Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 975 insertions, 0 deletions

diff --git a/third_party/aom/av1/encoder/palette.c b/third_party/aom/av1/encoder/palette.c
new file mode 100644
index 0000000000..7f79e9596e
--- /dev/null
+++ b/third_party/aom/av1/encoder/palette.c
@@ -0,0 +1,975 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <math.h>
+#include <stdlib.h>
+
+#include "av1/common/pred_common.h"
+
+#include "av1/encoder/block.h"
+#include "av1/encoder/cost.h"
+#include "av1/encoder/encoder.h"
+#include "av1/encoder/intra_mode_search.h"
+#include "av1/encoder/intra_mode_search_utils.h"
+#include "av1/encoder/palette.h"
+#include "av1/encoder/random.h"
+#include "av1/encoder/rdopt_utils.h"
+#include "av1/encoder/tx_search.h"
+
+#define AV1_K_MEANS_DIM 1
+#include "av1/encoder/k_means_template.h"
+#undef AV1_K_MEANS_DIM
+#define AV1_K_MEANS_DIM 2
+#include "av1/encoder/k_means_template.h"
+#undef AV1_K_MEANS_DIM
+
+static int int16_comparer(const void *a, const void *b) {
+  return (*(int16_t *)a - *(int16_t *)b);
+}
+
+int av1_remove_duplicates(int16_t *centroids, int num_centroids) {
+  int num_unique;  // number of unique centroids
+  int i;
+  qsort(centroids, num_centroids, sizeof(*centroids), int16_comparer);
+  // Remove duplicates.
+  num_unique = 1;
+  for (i = 1; i < num_centroids; ++i) {
+    if (centroids[i] != centroids[i - 1]) {  // found a new unique centroid
+      centroids[num_unique++] = centroids[i];
+    }
+  }
+  return num_unique;
+}
+
+static int delta_encode_cost(const int *colors, int num, int bit_depth,
+                             int min_val) {
+  if (num <= 0) return 0;
+  int bits_cost = bit_depth;
+  if (num == 1) return bits_cost;
+  bits_cost += 2;
+  int max_delta = 0;
+  int deltas[PALETTE_MAX_SIZE];
+  const int min_bits = bit_depth - 3;
+  for (int i = 1; i < num; ++i) {
+    const int delta = colors[i] - colors[i - 1];
+    deltas[i - 1] = delta;
+    assert(delta >= min_val);
+    if (delta > max_delta) max_delta = delta;
+  }
+  int bits_per_delta = AOMMAX(av1_ceil_log2(max_delta + 1 - min_val), min_bits);
+  assert(bits_per_delta <= bit_depth);
+  int range = (1 << bit_depth) - colors[0] - min_val;
+  for (int i = 0; i < num - 1; ++i) {
+    bits_cost += bits_per_delta;
+    range -= deltas[i];
+    bits_per_delta = AOMMIN(bits_per_delta, av1_ceil_log2(range));
+  }
+  return bits_cost;
+}
+
+int av1_index_color_cache(const uint16_t *color_cache, int n_cache,
+                          const uint16_t *colors, int n_colors,
+                          uint8_t *cache_color_found, int *out_cache_colors) {
+  if (n_cache <= 0) {
+    for (int i = 0; i < n_colors; ++i) out_cache_colors[i] = colors[i];
+    return n_colors;
+  }
+  memset(cache_color_found, 0, n_cache * sizeof(*cache_color_found));
+  int n_in_cache = 0;
+  int in_cache_flags[PALETTE_MAX_SIZE];
+  memset(in_cache_flags, 0, sizeof(in_cache_flags));
+  for (int i = 0; i < n_cache && n_in_cache < n_colors; ++i) {
+    for (int j = 0; j < n_colors; ++j) {
+      if (colors[j] == color_cache[i]) {
+        in_cache_flags[j] = 1;
+        cache_color_found[i] = 1;
+        ++n_in_cache;
+        break;
+      }
+    }
+  }
+  int j = 0;
+  for (int i = 0; i < n_colors; ++i)
+    if (!in_cache_flags[i]) out_cache_colors[j++] = colors[i];
+  assert(j == n_colors - n_in_cache);
+  return j;
+}
+
+int av1_get_palette_delta_bits_v(const PALETTE_MODE_INFO *const pmi,
+                                 int bit_depth, int *zero_count,
+                                 int *min_bits) {
+  const int n = pmi->palette_size[1];
+  const int max_val = 1 << bit_depth;
+  int max_d = 0;
+  *min_bits = bit_depth - 4;
+  *zero_count = 0;
+  for (int i = 1; i < n; ++i) {
+    const int delta = pmi->palette_colors[2 * PALETTE_MAX_SIZE + i] -
+                      pmi->palette_colors[2 * PALETTE_MAX_SIZE + i - 1];
+    const int v = abs(delta);
+    const int d = AOMMIN(v, max_val - v);
+    if (d > max_d) max_d = d;
+    if (d == 0) ++(*zero_count);
+  }
+  return AOMMAX(av1_ceil_log2(max_d + 1), *min_bits);
+}
+
+int av1_palette_color_cost_y(const PALETTE_MODE_INFO *const pmi,
+                             const uint16_t *color_cache, int n_cache,
+                             int bit_depth) {
+  const int n = pmi->palette_size[0];
+  int out_cache_colors[PALETTE_MAX_SIZE];
+  uint8_t cache_color_found[2 * PALETTE_MAX_SIZE];
+  const int n_out_cache =
+      av1_index_color_cache(color_cache, n_cache, pmi->palette_colors, n,
+                            cache_color_found, out_cache_colors);
+  const int total_bits =
+      n_cache + delta_encode_cost(out_cache_colors, n_out_cache, bit_depth, 1);
+  return av1_cost_literal(total_bits);
+}
+
+int av1_palette_color_cost_uv(const PALETTE_MODE_INFO *const pmi,
+                              const uint16_t *color_cache, int n_cache,
+                              int bit_depth) {
+  const int n = pmi->palette_size[1];
+  int total_bits = 0;
+  // U channel palette color cost.
