_MV && CONFIG_EXT_INTER
                             mode_ctx);

#if CONFIG_EXT_INTER
          if (b_mode == NEWMV || b_mode == NEWFROMNEARMV ||
              b_mode == NEW_NEWMV) {
#else
          if (b_mode == NEWMV) {
#endif  // CONFIG_EXT_INTER
            for (ref = 0; ref < 1 + is_compound; ++ref) {
#if CONFIG_REF_MV
              int nmv_ctx =
                  av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[ref]],
                              mbmi_ext->ref_mv_stack[mbmi->ref_frame[ref]]);
              const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
              av1_encode_mv(cpi, w, &mi->bmi[j].as_mv[ref].as_mv,
#if CONFIG_EXT_INTER
                            &mi->bmi[j].ref_mv[ref].as_mv,
#if CONFIG_REF_MV
                            is_compound,
#endif
#else
#if CONFIG_REF_MV
                            &mi->bmi[j].pred_mv_s8[ref].as_mv, is_compound,
#else
                            &mbmi_ext->ref_mvs[mbmi->ref_frame[ref]][0].as_mv,
#endif  // CONFIG_REF_MV
#endif  // CONFIG_EXT_INTER
                            nmvc, allow_hp);
            }
          }
#if CONFIG_EXT_INTER
          else if (b_mode == NEAREST_NEWMV || b_mode == NEAR_NEWMV) {
#if CONFIG_REF_MV
            int nmv_ctx =
                av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[1]],
                            mbmi_ext->ref_mv_stack[mbmi->ref_frame[1]]);
            const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
            av1_encode_mv(cpi, w, &mi->bmi[j].as_mv[1].as_mv,
                          &mi->bmi[j].ref_mv[1].as_mv,
#if CONFIG_REF_MV
                          is_compound,
#endif
                          nmvc, allow_hp);
          } else if (b_mode == NEW_NEARESTMV || b_mode == NEW_NEARMV) {
#if CONFIG_REF_MV
            int nmv_ctx =
                av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[0]],
                            mbmi_ext->ref_mv_stack[mbmi->ref_frame[0]]);
            const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
            av1_encode_mv(cpi, w, &mi->bmi[j].as_mv[0].as_mv,
                          &mi->bmi[j].ref_mv[0].as_mv,
#if CONFIG_REF_MV
                          is_compound,
#endif
                          nmvc, allow_hp);
          }
#endif  // CONFIG_EXT_INTER
        }
      }
    } else {
#if CONFIG_EXT_INTER
      if (mode == NEWMV || mode == NEWFROMNEARMV || mode == NEW_NEWMV) {
#else
      if (mode == NEWMV) {
#endif  // CONFIG_EXT_INTER
        int_mv ref_mv;
        for (ref = 0; ref < 1 + is_compound; ++ref) {
#if CONFIG_REF_MV
          int nmv_ctx =
              av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[ref]],
                          mbmi_ext->ref_mv_stack[mbmi->ref_frame[ref]]);
          const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
          ref_mv = mbmi_ext->ref_mvs[mbmi->ref_frame[ref]][0];
#if CONFIG_EXT_INTER
          if (mode == NEWFROMNEARMV)
            av1_encode_mv(cpi, w, &mbmi->mv[ref].as_mv,
                          &mbmi_ext->ref_mvs[mbmi->ref_frame[ref]][1].as_mv,
#if CONFIG_REF_MV
                          is_compound,
#endif
                          nmvc, allow_hp);
          else
#endif  // CONFIG_EXT_INTER
            av1_encode_mv(cpi, w, &mbmi->mv[ref].as_mv, &ref_mv.as_mv,
#if CONFIG_REF_MV
                          is_compound,
#endif
                          nmvc, allow_hp);
        }
#if CONFIG_EXT_INTER
      } else if (mode == NEAREST_NEWMV || mode == NEAR_NEWMV) {
#if CONFIG_REF_MV
        int nmv_ctx = av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[1]],
                                  mbmi_ext->ref_mv_stack[mbmi->ref_frame[1]]);
        const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
        av1_encode_mv(cpi, w, &mbmi->mv[1].as_mv,
                      &mbmi_ext->ref_mvs[mbmi->ref_frame[1]][0].as_mv,
#if CONFIG_REF_MV
                      is_compound,
#endif
                      nmvc, allow_hp);
      } else if (mode == NEW_NEARESTMV || mode == NEW_NEARMV) {
#if CONFIG_REF_MV
        int nmv_ctx = av1_nmv_ctx(mbmi_ext->ref_mv_count[mbmi->ref_frame[0]],
                                  mbmi_ext->ref_mv_stack[mbmi->ref_frame[0]]);
        const nmv_context *nmvc = &cm->fc->nmvc[nmv_ctx];
#endif
        av1_encode_mv(cpi, w, &mbmi->mv[0].as_mv,
                      &mbmi_ext->ref_mvs[mbmi->ref_frame[0]][0].as_mv,
#if CONFIG_REF_MV
                      is_compound,
#endif
                      nmvc, allow_hp);
#endif  // CONFIG_EXT_INTER
      }
    }

#if CONFIG_EXT_INTER
    if (cpi->common.reference_mode != COMPOUND_REFERENCE &&
#if CONFIG_SUPERTX
        !supertx_enabled &&
#endif  // CONFIG_SUPERTX
        is_interintra_allowed(mbmi)) {
      const int interintra = mbmi->ref_frame[1] == INTRA_FRAME;
      const int bsize_group = size_group_lookup[bsize];
      aom_write(w, interintra, cm->fc->interintra_prob[bsize_group]);
      if (interintra) {
        write_interintra_mode(w, mbmi->interintra_mode,
                              cm->fc->interintra_mode_prob[bsize_group]);
        if (is_interintra_wedge_used(bsize)) {
          aom_write(w, mbmi->use_wedge_interintra,
                    cm->fc->wedge_interintra_prob[bsize]);
          if (mbmi->use_wedge_interintra) {
            aom_write_literal(w, mbmi->interintra_wedge_index,
                              get_wedge_bits_lookup(bsize));
            assert(mbmi->interintra_wedge_sign == 0);
          }
        }
      }
    }
#endif  // CONFIG_EXT_INTER

#if CONFIG_OBMC || CONFIG_WARPED_MOTION
#if CONFIG_SUPERTX
    if (!supertx_enabled)
#endif  // CONFIG_SUPERTX
#if CONFIG_EXT_INTER
      if (mbmi->ref_frame[1] != INTRA_FRAME)
#endif  // CONFIG_EXT_INTER
        if (is_motvar_allowed(mbmi)) {
          // TODO(debargha): Might want to only emit this if SEG_LVL_SKIP
          // is not active, and assume SIMPLE_TRANSLATION in the decoder if
          // it is active.
          assert(mbmi->motion_variation < MOTION_VARIATIONS);
          av1_write_token(w, av1_motvar_tree, cm->fc->motvar_prob[bsize],
                          &motvar_encodings[mbmi->motion_variation]);
        }
#endif  // CONFIG_OBMC || CONFIG_WARPED_MOTION

#if CONFIG_EXT_INTER
    if (cpi->common.reference_mode != SINGLE_REFERENCE &&
        is_inter_compound_mode(mbmi->mode) &&
#if CONFIG_OBMC
        !(is_motvar_allowed(mbmi) &&
          mbmi->motion_variation != SIMPLE_TRANSLATION) &&
#endif  // CONFIG_OBMC
        is_interinter_wedge_used(bsize)) {
      aom_write(w, mbmi->use_wedge_interinter,
                cm->fc->wedge_interinter_prob[bsize]);
      if (mbmi->use_wedge_interinter) {
        aom_write_literal(w, mbmi->interinter_wedge_index,
                          get_wedge_bits_lookup(bsize));
        aom_write_bit(w, mbmi->interinter_wedge_sign);
      }
    }
#endif  // CONFIG_EXT_INTER

#if CONFIG_EXT_INTERP || CONFIG_DUAL_FILTER
    write_switchable_interp_filter(cpi, xd, w);
#endif  // CONFIG_EXT_INTERP
  }

  if (!FIXED_TX_TYPE) {
#if CONFIG_EXT_TX
    if (get_ext_tx_types(mbmi->tx_size, bsize, is_inter) > 1 &&
        cm->base_qindex > 0 && !mbmi->skip &&
#if CONFIG_SUPERTX
        !supertx_enabled &&
#endif  // CONFIG_SUPERTX
        !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP)) {
      int eset = get_ext_tx_set(mbmi->tx_size, bsize, is_inter);
      if (is_inter) {
        assert(ext_tx_used_inter[eset][mbmi->tx_type]);
        if (eset > 0)
          av1_write_token(
              w, av1_ext_tx_inter_tree[eset],
              cm->fc->inter_ext_tx_prob[eset][txsize_sqr_map[mbmi->tx_size]],
              &ext_tx_inter_encodings[eset][mbmi->tx_type]);
      } else if (ALLOW_INTRA_EXT_TX) {
        if (eset > 0)
          av1_write_token(
              w, av1_ext_tx_intra_tree[eset],
              cm->fc->intra_ext_tx_prob[eset][mbmi->tx_size][mbmi->mode],
              &ext_tx_intra_encodings[eset][mbmi->tx_type]);
      }
    }
#else
    if (mbmi->tx_size < TX_32X32 && cm->base_qindex > 0 && !mbmi->skip &&
#if CONFIG_SUPERTX
        !supertx_enabled &&
#endif  // CONFIG_SUPERTX
        !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP)) {
      if (is_inter) {
        av1_write_token(w, av1_ext_tx_tree,
                        cm->fc->inter_ext_tx_prob[mbmi->tx_size],
                        &ext_tx_encodings[mbmi->tx_type]);
      } else {
        av1_write_token(
            w, av1_ext_tx_tree,
            cm->fc->intra_ext_tx_prob
                [mbmi->tx_size][intra_mode_to_tx_type_context[mbmi->mode]],
            &ext_tx_encodings[mbmi->tx_type]);
      }
    } else {
      if (!mbmi->skip) {
#if CONFIG_SUPERTX
        if (!supertx_enabled)
#endif  // CONFIG_SUPERTX
          assert(mbmi->tx_type == DCT_DCT);
      }
    }
#endif  // CONFIG_EXT_TX
  }
}

static void write_mb_modes_kf(const AV1_COMMON *cm, const MACROBLOCKD *xd,
                              MODE_INFO **mi_8x8, aom_writer *w) {
  const struct segmentation *const seg = &cm->seg;
  const struct segmentation_probs *const segp = &cm->fc->seg;
  const MODE_INFO *const mi = mi_8x8[0];
  const MODE_INFO *const above_mi = xd->above_mi;
  const MODE_INFO *const left_mi = xd->left_mi;
  const MB_MODE_INFO *const mbmi = &mi->mbmi;
  const BLOCK_SIZE bsize = mbmi->sb_type;

  if (seg->update_map) write_segment_id(w, seg, segp, mbmi->segment_id);

  write_skip(cm, xd, mbmi->segment_id, mi, w);

  if (bsize >= BLOCK_8X8 && cm->tx_mode == TX_MODE_SELECT &&
      !xd->lossless[mbmi->segment_id])
    write_selected_tx_size(cm, xd, w);

  if (bsize >= BLOCK_8X8) {
    write_intra_mode(w, mbmi->mode,
                     get_y_mode_probs(cm, mi, above_mi, left_mi, 0));
  } else {
    const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
    const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
    int idx, idy;

    for (idy = 0; idy < 2; idy += num_4x4_h) {
      for (idx = 0; idx < 2; idx += num_4x4_w) {
        const int block = idy * 2 + idx;
        write_intra_mode(w, mi->bmi[block].as_mode,
                         get_y_mode_probs(cm, mi, above_mi, left_mi, block));
      }
    }
  }

  write_intra_mode(w, mbmi->uv_mode, cm->fc->uv_mode_prob[mbmi->mode]);
#if CONFIG_EXT_INTRA
  write_intra_angle_info(cm, xd, w);
#endif  // CONFIG_EXT_INTRA
  if (bsize >= BLOCK_8X8 && cm->allow_screen_content_tools)
    write_palette_mode_info(cm, xd, mi, w);
#if CONFIG_EXT_INTRA
  if (bsize >= BLOCK_8X8) write_ext_intra_mode_info(cm, mbmi, w);
#endif  // CONFIG_EXT_INTRA

  if (!FIXED_TX_TYPE) {
#if CONFIG_EXT_TX
    if (get_ext_tx_types(mbmi->tx_size, bsize, 0) > 1 && cm->base_qindex > 0 &&
        !mbmi->skip &&
        !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP) &&
        ALLOW_INTRA_EXT_TX) {
      int eset = get_ext_tx_set(mbmi->tx_size, bsize, 0);
      if (eset > 0)
        av1_write_token(
            w, av1_ext_tx_intra_tree[eset],
            cm->fc->intra_ext_tx_prob[eset][mbmi->tx_size][mbmi->mode],
            &ext_tx_intra_encodings[eset][mbmi->tx_type]);
    }
#else
    if (mbmi->tx_size < TX_32X32 && cm->base_qindex > 0 && !mbmi->skip &&
        !segfeature_active(&cm->seg, mbmi->segment_id, SEG_LVL_SKIP)) {
      av1_write_token(
          w, av1_ext_tx_tree,
          cm->fc->intra_ext_tx_prob[mbmi->tx_size]
                                   [intra_mode_to_tx_type_context[mbmi->mode]],
          &ext_tx_encodings[mbmi->tx_type]);
    }
#endif  // CONFIG_EXT_TX
  }
}

