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| 1 /* |
| 2 * Copyright (c) 2014 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 #include <math.h> |
| 13 |
| 14 #include "vp9/encoder/vp9_aq_cyclicrefresh.h" |
| 15 |
| 16 #include "vp9/common/vp9_seg_common.h" |
| 17 |
| 18 #include "vp9/encoder/vp9_ratectrl.h" |
| 19 #include "vp9/encoder/vp9_rdopt.h" |
| 20 #include "vp9/encoder/vp9_segmentation.h" |
| 21 |
| 22 struct CYCLIC_REFRESH { |
| 23 // Percentage of super-blocks per frame that are targeted as candidates |
| 24 // for cyclic refresh. |
| 25 int max_sbs_perframe; |
| 26 // Maximum q-delta as percentage of base q. |
| 27 int max_qdelta_perc; |
| 28 // Block size below which we don't apply cyclic refresh. |
| 29 BLOCK_SIZE min_block_size; |
| 30 // Superblock starting index for cycling through the frame. |
| 31 int sb_index; |
| 32 // Controls how long a block will need to wait to be refreshed again. |
| 33 int time_for_refresh; |
| 34 // Actual number of (8x8) blocks that were applied delta-q (segment 1). |
| 35 int num_seg_blocks; |
| 36 // Actual encoding bits for segment 1. |
| 37 int actual_seg_bits; |
| 38 // RD mult. parameters for segment 1. |
| 39 int rdmult; |
| 40 // Cyclic refresh map. |
| 41 signed char *map; |
| 42 // Projected rate and distortion for the current superblock. |
| 43 int64_t projected_rate_sb; |
| 44 int64_t projected_dist_sb; |
| 45 // Thresholds applied to projected rate/distortion of the superblock. |
| 46 int64_t thresh_rate_sb; |
| 47 int64_t thresh_dist_sb; |
| 48 }; |
| 49 |
| 50 CYCLIC_REFRESH *vp9_cyclic_refresh_alloc(int mi_rows, int mi_cols) { |
| 51 CYCLIC_REFRESH *const cr = vpx_calloc(1, sizeof(*cr)); |
| 52 if (cr == NULL) |
| 53 return NULL; |
| 54 |
| 55 cr->map = vpx_calloc(mi_rows * mi_cols, sizeof(*cr->map)); |
| 56 if (cr->map == NULL) { |
| 57 vpx_free(cr); |
| 58 return NULL; |
| 59 } |
| 60 |
| 61 return cr; |
| 62 } |
| 63 |
| 64 void vp9_cyclic_refresh_free(CYCLIC_REFRESH *cr) { |
| 65 vpx_free(cr->map); |
| 66 vpx_free(cr); |
| 67 } |
| 68 |
| 69 // Check if we should turn off cyclic refresh based on bitrate condition. |
| 70 static int apply_cyclic_refresh_bitrate(const VP9_COMMON *cm, |
| 71 const RATE_CONTROL *rc) { |
| 72 // Turn off cyclic refresh if bits available per frame is not sufficiently |
| 73 // larger than bit cost of segmentation. Segment map bit cost should scale |
| 74 // with number of seg blocks, so compare available bits to number of blocks. |
| 75 // Average bits available per frame = av_per_frame_bandwidth |
| 76 // Number of (8x8) blocks in frame = mi_rows * mi_cols; |
| 77 const float factor = 0.5; |
| 78 const int number_blocks = cm->mi_rows * cm->mi_cols; |
| 79 // The condition below corresponds to turning off at target bitrates: |
| 80 // ~24kbps for CIF, 72kbps for VGA (at 30fps). |
| 81 // Also turn off at very small frame sizes, to avoid too large fraction of |
| 82 // superblocks to be refreshed per frame. Threshold below is less than QCIF. |
| 83 if (rc->av_per_frame_bandwidth < factor * number_blocks || |
| 84 number_blocks / 64 < 5) |
| 85 return 0; |
| 86 else |
| 87 return 1; |
| 88 } |
| 89 |
| 90 // Check if this coding block, of size bsize, should be considered for refresh |
| 91 // (lower-qp coding). Decision can be based on various factors, such as |
| 92 // size of the coding block (i.e., below min_block size rejected), coding |
| 93 // mode, and rate/distortion. |
| 94 static int candidate_refresh_aq(const CYCLIC_REFRESH *cr, |
| 95 const MB_MODE_INFO *mbmi, |
| 96 BLOCK_SIZE bsize, int use_rd) { |
| 97 if (use_rd) { |
| 98 // If projected rate is below the thresh_rate (well below target, |
| 99 // so undershoot expected), accept it for lower-qp coding. |