+  int out_cache_colors[PALETTE_MAX_SIZE];
+  uint8_t cache_color_found[2 * PALETTE_MAX_SIZE];
+  const int n_out_cache = av1_index_color_cache(
+      color_cache, n_cache, pmi->palette_colors + PALETTE_MAX_SIZE, n,
+      cache_color_found, out_cache_colors);
+  total_bits +=
+      n_cache + delta_encode_cost(out_cache_colors, n_out_cache, bit_depth, 0);
+
+  // V channel palette color cost.
+  int zero_count = 0, min_bits_v = 0;
+  const int bits_v =
+      av1_get_palette_delta_bits_v(pmi, bit_depth, &zero_count, &min_bits_v);
+  const int bits_using_delta =
+      2 + bit_depth + (bits_v + 1) * (n - 1) - zero_count;
+  const int bits_using_raw = bit_depth * n;
+  total_bits += 1 + AOMMIN(bits_using_delta, bits_using_raw);
+  return av1_cost_literal(total_bits);
+}
+
+// Extends 'color_map' array from 'orig_width x orig_height' to 'new_width x
+// new_height'. Extra rows and columns are filled in by copying last valid
+// row/column.
+static AOM_INLINE void extend_palette_color_map(uint8_t *const color_map,
+                                                int orig_width, int orig_height,
+                                                int new_width, int new_height) {
+  int j;
+  assert(new_width >= orig_width);
+  assert(new_height >= orig_height);
+  if (new_width == orig_width && new_height == orig_height) return;
+
+  for (j = orig_height - 1; j >= 0; --j) {
+    memmove(color_map + j * new_width, color_map + j * orig_width, orig_width);
+    // Copy last column to extra columns.
+    memset(color_map + j * new_width + orig_width,
+           color_map[j * new_width + orig_width - 1], new_width - orig_width);
+  }
+  // Copy last row to extra rows.
+  for (j = orig_height; j < new_height; ++j) {
+    memcpy(color_map + j * new_width, color_map + (orig_height - 1) * new_width,
+           new_width);
+  }
+}
+
+// Bias toward using colors in the cache.
+// TODO(huisu): Try other schemes to improve compression.
+static AOM_INLINE void optimize_palette_colors(uint16_t *color_cache,
+                                               int n_cache, int n_colors,
+                                               int stride, int16_t *centroids,
+                                               int bit_depth) {
+  if (n_cache <= 0) return;
+  for (int i = 0; i < n_colors * stride; i += stride) {
+    int min_diff = abs((int)centroids[i] - (int)color_cache[0]);
+    int idx = 0;
+    for (int j = 1; j < n_cache; ++j) {
+      const int this_diff = abs((int)centroids[i] - (int)color_cache[j]);
+      if (this_diff < min_diff) {
+        min_diff = this_diff;
+        idx = j;
+      }
+    }
+    const int min_threshold = 4 << (bit_depth - 8);
+    if (min_diff <= min_threshold) centroids[i] = color_cache[idx];
+  }
+}
+
+/*!\brief Calculate the luma palette cost from a given color palette
+ *
+ * \ingroup palette_mode_search
+ * \callergraph
+ * Given the base colors as specified in centroids[], calculate the RD cost
+ * of palette mode.
+ */
+static AOM_INLINE void palette_rd_y(
+    const AV1_COMP *const cpi, MACROBLOCK *x, MB_MODE_INFO *mbmi,
+    BLOCK_SIZE bsize, int dc_mode_cost, const int16_t *data, int16_t *centroids,
+    int n, uint16_t *color_cache, int n_cache, bool do_header_rd_based_gating,
+    MB_MODE_INFO *best_mbmi, uint8_t *best_palette_color_map, int64_t *best_rd,
+    int *rate, int *rate_tokenonly, int64_t *distortion, uint8_t *skippable,
+    int *beat_best_rd, PICK_MODE_CONTEXT *ctx, uint8_t *blk_skip,
+    uint8_t *tx_type_map, int *beat_best_palette_rd,
+    bool *do_header_rd_based_breakout, int discount_color_cost) {
+  if (do_header_rd_based_breakout != NULL) *do_header_rd_based_breakout = false;
+  optimize_palette_colors(color_cache, n_cache, n, 1, centroids,
+                          cpi->common.seq_params->bit_depth);
+  const int num_unique_colors = av1_remove_duplicates(centroids, n);
+  if (num_unique_colors < PALETTE_MIN_SIZE) {
+    // Too few unique colors to create a palette. And DC_PRED will work
+    // well for that case anyway. So skip.
+    return;
+  }
+  PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;
+  if (cpi->common.seq_params->use_highbitdepth) {
+    for (int i = 0; i < num_unique_colors; ++i) {
+      pmi->palette_colors[i] = clip_pixel_highbd(
+          (int)centroids[i], cpi->common.seq_params->bit_depth);
+    }
+  } else {
+    for (int i = 0; i < num_unique_colors; ++i) {
+      pmi->palette_colors[i] = clip_pixel(centroids[i]);
+    }
+  }
+  pmi->palette_size[0] = num_unique_colors;
+  MACROBLOCKD *const xd = &x->e_mbd;
+  uint8_t *const color_map = xd->plane[0].color_index_map;
+  int block_width, block_height, rows, cols;
+  av1_get_block_dimensions(bsize, 0, xd, &block_width, &block_height, &rows,
+                           &cols);
+  av1_calc_indices(data, centroids, color_map, rows * cols, num_unique_colors,
+                   1);
+  extend_palette_color_map(color_map, cols, rows, block_width, block_height);
+
+  RD_STATS tokenonly_rd_stats;
+  int this_rate;
+
+  if (do_header_rd_based_gating) {
+    assert(do_header_rd_based_breakout != NULL);
+    const int palette_mode_rate = intra_mode_info_cost_y(
+        cpi, x, mbmi, bsize, dc_mode_cost, discount_color_cost);
+    const int64_t header_rd = RDCOST(x->rdmult, palette_mode_rate, 0);
+    // Less aggressive pruning when prune_luma_palette_size_search_level == 1.
+    const int header_rd_shift =
+        (cpi->sf.intra_sf.prune_luma_palette_size_search_level == 1) ? 1 : 0;
+    // Terminate further palette_size search, if the header cost corresponding
+    // to lower palette_size is more than *best_rd << header_rd_shift. This
+    // logic is implemented with a right shift in the LHS to prevent a possible
+    // overflow with the left shift in RHS.
