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      1 /*
      2  *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include <limits.h>
     12 
     13 #include "vpx_mem/vpx_mem.h"
     14 
     15 #include "vp9/common/vp9_pred_common.h"
     16 #include "vp9/common/vp9_tile_common.h"
     17 
     18 #include "vp9/encoder/vp9_cost.h"
     19 #include "vp9/encoder/vp9_segmentation.h"
     20 
     21 void vp9_enable_segmentation(struct segmentation *seg) {
     22   seg->enabled = 1;
     23   seg->update_map = 1;
     24   seg->update_data = 1;
     25 }
     26 
     27 void vp9_disable_segmentation(struct segmentation *seg) {
     28   seg->enabled = 0;
     29   seg->update_map = 0;
     30   seg->update_data = 0;
     31 }
     32 
     33 void vp9_set_segment_data(struct segmentation *seg, signed char *feature_data,
     34                           unsigned char abs_delta) {
     35   seg->abs_delta = abs_delta;
     36 
     37   memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
     38 }
     39 void vp9_disable_segfeature(struct segmentation *seg, int segment_id,
     40                             SEG_LVL_FEATURES feature_id) {
     41   seg->feature_mask[segment_id] &= ~(1 << feature_id);
     42 }
     43 
     44 void vp9_clear_segdata(struct segmentation *seg, int segment_id,
     45                        SEG_LVL_FEATURES feature_id) {
     46   seg->feature_data[segment_id][feature_id] = 0;
     47 }
     48 
     49 void vp9_psnr_aq_mode_setup(struct segmentation *seg) {
     50   int i;
     51 
     52   vp9_enable_segmentation(seg);
     53   vp9_clearall_segfeatures(seg);
     54   seg->abs_delta = SEGMENT_DELTADATA;
     55 
     56   for (i = 0; i < MAX_SEGMENTS; ++i) {
     57     vp9_set_segdata(seg, i, SEG_LVL_ALT_Q, 2 * (i - (MAX_SEGMENTS / 2)));
     58     vp9_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
     59   }
     60 }
     61 
     62 // Based on set of segment counts calculate a probability tree
     63 static void calc_segtree_probs(int *segcounts, vpx_prob *segment_tree_probs) {
     64   // Work out probabilities of each segment
     65   const int c01 = segcounts[0] + segcounts[1];
     66   const int c23 = segcounts[2] + segcounts[3];
     67   const int c45 = segcounts[4] + segcounts[5];
     68   const int c67 = segcounts[6] + segcounts[7];
     69 
     70   segment_tree_probs[0] = get_binary_prob(c01 + c23, c45 + c67);
     71   segment_tree_probs[1] = get_binary_prob(c01, c23);
     72   segment_tree_probs[2] = get_binary_prob(c45, c67);
     73   segment_tree_probs[3] = get_binary_prob(segcounts[0], segcounts[1]);
     74   segment_tree_probs[4] = get_binary_prob(segcounts[2], segcounts[3]);
     75   segment_tree_probs[5] = get_binary_prob(segcounts[4], segcounts[5]);
     76   segment_tree_probs[6] = get_binary_prob(segcounts[6], segcounts[7]);
     77 }
     78 
     79 // Based on set of segment counts and probabilities calculate a cost estimate
     80 static int cost_segmap(int *segcounts, vpx_prob *probs) {
     81   const int c01 = segcounts[0] + segcounts[1];
     82   const int c23 = segcounts[2] + segcounts[3];
     83   const int c45 = segcounts[4] + segcounts[5];
     84   const int c67 = segcounts[6] + segcounts[7];
     85   const int c0123 = c01 + c23;
     86   const int c4567 = c45 + c67;
     87 
     88   // Cost the top node of the tree
     89   int cost = c0123 * vp9_cost_zero(probs[0]) + c4567 * vp9_cost_one(probs[0]);
     90 
     91   // Cost subsequent levels
     92   if (c0123 > 0) {
     93     cost += c01 * vp9_cost_zero(probs[1]) + c23 * vp9_cost_one(probs[1]);
     94 
     95     if (c01 > 0)
     96       cost += segcounts[0] * vp9_cost_zero(probs[3]) +
     97               segcounts[1] * vp9_cost_one(probs[3]);
     98     if (c23 > 0)
     99       cost += segcounts[2] * vp9_cost_zero(probs[4]) +
    100               segcounts[3] * vp9_cost_one(probs[4]);
    101   }
    102 
    103   if (c4567 > 0) {
    104     cost += c45 * vp9_cost_zero(probs[2]) + c67 * vp9_cost_one(probs[2]);
