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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 
     12 #include <limits.h>
     13 #include "vpx_mem/vpx_mem.h"
     14 #include "vp9/encoder/vp9_segmentation.h"
     15 #include "vp9/common/vp9_pred_common.h"
     16 #include "vp9/common/vp9_tile_common.h"
     17 
     18 void vp9_enable_segmentation(VP9_PTR ptr) {
     19   VP9_COMP *cpi = (VP9_COMP *)ptr;
     20   struct segmentation *const seg =  &cpi->common.seg;
     21 
     22   seg->enabled = 1;
     23   seg->update_map = 1;
     24   seg->update_data = 1;
     25 }
     26 
     27 void vp9_disable_segmentation(VP9_PTR ptr) {
     28   VP9_COMP *cpi = (VP9_COMP *)ptr;
     29   struct segmentation *const seg =  &cpi->common.seg;
     30   seg->enabled = 0;
     31 }
     32 
     33 void vp9_set_segmentation_map(VP9_PTR ptr,
     34                               unsigned char *segmentation_map) {
     35   VP9_COMP *cpi = (VP9_COMP *)ptr;
     36   struct segmentation *const seg = &cpi->common.seg;
     37 
     38   // Copy in the new segmentation map
     39   vpx_memcpy(cpi->segmentation_map, segmentation_map,
     40              (cpi->common.mi_rows * cpi->common.mi_cols));
     41 
     42   // Signal that the map should be updated.
     43   seg->update_map = 1;
     44   seg->update_data = 1;
     45 }
     46 
     47 void vp9_set_segment_data(VP9_PTR ptr,
     48                           signed char *feature_data,
     49                           unsigned char abs_delta) {
     50   VP9_COMP *cpi = (VP9_COMP *)ptr;
     51   struct segmentation *const seg = &cpi->common.seg;
     52 
     53   seg->abs_delta = abs_delta;
     54 
     55   vpx_memcpy(seg->feature_data, feature_data, sizeof(seg->feature_data));
     56 
     57   // TBD ?? Set the feature mask
     58   // vpx_memcpy(cpi->mb.e_mbd.segment_feature_mask, 0,
     59   //            sizeof(cpi->mb.e_mbd.segment_feature_mask));
     60 }
     61 
     62 // Based on set of segment counts calculate a probability tree
     63 static void calc_segtree_probs(int *segcounts, vp9_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, vp9_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]) +
     90              c4567 * vp9_cost_one(probs[0]);
     91 
     92   // Cost subsequent levels
     93   if (c0123 > 0) {
     94     cost += c01 * vp9_cost_zero(probs[1]) +
     95             c23 * vp9_cost_one(probs[1]);
     96 
     97     if (c01 > 0)
     98       cost += segcounts[0] * vp9_cost_zero(probs[3]) +
     99               segcounts[1] * vp9_cost_one(probs[3]);
    100     if (c23 > 0)
    101       cost += segcounts[2] * vp9_cost_zero(probs[4]) +
    102               segcounts[3] * vp9_cost_one(probs[4]);
    103   }
    104 
    105   if (c4567 > 0) {
    106     cost += c45 * vp9_cost_zero(probs[2]) +
    107             c67 * vp9_cost_one(probs[2]);
    108 
    109     if (c45 > 0)
    110       cost += segcounts[4] * vp9_cost_zero(probs[5]) +
    111               segcounts[5] * vp9_cost_one(probs[5]);
    112     if (c67 > 0)
    113       cost += segcounts[6] * vp9_cost_zero(probs[6]) +
    114               segcounts[7] * vp9_cost_one(probs[6]);
    115   }
    116 
    117   return cost;
    118 }
    119 
    120 static void count_segs(VP9_COMP *cpi, MODE_INFO **mi_8x8,
    121                        int *no_pred_segcounts,
    122                        int (*temporal_predictor_count)[2],
    123                        int *t_unpred_seg_counts,
    124                        int bw, int bh, int mi_row, int mi_col) {
    125   VP9_COMMON *const cm = &cpi->common;
    126   MACROBLOCKD *const xd = &cpi->mb.e_mbd;
    127   int segment_id;
    128 
    129   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
    130     return;
    131 
    132   segment_id = mi_8x8[0]->mbmi.segment_id;
    133 
    134   set_mi_row_col(cm, xd, mi_row, bh, mi_col, bw);
    135 
    136   // Count the number of hits on each segment with no prediction
    137   no_pred_segcounts[segment_id]++;
    138 
    139   // Temporal prediction not allowed on key frames
    140   if (cm->frame_type != KEY_FRAME) {
    141     const BLOCK_SIZE bsize = mi_8x8[0]->mbmi.sb_type;
    142     // Test to see if the segment id matches the predicted value.