+    if ((header_rd >> header_rd_shift) > *best_rd) {
+      *do_header_rd_based_breakout = true;
+      return;
+    }
+    av1_pick_uniform_tx_size_type_yrd(cpi, x, &tokenonly_rd_stats, bsize,
+                                      *best_rd);
+    if (tokenonly_rd_stats.rate == INT_MAX) return;
+    this_rate = tokenonly_rd_stats.rate + palette_mode_rate;
+  } else {
+    av1_pick_uniform_tx_size_type_yrd(cpi, x, &tokenonly_rd_stats, bsize,
+                                      *best_rd);
+    if (tokenonly_rd_stats.rate == INT_MAX) return;
+    this_rate = tokenonly_rd_stats.rate +
+                intra_mode_info_cost_y(cpi, x, mbmi, bsize, dc_mode_cost,
+                                       discount_color_cost);
+  }
+
+  int64_t this_rd = RDCOST(x->rdmult, this_rate, tokenonly_rd_stats.dist);
+  if (!xd->lossless[mbmi->segment_id] && block_signals_txsize(mbmi->bsize)) {
+    tokenonly_rd_stats.rate -= tx_size_cost(x, bsize, mbmi->tx_size);
+  }
+  // Collect mode stats for multiwinner mode processing
+  const int txfm_search_done = 1;
+  store_winner_mode_stats(
+      &cpi->common, x, mbmi, NULL, NULL, NULL, THR_DC, color_map, bsize,
+      this_rd, cpi->sf.winner_mode_sf.multi_winner_mode_type, txfm_search_done);
+  if (this_rd < *best_rd) {
+    *best_rd = this_rd;
+    // Setting beat_best_rd flag because current mode rd is better than best_rd.
+    // This flag need to be updated only for palette evaluation in key frames
+    if (beat_best_rd) *beat_best_rd = 1;
+    memcpy(best_palette_color_map, color_map,
+           block_width * block_height * sizeof(color_map[0]));
+    *best_mbmi = *mbmi;
+    memcpy(blk_skip, x->txfm_search_info.blk_skip,
+           sizeof(x->txfm_search_info.blk_skip[0]) * ctx->num_4x4_blk);
+    av1_copy_array(tx_type_map, xd->tx_type_map, ctx->num_4x4_blk);
+    if (rate) *rate = this_rate;
+    if (rate_tokenonly) *rate_tokenonly = tokenonly_rd_stats.rate;
+    if (distortion) *distortion = tokenonly_rd_stats.dist;
+    if (skippable) *skippable = tokenonly_rd_stats.skip_txfm;
+    if (beat_best_palette_rd) *beat_best_palette_rd = 1;
+  }
+}
+
+static AOM_INLINE int is_iter_over(int curr_idx, int end_idx, int step_size) {
+  assert(step_size != 0);
+  return (step_size > 0) ? curr_idx >= end_idx : curr_idx <= end_idx;
+}
+
+// Performs count-based palette search with number of colors in interval
+// [start_n, end_n) with step size step_size. If step_size < 0, then end_n can
+// be less than start_n. Saves the last numbers searched in last_n_searched and
+// returns the best number of colors found.
+static AOM_INLINE int perform_top_color_palette_search(
+    const AV1_COMP *const cpi, MACROBLOCK *x, MB_MODE_INFO *mbmi,
+    BLOCK_SIZE bsize, int dc_mode_cost, const int16_t *data,
+    int16_t *top_colors, int start_n, int end_n, int step_size,
+    bool do_header_rd_based_gating, int *last_n_searched, uint16_t *color_cache,
+    int n_cache, MB_MODE_INFO *best_mbmi, uint8_t *best_palette_color_map,
+    int64_t *best_rd, int *rate, int *rate_tokenonly, int64_t *distortion,
+    uint8_t *skippable, int *beat_best_rd, PICK_MODE_CONTEXT *ctx,
+    uint8_t *best_blk_skip, uint8_t *tx_type_map, int discount_color_cost) {
+  int16_t centroids[PALETTE_MAX_SIZE];
+  int n = start_n;
+  int top_color_winner = end_n;
+  /* clang-format off */
+  assert(IMPLIES(step_size < 0, start_n > end_n));
+  /* clang-format on */
+  assert(IMPLIES(step_size > 0, start_n < end_n));
+  while (!is_iter_over(n, end_n, step_size)) {
+    int beat_best_palette_rd = 0;
+    bool do_header_rd_based_breakout = false;
+    memcpy(centroids, top_colors, n * sizeof(top_colors[0]));
+    palette_rd_y(cpi, x, mbmi, bsize, dc_mode_cost, data, centroids, n,
+                 color_cache, n_cache, do_header_rd_based_gating, best_mbmi,
+                 best_palette_color_map, best_rd, rate, rate_tokenonly,
+                 distortion, skippable, beat_best_rd, ctx, best_blk_skip,
+                 tx_type_map, &beat_best_palette_rd,
+                 &do_header_rd_based_breakout, discount_color_cost);
+    *last_n_searched = n;
+    if (do_header_rd_based_breakout) {
+      // Terminate palette_size search by setting last_n_searched to end_n.
+      *last_n_searched = end_n;
+      break;
+    }
+    if (beat_best_palette_rd) {
+      top_color_winner = n;
+    } else if (cpi->sf.intra_sf.prune_palette_search_level == 2) {
+      // At search level 2, we return immediately if we don't see an improvement
+      return top_color_winner;
+    }
+    n += step_size;
+  }
+  return top_color_winner;
+}
+
+// Performs k-means based palette search with number of colors in interval
+// [start_n, end_n) with step size step_size. If step_size < 0, then end_n can
+// be less than start_n. Saves the last numbers searched in last_n_searched and
+// returns the best number of colors found.