#if CONFIG_SUPERTX
#define write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled, \
                              mi_row, mi_col)                              \
  write_modes_b(cpi, tile, w, tok, tok_end, supertx_enabled, mi_row, mi_col)
#else
#define write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled, \
                              mi_row, mi_col)                              \
  write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col)
#endif  // CONFIG_ANS && CONFIG_SUPERTX

static void write_modes_b(AV1_COMP *cpi, const TileInfo *const tile,
                          aom_writer *w, const TOKENEXTRA **tok,
                          const TOKENEXTRA *const tok_end,
#if CONFIG_SUPERTX
                          int supertx_enabled,
#endif
                          int mi_row, int mi_col) {
  AV1_COMMON *const cm = &cpi->common;
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
  MODE_INFO *m;
  int plane;
  int bh, bw;
#if CONFIG_ANS
  (void)tok;
  (void)tok_end;
  (void)plane;
#endif  // !CONFIG_ANS

  xd->mi = cm->mi_grid_visible + (mi_row * cm->mi_stride + mi_col);
  m = xd->mi[0];

  assert(m->mbmi.sb_type <= cm->sb_size);

  bh = num_8x8_blocks_high_lookup[m->mbmi.sb_type];
  bw = num_8x8_blocks_wide_lookup[m->mbmi.sb_type];

  cpi->td.mb.mbmi_ext = cpi->mbmi_ext_base + (mi_row * cm->mi_cols + mi_col);

  set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
  if (frame_is_intra_only(cm)) {
    write_mb_modes_kf(cm, xd, xd->mi, w);
  } else {
#if CONFIG_VAR_TX
    xd->above_txfm_context = cm->above_txfm_context + mi_col;
    xd->left_txfm_context =
        xd->left_txfm_context_buffer + (mi_row & MAX_MIB_MASK);
#endif
#if CONFIG_EXT_INTERP
    // av1_is_interp_needed needs the ref frame buffers set up to look
    // up if they are scaled. av1_is_interp_needed is in turn needed by
    // write_switchable_interp_filter, which is called by pack_inter_mode_mvs.
    set_ref_ptrs(cm, xd, m->mbmi.ref_frame[0], m->mbmi.ref_frame[1]);
#endif  // CONFIG_EXT_INTERP
#if 0
    // NOTE(zoeliu): For debug
    if (cm->current_video_frame == FRAME_TO_CHECK && cm->show_frame == 1) {
      const PREDICTION_MODE mode = m->mbmi.mode;
      const int segment_id = m->mbmi.segment_id;
      const BLOCK_SIZE bsize = m->mbmi.sb_type;

      // For sub8x8, simply dump out the first sub8x8 block info
      const PREDICTION_MODE b_mode =
          (bsize < BLOCK_8X8) ? m->bmi[0].as_mode : -1;
      const int mv_x = (bsize < BLOCK_8X8) ?
          m->bmi[0].as_mv[0].as_mv.row : m->mbmi.mv[0].as_mv.row;
      const int mv_y = (bsize < BLOCK_8X8) ?
          m->bmi[0].as_mv[0].as_mv.col : m->mbmi.mv[0].as_mv.col;

      printf("Before pack_inter_mode_mvs(): "
             "Frame=%d, (mi_row,mi_col)=(%d,%d), "
             "mode=%d, segment_id=%d, bsize=%d, b_mode=%d, "
             "mv[0]=(%d, %d), ref[0]=%d, ref[1]=%d\n",
             cm->current_video_frame, mi_row, mi_col,
             mode, segment_id, bsize, b_mode, mv_x, mv_y,
             m->mbmi.ref_frame[0], m->mbmi.ref_frame[1]);
    }
#endif  // 0
    pack_inter_mode_mvs(cpi, m,
#if CONFIG_SUPERTX
                        supertx_enabled,
#endif
                        w);
  }

  for (plane = 0; plane <= 1; ++plane) {
    if (m->mbmi.palette_mode_info.palette_size[plane] > 0) {
      const int rows = (4 * num_4x4_blocks_high_lookup[m->mbmi.sb_type]) >>
                       (xd->plane[plane].subsampling_y);
      const int cols = (4 * num_4x4_blocks_wide_lookup[m->mbmi.sb_type]) >>
                       (xd->plane[plane].subsampling_x);
      assert(*tok < tok_end);
      pack_palette_tokens(w, tok, m->mbmi.palette_mode_info.palette_size[plane],
                          rows * cols - 1);
      assert(*tok < tok_end + m->mbmi.skip);
    }
  }

#if CONFIG_SUPERTX
  if (supertx_enabled) return;
#endif  // CONFIG_SUPERTX

  if (!m->mbmi.skip) {
    assert(*tok < tok_end);
    for (plane = 0; plane < MAX_MB_PLANE; ++plane) {
#if CONFIG_VAR_TX
      const struct macroblockd_plane *const pd = &xd->plane[plane];
      MB_MODE_INFO *mbmi = &m->mbmi;
      BLOCK_SIZE bsize = mbmi->sb_type;
      const BLOCK_SIZE plane_bsize =
          get_plane_block_size(AOMMAX(bsize, BLOCK_8X8), pd);

      const int num_4x4_w = num_4x4_blocks_wide_lookup[plane_bsize];
      const int num_4x4_h = num_4x4_blocks_high_lookup[plane_bsize];
      int row, col;
#if CONFIG_EXT_TX && CONFIG_RECT_TX
      TX_SIZE tx_size =
          plane ? get_uv_tx_size(mbmi, &xd->plane[plane]) : mbmi->tx_size;

      if (is_inter_block(mbmi) && tx_size < TX_SIZES) {
#else
      if (is_inter_block(mbmi)) {
#endif
        const TX_SIZE max_tx_size = max_txsize_lookup[plane_bsize];
        const BLOCK_SIZE txb_size = txsize_to_bsize[max_tx_size];
        int bw = num_4x4_blocks_wide_lookup[txb_size];
        int block = 0;
        const int step = num_4x4_blocks_txsize_lookup[max_tx_size];
        for (row = 0; row < num_4x4_h; row += bw) {
          for (col = 0; col < num_4x4_w; col += bw) {
            pack_txb_tokens(w, tok, tok_end, xd, mbmi, plane, plane_bsize,
                            cm->bit_depth, block, row, col, max_tx_size);
            block += step;
          }
        }
      } else {
        TX_SIZE tx = plane ? get_uv_tx_size(&m->mbmi, &xd->plane[plane])
                           : m->mbmi.tx_size;
        BLOCK_SIZE txb_size = txsize_to_bsize[tx];
        int bw = num_4x4_blocks_wide_lookup[txb_size];
        int bh = num_4x4_blocks_high_lookup[txb_size];

        for (row = 0; row < num_4x4_h; row += bh)
          for (col = 0; col < num_4x4_w; col += bw)
            pack_mb_tokens(w, tok, tok_end, cm->bit_depth, tx);
      }
#else
      TX_SIZE tx =
          plane ? get_uv_tx_size(&m->mbmi, &xd->plane[plane]) : m->mbmi.tx_size;
      pack_mb_tokens(w, tok, tok_end, cm->bit_depth, tx);
#endif  // CONFIG_VAR_TX
      assert(*tok < tok_end && (*tok)->token == EOSB_TOKEN);
      (*tok)++;
    }
  }
}

static void write_partition(const AV1_COMMON *const cm,
                            const MACROBLOCKD *const xd, int hbs, int mi_row,
                            int mi_col, PARTITION_TYPE p, BLOCK_SIZE bsize,
                            aom_writer *w) {
  const int ctx = partition_plane_context(xd, mi_row, mi_col, bsize);
  const aom_prob *const probs = cm->fc->partition_prob[ctx];
  const int has_rows = (mi_row + hbs) < cm->mi_rows;
  const int has_cols = (mi_col + hbs) < cm->mi_cols;

  if (has_rows && has_cols) {
#if CONFIG_EXT_PARTITION_TYPES
    if (bsize <= BLOCK_8X8)
      av1_write_token(w, av1_partition_tree, probs, &partition_encodings[p]);
    else
      av1_write_token(w, av1_ext_partition_tree, probs,
                      &ext_partition_encodings[p]);
#else
    av1_write_token(w, av1_partition_tree, probs, &partition_encodings[p]);
#endif  // CONFIG_EXT_PARTITION_TYPES
  } else if (!has_rows && has_cols) {
    assert(p == PARTITION_SPLIT || p == PARTITION_HORZ);
    aom_write(w, p == PARTITION_SPLIT, probs[1]);
  } else if (has_rows && !has_cols) {
    assert(p == PARTITION_SPLIT || p == PARTITION_VERT);
    aom_write(w, p == PARTITION_SPLIT, probs[2]);
  } else {
    assert(p == PARTITION_SPLIT);
  }
}

#if CONFIG_SUPERTX
#define write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,   \
                               mi_row, mi_col, bsize)                         \
  write_modes_sb(cpi, tile, w, tok, tok_end, supertx_enabled, mi_row, mi_col, \
                 bsize)
#else
#define write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled, \
                               mi_row, mi_col, bsize)                       \
  write_modes_sb(cpi, tile, w, tok, tok_end, mi_row, mi_col, bsize)
#endif  // CONFIG_ANS && CONFIG_SUPERTX

static void write_modes_sb(AV1_COMP *const cpi, const TileInfo *const tile,
                           aom_writer *const w, const TOKENEXTRA **tok,
                           const TOKENEXTRA *const tok_end,
#if CONFIG_SUPERTX
                           int supertx_enabled,
#endif
                           int mi_row, int mi_col, BLOCK_SIZE bsize) {
  const AV1_COMMON *const cm = &cpi->common;
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
  const int hbs = num_8x8_blocks_wide_lookup[bsize] / 2;
  const PARTITION_TYPE partition = get_partition(cm, mi_row, mi_col, bsize);
  const BLOCK_SIZE subsize = get_subsize(bsize, partition);
#if CONFIG_SUPERTX
  const int mi_offset = mi_row * cm->mi_stride + mi_col;
  MB_MODE_INFO *mbmi;
  const int pack_token = !supertx_enabled;
  TX_SIZE supertx_size;
  int plane;
#endif

  if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;