    105 
    106     if (c45 > 0)
    107       cost += segcounts[4] * vp9_cost_zero(probs[5]) +
    108               segcounts[5] * vp9_cost_one(probs[5]);
    109     if (c67 > 0)
    110       cost += segcounts[6] * vp9_cost_zero(probs[6]) +
    111               segcounts[7] * vp9_cost_one(probs[6]);
    112   }
    113 
    114   return cost;
    115 }
    116 
    117 static void count_segs(const VP9_COMMON *cm, MACROBLOCKD *xd,
    118                        const TileInfo *tile, MODE_INFO **mi,
    119                        int *no_pred_segcounts,
    120                        int (*temporal_predictor_count)[2],
    121                        int *t_unpred_seg_counts, int bw, int bh, int mi_row,
    122                        int mi_col) {
    123   int segment_id;
    124 
    125   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
    126 
    127   xd->mi = mi;
    128   segment_id = xd->mi[0]->segment_id;
    129 
    130   set_mi_row_col(xd, tile, mi_row, bh, mi_col, bw, cm->mi_rows, cm->mi_cols);
    131 
    132   // Count the number of hits on each segment with no prediction
    133   no_pred_segcounts[segment_id]++;
    134 
    135   // Temporal prediction not allowed on key frames
    136   if (cm->frame_type != KEY_FRAME) {
    137     const BLOCK_SIZE bsize = xd->mi[0]->sb_type;
    138     // Test to see if the segment id matches the predicted value.
    139     const int pred_segment_id =
    140         get_segment_id(cm, cm->last_frame_seg_map, bsize, mi_row, mi_col);
    141     const int pred_flag = pred_segment_id == segment_id;
    142     const int pred_context = vp9_get_pred_context_seg_id(xd);
    143 
    144     // Store the prediction status for this mb and update counts
    145     // as appropriate
    146     xd->mi[0]->seg_id_predicted = pred_flag;
    147     temporal_predictor_count[pred_context][pred_flag]++;
    148 
    149     // Update the "unpredicted" segment count
    150     if (!pred_flag) t_unpred_seg_counts[segment_id]++;
    151   }
    152 }
    153 
    154 static void count_segs_sb(const VP9_COMMON *cm, MACROBLOCKD *xd,
    155                           const TileInfo *tile, MODE_INFO **mi,
    156                           int *no_pred_segcounts,
    157                           int (*temporal_predictor_count)[2],
    158                           int *t_unpred_seg_counts, int mi_row, int mi_col,
    159                           BLOCK_SIZE bsize) {
    160   const int mis = cm->mi_stride;
    161   int bw, bh;
    162   const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
    163 
    164   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols) return;
    165 
    166   bw = num_8x8_blocks_wide_lookup[mi[0]->sb_type];
    167   bh = num_8x8_blocks_high_lookup[mi[0]->sb_type];
    168 
    169   if (bw == bs && bh == bs) {
    170     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
    171                t_unpred_seg_counts, bs, bs, mi_row, mi_col);
    172   } else if (bw == bs && bh < bs) {
    173     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
    174                t_unpred_seg_counts, bs, hbs, mi_row, mi_col);
    175     count_segs(cm, xd, tile, mi + hbs * mis, no_pred_segcounts,
    176                temporal_predictor_count, t_unpred_seg_counts, bs, hbs,
    177                mi_row + hbs, mi_col);
    178   } else if (bw < bs && bh == bs) {
    179     count_segs(cm, xd, tile, mi, no_pred_segcounts, temporal_predictor_count,
    180                t_unpred_seg_counts, hbs, bs, mi_row, mi_col);
    181     count_segs(cm, xd, tile, mi + hbs, no_pred_segcounts,
    182                temporal_predictor_count, t_unpred_seg_counts, hbs, bs, mi_row,
    183                mi_col + hbs);
    184   } else {
    185     const BLOCK_SIZE subsize = subsize_lookup[PARTITION_SPLIT][bsize];
    186     int n;
    187 
    188     assert(bw < bs && bh < bs);
    189 
    190     for (n = 0; n < 4; n++) {
    191       const int mi_dc = hbs * (n & 1);