+static AOM_INLINE int perform_k_means_palette_search(
+    const AV1_COMP *const cpi, MACROBLOCK *x, MB_MODE_INFO *mbmi,
+    BLOCK_SIZE bsize, int dc_mode_cost, const int16_t *data, int lower_bound,
+    int upper_bound, int start_n, int end_n, int step_size,
+    bool do_header_rd_based_gating, int *last_n_searched, uint16_t *color_cache,
+    int n_cache, MB_MODE_INFO *best_mbmi, uint8_t *best_palette_color_map,
+    int64_t *best_rd, int *rate, int *rate_tokenonly, int64_t *distortion,
+    uint8_t *skippable, int *beat_best_rd, PICK_MODE_CONTEXT *ctx,
+    uint8_t *best_blk_skip, uint8_t *tx_type_map, uint8_t *color_map,
+    int data_points, int discount_color_cost) {
+  int16_t centroids[PALETTE_MAX_SIZE];
+  const int max_itr = 50;
+  int n = start_n;
+  int top_color_winner = end_n;
+  /* clang-format off */
+  assert(IMPLIES(step_size < 0, start_n > end_n));
+  /* clang-format on */
+  assert(IMPLIES(step_size > 0, start_n < end_n));
+  while (!is_iter_over(n, end_n, step_size)) {
+    int beat_best_palette_rd = 0;
+    bool do_header_rd_based_breakout = false;
+    for (int i = 0; i < n; ++i) {
+      centroids[i] =
+          lower_bound + (2 * i + 1) * (upper_bound - lower_bound) / n / 2;
+    }
+    av1_k_means(data, centroids, color_map, data_points, n, 1, max_itr);
+    palette_rd_y(cpi, x, mbmi, bsize, dc_mode_cost, data, centroids, n,
+                 color_cache, n_cache, do_header_rd_based_gating, best_mbmi,
+                 best_palette_color_map, best_rd, rate, rate_tokenonly,
+                 distortion, skippable, beat_best_rd, ctx, best_blk_skip,
+                 tx_type_map, &beat_best_palette_rd,
+                 &do_header_rd_based_breakout, discount_color_cost);
+    *last_n_searched = n;
+    if (do_header_rd_based_breakout) {
+      // Terminate palette_size search by setting last_n_searched to end_n.
+      *last_n_searched = end_n;
+      break;
+    }
+    if (beat_best_palette_rd) {
+      top_color_winner = n;
+    } else if (cpi->sf.intra_sf.prune_palette_search_level == 2) {
+      // At search level 2, we return immediately if we don't see an improvement
+      return top_color_winner;
+    }
+    n += step_size;
+  }
+  return top_color_winner;
+}
+
+// Sets the parameters to search the current number of colors +- 1
+static AOM_INLINE void set_stage2_params(int *min_n, int *max_n, int *step_size,
+                                         int winner, int end_n) {
+  // Set min to winner - 1 unless we are already at the border, then we set it
+  // to winner + 1
+  *min_n = (winner == PALETTE_MIN_SIZE) ? (PALETTE_MIN_SIZE + 1)
+                                        : AOMMAX(winner - 1, PALETTE_MIN_SIZE);
+  // Set max to winner + 1 unless we are already at the border, then we set it
+  // to winner - 1
+  *max_n =
+      (winner == end_n) ? (winner - 1) : AOMMIN(winner + 1, PALETTE_MAX_SIZE);
+
+  // Set the step size to max_n - min_n so we only search those two values.
+  // If max_n == min_n, then set step_size to 1 to avoid infinite loop later.
+  *step_size = AOMMAX(1, *max_n - *min_n);
+}
+
+static AOM_INLINE void fill_data_and_get_bounds(const uint8_t *src,
+                                                const int src_stride,
+                                                const int rows, const int cols,
+                                                const int is_high_bitdepth,
+                                                int16_t *data, int *lower_bound,
+                                                int *upper_bound) {
+  if (is_high_bitdepth) {
+    const uint16_t *src_ptr = CONVERT_TO_SHORTPTR(src);
+    *lower_bound = *upper_bound = src_ptr[0];
+    for (int r = 0; r < rows; ++r) {
+      for (int c = 0; c < cols; ++c) {
+        const int val = src_ptr[c];
+        data[c] = (int16_t)val;
+        *lower_bound = AOMMIN(*lower_bound, val);
+        *upper_bound = AOMMAX(*upper_bound, val);
+      }
+      src_ptr += src_stride;
+      data += cols;
+    }
+    return;
+  }
+
+  // low bit depth
+  *lower_bound = *upper_bound = src[0];
+  for (int r = 0; r < rows; ++r) {
+    for (int c = 0; c < cols; ++c) {
+      const int val = src[c];
+      data[c] = (int16_t)val;
+      *lower_bound = AOMMIN(*lower_bound, val);
+      *upper_bound = AOMMAX(*upper_bound, val);
+    }
+    src += src_stride;
+    data += cols;
+  }
+}
+
+/*! \brief Colors are sorted by their count: the higher the better.
+ */
+struct ColorCount {
+  //! Color index in the histogram.
+  int index;
+  //! Histogram count.
+  int count;
+};
+
+int color_count_comp(const void *c1, const void *c2) {
+  const struct ColorCount *color_count1 = (const struct ColorCount *)c1;
+  const struct ColorCount *color_count2 = (const struct ColorCount *)c2;
+  if (color_count1->count > color_count2->count) return -1;
+  if (color_count1->count < color_count2->count) return 1;
+  if (color_count1->index < color_count2->index) return -1;
+  return 1;
+}
+
+static void find_top_colors(const int *const count_buf, int bit_depth,
+                            int n_colors, int16_t *top_colors) {
+  // Top color array, serving as a priority queue if more than n_colors are
+  // found.
+  struct ColorCount top_color_counts[PALETTE_MAX_SIZE] = { { 0 } };
+  int n_color_count = 0;
+  for (int i = 0; i < (1 << bit_depth); ++i) {
+    if (count_buf[i] > 0) {
+      if (n_color_count < n_colors) {
+        // Keep adding to the top colors.
+        top_color_counts[n_color_count].index = i;
+        top_color_counts[n_color_count].count = count_buf[i];
+        ++n_color_count;
+        if (n_color_count == n_colors) {
+          qsort(top_color_counts, n_colors, sizeof(top_color_counts[0]),
+                color_count_comp);
+        }
+      } else {
+        // Check the worst in the sorted top.
+        if (count_buf[i] > top_color_counts[n_colors - 1].count) {
+          int j = n_colors - 1;
+          // Move up to the best one.