  write_partition(cm, xd, hbs, mi_row, mi_col, partition, bsize, w);
#if CONFIG_SUPERTX
  mbmi = &cm->mi_grid_visible[mi_offset]->mbmi;
  xd->mi = cm->mi_grid_visible + mi_offset;
  set_mi_row_col(xd, tile, mi_row, num_8x8_blocks_high_lookup[bsize], mi_col,
                 num_8x8_blocks_wide_lookup[bsize], cm->mi_rows, cm->mi_cols);
  if (!supertx_enabled && !frame_is_intra_only(cm) &&
      partition != PARTITION_NONE && bsize <= MAX_SUPERTX_BLOCK_SIZE &&
      !xd->lossless[0]) {
    aom_prob prob;
    supertx_size = max_txsize_lookup[bsize];
    prob = cm->fc->supertx_prob[partition_supertx_context_lookup[partition]]
                               [supertx_size];
    supertx_enabled = (xd->mi[0]->mbmi.tx_size == supertx_size);
    aom_write(w, supertx_enabled, prob);
  }
#endif  // CONFIG_SUPERTX
  if (subsize < BLOCK_8X8) {
    write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled, mi_row,
                          mi_col);
  } else {
    switch (partition) {
      case PARTITION_NONE:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        break;
      case PARTITION_HORZ:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        if (mi_row + hbs < cm->mi_rows)
          write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                                mi_row + hbs, mi_col);
        break;
      case PARTITION_VERT:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        if (mi_col + hbs < cm->mi_cols)
          write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                                mi_row, mi_col + hbs);
        break;
      case PARTITION_SPLIT:
        write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                               mi_row, mi_col, subsize);
        write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                               mi_row, mi_col + hbs, subsize);
        write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                               mi_row + hbs, mi_col, subsize);
        write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                               mi_row + hbs, mi_col + hbs, subsize);
        break;
#if CONFIG_EXT_PARTITION_TYPES
      case PARTITION_HORZ_A:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col + hbs);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row + hbs, mi_col);
        break;
      case PARTITION_HORZ_B:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row + hbs, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row + hbs, mi_col + hbs);
        break;
      case PARTITION_VERT_A:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row + hbs, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col + hbs);
        break;
      case PARTITION_VERT_B:
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row, mi_col + hbs);
        write_modes_b_wrapper(cpi, tile, w, tok, tok_end, supertx_enabled,
                              mi_row + hbs, mi_col + hbs);
        break;
#endif  // CONFIG_EXT_PARTITION_TYPES
      default: assert(0);
    }
  }
#if CONFIG_SUPERTX
  if (partition != PARTITION_NONE && supertx_enabled && pack_token) {
    int skip;
    xd->mi = cm->mi_grid_visible + mi_offset;
    supertx_size = mbmi->tx_size;
    set_mi_row_col(xd, tile, mi_row, num_8x8_blocks_high_lookup[bsize], mi_col,
                   num_8x8_blocks_wide_lookup[bsize], cm->mi_rows, cm->mi_cols);

    assert(IMPLIES(!cm->seg.enabled, mbmi->segment_id_supertx == 0));
    assert(mbmi->segment_id_supertx < MAX_SEGMENTS);

    skip = write_skip(cm, xd, mbmi->segment_id_supertx, xd->mi[0], w);
#if CONFIG_EXT_TX
    if (get_ext_tx_types(supertx_size, bsize, 1) > 1 && !skip) {
      int eset = get_ext_tx_set(supertx_size, bsize, 1);
      if (eset > 0) {
        av1_write_token(w, av1_ext_tx_inter_tree[eset],
                        cm->fc->inter_ext_tx_prob[eset][supertx_size],
                        &ext_tx_inter_encodings[eset][mbmi->tx_type]);
      }
    }
#else
    if (supertx_size < TX_32X32 && !skip) {
      av1_write_token(w, av1_ext_tx_tree,
                      cm->fc->inter_ext_tx_prob[supertx_size],
                      &ext_tx_encodings[mbmi->tx_type]);
    }
#endif  // CONFIG_EXT_TX

    if (!skip) {
      assert(*tok < tok_end);
      for (plane = 0; plane < MAX_MB_PLANE; ++plane) {
        const int mbmi_txb_size = txsize_to_bsize[mbmi->tx_size];
        const int num_4x4_w = num_4x4_blocks_wide_lookup[mbmi_txb_size];
        const int num_4x4_h = num_4x4_blocks_high_lookup[mbmi_txb_size];
        int row, col;
        TX_SIZE tx =
            plane ? get_uv_tx_size(mbmi, &xd->plane[plane]) : mbmi->tx_size;
        BLOCK_SIZE txb_size = txsize_to_bsize[tx];
        int bw = num_4x4_blocks_wide_lookup[txb_size];

        for (row = 0; row < num_4x4_h; row += bw)
          for (col = 0; col < num_4x4_w; col += bw)
            pack_mb_tokens(w, tok, tok_end, cm->bit_depth, tx);
        assert(*tok < tok_end && (*tok)->token == EOSB_TOKEN);
        (*tok)++;
      }
    }
  }
#endif  // CONFIG_SUPERTX

// update partition context
#if CONFIG_EXT_PARTITION_TYPES
  update_ext_partition_context(xd, mi_row, mi_col, subsize, bsize, partition);
#else
  if (bsize >= BLOCK_8X8 &&
      (bsize == BLOCK_8X8 || partition != PARTITION_SPLIT))
    update_partition_context(xd, mi_row, mi_col, subsize, bsize);

#if DERING_REFINEMENT
  if (bsize == BLOCK_64X64 && cm->dering_level != 0 &&
      !sb_all_skip(cm, mi_row, mi_col)) {
    aom_write_literal(
        w,
        cm->mi_grid_visible[mi_row * cm->mi_stride + mi_col]->mbmi.dering_gain,
        DERING_REFINEMENT_BITS);
  }
#endif
#endif  // CONFIG_EXT_PARTITION_TYPES
}

static void write_modes(AV1_COMP *const cpi, const TileInfo *const tile,
                        aom_writer *const w, const TOKENEXTRA **tok,
                        const TOKENEXTRA *const tok_end) {
  AV1_COMMON *const cm = &cpi->common;
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
  const int mi_row_start = tile->mi_row_start;
  const int mi_row_end = tile->mi_row_end;
  const int mi_col_start = tile->mi_col_start;
  const int mi_col_end = tile->mi_col_end;
  int mi_row, mi_col;

  av1_zero_above_context(cm, mi_col_start, mi_col_end);

  for (mi_row = mi_row_start; mi_row < mi_row_end; mi_row += cm->mib_size) {
    av1_zero_left_context(xd);

    for (mi_col = mi_col_start; mi_col < mi_col_end; mi_col += cm->mib_size) {
      write_modes_sb_wrapper(cpi, tile, w, tok, tok_end, 0, mi_row, mi_col,
                             cm->sb_size);
    }
  }
}

static void build_tree_distribution(AV1_COMP *cpi, TX_SIZE tx_size,
                                    av1_coeff_stats *coef_branch_ct,
                                    av1_coeff_probs_model *coef_probs) {
  av1_coeff_count *coef_counts = cpi->td.rd_counts.coef_counts[tx_size];
  unsigned int(*eob_branch_ct)[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS] =
      cpi->common.counts.eob_branch[tx_size];
  int i, j, k, l, m;

  for (i = 0; i < PLANE_TYPES; ++i) {
    for (j = 0; j < REF_TYPES; ++j) {
      for (k = 0; k < COEF_BANDS; ++k) {
        for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
          av1_tree_probs_from_distribution(av1_coef_tree,
                                           coef_branch_ct[i][j][k][l],
                                           coef_counts[i][j][k][l]);
          coef_branch_ct[i][j][k][l][0][1] =
              eob_branch_ct[i][j][k][l] - coef_branch_ct[i][j][k][l][0][0];
          for (m = 0; m < UNCONSTRAINED_NODES; ++m)
            coef_probs[i][j][k][l][m] =
                get_binary_prob(coef_branch_ct[i][j][k][l][m][0],
                                coef_branch_ct[i][j][k][l][m][1]);
        }
      }
    }
  }
}

static void update_coef_probs_common(aom_writer *const bc, AV1_COMP *cpi,
                                     TX_SIZE tx_size,
                                     av1_coeff_stats *frame_branch_ct,
                                     av1_coeff_probs_model *new_coef_probs) {
  av1_coeff_probs_model *old_coef_probs = cpi->common.fc->coef_probs[tx_size];
  const aom_prob upd = DIFF_UPDATE_PROB;
  const int entropy_nodes_update = UNCONSTRAINED_NODES;
  int i, j, k, l, t;
  int stepsize = cpi->sf.coeff_prob_appx_step;

  switch (cpi->sf.use_fast_coef_updates) {
    case TWO_LOOP: {
      /* dry run to see if there is any update at all needed */
      int savings = 0;
      int update[2] = { 0, 0 };
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                const aom_prob oldp = old_coef_probs[i][j][k][l][t];
                int s;
                int u = 0;
                if (t == PIVOT_NODE)
                  s = av1_prob_diff_update_savings_search_model(
                      frame_branch_ct[i][j][k][l][0],
                      old_coef_probs[i][j][k][l], &newp, upd, stepsize);
                else
                  s = av1_prob_diff_update_savings_search(
                      frame_branch_ct[i][j][k][l][t], oldp, &newp, upd);
                if (s > 0 && newp != oldp) u = 1;
                if (u)
                  savings += s - (int)(av1_cost_zero(upd));
                else
                  savings -= (int)(av1_cost_zero(upd));
                update[u]++;
              }
            }
          }
        }
      }

      /* Is coef updated at all */
      if (update[1] == 0 || savings < 0) {
        aom_write_bit(bc, 0);
        return;
      }
      aom_write_bit(bc, 1);
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              // calc probs and branch cts for this frame only
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                aom_prob *oldp = old_coef_probs[i][j][k][l] + t;
                const aom_prob upd = DIFF_UPDATE_PROB;
                int s;
                int u = 0;
                if (t == PIVOT_NODE)
                  s = av1_prob_diff_update_savings_search_model(
                      frame_branch_ct[i][j][k][l][0],
                      old_coef_probs[i][j][k][l], &newp, upd, stepsize);
                else
                  s = av1_prob_diff_update_savings_search(
                      frame_branch_ct[i][j][k][l][t], *oldp, &newp, upd);
                if (s > 0 && newp != *oldp) u = 1;
                aom_write(bc, u, upd);
                if (u) {
                  /* send/use new probability */
                  av1_write_prob_diff_update(bc, newp, *oldp);
                  *oldp = newp;
                }
              }
            }
          }
        }
      }
      return;
    }

    case ONE_LOOP_REDUCED: {
      int updates = 0;
      int noupdates_before_first = 0;
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              // calc probs and branch cts for this frame only
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                aom_prob *oldp = old_coef_probs[i][j][k][l] + t;
                int s;
                int u = 0;

                if (t == PIVOT_NODE) {
                  s = av1_prob_diff_update_savings_search_model(
                      frame_branch_ct[i][j][k][l][0],
                      old_coef_probs[i][j][k][l], &newp, upd, stepsize);
                } else {
                  s = av1_prob_diff_update_savings_search(
                      frame_branch_ct[i][j][k][l][t], *oldp, &newp, upd);
                }

                if (s > 0 && newp != *oldp) u = 1;
                updates += u;
                if (u == 0 && updates == 0) {
                  noupdates_before_first++;
                  continue;
                }
                if (u == 1 && updates == 1) {
                  int v;
                  // first update
                  aom_write_bit(bc, 1);
                  for (v = 0; v < noupdates_before_first; ++v)
                    aom_write(bc, 0, upd);
                }
                aom_write(bc, u, upd);
                if (u) {
                  /* send/use new probability */
                  av1_write_prob_diff_update(bc, newp, *oldp);
                  *oldp = newp;
                }
              }
            }
          }
        }
      }
      if (updates == 0) {
        aom_write_bit(bc, 0);  // no updates
      }
      return;
    }
    default: assert(0);
  }
}