    143     const int pred_segment_id = vp9_get_segment_id(cm, cm->last_frame_seg_map,
    144                                                    bsize, mi_row, mi_col);
    145     const int pred_flag = pred_segment_id == segment_id;
    146     const int pred_context = vp9_get_pred_context_seg_id(xd);
    147 
    148     // Store the prediction status for this mb and update counts
    149     // as appropriate
    150     vp9_set_pred_flag_seg_id(xd, pred_flag);
    151     temporal_predictor_count[pred_context][pred_flag]++;
    152 
    153     if (!pred_flag)
    154       // Update the "unpredicted" segment count
    155       t_unpred_seg_counts[segment_id]++;
    156   }
    157 }
    158 
    159 static void count_segs_sb(VP9_COMP *cpi, MODE_INFO **mi_8x8,
    160                           int *no_pred_segcounts,
    161                           int (*temporal_predictor_count)[2],
    162                           int *t_unpred_seg_counts,
    163                           int mi_row, int mi_col,
    164                           BLOCK_SIZE bsize) {
    165   const VP9_COMMON *const cm = &cpi->common;
    166   const int mis = cm->mode_info_stride;
    167   int bw, bh;
    168   const int bs = num_8x8_blocks_wide_lookup[bsize], hbs = bs / 2;
    169 
    170   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
    171     return;
    172 
    173   bw = num_8x8_blocks_wide_lookup[mi_8x8[0]->mbmi.sb_type];
    174   bh = num_8x8_blocks_high_lookup[mi_8x8[0]->mbmi.sb_type];
    175 
    176   if (bw == bs && bh == bs) {
    177     count_segs(cpi, mi_8x8, no_pred_segcounts, temporal_predictor_count,
    178                t_unpred_seg_counts, bs, bs, mi_row, mi_col);
    179   } else if (bw == bs && bh < bs) {
    180     count_segs(cpi, mi_8x8, no_pred_segcounts, temporal_predictor_count,
    181                t_unpred_seg_counts, bs, hbs, mi_row, mi_col);
    182     count_segs(cpi, mi_8x8 + hbs * mis, no_pred_segcounts,
    183                temporal_predictor_count, t_unpred_seg_counts, bs, hbs,
    184                mi_row + hbs, mi_col);
    185   } else if (bw < bs && bh == bs) {
    186     count_segs(cpi, mi_8x8, no_pred_segcounts, temporal_predictor_count,
    187                t_unpred_seg_counts, hbs, bs, mi_row, mi_col);
    188     count_segs(cpi, mi_8x8 + hbs, no_pred_segcounts, temporal_predictor_count,
    189                t_unpred_seg_counts, hbs, bs, mi_row, mi_col + hbs);
    190   } else {
    191     const BLOCK_SIZE subsize = subsize_lookup[PARTITION_SPLIT][bsize];
    192     int n;
    193 
    194     assert(bw < bs && bh < bs);
    195 
    196     for (n = 0; n < 4; n++) {
    197       const int mi_dc = hbs * (n & 1);
    198       const int mi_dr = hbs * (n >> 1);
    199 
    200       count_segs_sb(cpi, &mi_8x8[mi_dr * mis + mi_dc],
    201                     no_pred_segcounts, temporal_predictor_count,
    202                     t_unpred_seg_counts,
    203                     mi_row + mi_dr, mi_col + mi_dc, subsize);
    204     }
    205   }
    206 }
    207 
    208 void vp9_choose_segmap_coding_method(VP9_COMP *cpi) {
    209   VP9_COMMON *const cm = &cpi->common;
    210   struct segmentation *seg = &cm->seg;
    211 