+          while (j >= 1 && count_buf[i] > top_color_counts[j - 1].count) --j;
+          memmove(top_color_counts + j + 1, top_color_counts + j,
+                  (n_colors - j - 1) * sizeof(top_color_counts[0]));
+          top_color_counts[j].index = i;
+          top_color_counts[j].count = count_buf[i];
+        }
+      }
+    }
+  }
+  assert(n_color_count == n_colors);
+
+  for (int i = 0; i < n_colors; ++i) {
+    top_colors[i] = top_color_counts[i].index;
+  }
+}
+
+void av1_rd_pick_palette_intra_sby(
+    const AV1_COMP *cpi, MACROBLOCK *x, BLOCK_SIZE bsize, int dc_mode_cost,
+    MB_MODE_INFO *best_mbmi, uint8_t *best_palette_color_map, int64_t *best_rd,
+    int *rate, int *rate_tokenonly, int64_t *distortion, uint8_t *skippable,
+    int *beat_best_rd, PICK_MODE_CONTEXT *ctx, uint8_t *best_blk_skip,
+    uint8_t *tx_type_map) {
+  MACROBLOCKD *const xd = &x->e_mbd;
+  MB_MODE_INFO *const mbmi = xd->mi[0];
+  assert(!is_inter_block(mbmi));
+  assert(av1_allow_palette(cpi->common.features.allow_screen_content_tools,
+                           bsize));
+  assert(PALETTE_MAX_SIZE == 8);
+  assert(PALETTE_MIN_SIZE == 2);
+
+  const int src_stride = x->plane[0].src.stride;
+  const uint8_t *const src = x->plane[0].src.buf;
+  int block_width, block_height, rows, cols;
+  av1_get_block_dimensions(bsize, 0, xd, &block_width, &block_height, &rows,
+                           &cols);
+  const SequenceHeader *const seq_params = cpi->common.seq_params;
+  const int is_hbd = seq_params->use_highbitdepth;
+  const int bit_depth = seq_params->bit_depth;
+  const int discount_color_cost = cpi->sf.rt_sf.use_nonrd_pick_mode;
+  int unused;
+
+  int count_buf[1 << 12];  // Maximum (1 << 12) color levels.
+  int colors, colors_threshold = 0;
+  if (is_hbd) {
+    int count_buf_8bit[1 << 8];  // Maximum (1 << 8) bins for hbd path.
+    av1_count_colors_highbd(src, src_stride, rows, cols, bit_depth, count_buf,
+                            count_buf_8bit, &colors_threshold, &colors);
+  } else {
+    av1_count_colors(src, src_stride, rows, cols, count_buf, &colors);
+    colors_threshold = colors;
+  }
+
+  uint8_t *const color_map = xd->plane[0].color_index_map;
+  int color_thresh_palette = 64;
+  // Allow for larger color_threshold for palette search, based on color,
+  // scene_change, and block source variance.
+  // Since palette is Y based, only allow larger threshold if block
+  // color_dist is below threshold.
+  if (cpi->sf.rt_sf.use_nonrd_pick_mode &&
+      cpi->sf.rt_sf.increase_color_thresh_palette && cpi->rc.high_source_sad &&
+      x->source_variance > 50) {
+    int64_t norm_color_dist = 0;
+    if (x->color_sensitivity[0] || x->color_sensitivity[1]) {
+      norm_color_dist = x->min_dist_inter_uv >>
+                        (mi_size_wide_log2[bsize] + mi_size_high_log2[bsize]);
+      if (x->color_sensitivity[0] && x->color_sensitivity[1])
+        norm_color_dist = norm_color_dist >> 1;
+    }
+    if (norm_color_dist < 8000) color_thresh_palette += 20;
+  }
+  if (colors_threshold > 1 && colors_threshold <= color_thresh_palette) {
+    int16_t *const data = x->palette_buffer->kmeans_data_buf;
+    int16_t centroids[PALETTE_MAX_SIZE];
+    int lower_bound, upper_bound;
+    fill_data_and_get_bounds(src, src_stride, rows, cols, is_hbd, data,
+                             &lower_bound, &upper_bound);
+
+    mbmi->mode = DC_PRED;
+    mbmi->filter_intra_mode_info.use_filter_intra = 0;
+
+    uint16_t color_cache[2 * PALETTE_MAX_SIZE];
+    const int n_cache = av1_get_palette_cache(xd, 0, color_cache);
+
+    // Find the dominant colors, stored in top_colors[].
+    int16_t top_colors[PALETTE_MAX_SIZE] = { 0 };
+    find_top_colors(count_buf, bit_depth, AOMMIN(colors, PALETTE_MAX_SIZE),
+                    top_colors);
+
+    // The following are the approaches used for header rdcost based gating
+    // for early termination for different values of prune_palette_search_level.
+    // 0: Pruning based on header rdcost for ascending order palette_size
+    // search.
+    // 1: When colors > PALETTE_MIN_SIZE, enabled only for coarse palette_size
+    // search and for finer search do_header_rd_based_gating parameter is
+    // explicitly passed as 'false'.
+    // 2: Enabled only for ascending order palette_size search and for
+    // descending order search do_header_rd_based_gating parameter is explicitly
+    // passed as 'false'.
+    const bool do_header_rd_based_gating =
+        cpi->sf.intra_sf.prune_luma_palette_size_search_level != 0;
+
+    // TODO(huisu@google.com): Try to avoid duplicate computation in cases
+    // where the dominant colors and the k-means results are similar.
+    if ((cpi->sf.intra_sf.prune_palette_search_level == 1) &&
+        (colors > PALETTE_MIN_SIZE)) {
+      // Start index and step size below are chosen to evaluate unique
+      // candidates in neighbor search, in case a winner candidate is found in
+      // coarse search. Example,
+      // 1) 8 colors (end_n = 8): 2,3,4,5,6,7,8. start_n is chosen as 2 and step
+      // size is chosen as 3. Therefore, coarse search will evaluate 2, 5 and 8.
+      // If winner is found at 5, then 4 and 6 are evaluated. Similarly, for 2
+      // (3) and 8 (7).
+      // 2) 7 colors (end_n = 7): 2,3,4,5,6,7. If start_n is chosen as 2 (same
+      // as for 8 colors) then step size should also be 2, to cover all
+      // candidates. Coarse search will evaluate 2, 4 and 6. If winner is either
+      // 2 or 4, 3 will be evaluated. Instead, if start_n=3 and step_size=3,
+      // coarse search will evaluate 3 and 6. For the winner, unique neighbors
+      // (3: 2,4 or 6: 5,7) would be evaluated.