#if CONFIG_ENTROPY
// Calculate the token counts between subsequent subframe updates.
static void get_coef_counts_diff(
    AV1_COMP *cpi, int index,
    av1_coeff_count coef_counts[TX_SIZES][PLANE_TYPES],
    unsigned int eob_counts[TX_SIZES][PLANE_TYPES][REF_TYPES][COEF_BANDS]
                           [COEFF_CONTEXTS]) {
  int i, j, k, l, m, tx_size, val;
  const int max_idx = cpi->common.coef_probs_update_idx;
  const TX_MODE tx_mode = cpi->common.tx_mode;
  const TX_SIZE max_tx_size = tx_mode_to_biggest_tx_size[tx_mode];
  const SUBFRAME_STATS *subframe_stats = &cpi->subframe_stats;

  assert(max_idx < COEF_PROBS_BUFS);

  for (tx_size = TX_4X4; tx_size <= max_tx_size; ++tx_size)
    for (i = 0; i < PLANE_TYPES; ++i)
      for (j = 0; j < REF_TYPES; ++j)
        for (k = 0; k < COEF_BANDS; ++k)
          for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
            if (index == max_idx) {
              val =
                  cpi->common.counts.eob_branch[tx_size][i][j][k][l] -
                  subframe_stats->eob_counts_buf[max_idx][tx_size][i][j][k][l];
            } else {
              val = subframe_stats
                        ->eob_counts_buf[index + 1][tx_size][i][j][k][l] -
                    subframe_stats->eob_counts_buf[index][tx_size][i][j][k][l];
            }
            assert(val >= 0);
            eob_counts[tx_size][i][j][k][l] = val;

            for (m = 0; m < ENTROPY_TOKENS; ++m) {
              if (index == max_idx) {
                val = cpi->td.rd_counts.coef_counts[tx_size][i][j][k][l][m] -
                      subframe_stats
                          ->coef_counts_buf[max_idx][tx_size][i][j][k][l][m];
              } else {
                val = subframe_stats
                          ->coef_counts_buf[index + 1][tx_size][i][j][k][l][m] -
                      subframe_stats
                          ->coef_counts_buf[index][tx_size][i][j][k][l][m];
              }
              assert(val >= 0);
              coef_counts[tx_size][i][j][k][l][m] = val;
            }
          }
}

static void update_coef_probs_subframe(
    aom_writer *const bc, AV1_COMP *cpi, TX_SIZE tx_size,
    av1_coeff_stats branch_ct[COEF_PROBS_BUFS][TX_SIZES][PLANE_TYPES],
    av1_coeff_probs_model *new_coef_probs) {
  av1_coeff_probs_model *old_coef_probs = cpi->common.fc->coef_probs[tx_size];
  const aom_prob upd = DIFF_UPDATE_PROB;
  const int entropy_nodes_update = UNCONSTRAINED_NODES;
  int i, j, k, l, t;
  int stepsize = cpi->sf.coeff_prob_appx_step;
  const int max_idx = cpi->common.coef_probs_update_idx;
  int idx;
  unsigned int this_branch_ct[ENTROPY_NODES][COEF_PROBS_BUFS][2];

  switch (cpi->sf.use_fast_coef_updates) {
    case TWO_LOOP: {
      /* dry run to see if there is any update at all needed */
      int savings = 0;
      int update[2] = { 0, 0 };
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              for (t = 0; t < ENTROPY_NODES; ++t) {
                for (idx = 0; idx <= max_idx; ++idx) {
                  memcpy(this_branch_ct[t][idx],
                         branch_ct[idx][tx_size][i][j][k][l][t],
                         2 * sizeof(this_branch_ct[t][idx][0]));
                }
              }
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                const aom_prob oldp = old_coef_probs[i][j][k][l][t];
                int s, u = 0;

                if (t == PIVOT_NODE)
                  s = av1_prob_update_search_model_subframe(
                      this_branch_ct, old_coef_probs[i][j][k][l], &newp, upd,
                      stepsize, max_idx);
                else
                  s = av1_prob_update_search_subframe(this_branch_ct[t], oldp,
                                                      &newp, upd, max_idx);
                if (s > 0 && newp != oldp) u = 1;
                if (u)
                  savings += s - (int)(av1_cost_zero(upd));
                else
                  savings -= (int)(av1_cost_zero(upd));
                update[u]++;
              }
            }
          }
        }
      }

      /* Is coef updated at all */
      if (update[1] == 0 || savings < 0) {
        aom_write_bit(bc, 0);
        return;
      }
      aom_write_bit(bc, 1);
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              for (t = 0; t < ENTROPY_NODES; ++t) {
                for (idx = 0; idx <= max_idx; ++idx) {
                  memcpy(this_branch_ct[t][idx],
                         branch_ct[idx][tx_size][i][j][k][l][t],
                         2 * sizeof(this_branch_ct[t][idx][0]));
                }
              }
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                aom_prob *oldp = old_coef_probs[i][j][k][l] + t;
                const aom_prob upd = DIFF_UPDATE_PROB;
                int s;
                int u = 0;

                if (t == PIVOT_NODE)
                  s = av1_prob_update_search_model_subframe(
                      this_branch_ct, old_coef_probs[i][j][k][l], &newp, upd,
                      stepsize, max_idx);
                else
                  s = av1_prob_update_search_subframe(this_branch_ct[t], *oldp,
                                                      &newp, upd, max_idx);
                if (s > 0 && newp != *oldp) u = 1;
                aom_write(bc, u, upd);
                if (u) {
                  /* send/use new probability */
                  av1_write_prob_diff_update(bc, newp, *oldp);
                  *oldp = newp;
                }
              }
            }
          }
        }
      }
      return;
    }

    case ONE_LOOP_REDUCED: {
      int updates = 0;
      int noupdates_before_first = 0;
      for (i = 0; i < PLANE_TYPES; ++i) {
        for (j = 0; j < REF_TYPES; ++j) {
          for (k = 0; k < COEF_BANDS; ++k) {
            for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
              for (t = 0; t < ENTROPY_NODES; ++t) {
                for (idx = 0; idx <= max_idx; ++idx) {
                  memcpy(this_branch_ct[t][idx],
                         branch_ct[idx][tx_size][i][j][k][l][t],
                         2 * sizeof(this_branch_ct[t][idx][0]));
                }
              }
              for (t = 0; t < entropy_nodes_update; ++t) {
                aom_prob newp = new_coef_probs[i][j][k][l][t];
                aom_prob *oldp = old_coef_probs[i][j][k][l] + t;
                int s;
                int u = 0;

                if (t == PIVOT_NODE)
                  s = av1_prob_update_search_model_subframe(
                      this_branch_ct, old_coef_probs[i][j][k][l], &newp, upd,
                      stepsize, max_idx);
                else
                  s = av1_prob_update_search_subframe(this_branch_ct[t], *oldp,
                                                      &newp, upd, max_idx);
                if (s > 0 && newp != *oldp) u = 1;
                updates += u;
                if (u == 0 && updates == 0) {
                  noupdates_before_first++;
                  continue;
                }
                if (u == 1 && updates == 1) {
                  int v;
                  // first update
                  aom_write_bit(bc, 1);
                  for (v = 0; v < noupdates_before_first; ++v)
                    aom_write(bc, 0, upd);
                }
                aom_write(bc, u, upd);
                if (u) {
                  /* send/use new probability */
                  av1_write_prob_diff_update(bc, newp, *oldp);
                  *oldp = newp;
                }
              }
            }
          }
        }
      }
      if (updates == 0) {
        aom_write_bit(bc, 0);  // no updates
      }
      return;
    }
    default: assert(0);
  }
}
#endif  // CONFIG_ENTROPY

static void update_coef_probs(AV1_COMP *cpi, aom_writer *w) {
  const TX_MODE tx_mode = cpi->common.tx_mode;
  const TX_SIZE max_tx_size = tx_mode_to_biggest_tx_size[tx_mode];
  TX_SIZE tx_size;
#if CONFIG_ANS
  int update = 0;
#endif  // CONFIG_ANS
#if CONFIG_ENTROPY
  AV1_COMMON *cm = &cpi->common;
  SUBFRAME_STATS *subframe_stats = &cpi->subframe_stats;
  unsigned int eob_counts_copy[TX_SIZES][PLANE_TYPES][REF_TYPES][COEF_BANDS]
                              [COEFF_CONTEXTS];
  int i;
  av1_coeff_probs_model dummy_frame_coef_probs[PLANE_TYPES];

  if (cm->do_subframe_update &&
      cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
    av1_copy(cpi->common.fc->coef_probs,
             subframe_stats->enc_starting_coef_probs);
    for (i = 0; i <= cpi->common.coef_probs_update_idx; ++i) {
      get_coef_counts_diff(cpi, i, cpi->wholeframe_stats.coef_counts_buf[i],
                           cpi->wholeframe_stats.eob_counts_buf[i]);
    }
  }
#endif  // CONFIG_ENTROPY

  for (tx_size = TX_4X4; tx_size <= max_tx_size; ++tx_size) {
    av1_coeff_stats frame_branch_ct[PLANE_TYPES];
    av1_coeff_probs_model frame_coef_probs[PLANE_TYPES];
    if (cpi->td.counts->tx_size_totals[tx_size] <= 20 ||
        (tx_size >= TX_16X16 && cpi->sf.tx_size_search_method == USE_TX_8X8)) {
      aom_write_bit(w, 0);
    } else {
#if CONFIG_ENTROPY
      if (cm->do_subframe_update &&
          cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
        unsigned int
            eob_counts_copy[PLANE_TYPES][REF_TYPES][COEF_BANDS][COEFF_CONTEXTS];
        av1_coeff_count coef_counts_copy[PLANE_TYPES];
        av1_copy(eob_counts_copy, cpi->common.counts.eob_branch[tx_size]);
        av1_copy(coef_counts_copy, cpi->td.rd_counts.coef_counts[tx_size]);
        build_tree_distribution(cpi, tx_size, frame_branch_ct,
                                frame_coef_probs);
        for (i = 0; i <= cpi->common.coef_probs_update_idx; ++i) {
          av1_copy(cpi->common.counts.eob_branch[tx_size],
                   cpi->wholeframe_stats.eob_counts_buf[i][tx_size]);
          av1_copy(cpi->td.rd_counts.coef_counts[tx_size],
                   cpi->wholeframe_stats.coef_counts_buf[i][tx_size]);
          build_tree_distribution(cpi, tx_size, cpi->branch_ct_buf[i][tx_size],
                                  dummy_frame_coef_probs);
        }
        av1_copy(cpi->common.counts.eob_branch[tx_size], eob_counts_copy);
        av1_copy(cpi->td.rd_counts.coef_counts[tx_size], coef_counts_copy);

        update_coef_probs_subframe(w, cpi, tx_size, cpi->branch_ct_buf,
                                   frame_coef_probs);
#if CONFIG_ANS
        update = 1;
#endif  // CONFIG_ANS
      } else {
#endif  // CONFIG_ENTROPY
        build_tree_distribution(cpi, tx_size, frame_branch_ct,
                                frame_coef_probs);
        update_coef_probs_common(w, cpi, tx_size, frame_branch_ct,
                                 frame_coef_probs);
#if CONFIG_ANS
        update = 1;
#endif  // CONFIG_ANS
#if CONFIG_ENTROPY
      }
#endif  // CONFIG_ENTROPY
    }
  }

#if CONFIG_ENTROPY
  av1_copy(cm->starting_coef_probs, cm->fc->coef_probs);
  av1_copy(subframe_stats->coef_probs_buf[0], cm->fc->coef_probs);
  if (cm->do_subframe_update &&
      cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_BACKWARD) {
    av1_copy(eob_counts_copy, cm->counts.eob_branch);
    for (i = 1; i <= cpi->common.coef_probs_update_idx; ++i) {
      for (tx_size = TX_4X4; tx_size <= max_tx_size; ++tx_size)
        av1_full_to_model_counts(cm->counts.coef[tx_size],
                                 subframe_stats->coef_counts_buf[i][tx_size]);
      av1_copy(cm->counts.eob_branch, subframe_stats->eob_counts_buf[i]);
      av1_partial_adapt_probs(cm, 0, 0);
      av1_copy(subframe_stats->coef_probs_buf[i], cm->fc->coef_probs);
    }
    av1_copy(cm->fc->coef_probs, subframe_stats->coef_probs_buf[0]);
    av1_copy(cm->counts.eob_branch, eob_counts_copy);
  }
#endif  // CONFIG_ENTROPY
#if CONFIG_ANS
  if (update) av1_coef_pareto_cdfs(cpi->common.fc);
#endif  // CONFIG_ANS
}