    192       const int mi_dr = hbs * (n >> 1);
    193 
    194       count_segs_sb(cm, xd, tile, &mi[mi_dr * mis + mi_dc], no_pred_segcounts,
    195                     temporal_predictor_count, t_unpred_seg_counts,
    196                     mi_row + mi_dr, mi_col + mi_dc, subsize);
    197     }
    198   }
    199 }
    200 
    201 void vp9_choose_segmap_coding_method(VP9_COMMON *cm, MACROBLOCKD *xd) {
    202   struct segmentation *seg = &cm->seg;
    203 
    204   int no_pred_cost;
    205   int t_pred_cost = INT_MAX;
    206 
    207   int i, tile_col, mi_row, mi_col;
    208 
    209   int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
    210   int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
    211   int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
    212 
    213   vpx_prob no_pred_tree[SEG_TREE_PROBS];
    214   vpx_prob t_pred_tree[SEG_TREE_PROBS];
    215   vpx_prob t_nopred_prob[PREDICTION_PROBS];
    216 
    217   // Set default state for the segment tree probabilities and the
    218   // temporal coding probabilities
    219   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
    220   memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
    221 
    222   // First of all generate stats regarding how well the last segment map
    223   // predicts this one
    224   for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
    225     TileInfo tile;
    226     MODE_INFO **mi_ptr;
    227     vp9_tile_init(&tile, cm, 0, tile_col);
    228 
    229     mi_ptr = cm->mi_grid_visible + tile.mi_col_start;
    230     for (mi_row = 0; mi_row < cm->mi_rows;
    231          mi_row += 8, mi_ptr += 8 * cm->mi_stride) {
    232       MODE_INFO **mi = mi_ptr;
    233       for (mi_col = tile.mi_col_start; mi_col < tile.mi_col_end;
    234            mi_col += 8, mi += 8)
    235         count_segs_sb(cm, xd, &tile, mi, no_pred_segcounts,
    236                       temporal_predictor_count, t_unpred_seg_counts, mi_row,
    237                       mi_col, BLOCK_64X64);
    238     }
    239   }
    240 
    241   // Work out probability tree for coding segments without prediction
    242   // and the cost.
    243   calc_segtree_probs(no_pred_segcounts, no_pred_tree);
    244   no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
    245 
    246   // Key frames cannot use temporal prediction
    247   if (!frame_is_intra_only(cm)) {
    248     // Work out probability tree for coding those segments not
    249     // predicted using the temporal method and the cost.
    250     calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
    251     t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
    252 
    253     // Add in the cost of the signaling for each prediction context.
    254     for (i = 0; i < PREDICTION_PROBS; i++) {
    255       const int count0 = temporal_predictor_count[i][0];
    256       const int count1 = temporal_predictor_count[i][1];
    257 
    258       t_nopred_prob[i] = get_binary_prob(count0, count1);
    259 
    260       // Add in the predictor signaling cost
    261       t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
    262                      count1 * vp9_cost_one(t_nopred_prob[i]);
    263     }
    264   }
    265 
    266   // Now choose which coding method to use.
    267   if (t_pred_cost < no_pred_cost) {
    268     seg->temporal_update = 1;
    269     memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
    270     memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
    271   } else {
    272     seg->temporal_update = 0;
    273     memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
    274   }
    275 }
    276 
    277 void vp9_reset_segment_features(struct segmentation *seg) {
    278   // Set up default state for MB feature flags
    279   seg->enabled = 0;
    280   seg->update_map = 0;
    281   seg->update_data = 0;
    282   memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
    283   vp9_clearall_segfeatures(seg);
    284 }
    285