+
+      // Start index for coarse palette search for dominant colors and k-means
+      const uint8_t start_n_lookup_table[PALETTE_MAX_SIZE + 1] = { 0, 0, 0,
+                                                                   3, 3, 2,
+                                                                   3, 3, 2 };
+      // Step size for coarse palette search for dominant colors and k-means
+      const uint8_t step_size_lookup_table[PALETTE_MAX_SIZE + 1] = { 0, 0, 0,
+                                                                     3, 3, 3,
+                                                                     3, 3, 3 };
+
+      // Choose the start index and step size for coarse search based on number
+      // of colors
+      const int max_n = AOMMIN(colors, PALETTE_MAX_SIZE);
+      const int min_n = start_n_lookup_table[max_n];
+      const int step_size = step_size_lookup_table[max_n];
+      assert(min_n >= PALETTE_MIN_SIZE);
+      // Perform top color coarse palette search to find the winner candidate
+      const int top_color_winner = perform_top_color_palette_search(
+          cpi, x, mbmi, bsize, dc_mode_cost, data, top_colors, min_n, max_n + 1,
+          step_size, do_header_rd_based_gating, &unused, color_cache, n_cache,
+          best_mbmi, best_palette_color_map, best_rd, rate, rate_tokenonly,
+          distortion, skippable, beat_best_rd, ctx, best_blk_skip, tx_type_map,
+          discount_color_cost);
+      // Evaluate neighbors for the winner color (if winner is found) in the
+      // above coarse search for dominant colors
+      if (top_color_winner <= max_n) {
+        int stage2_min_n, stage2_max_n, stage2_step_size;
+        set_stage2_params(&stage2_min_n, &stage2_max_n, &stage2_step_size,
+                          top_color_winner, max_n);
+        // perform finer search for the winner candidate
+        perform_top_color_palette_search(
+            cpi, x, mbmi, bsize, dc_mode_cost, data, top_colors, stage2_min_n,
+            stage2_max_n + 1, stage2_step_size,
+            /*do_header_rd_based_gating=*/false, &unused, color_cache, n_cache,
+            best_mbmi, best_palette_color_map, best_rd, rate, rate_tokenonly,
+            distortion, skippable, beat_best_rd, ctx, best_blk_skip,
+            tx_type_map, discount_color_cost);
+      }
+      // K-means clustering.
+      // Perform k-means coarse palette search to find the winner candidate
+      const int k_means_winner = perform_k_means_palette_search(
+          cpi, x, mbmi, bsize, dc_mode_cost, data, lower_bound, upper_bound,
+          min_n, max_n + 1, step_size, do_header_rd_based_gating, &unused,
+          color_cache, n_cache, best_mbmi, best_palette_color_map, best_rd,
+          rate, rate_tokenonly, distortion, skippable, beat_best_rd, ctx,
+          best_blk_skip, tx_type_map, color_map, rows * cols,
+          discount_color_cost);
+      // Evaluate neighbors for the winner color (if winner is found) in the
+      // above coarse search for k-means
+      if (k_means_winner <= max_n) {
+        int start_n_stage2, end_n_stage2, step_size_stage2;
+        set_stage2_params(&start_n_stage2, &end_n_stage2, &step_size_stage2,
+                          k_means_winner, max_n);
+        // perform finer search for the winner candidate
+        perform_k_means_palette_search(
+            cpi, x, mbmi, bsize, dc_mode_cost, data, lower_bound, upper_bound,
+            start_n_stage2, end_n_stage2 + 1, step_size_stage2,
+            /*do_header_rd_based_gating=*/false, &unused, color_cache, n_cache,
+            best_mbmi, best_palette_color_map, best_rd, rate, rate_tokenonly,
+            distortion, skippable, beat_best_rd, ctx, best_blk_skip,
+            tx_type_map, color_map, rows * cols, discount_color_cost);
+      }
+    } else {
+      const int max_n = AOMMIN(colors, PALETTE_MAX_SIZE),
+                min_n = PALETTE_MIN_SIZE;
+      // Perform top color palette search in ascending order
+      int last_n_searched = min_n;
+      perform_top_color_palette_search(
+          cpi, x, mbmi, bsize, dc_mode_cost, data, top_colors, min_n, max_n + 1,
+          1, do_header_rd_based_gating, &last_n_searched, color_cache, n_cache,
+          best_mbmi, best_palette_color_map, best_rd, rate, rate_tokenonly,
+          distortion, skippable, beat_best_rd, ctx, best_blk_skip, tx_type_map,
+          discount_color_cost);
+      if (last_n_searched < max_n) {
+        // Search in descending order until we get to the previous best
+        perform_top_color_palette_search(
+            cpi, x, mbmi, bsize, dc_mode_cost, data, top_colors, max_n,
+            last_n_searched, -1, /*do_header_rd_based_gating=*/false, &unused,
+            color_cache, n_cache, best_mbmi, best_palette_color_map, best_rd,
+            rate, rate_tokenonly, distortion, skippable, beat_best_rd, ctx,
+            best_blk_skip, tx_type_map, discount_color_cost);
+      }
+      // K-means clustering.
+      if (colors == PALETTE_MIN_SIZE) {
+        // Special case: These colors automatically become the centroids.