#if CONFIG_LOOP_RESTORATION
static void encode_restoration(AV1_COMMON *cm,
                               struct aom_write_bit_buffer *wb) {
  int i;
  RestorationInfo *rst = &cm->rst_info;
  aom_wb_write_bit(wb, rst->restoration_type != RESTORE_NONE);
  if (rst->restoration_type != RESTORE_NONE) {
    if (rst->restoration_type == RESTORE_BILATERAL) {
      aom_wb_write_bit(wb, 1);
      for (i = 0; i < cm->rst_internal.ntiles; ++i) {
        if (rst->bilateral_level[i] >= 0) {
          aom_wb_write_bit(wb, 1);
          aom_wb_write_literal(wb, rst->bilateral_level[i],
                               av1_bilateral_level_bits(cm));
        } else {
          aom_wb_write_bit(wb, 0);
        }
      }
    } else {
      aom_wb_write_bit(wb, 0);
      for (i = 0; i < cm->rst_internal.ntiles; ++i) {
        if (rst->wiener_level[i]) {
          aom_wb_write_bit(wb, 1);
          aom_wb_write_literal(wb, rst->vfilter[i][0] - WIENER_FILT_TAP0_MINV,
                               WIENER_FILT_TAP0_BITS);
          aom_wb_write_literal(wb, rst->vfilter[i][1] - WIENER_FILT_TAP1_MINV,
                               WIENER_FILT_TAP1_BITS);
          aom_wb_write_literal(wb, rst->vfilter[i][2] - WIENER_FILT_TAP2_MINV,
                               WIENER_FILT_TAP2_BITS);
          aom_wb_write_literal(wb, rst->hfilter[i][0] - WIENER_FILT_TAP0_MINV,
                               WIENER_FILT_TAP0_BITS);
          aom_wb_write_literal(wb, rst->hfilter[i][1] - WIENER_FILT_TAP1_MINV,
                               WIENER_FILT_TAP1_BITS);
          aom_wb_write_literal(wb, rst->hfilter[i][2] - WIENER_FILT_TAP2_MINV,
                               WIENER_FILT_TAP2_BITS);
        } else {
          aom_wb_write_bit(wb, 0);
        }
      }
    }
  }
}
#endif  // CONFIG_LOOP_RESTORATION

static void encode_loopfilter(AV1_COMMON *cm, struct aom_write_bit_buffer *wb) {
  int i;
  struct loopfilter *lf = &cm->lf;

  // Encode the loop filter level and type
  aom_wb_write_literal(wb, lf->filter_level, 6);
  aom_wb_write_literal(wb, lf->sharpness_level, 3);

  // Write out loop filter deltas applied at the MB level based on mode or
  // ref frame (if they are enabled).
  aom_wb_write_bit(wb, lf->mode_ref_delta_enabled);

  if (lf->mode_ref_delta_enabled) {
    aom_wb_write_bit(wb, lf->mode_ref_delta_update);
    if (lf->mode_ref_delta_update) {
      for (i = 0; i < TOTAL_REFS_PER_FRAME; i++) {
        const int delta = lf->ref_deltas[i];
        const int changed = delta != lf->last_ref_deltas[i];
        aom_wb_write_bit(wb, changed);
        if (changed) {
          lf->last_ref_deltas[i] = delta;
          aom_wb_write_inv_signed_literal(wb, delta, 6);
        }
      }

      for (i = 0; i < MAX_MODE_LF_DELTAS; i++) {
        const int delta = lf->mode_deltas[i];
        const int changed = delta != lf->last_mode_deltas[i];
        aom_wb_write_bit(wb, changed);
        if (changed) {
          lf->last_mode_deltas[i] = delta;
          aom_wb_write_inv_signed_literal(wb, delta, 6);
        }
      }
    }
  }
}

#if CONFIG_CLPF
static void encode_clpf(const AV1_COMMON *cm, struct aom_write_bit_buffer *wb) {
  aom_wb_write_literal(wb, cm->clpf, 1);
}
#endif

#if CONFIG_DERING
static void encode_dering(int level, struct aom_write_bit_buffer *wb) {
  aom_wb_write_literal(wb, level, DERING_LEVEL_BITS);
}
#endif  // CONFIG_DERING

static void write_delta_q(struct aom_write_bit_buffer *wb, int delta_q) {
  if (delta_q != 0) {
    aom_wb_write_bit(wb, 1);
    aom_wb_write_inv_signed_literal(wb, delta_q, 6);
  } else {
    aom_wb_write_bit(wb, 0);
  }
}

static void encode_quantization(const AV1_COMMON *const cm,
                                struct aom_write_bit_buffer *wb) {
  aom_wb_write_literal(wb, cm->base_qindex, QINDEX_BITS);
  write_delta_q(wb, cm->y_dc_delta_q);
  write_delta_q(wb, cm->uv_dc_delta_q);
  write_delta_q(wb, cm->uv_ac_delta_q);
#if CONFIG_AOM_QM
  aom_wb_write_bit(wb, cm->using_qmatrix);
  if (cm->using_qmatrix) {
    aom_wb_write_literal(wb, cm->min_qmlevel, QM_LEVEL_BITS);
    aom_wb_write_literal(wb, cm->max_qmlevel, QM_LEVEL_BITS);
  }
#endif
}

static void encode_segmentation(AV1_COMMON *cm, MACROBLOCKD *xd,
                                struct aom_write_bit_buffer *wb) {
  int i, j;
  const struct segmentation *seg = &cm->seg;

  aom_wb_write_bit(wb, seg->enabled);
  if (!seg->enabled) return;

  // Segmentation map
  if (!frame_is_intra_only(cm) && !cm->error_resilient_mode) {
    aom_wb_write_bit(wb, seg->update_map);
  } else {
    assert(seg->update_map == 1);
  }
  if (seg->update_map) {
    // Select the coding strategy (temporal or spatial)
    av1_choose_segmap_coding_method(cm, xd);

    // Write out the chosen coding method.
    if (!frame_is_intra_only(cm) && !cm->error_resilient_mode) {
      aom_wb_write_bit(wb, seg->temporal_update);
    } else {
      assert(seg->temporal_update == 0);
    }
  }

  // Segmentation data
  aom_wb_write_bit(wb, seg->update_data);
  if (seg->update_data) {
    aom_wb_write_bit(wb, seg->abs_delta);

    for (i = 0; i < MAX_SEGMENTS; i++) {
      for (j = 0; j < SEG_LVL_MAX; j++) {
        const int active = segfeature_active(seg, i, j);
        aom_wb_write_bit(wb, active);
        if (active) {
          const int data = get_segdata(seg, i, j);
          const int data_max = av1_seg_feature_data_max(j);

          if (av1_is_segfeature_signed(j)) {
            encode_unsigned_max(wb, abs(data), data_max);
            aom_wb_write_bit(wb, data < 0);
          } else {
            encode_unsigned_max(wb, data, data_max);
          }
        }
      }
    }
  }
}

static void update_seg_probs(AV1_COMP *cpi, aom_writer *w) {
  AV1_COMMON *cm = &cpi->common;

  if (!cm->seg.enabled || !cm->seg.update_map) return;

  if (cm->seg.temporal_update) {
    int i;

    for (i = 0; i < PREDICTION_PROBS; i++)
      av1_cond_prob_diff_update(w, &cm->fc->seg.pred_probs[i],
                                cm->counts.seg.pred[i]);

    prob_diff_update(av1_segment_tree, cm->fc->seg.tree_probs,
                     cm->counts.seg.tree_mispred, MAX_SEGMENTS, w);
  } else {
    prob_diff_update(av1_segment_tree, cm->fc->seg.tree_probs,
                     cm->counts.seg.tree_total, MAX_SEGMENTS, w);
  }
}

static void write_txfm_mode(TX_MODE mode, struct aom_write_bit_buffer *wb) {
  aom_wb_write_bit(wb, mode == TX_MODE_SELECT);
  if (mode != TX_MODE_SELECT) aom_wb_write_literal(wb, mode, 2);
}

static void update_txfm_probs(AV1_COMMON *cm, aom_writer *w,
                              FRAME_COUNTS *counts) {
  if (cm->tx_mode == TX_MODE_SELECT) {
    int i, j;
    for (i = 0; i < TX_SIZES - 1; ++i)
      for (j = 0; j < TX_SIZE_CONTEXTS; ++j)
        prob_diff_update(av1_tx_size_tree[i], cm->fc->tx_size_probs[i][j],
                         counts->tx_size[i][j], i + 2, w);
  }
}

static void write_interp_filter(INTERP_FILTER filter,
                                struct aom_write_bit_buffer *wb) {
  aom_wb_write_bit(wb, filter == SWITCHABLE);
  if (filter != SWITCHABLE)
    aom_wb_write_literal(wb, filter, 2 + CONFIG_EXT_INTERP);
}

static void fix_interp_filter(AV1_COMMON *cm, FRAME_COUNTS *counts) {
  if (cm->interp_filter == SWITCHABLE) {
    // Check to see if only one of the filters is actually used
    int count[SWITCHABLE_FILTERS];
    int i, j, c = 0;
    for (i = 0; i < SWITCHABLE_FILTERS; ++i) {
      count[i] = 0;
      for (j = 0; j < SWITCHABLE_FILTER_CONTEXTS; ++j)
        count[i] += counts->switchable_interp[j][i];
      c += (count[i] > 0);
    }
    if (c == 1) {
      // Only one filter is used. So set the filter at frame level
      for (i = 0; i < SWITCHABLE_FILTERS; ++i) {
        if (count[i]) {
          cm->interp_filter = i;
          break;
        }
      }
    }
  }
}

static void write_tile_info(const AV1_COMMON *const cm,
                            struct aom_write_bit_buffer *wb) {
#if CONFIG_EXT_TILE
  const int tile_width =
      ALIGN_POWER_OF_TWO(cm->tile_width, cm->mib_size_log2) >>
      cm->mib_size_log2;
  const int tile_height =
      ALIGN_POWER_OF_TWO(cm->tile_height, cm->mib_size_log2) >>
      cm->mib_size_log2;

  assert(tile_width > 0);
  assert(tile_height > 0);

// Write the tile sizes
#if CONFIG_EXT_PARTITION
  if (cm->sb_size == BLOCK_128X128) {
    assert(tile_width <= 32);
    assert(tile_height <= 32);
    aom_wb_write_literal(wb, tile_width - 1, 5);
    aom_wb_write_literal(wb, tile_height - 1, 5);
  } else
#endif  // CONFIG_EXT_PARTITION
  {
    assert(tile_width <= 64);
    assert(tile_height <= 64);
    aom_wb_write_literal(wb, tile_width - 1, 6);
    aom_wb_write_literal(wb, tile_height - 1, 6);
  }
#else
  int min_log2_tile_cols, max_log2_tile_cols, ones;
  av1_get_tile_n_bits(cm->mi_cols, &min_log2_tile_cols, &max_log2_tile_cols);

  // columns
  ones = cm->log2_tile_cols - min_log2_tile_cols;
  while (ones--) aom_wb_write_bit(wb, 1);

  if (cm->log2_tile_cols < max_log2_tile_cols) aom_wb_write_bit(wb, 0);

  // rows
  aom_wb_write_bit(wb, cm->log2_tile_rows != 0);
  if (cm->log2_tile_rows != 0) aom_wb_write_bit(wb, cm->log2_tile_rows != 1);
#endif  // CONFIG_EXT_TILE
}

static int get_refresh_mask(AV1_COMP *cpi) {
  int refresh_mask = 0;

