/* * 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 #include #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); }