+        assert(colors == 2);
+        centroids[0] = lower_bound;
+        centroids[1] = upper_bound;
+        palette_rd_y(cpi, x, mbmi, bsize, dc_mode_cost, data, centroids, colors,
+                     color_cache, n_cache, /*do_header_rd_based_gating=*/false,
+                     best_mbmi, best_palette_color_map, best_rd, rate,
+                     rate_tokenonly, distortion, skippable, beat_best_rd, ctx,
+                     best_blk_skip, tx_type_map, NULL, NULL,
+                     discount_color_cost);
+      } else {
+        // Perform k-means palette search in ascending order
+        last_n_searched = min_n;
+        perform_k_means_palette_search(
+            cpi, x, mbmi, bsize, dc_mode_cost, data, lower_bound, upper_bound,
+            min_n, max_n + 1, 1, do_header_rd_based_gating, &last_n_searched,
+            color_cache, n_cache, best_mbmi, best_palette_color_map, best_rd,
+            rate, rate_tokenonly, distortion, skippable, beat_best_rd, ctx,
+            best_blk_skip, tx_type_map, color_map, rows * cols,
+            discount_color_cost);
+        if (last_n_searched < max_n) {
+          // Search in descending order until we get to the previous best
+          perform_k_means_palette_search(
+              cpi, x, mbmi, bsize, dc_mode_cost, data, lower_bound, upper_bound,
+              max_n, last_n_searched, -1, /*do_header_rd_based_gating=*/false,
+              &unused, color_cache, n_cache, best_mbmi, best_palette_color_map,
+              best_rd, rate, rate_tokenonly, distortion, skippable,
+              beat_best_rd, ctx, best_blk_skip, tx_type_map, color_map,
+              rows * cols, discount_color_cost);
+        }
+      }
+    }
+  }
+
+  if (best_mbmi->palette_mode_info.palette_size[0] > 0) {
+    memcpy(color_map, best_palette_color_map,
+           block_width * block_height * sizeof(best_palette_color_map[0]));
+    // Gather the stats to determine whether to use screen content tools in
+    // function av1_determine_sc_tools_with_encoding().
+    x->palette_pixels += (block_width * block_height);
+  }
+  *mbmi = *best_mbmi;
+}
+
+void av1_rd_pick_palette_intra_sbuv(const AV1_COMP *cpi, MACROBLOCK *x,
+                                    int dc_mode_cost,
+                                    uint8_t *best_palette_color_map,
+                                    MB_MODE_INFO *const best_mbmi,
+                                    int64_t *best_rd, int *rate,
+                                    int *rate_tokenonly, int64_t *distortion,
+                                    uint8_t *skippable) {
+  MACROBLOCKD *const xd = &x->e_mbd;
+  MB_MODE_INFO *const mbmi = xd->mi[0];
+  assert(!is_inter_block(mbmi));
+  assert(av1_allow_palette(cpi->common.features.allow_screen_content_tools,
+                           mbmi->bsize));
+  PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;
+  const BLOCK_SIZE bsize = mbmi->bsize;
+  const SequenceHeader *const seq_params = cpi->common.seq_params;
+  int this_rate;
+  int64_t this_rd;
+  int colors_u, colors_v;
+  int colors_threshold_u = 0, colors_threshold_v = 0, colors_threshold = 0;
+  const int src_stride = x->plane[1].src.stride;
+  const uint8_t *const src_u = x->plane[1].src.buf;
+  const uint8_t *const src_v = x->plane[2].src.buf;
+  uint8_t *const color_map = xd->plane[1].color_index_map;
+  RD_STATS tokenonly_rd_stats;
+  int plane_block_width, plane_block_height, rows, cols;
+  av1_get_block_dimensions(bsize, 1, xd, &plane_block_width,
+                           &plane_block_height, &rows, &cols);
+
+  mbmi->uv_mode = UV_DC_PRED;
+  if (seq_params->use_highbitdepth) {
+    int count_buf[1 << 12];      // Maximum (1 << 12) color levels.
+    int count_buf_8bit[1 << 8];  // Maximum (1 << 8) bins for hbd path.
+    av1_count_colors_highbd(src_u, src_stride, rows, cols,
+                            seq_params->bit_depth, count_buf, count_buf_8bit,
+                            &colors_threshold_u, &colors_u);
+    av1_count_colors_highbd(src_v, src_stride, rows, cols,
+                            seq_params->bit_depth, count_buf, count_buf_8bit,
+                            &colors_threshold_v, &colors_v);
+  } else {
+    int count_buf[1 << 8];
+    av1_count_colors(src_u, src_stride, rows, cols, count_buf, &colors_u);
+    av1_count_colors(src_v, src_stride, rows, cols, count_buf, &colors_v);
+    colors_threshold_u = colors_u;
+    colors_threshold_v = colors_v;
+  }
+
+  uint16_t color_cache[2 * PALETTE_MAX_SIZE];
+  const int n_cache = av1_get_palette_cache(xd, 1, color_cache);
+
+  colors_threshold = colors_threshold_u > colors_threshold_v
+                         ? colors_threshold_u
+                         : colors_threshold_v;
+  if (colors_threshold > 1 && colors_threshold <= 64) {
+    int r, c, n, i, j;
+    const int max_itr = 50;
+    int lb_u, ub_u, val_u;
+    int lb_v, ub_v, val_v;
+    int16_t *const data = x->palette_buffer->kmeans_data_buf;
+    int16_t centroids[2 * PALETTE_MAX_SIZE];
+
+    uint16_t *src_u16 = CONVERT_TO_SHORTPTR(src_u);
+    uint16_t *src_v16 = CONVERT_TO_SHORTPTR(src_v);
+    if (seq_params->use_highbitdepth) {
+      lb_u = src_u16[0];
+      ub_u = src_u16[0];
+      lb_v = src_v16[0];
+      ub_v = src_v16[0];
+    } else {
+      lb_u = src_u[0];
+      ub_u = src_u[0];
+      lb_v = src_v[0];
+      ub_v = src_v[0];
+    }
+
+    for (r = 0; r < rows; ++r) {
+      for (c = 0; c < cols; ++c) {
+        if (seq_params->use_highbitdepth) {
+          val_u = src_u16[r * src_stride + c];
+          val_v = src_v16[r * src_stride + c];
+          data[(r * cols + c) * 2] = val_u;
+          data[(r * cols + c) * 2 + 1] = val_v;
+        } else {
+          val_u = src_u[r * src_stride + c];
+          val_v = src_v[r * src_stride + c];
+          data[(r * cols + c) * 2] = val_u;
+          data[(r * cols + c) * 2 + 1] = val_v;
+        }
+        if (val_u < lb_u)
+          lb_u = val_u;
+        else if (val_u > ub_u)
+          ub_u = val_u;
+        if (val_v < lb_v)
+          lb_v = val_v;
+        else if (val_v > ub_v)
+          ub_v = val_v;
+      }
+    }
+
+    const int colors = colors_u > colors_v ? colors_u : colors_v;
+    const int max_colors =
+        colors > PALETTE_MAX_SIZE ? PALETTE_MAX_SIZE : colors;
+    for (n = PALETTE_MIN_SIZE; n <= max_colors; ++n) {
+      for (i = 0; i < n; ++i) {
+        centroids[i * 2] = lb_u + (2 * i + 1) * (ub_u - lb_u) / n / 2;
+        centroids[i * 2 + 1] = lb_v + (2 * i + 1) * (ub_v - lb_v) / n / 2;
+      }
+      av1_k_means(data, centroids, color_map, rows * cols, n, 2, max_itr);
+      optimize_palette_colors(color_cache, n_cache, n, 2, centroids,
+                              cpi->common.seq_params->bit_depth);
+      // Sort the U channel colors in ascending order.