#if CONFIG_EXT_REFS
  // NOTE(zoeliu): When LAST_FRAME is to get refreshed, the decoder will be
  // notified to get LAST3_FRAME refreshed and then the virtual indexes for all
  // the 3 LAST reference frames will be updated accordingly, i.e.:
  // (1) The original virtual index for LAST3_FRAME will become the new virtual
  //     index for LAST_FRAME; and
  // (2) The original virtual indexes for LAST_FRAME and LAST2_FRAME will be
  //     shifted and become the new virtual indexes for LAST2_FRAME and
  //     LAST3_FRAME.
  refresh_mask |=
      (cpi->refresh_last_frame << cpi->lst_fb_idxes[LAST_REF_FRAMES - 1]);
  if (cpi->rc.is_bwd_ref_frame && cpi->num_extra_arfs) {
    // We have swapped the virtual indices
    refresh_mask |= (cpi->refresh_bwd_ref_frame << cpi->arf_map[0]);
  } else {
    refresh_mask |= (cpi->refresh_bwd_ref_frame << cpi->bwd_fb_idx);
  }
#else
  refresh_mask |= (cpi->refresh_last_frame << cpi->lst_fb_idx);
#endif  // CONFIG_EXT_REFS

  if (av1_preserve_existing_gf(cpi)) {
    // We have decided to preserve the previously existing golden frame as our
    // new ARF frame. However, in the short term we leave it in the GF slot and,
    // if we're updating the GF with the current decoded frame, we save it
    // instead to the ARF slot.
    // Later, in the function av1_encoder.c:av1_update_reference_frames() we
    // will swap gld_fb_idx and alt_fb_idx to achieve our objective. We do it
    // there so that it can be done outside of the recode loop.
    // Note: This is highly specific to the use of ARF as a forward reference,
    // and this needs to be generalized as other uses are implemented
    // (like RTC/temporal scalability).
    return refresh_mask | (cpi->refresh_golden_frame << cpi->alt_fb_idx);
  } else {
    int arf_idx = cpi->alt_fb_idx;
#if CONFIG_EXT_REFS
    const GF_GROUP *const gf_group = &cpi->twopass.gf_group;
    arf_idx = cpi->arf_map[gf_group->arf_update_idx[gf_group->index]];
#else
    if ((cpi->oxcf.pass == 2) && cpi->multi_arf_allowed) {
      const GF_GROUP *const gf_group = &cpi->twopass.gf_group;
      arf_idx = gf_group->arf_update_idx[gf_group->index];
    }
#endif  // CONFIG_EXT_REFS
    return refresh_mask | (cpi->refresh_golden_frame << cpi->gld_fb_idx) |
           (cpi->refresh_alt_ref_frame << arf_idx);
  }
}

#if CONFIG_EXT_TILE
static INLINE int find_identical_tile(
    const int tile_row, const int tile_col,
    TileBufferEnc (*const tile_buffers)[1024]) {
  const MV32 candidate_offset[1] = { { 1, 0 } };
  const uint8_t *const cur_tile_data =
      tile_buffers[tile_row][tile_col].data + 4;
  const unsigned int cur_tile_size = tile_buffers[tile_row][tile_col].size;

  int i;

  if (tile_row == 0) return 0;

  // (TODO: yunqingwang) For now, only above tile is checked and used.
  // More candidates such as left tile can be added later.
  for (i = 0; i < 1; i++) {
    int row_offset = candidate_offset[0].row;
    int col_offset = candidate_offset[0].col;
    int row = tile_row - row_offset;
    int col = tile_col - col_offset;
    uint8_t tile_hdr;
    const uint8_t *tile_data;
    TileBufferEnc *candidate;

    if (row < 0 || col < 0) continue;

    tile_hdr = *(tile_buffers[row][col].data);

    // Read out tcm bit
    if ((tile_hdr >> 7) == 1) {
      // The candidate is a copy tile itself
      row_offset += tile_hdr & 0x7f;
      row = tile_row - row_offset;
    }

    candidate = &tile_buffers[row][col];

    if (row_offset >= 128 || candidate->size != cur_tile_size) continue;

    tile_data = candidate->data + 4;

    if (memcmp(tile_data, cur_tile_data, cur_tile_size) != 0) continue;

    // Identical tile found
    assert(row_offset > 0);
    return row_offset;
  }

  // No identical tile found
  return 0;
}
#endif  // CONFIG_EXT_TILE

static uint32_t write_tiles(AV1_COMP *const cpi, uint8_t *const dst,
                            unsigned int *max_tile_size,
                            unsigned int *max_tile_col_size) {
  const AV1_COMMON *const cm = &cpi->common;
#if CONFIG_ANS
  struct AnsCoder token_ans;
#else
  aom_writer mode_bc;
#endif  // CONFIG_ANS
  int tile_row, tile_col;
  TOKENEXTRA *(*const tok_buffers)[MAX_TILE_COLS] = cpi->tile_tok;
  TileBufferEnc (*const tile_buffers)[MAX_TILE_COLS] = cpi->tile_buffers;
  size_t total_size = 0;
  const int tile_cols = cm->tile_cols;
  const int tile_rows = cm->tile_rows;
#if CONFIG_EXT_TILE
  const int have_tiles = tile_cols * tile_rows > 1;
#endif  // CONFIG_EXT_TILE
#if CONFIG_ANS
  BufAnsCoder *buf_ans = &cpi->buf_ans;
#endif  // CONFIG_ANS

  *max_tile_size = 0;
  *max_tile_col_size = 0;

// All tile size fields are output on 4 bytes. A call to remux_tiles will
// later compact the data if smaller headers are adequate.

#if CONFIG_EXT_TILE
  for (tile_col = 0; tile_col < tile_cols; tile_col++) {
    TileInfo tile_info;
    const int is_last_col = (tile_col == tile_cols - 1);
    const size_t col_offset = total_size;

    av1_tile_set_col(&tile_info, cm, tile_col);

    // The last column does not have a column header
    if (!is_last_col) total_size += 4;

    for (tile_row = 0; tile_row < tile_rows; tile_row++) {
      TileBufferEnc *const buf = &tile_buffers[tile_row][tile_col];
      unsigned int tile_size;
      const TOKENEXTRA *tok = tok_buffers[tile_row][tile_col];
      const TOKENEXTRA *tok_end = tok + cpi->tok_count[tile_row][tile_col];
      const int data_offset = have_tiles ? 4 : 0;

      av1_tile_set_row(&tile_info, cm, tile_row);

      buf->data = dst + total_size;

      // Is CONFIG_EXT_TILE = 1, every tile in the row has a header,
      // even for the last one, unless no tiling is used at all.
      total_size += data_offset;
#if !CONFIG_ANS
      aom_start_encode(&mode_bc, buf->data + data_offset);
      write_modes(cpi, &tile_info, &mode_bc, &tok, tok_end);
      assert(tok == tok_end);
      aom_stop_encode(&mode_bc);
      tile_size = mode_bc.pos;
#else
      buf_ans_write_reset(buf_ans);
      write_modes(cpi, &tile_info, buf_ans, &tok, tok_end);
      assert(tok == tok_end);
      ans_write_init(&token_ans, buf->data + data_offset);
      buf_ans_flush(buf_ans, &token_ans);
      tile_size = ans_write_end(&token_ans);
#endif  // !CONFIG_ANS

      buf->size = tile_size;

      // Record the maximum tile size we see, so we can compact headers later.
      *max_tile_size = AOMMAX(*max_tile_size, tile_size);

      if (have_tiles) {
        // tile header: size of this tile, or copy offset
        uint32_t tile_header = tile_size;

        // Check if this tile is a copy tile.
        // Very low chances to have copy tiles on the key frames, so don't
        // search on key frames to reduce unnecessary search.
        if (cm->frame_type != KEY_FRAME) {
          const int idendical_tile_offset =
              find_identical_tile(tile_row, tile_col, tile_buffers);

          if (idendical_tile_offset > 0) {
            tile_size = 0;
            tile_header = idendical_tile_offset | 0x80;
            tile_header <<= 24;
          }
        }

        mem_put_le32(buf->data, tile_header);
      }

      total_size += tile_size;
    }

    if (!is_last_col) {
      size_t col_size = total_size - col_offset - 4;
      mem_put_le32(dst + col_offset, col_size);

      // If it is not final packing, record the maximum tile column size we see,
      // otherwise, check if the tile size is out of the range.
      *max_tile_col_size = AOMMAX(*max_tile_col_size, col_size);
    }
  }
#else
  for (tile_row = 0; tile_row < tile_rows; tile_row++) {
    TileInfo tile_info;
    const int is_last_row = (tile_row == tile_rows - 1);

    av1_tile_set_row(&tile_info, cm, tile_row);

    for (tile_col = 0; tile_col < tile_cols; tile_col++) {
      TileBufferEnc *const buf = &tile_buffers[tile_row][tile_col];
      const int is_last_col = (tile_col == tile_cols - 1);
      const int is_last_tile = is_last_col && is_last_row;
      unsigned int tile_size;
      const TOKENEXTRA *tok = tok_buffers[tile_row][tile_col];
      const TOKENEXTRA *tok_end = tok + cpi->tok_count[tile_row][tile_col];

      av1_tile_set_col(&tile_info, cm, tile_col);

      buf->data = dst + total_size;

      // The last tile does not have a header.
      if (!is_last_tile) total_size += 4;

#if !CONFIG_ANS
      aom_start_encode(&mode_bc, dst + total_size);
      write_modes(cpi, &tile_info, &mode_bc, &tok, tok_end);
      assert(tok == tok_end);
      aom_stop_encode(&mode_bc);
      tile_size = mode_bc.pos;
#else
      buf_ans_write_reset(buf_ans);
      write_modes(cpi, &tile_info, buf_ans, &tok, tok_end);
      assert(tok == tok_end);
      ans_write_init(&token_ans, dst + total_size);
      buf_ans_flush(buf_ans, &token_ans);
      tile_size = ans_write_end(&token_ans);
#endif  // !CONFIG_ANS

      assert(tile_size > 0);

      buf->size = tile_size;

      if (!is_last_tile) {
        *max_tile_size = AOMMAX(*max_tile_size, tile_size);
        // size of this tile
        mem_put_le32(buf->data, tile_size);
      }

      total_size += tile_size;
    }
  }
#endif  // CONFIG_EXT_TILE
  return (uint32_t)total_size;
}

static void write_render_size(const AV1_COMMON *cm,
                              struct aom_write_bit_buffer *wb) {
  const int scaling_active =
      cm->width != cm->render_width || cm->height != cm->render_height;
  aom_wb_write_bit(wb, scaling_active);
  if (scaling_active) {
    aom_wb_write_literal(wb, cm->render_width - 1, 16);
    aom_wb_write_literal(wb, cm->render_height - 1, 16);
  }
}

static void write_frame_size(const AV1_COMMON *cm,
                             struct aom_write_bit_buffer *wb) {
  aom_wb_write_literal(wb, cm->width - 1, 16);
  aom_wb_write_literal(wb, cm->height - 1, 16);

  write_render_size(cm, wb);
}

static void write_frame_size_with_refs(AV1_COMP *cpi,
                                       struct aom_write_bit_buffer *wb) {
  AV1_COMMON *const cm = &cpi->common;
  int found = 0;

  MV_REFERENCE_FRAME ref_frame;
  for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
    YV12_BUFFER_CONFIG *cfg = get_ref_frame_buffer(cpi, ref_frame);

    if (cfg != NULL) {
      found =
          cm->width == cfg->y_crop_width && cm->height == cfg->y_crop_height;
      found &= cm->render_width == cfg->render_width &&
               cm->render_height == cfg->render_height;
    }
    aom_wb_write_bit(wb, found);
    if (found) {
      break;
    }
  }

  if (!found) {
    aom_wb_write_literal(wb, cm->width - 1, 16);
    aom_wb_write_literal(wb, cm->height - 1, 16);
    write_render_size(cm, wb);
  }
}

static void write_sync_code(struct aom_write_bit_buffer *wb) {
  aom_wb_write_literal(wb, AV1_SYNC_CODE_0, 8);
  aom_wb_write_literal(wb, AV1_SYNC_CODE_1, 8);
  aom_wb_write_literal(wb, AV1_SYNC_CODE_2, 8);
}

static void write_profile(BITSTREAM_PROFILE profile,
                          struct aom_write_bit_buffer *wb) {
  switch (profile) {
    case PROFILE_0: aom_wb_write_literal(wb, 0, 2); break;
    case PROFILE_1: aom_wb_write_literal(wb, 2, 2); break;
    case PROFILE_2: aom_wb_write_literal(wb, 1, 2); break;
    case PROFILE_3: aom_wb_write_literal(wb, 6, 3); break;
    default: assert(0);
  }
}

static void write_bitdepth_colorspace_sampling(
    AV1_COMMON *const cm, struct aom_write_bit_buffer *wb) {
  if (cm->profile >= PROFILE_2) {
    assert(cm->bit_depth > AOM_BITS_8);
    aom_wb_write_bit(wb, cm->bit_depth == AOM_BITS_10 ? 0 : 1);
  }
  aom_wb_write_literal(wb, cm->color_space, 3);
  if (cm->color_space != AOM_CS_SRGB) {
    // 0: [16, 235] (i.e. xvYCC), 1: [0, 255]
    aom_wb_write_bit(wb, cm->color_range);
    if (cm->profile == PROFILE_1 || cm->profile == PROFILE_3) {
      assert(cm->subsampling_x != 1 || cm->subsampling_y != 1);
      aom_wb_write_bit(wb, cm->subsampling_x);
      aom_wb_write_bit(wb, cm->subsampling_y);
      aom_wb_write_bit(wb, 0);  // unused
    } else {
      assert(cm->subsampling_x == 1 && cm->subsampling_y == 1);
    }
  } else {
    assert(cm->profile == PROFILE_1 || cm->profile == PROFILE_3);
    aom_wb_write_bit(wb, 0);  // unused
  }
}

static void write_uncompressed_header(AV1_COMP *cpi,
                                      struct aom_write_bit_buffer *wb) {
  AV1_COMMON *const cm = &cpi->common;
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;

  aom_wb_write_literal(wb, AOM_FRAME_MARKER, 2);

  write_profile(cm->profile, wb);