    212   int no_pred_cost;
    213   int t_pred_cost = INT_MAX;
    214 
    215   int i, tile_col, mi_row, mi_col;
    216 
    217   int temporal_predictor_count[PREDICTION_PROBS][2] = { { 0 } };
    218   int no_pred_segcounts[MAX_SEGMENTS] = { 0 };
    219   int t_unpred_seg_counts[MAX_SEGMENTS] = { 0 };
    220 
    221   vp9_prob no_pred_tree[SEG_TREE_PROBS];
    222   vp9_prob t_pred_tree[SEG_TREE_PROBS];
    223   vp9_prob t_nopred_prob[PREDICTION_PROBS];
    224 
    225   const int mis = cm->mode_info_stride;
    226   MODE_INFO **mi_ptr, **mi;
    227 
    228   // Set default state for the segment tree probabilities and the
    229   // temporal coding probabilities
    230   vpx_memset(seg->tree_probs, 255, sizeof(seg->tree_probs));
    231   vpx_memset(seg->pred_probs, 255, sizeof(seg->pred_probs));
    232 
    233   // First of all generate stats regarding how well the last segment map
    234   // predicts this one
    235   for (tile_col = 0; tile_col < 1 << cm->log2_tile_cols; tile_col++) {
    236     vp9_get_tile_col_offsets(cm, tile_col);
    237     mi_ptr = cm->mi_grid_visible + cm->cur_tile_mi_col_start;
    238     for (mi_row = 0; mi_row < cm->mi_rows;
    239          mi_row += 8, mi_ptr += 8 * mis) {
    240       mi = mi_ptr;
    241       for (mi_col = cm->cur_tile_mi_col_start; mi_col < cm->cur_tile_mi_col_end;
    242            mi_col += 8, mi += 8)
    243         count_segs_sb(cpi, mi, no_pred_segcounts, temporal_predictor_count,
    244                       t_unpred_seg_counts, mi_row, mi_col, BLOCK_64X64);
    245     }
    246   }
    247 
    248   // Work out probability tree for coding segments without prediction
    249   // and the cost.
    250   calc_segtree_probs(no_pred_segcounts, no_pred_tree);
    251   no_pred_cost = cost_segmap(no_pred_segcounts, no_pred_tree);
    252 
    253   // Key frames cannot use temporal prediction
    254   if (cm->frame_type != KEY_FRAME) {
    255     // Work out probability tree for coding those segments not
    256     // predicted using the temporal method and the cost.
    257     calc_segtree_probs(t_unpred_seg_counts, t_pred_tree);
    258     t_pred_cost = cost_segmap(t_unpred_seg_counts, t_pred_tree);
    259 
    260     // Add in the cost of the signalling for each prediction context
    261     for (i = 0; i < PREDICTION_PROBS; i++) {
    262       const int count0 = temporal_predictor_count[i][0];
    263       const int count1 = temporal_predictor_count[i][1];
    264 
    265       t_nopred_prob[i] = get_binary_prob(count0, count1);
    266 
    267       // Add in the predictor signaling cost
    268       t_pred_cost += count0 * vp9_cost_zero(t_nopred_prob[i]) +
    269                      count1 * vp9_cost_one(t_nopred_prob[i]);
    270     }
    271   }
    272 
    273   // Now choose which coding method to use.
    274   if (t_pred_cost < no_pred_cost) {
    275     seg->temporal_update = 1;
    276     vpx_memcpy(seg->tree_probs, t_pred_tree, sizeof(t_pred_tree));
    277     vpx_memcpy(seg->pred_probs, t_nopred_prob, sizeof(t_nopred_prob));
    278   } else {
    279     seg->temporal_update = 0;
    280     vpx_memcpy(seg->tree_probs, no_pred_tree, sizeof(no_pred_tree));
    281   }
    282 }
    283