+      for (i = 0; i < 2 * (n - 1); i += 2) {
+        int min_idx = i;
+        int min_val = centroids[i];
+        for (j = i + 2; j < 2 * n; j += 2)
+          if (centroids[j] < min_val) min_val = centroids[j], min_idx = j;
+        if (min_idx != i) {
+          int temp_u = centroids[i], temp_v = centroids[i + 1];
+          centroids[i] = centroids[min_idx];
+          centroids[i + 1] = centroids[min_idx + 1];
+          centroids[min_idx] = temp_u, centroids[min_idx + 1] = temp_v;
+        }
+      }
+      av1_calc_indices(data, centroids, color_map, rows * cols, n, 2);
+      extend_palette_color_map(color_map, cols, rows, plane_block_width,
+                               plane_block_height);
+      pmi->palette_size[1] = n;
+      for (i = 1; i < 3; ++i) {
+        for (j = 0; j < n; ++j) {
+          if (seq_params->use_highbitdepth)
+            pmi->palette_colors[i * PALETTE_MAX_SIZE + j] = clip_pixel_highbd(
+                (int)centroids[j * 2 + i - 1], seq_params->bit_depth);
+          else
+            pmi->palette_colors[i * PALETTE_MAX_SIZE + j] =
+                clip_pixel((int)centroids[j * 2 + i - 1]);
+        }
+      }
+
+      if (cpi->sf.intra_sf.early_term_chroma_palette_size_search) {
+        const int palette_mode_rate =
+            intra_mode_info_cost_uv(cpi, x, mbmi, bsize, dc_mode_cost);
+        const int64_t header_rd = RDCOST(x->rdmult, palette_mode_rate, 0);
+        // Terminate further palette_size search, if header cost corresponding
+        // to lower palette_size is more than the best_rd.
+        if (header_rd >= *best_rd) break;
+        av1_txfm_uvrd(cpi, x, &tokenonly_rd_stats, bsize, *best_rd);
+        if (tokenonly_rd_stats.rate == INT_MAX) continue;
+        this_rate = tokenonly_rd_stats.rate + palette_mode_rate;
+      } else {
+        av1_txfm_uvrd(cpi, x, &tokenonly_rd_stats, bsize, *best_rd);
+        if (tokenonly_rd_stats.rate == INT_MAX) continue;
+        this_rate = tokenonly_rd_stats.rate +
+                    intra_mode_info_cost_uv(cpi, x, mbmi, bsize, dc_mode_cost);
+      }
+
+      this_rd = RDCOST(x->rdmult, this_rate, tokenonly_rd_stats.dist);
+      if (this_rd < *best_rd) {
+        *best_rd = this_rd;
+        *best_mbmi = *mbmi;
+        memcpy(best_palette_color_map, color_map,
+               plane_block_width * plane_block_height *
+                   sizeof(best_palette_color_map[0]));
+        *rate = this_rate;
+        *distortion = tokenonly_rd_stats.dist;
+        *rate_tokenonly = tokenonly_rd_stats.rate;
+        *skippable = tokenonly_rd_stats.skip_txfm;
+      }
+    }
+  }
+  if (best_mbmi->palette_mode_info.palette_size[1] > 0) {
+    memcpy(color_map, best_palette_color_map,
+           plane_block_width * plane_block_height *
+               sizeof(best_palette_color_map[0]));
+  }
+}
+
+void av1_restore_uv_color_map(const AV1_COMP *cpi, MACROBLOCK *x) {
+  MACROBLOCKD *const xd = &x->e_mbd;
+  MB_MODE_INFO *const mbmi = xd->mi[0];
+  PALETTE_MODE_INFO *const pmi = &mbmi->palette_mode_info;
+  const BLOCK_SIZE bsize = mbmi->bsize;
+  int src_stride = x->plane[1].src.stride;
+  const uint8_t *const src_u = x->plane[1].src.buf;
+  const uint8_t *const src_v = x->plane[2].src.buf;
+  int16_t *const data = x->palette_buffer->kmeans_data_buf;
+  int16_t centroids[2 * PALETTE_MAX_SIZE];
+  uint8_t *const color_map = xd->plane[1].color_index_map;
+  int r, c;
+  const uint16_t *const src_u16 = CONVERT_TO_SHORTPTR(src_u);
+  const uint16_t *const src_v16 = CONVERT_TO_SHORTPTR(src_v);
+  int plane_block_width, plane_block_height, rows, cols;
+  av1_get_block_dimensions(bsize, 1, xd, &plane_block_width,
+                           &plane_block_height, &rows, &cols);
+
+  for (r = 0; r < rows; ++r) {
+    for (c = 0; c < cols; ++c) {
+      if (cpi->common.seq_params->use_highbitdepth) {
+        data[(r * cols + c) * 2] = src_u16[r * src_stride + c];
+        data[(r * cols + c) * 2 + 1] = src_v16[r * src_stride + c];
+      } else {
+        data[(r * cols + c) * 2] = src_u[r * src_stride + c];
+        data[(r * cols + c) * 2 + 1] = src_v[r * src_stride + c];
+      }
+    }
+  }
+
+  for (r = 1; r < 3; ++r) {
+    for (c = 0; c < pmi->palette_size[1]; ++c) {
+      centroids[c * 2 + r - 1] = pmi->palette_colors[r * PALETTE_MAX_SIZE + c];
+    }
+  }
+
+  av1_calc_indices(data, centroids, color_map, rows * cols,
+                   pmi->palette_size[1], 2);
+  extend_palette_color_map(color_map, cols, rows, plane_block_width,
+                           plane_block_height);
+}