#if CONFIG_EXT_REFS
  // NOTE: By default all coded frames to be used as a reference
  cm->is_reference_frame = 1;

  if (cm->show_existing_frame) {
    RefCntBuffer *const frame_bufs = cm->buffer_pool->frame_bufs;
    const int frame_to_show = cm->ref_frame_map[cpi->existing_fb_idx_to_show];

    if (frame_to_show < 0 || frame_bufs[frame_to_show].ref_count < 1) {
      aom_internal_error(&cm->error, AOM_CODEC_UNSUP_BITSTREAM,
                         "Buffer %d does not contain a reconstructed frame",
                         frame_to_show);
    }
    ref_cnt_fb(frame_bufs, &cm->new_fb_idx, frame_to_show);

    aom_wb_write_bit(wb, 1);  // show_existing_frame
    aom_wb_write_literal(wb, cpi->existing_fb_idx_to_show, 3);

    return;
  } else {
#endif                        // CONFIG_EXT_REFS
    aom_wb_write_bit(wb, 0);  // show_existing_frame
#if CONFIG_EXT_REFS
  }
#endif  // CONFIG_EXT_REFS

  aom_wb_write_bit(wb, cm->frame_type);
  aom_wb_write_bit(wb, cm->show_frame);
  aom_wb_write_bit(wb, cm->error_resilient_mode);

  if (cm->frame_type == KEY_FRAME) {
    write_sync_code(wb);
    write_bitdepth_colorspace_sampling(cm, wb);
    write_frame_size(cm, wb);
    if (frame_is_intra_only(cm))
      aom_wb_write_bit(wb, cm->allow_screen_content_tools);
  } else {
    if (!cm->show_frame) aom_wb_write_bit(wb, cm->intra_only);

    if (!cm->error_resilient_mode) {
      if (cm->intra_only) {
        aom_wb_write_bit(wb,
                         cm->reset_frame_context == RESET_FRAME_CONTEXT_ALL);
      } else {
        aom_wb_write_bit(wb,
                         cm->reset_frame_context != RESET_FRAME_CONTEXT_NONE);
        if (cm->reset_frame_context != RESET_FRAME_CONTEXT_NONE)
          aom_wb_write_bit(wb,
                           cm->reset_frame_context == RESET_FRAME_CONTEXT_ALL);
      }
    }

#if CONFIG_EXT_REFS
    cpi->refresh_frame_mask = get_refresh_mask(cpi);
#endif  // CONFIG_EXT_REFS

    if (cm->intra_only) {
      write_sync_code(wb);
      write_bitdepth_colorspace_sampling(cm, wb);

#if CONFIG_EXT_REFS
      aom_wb_write_literal(wb, cpi->refresh_frame_mask, REF_FRAMES);
#else
      aom_wb_write_literal(wb, get_refresh_mask(cpi), REF_FRAMES);
#endif  // CONFIG_EXT_REFS
      write_frame_size(cm, wb);
    } else {
      MV_REFERENCE_FRAME ref_frame;

#if CONFIG_EXT_REFS
      aom_wb_write_literal(wb, cpi->refresh_frame_mask, REF_FRAMES);
#else
      aom_wb_write_literal(wb, get_refresh_mask(cpi), REF_FRAMES);
#endif  // CONFIG_EXT_REFS

#if CONFIG_EXT_REFS
      if (!cpi->refresh_frame_mask) {
        // NOTE: "cpi->refresh_frame_mask == 0" indicates that the coded frame
        //       will not be used as a reference
        cm->is_reference_frame = 0;
      }
#endif  // CONFIG_EXT_REFS

      for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
        assert(get_ref_frame_map_idx(cpi, ref_frame) != INVALID_IDX);
        aom_wb_write_literal(wb, get_ref_frame_map_idx(cpi, ref_frame),
                             REF_FRAMES_LOG2);
        aom_wb_write_bit(wb, cm->ref_frame_sign_bias[ref_frame]);
      }

      write_frame_size_with_refs(cpi, wb);

      aom_wb_write_bit(wb, cm->allow_high_precision_mv);

      fix_interp_filter(cm, cpi->td.counts);
      write_interp_filter(cm->interp_filter, wb);
    }
  }

  if (!cm->error_resilient_mode) {
    aom_wb_write_bit(
        wb, cm->refresh_frame_context == REFRESH_FRAME_CONTEXT_FORWARD);
  }

  aom_wb_write_literal(wb, cm->frame_context_idx, FRAME_CONTEXTS_LOG2);

  assert(cm->mib_size == num_8x8_blocks_wide_lookup[cm->sb_size]);
  assert(cm->mib_size == 1 << cm->mib_size_log2);
#if CONFIG_EXT_PARTITION
  assert(cm->sb_size == BLOCK_128X128 || cm->sb_size == BLOCK_64X64);
  aom_wb_write_bit(wb, cm->sb_size == BLOCK_128X128 ? 1 : 0);
#else
  assert(cm->sb_size == BLOCK_64X64);
#endif  // CONFIG_EXT_PARTITION

  encode_loopfilter(cm, wb);
#if CONFIG_CLPF
  encode_clpf(cm, wb);
#endif
#if CONFIG_DERING
  encode_dering(cm->dering_level, wb);
#endif  // CONFIG_DERING
#if CONFIG_LOOP_RESTORATION
  encode_restoration(cm, wb);
#endif  // CONFIG_LOOP_RESTORATION
  encode_quantization(cm, wb);
  encode_segmentation(cm, xd, wb);
  if (!cm->seg.enabled && xd->lossless[0])
    cm->tx_mode = TX_4X4;
  else
    write_txfm_mode(cm->tx_mode, wb);

  if (cpi->allow_comp_inter_inter) {
    const int use_hybrid_pred = cm->reference_mode == REFERENCE_MODE_SELECT;
    const int use_compound_pred = cm->reference_mode != SINGLE_REFERENCE;

    aom_wb_write_bit(wb, use_hybrid_pred);
    if (!use_hybrid_pred) aom_wb_write_bit(wb, use_compound_pred);
  }

  write_tile_info(cm, wb);
}

#if CONFIG_GLOBAL_MOTION
static void write_global_motion_params(Global_Motion_Params *params,
                                       aom_prob *probs, aom_writer *w) {
  GLOBAL_MOTION_TYPE gmtype = get_gmtype(params);
  av1_write_token(w, av1_global_motion_types_tree, probs,
                  &global_motion_types_encodings[gmtype]);
  switch (gmtype) {
    case GLOBAL_ZERO: break;
    case GLOBAL_AFFINE:
      av1_write_primitive_symmetric(
          w, params->motion_params.wmmat[4] >> GM_ALPHA_PREC_DIFF,
          GM_ABS_ALPHA_BITS);
      av1_write_primitive_symmetric(
          w, (params->motion_params.wmmat[5] >> GM_ALPHA_PREC_DIFF) -
                 (1 << GM_ALPHA_PREC_BITS),
          GM_ABS_ALPHA_BITS);
    // fallthrough intended
    case GLOBAL_ROTZOOM:
      aom_write_primitive_symmetric(
          w, (params->motion_params.wmmat[2] >> GM_ALPHA_PREC_DIFF) -
                 (1 << GM_ALPHA_PREC_BITS),
          GM_ABS_ALPHA_BITS);
      aom_write_primitive_symmetric(
          w, params->motion_params.wmmat[3] >> GM_ALPHA_PREC_DIFF,
          GM_ABS_ALPHA_BITS);
    // fallthrough intended
    case GLOBAL_TRANSLATION:
      aom_write_primitive_symmetric(
          w, params->motion_params.wmmat[0] >> GM_TRANS_PREC_DIFF,
          GM_ABS_TRANS_BITS);
      aom_write_primitive_symmetric(
          w, params->motion_params.wmmat[1] >> GM_TRANS_PREC_DIFF,
          GM_ABS_TRANS_BITS);
      break;
    default: assert(0);
  }
}

static void write_global_motion(AV1_COMP *cpi, aom_writer *w) {
  AV1_COMMON *const cm = &cpi->common;
  int frame;
  for (frame = LAST_FRAME; frame <= ALTREF_FRAME; ++frame) {
    if (!cpi->global_motion_used[frame]) {
      memset(&cm->global_motion[frame], 0, sizeof(*cm->global_motion));
    }
    write_global_motion_params(&cm->global_motion[frame],
                               cm->fc->global_motion_types_prob, w);
  }
}
#endif

static uint32_t write_compressed_header(AV1_COMP *cpi, uint8_t *data) {
  AV1_COMMON *const cm = &cpi->common;
#if CONFIG_SUPERTX
  MACROBLOCKD *const xd = &cpi->td.mb.e_mbd;
#endif  // CONFIG_SUPERTX
  FRAME_CONTEXT *const fc = cm->fc;
  FRAME_COUNTS *counts = cpi->td.counts;
  aom_writer *header_bc;
  int i, j;

#if CONFIG_ANS
  struct AnsCoder header_ans;
  int header_size;
  header_bc = &cpi->buf_ans;
  buf_ans_write_reset(header_bc);
#else
  aom_writer real_header_bc;
  header_bc = &real_header_bc;
  aom_start_encode(header_bc, data);
#endif
  update_txfm_probs(cm, header_bc, counts);
  update_coef_probs(cpi, header_bc);

#if CONFIG_VAR_TX
  update_txfm_partition_probs(cm, header_bc, counts);
#endif

  update_skip_probs(cm, header_bc, counts);
  update_seg_probs(cpi, header_bc);

  for (i = 0; i < INTRA_MODES; ++i)
    prob_diff_update(av1_intra_mode_tree, fc->uv_mode_prob[i],
                     counts->uv_mode[i], INTRA_MODES, header_bc);

#if CONFIG_EXT_PARTITION_TYPES
  prob_diff_update(av1_partition_tree, fc->partition_prob[0],
                   counts->partition[0], PARTITION_TYPES, header_bc);
  for (i = 1; i < PARTITION_CONTEXTS; ++i)
    prob_diff_update(av1_ext_partition_tree, fc->partition_prob[i],
                     counts->partition[i], EXT_PARTITION_TYPES, header_bc);
#else
  for (i = 0; i < PARTITION_CONTEXTS; ++i)
    prob_diff_update(av1_partition_tree, fc->partition_prob[i],
                     counts->partition[i], PARTITION_TYPES, header_bc);
#endif  // CONFIG_EXT_PARTITION_TYPES

#if CONFIG_EXT_INTRA
  for (i = 0; i < INTRA_FILTERS + 1; ++i)
    prob_diff_update(av1_intra_filter_tree, fc->intra_filter_probs[i],
                     counts->intra_filter[i], INTRA_FILTERS, header_bc);
#endif  // CONFIG_EXT_INTRA

  if (frame_is_intra_only(cm)) {
    av1_copy(cm->kf_y_prob, av1_kf_y_mode_prob);
    for (i = 0; i < INTRA_MODES; ++i)
      for (j = 0; j < INTRA_MODES; ++j)
        prob_diff_update(av1_intra_mode_tree, cm->kf_y_prob[i][j],
                         counts->kf_y_mode[i][j], INTRA_MODES, header_bc);
  } else {
#if CONFIG_REF_MV
    update_inter_mode_probs(cm, header_bc, counts);
#else
    for (i = 0; i < INTER_MODE_CONTEXTS; ++i)
      prob_diff_update(av1_inter_mode_tree, cm->fc->inter_mode_probs[i],
                       counts->inter_mode[i], INTER_MODES, header_bc);
#endif

#if CONFIG_EXT_INTER
    update_inter_compound_mode_probs(cm, header_bc);

    if (cm->reference_mode != COMPOUND_REFERENCE) {
      for (i = 0; i < BLOCK_SIZE_GROUPS; i++) {
        if (is_interintra_allowed_bsize_group(i)) {
          av1_cond_prob_diff_update(header_bc, &fc->interintra_prob[i],
                                    cm->counts.interintra[i]);
        }
      }
      for (i = 0; i < BLOCK_SIZE_GROUPS; i++) {
        prob_diff_update(
            av1_interintra_mode_tree, cm->fc->interintra_mode_prob[i],
            counts->interintra_mode[i], INTERINTRA_MODES, header_bc);
      }
      for (i = 0; i < BLOCK_SIZES; i++) {
        if (is_interintra_allowed_bsize(i) && is_interintra_wedge_used(i))
          av1_cond_prob_diff_update(header_bc, &fc->wedge_interintra_prob[i],
                                    cm->counts.wedge_interintra[i]);
      }
    }
    if (cm->reference_mode != SINGLE_REFERENCE) {
      for (i = 0; i < BLOCK_SIZES; i++)
        if (is_interinter_wedge_used(i))
          av1_cond_prob_diff_update(header_bc, &fc->wedge_interinter_prob[i],
                                    cm->counts.wedge_interinter[i]);
    }
#endif  // CONFIG_EXT_INTER

#if CONFIG_OBMC || CONFIG_WARPED_MOTION
    for (i = BLOCK_8X8; i < BLOCK_SIZES; ++i)
      prob_diff_update(av1_motvar_tree, fc->motvar_prob[i], counts->motvar[i],
                       MOTION_VARIATIONS, header_bc);
#endif  // CONFIG_OBMC || CONFIG_WARPED_MOTION

    if (cm->interp_filter == SWITCHABLE)
      update_switchable_interp_probs(cm, header_bc, counts);

    for (i = 0; i < INTRA_INTER_CONTEXTS; i++)
      av1_cond_prob_diff_update(header_bc, &fc->intra_inter_prob[i],
                                counts->intra_inter[i]);

    if (cpi->allow_comp_inter_inter) {
      const int use_hybrid_pred = cm->reference_mode == REFERENCE_MODE_SELECT;
      if (use_hybrid_pred)
        for (i = 0; i < COMP_INTER_CONTEXTS; i++)
          av1_cond_prob_diff_update(header_bc, &fc->comp_inter_prob[i],
                                    counts->comp_inter[i]);
    }

    if (cm->reference_mode != COMPOUND_REFERENCE) {
      for (i = 0; i < REF_CONTEXTS; i++) {
        for (j = 0; j < (SINGLE_REFS - 1); j++) {
          av1_cond_prob_diff_update(header_bc, &fc->single_ref_prob[i][j],
                                    counts->single_ref[i][j]);
        }
      }
    }

    if (cm->reference_mode != SINGLE_REFERENCE) {
      for (i = 0; i < REF_CONTEXTS; i++) {
#if CONFIG_EXT_REFS
        for (j = 0; j < (FWD_REFS - 1); j++) {
          av1_cond_prob_diff_update(header_bc, &fc->comp_ref_prob[i][j],
                                    counts->comp_ref[i][j]);
        }
        for (j = 0; j < (BWD_REFS - 1); j++) {
          av1_cond_prob_diff_update(header_bc, &fc->comp_bwdref_prob[i][j],
                                    counts->comp_bwdref[i][j]);
        }
#else
        for (j = 0; j < (COMP_REFS - 1); j++) {
          av1_cond_prob_diff_update(header_bc, &fc->comp_ref_prob[i][j],
                                    counts->comp_ref[i][j]);
        }
#endif  // CONFIG_EXT_REFS
      }
    }

    for (i = 0; i < BLOCK_SIZE_GROUPS; ++i)
      prob_diff_update(av1_intra_mode_tree, cm->fc->y_mode_prob[i],
                       counts->y_mode[i], INTRA_MODES, header_bc);

    aom_write_nmv_probs(cm, cm->allow_high_precision_mv, header_bc,
#if CONFIG_REF_MV
                        counts->mv);
#else
                        &counts->mv);
#endif
    update_ext_tx_probs(cm, header_bc);
#if CONFIG_SUPERTX
    if (!xd->lossless[0]) update_supertx_probs(cm, header_bc);
#endif  // CONFIG_SUPERTX
  }
#if CONFIG_GLOBAL_MOTION
  write_global_motion(cpi, header_bc);
#endif  // CONFIG_GLOBAL_MOTION
#if CONFIG_ANS
  ans_write_init(&header_ans, data);
  buf_ans_flush(header_bc, &header_ans);
  header_size = ans_write_end(&header_ans);
  assert(header_size <= 0xffff);
  return header_size;
#else
  aom_stop_encode(header_bc);
  assert(header_bc->pos <= 0xffff);
  return header_bc->pos;
#endif  // CONFIG_ANS
}

static int choose_size_bytes(uint32_t size, int spare_msbs) {
  // Choose the number of bytes required to represent size, without
  // using the 'spare_msbs' number of most significant bits.

  // Make sure we will fit in 4 bytes to start with..
  if (spare_msbs > 0 && size >> (32 - spare_msbs) != 0) return -1;

  // Normalise to 32 bits
  size <<= spare_msbs;

  if (size >> 24 != 0)
    return 4;
  else if (size >> 16 != 0)
    return 3;
  else if (size >> 8 != 0)
    return 2;
  else
    return 1;
}

static void mem_put_varsize(uint8_t *const dst, const int sz, const int val) {
  switch (sz) {
    case 1: dst[0] = (uint8_t)(val & 0xff); break;
    case 2: mem_put_le16(dst, val); break;
    case 3: mem_put_le24(dst, val); break;
    case 4: mem_put_le32(dst, val); break;
    default: assert("Invalid size" && 0); break;
  }
}

static int remux_tiles(const AV1_COMMON *const cm, uint8_t *dst,
                       const uint32_t data_size, const uint32_t max_tile_size,
                       const uint32_t max_tile_col_size,
                       int *const tile_size_bytes,
                       int *const tile_col_size_bytes) {
// Choose the tile size bytes (tsb) and tile column size bytes (tcsb)
#if CONFIG_EXT_TILE
  // The top bit in the tile size field indicates tile copy mode, so we
  // have 1 less bit to code the tile size
  const int tsb = choose_size_bytes(max_tile_size, 1);
  const int tcsb = choose_size_bytes(max_tile_col_size, 0);
#else
  const int tsb = choose_size_bytes(max_tile_size, 0);
  const int tcsb = 4;  // This is ignored
  (void)max_tile_col_size;
#endif  // CONFIG_EXT_TILE

  assert(tsb > 0);
  assert(tcsb > 0);

  *tile_size_bytes = tsb;
  *tile_col_size_bytes = tcsb;

  if (tsb == 4 && tcsb == 4) {
    return data_size;
  } else {
    uint32_t wpos = 0;
    uint32_t rpos = 0;

#if CONFIG_EXT_TILE
    int tile_row;
    int tile_col;

    for (tile_col = 0; tile_col < cm->tile_cols; tile_col++) {
      // All but the last column has a column header
      if (tile_col < cm->tile_cols - 1) {
        uint32_t tile_col_size = mem_get_le32(dst + rpos);
        rpos += 4;

        // Adjust the tile column size by the number of bytes removed
        // from the tile size fields.
        tile_col_size -= (4 - tsb) * cm->tile_rows;

        mem_put_varsize(dst + wpos, tcsb, tile_col_size);
        wpos += tcsb;
      }

      for (tile_row = 0; tile_row < cm->tile_rows; tile_row++) {
        // All, including the last row has a header
        uint32_t tile_header = mem_get_le32(dst + rpos);
        rpos += 4;

        // If this is a copy tile, we need to shift the MSB to the
        // top bit of the new width, and there is no data to copy.
        if (tile_header >> 31 != 0) {
          if (tsb < 4) tile_header >>= 32 - 8 * tsb;
          mem_put_varsize(dst + wpos, tsb, tile_header);
          wpos += tsb;
        } else {
          mem_put_varsize(dst + wpos, tsb, tile_header);
          wpos += tsb;

          memmove(dst + wpos, dst + rpos, tile_header);
          rpos += tile_header;
          wpos += tile_header;
        }
      }
    }
#else
    const int n_tiles = cm->tile_cols * cm->tile_rows;
    int n;

    for (n = 0; n < n_tiles; n++) {
      int tile_size;

      if (n == n_tiles - 1) {
        tile_size = data_size - rpos;
      } else {
        tile_size = mem_get_le32(dst + rpos);
        rpos += 4;
        mem_put_varsize(dst + wpos, tsb, tile_size);
        wpos += tsb;
      }

      memmove(dst + wpos, dst + rpos, tile_size);

      rpos += tile_size;
      wpos += tile_size;
    }
#endif  // CONFIG_EXT_TILE

    assert(rpos > wpos);
    assert(rpos == data_size);

    return wpos;
  }
}

void av1_pack_bitstream(AV1_COMP *const cpi, uint8_t *dst, size_t *size) {
  uint8_t *data = dst;
  uint32_t compressed_header_size;
  uint32_t uncompressed_header_size;
  uint32_t data_size;
  struct aom_write_bit_buffer wb = { data, 0 };
  struct aom_write_bit_buffer saved_wb;
  unsigned int max_tile_size;
  unsigned int max_tile_col_size;
  int tile_size_bytes;
  int tile_col_size_bytes;

  AV1_COMMON *const cm = &cpi->common;
  const int have_tiles = cm->tile_cols * cm->tile_rows > 1;

#if CONFIG_BITSTREAM_DEBUG
  bitstream_queue_reset_write();
#endif

  // Write the uncompressed header
  write_uncompressed_header(cpi, &wb);

#if CONFIG_EXT_REFS
  if (cm->show_existing_frame) {
    *size = aom_wb_bytes_written(&wb);
    return;
  }
#endif  // CONFIG_EXT_REFS

  // We do not know these in advance. Output placeholder bit.
  saved_wb = wb;
  // Write tile size magnitudes
  if (have_tiles) {
// Note that the last item in the uncompressed header is the data
// describing tile configuration.
#if CONFIG_EXT_TILE
    // Number of bytes in tile column size - 1
    aom_wb_write_literal(&wb, 0, 2);
#endif  // CONFIG_EXT_TILE
    // Number of bytes in tile size - 1
    aom_wb_write_literal(&wb, 0, 2);
  }
  // Size of compressed header
  aom_wb_write_literal(&wb, 0, 16);

  uncompressed_header_size = (uint32_t)aom_wb_bytes_written(&wb);
  data += uncompressed_header_size;

  aom_clear_system_state();

  // Write the compressed header
  compressed_header_size = write_compressed_header(cpi, data);
  data += compressed_header_size;

  // Write the encoded tile data
  data_size = write_tiles(cpi, data, &max_tile_size, &max_tile_col_size);

  if (have_tiles) {
    data_size =
        remux_tiles(cm, data, data_size, max_tile_size, max_tile_col_size,
                    &tile_size_bytes, &tile_col_size_bytes);
  }

  data += data_size;

  // Now fill in the gaps in the uncompressed header.
  if (have_tiles) {
#if CONFIG_EXT_TILE
    assert(tile_col_size_bytes >= 1 && tile_col_size_bytes <= 4);
    aom_wb_write_literal(&saved_wb, tile_col_size_bytes - 1, 2);
#endif  // CONFIG_EXT_TILE
    assert(tile_size_bytes >= 1 && tile_size_bytes <= 4);
    aom_wb_write_literal(&saved_wb, tile_size_bytes - 1, 2);
  }
  // TODO(jbb): Figure out what to do if compressed_header_size > 16 bits.
  assert(compressed_header_size <= 0xffff);
  aom_wb_write_literal(&saved_wb, compressed_header_size, 16);

  *size = data - dst;
}