| 100 if (cr->projected_rate_sb < cr->thresh_rate_sb) |
| 101 return 1; |
| 102 // Otherwise, reject the block for lower-qp coding if any of the following: |
| 103 // 1) prediction block size is below min_block_size |
| 104 // 2) mode is non-zero mv and projected distortion is above thresh_dist |
| 105 // 3) mode is an intra-mode (we may want to allow some of this under |
| 106 // another thresh_dist) |
| 107 else if (bsize < cr->min_block_size || |
| 108 (mbmi->mv[0].as_int != 0 && |
| 109 cr->projected_dist_sb > cr->thresh_dist_sb) || |
| 110 !is_inter_block(mbmi)) |
| 111 return 0; |
| 112 else |
| 113 return 1; |
| 114 } else { |
| 115 // Rate/distortion not used for update. |
| 116 if (bsize < cr->min_block_size || |
| 117 mbmi->mv[0].as_int != 0 || |
| 118 !is_inter_block(mbmi)) |
| 119 return 0; |
| 120 else |
| 121 return 1; |
| 122 } |
| 123 } |
| 124 |
| 125 // Prior to coding a given prediction block, of size bsize at (mi_row, mi_col), |
| 126 // check if we should reset the segment_id, and update the cyclic_refresh map |
| 127 // and segmentation map. |
| 128 void vp9_cyclic_refresh_update_segment(VP9_COMP *const cpi, |
| 129 MB_MODE_INFO *const mbmi, |
| 130 int mi_row, int mi_col, |
| 131 BLOCK_SIZE bsize, int use_rd) { |
| 132 const VP9_COMMON *const cm = &cpi->common; |
| 133 CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; |
| 134 const int bw = num_8x8_blocks_wide_lookup[bsize]; |
| 135 const int bh = num_8x8_blocks_high_lookup[bsize]; |
| 136 const int xmis = MIN(cm->mi_cols - mi_col, bw); |
| 137 const int ymis = MIN(cm->mi_rows - mi_row, bh); |
| 138 const int block_index = mi_row * cm->mi_cols + mi_col; |
| 139 const int refresh_this_block = candidate_refresh_aq(cr, mbmi, bsize, use_rd); |
| 140 // Default is to not update the refresh map. |
| 141 int new_map_value = cr->map[block_index]; |
| 142 int x = 0; int y = 0; |
| 143 |
| 144 // Check if we should reset the segment_id for this block. |
| 145 if (mbmi->segment_id > 0 && !refresh_this_block) |
| 146 mbmi->segment_id = 0; |
| 147 |
| 148 // Update the cyclic refresh map, to be used for setting segmentation map |
| 149 // for the next frame. If the block will be refreshed this frame, mark it |
| 150 // as clean. The magnitude of the -ve influences how long before we consider |
| 151 // it for refresh again. |
| 152 if (mbmi->segment_id == 1) { |
| 153 new_map_value = -cr->time_for_refresh; |
| 154 } else if (refresh_this_block) { |
| 155 // Else if it is accepted as candidate for refresh, and has not already |
| 156 // been refreshed (marked as 1) then mark it as a candidate for cleanup |
| 157 // for future time (marked as 0), otherwise don't update it. |
| 158 if (cr->map[block_index] == 1) |
| 159 new_map_value = 0; |
| 160 } else { |
| 161 // Leave it marked as block that is not candidate for refresh. |
| 162 new_map_value = 1; |
| 163 } |
| 164 // Update entries in the cyclic refresh map with new_map_value, and |
| 165 // copy mbmi->segment_id into global segmentation map. |
| 166 for (y = 0; y < ymis; y++) |
| 167 for (x = 0; x < xmis; x++) { |
| 168 cr->map[block_index + y * cm->mi_cols + x] = new_map_value; |
| 169 cpi->segmentation_map[block_index + y * cm->mi_cols + x] = |
| 170 mbmi->segment_id; |
| 171 } |
| 172 // Keep track of actual number (in units of 8x8) of blocks in segment 1 used |
| 173 // for encoding this frame. |
| 174 if (mbmi->segment_id) |
| 175 cr->num_seg_blocks += xmis * ymis; |
| 176 } |
| 177 |
| 178 // Setup cyclic background refresh: set delta q and segmentation map. |
| 179 void vp9_cyclic_refresh_setup(VP9_COMP *const cpi) { |
| 180 VP9_COMMON *const cm = &cpi->common; |
| 181 const RATE_CONTROL *const rc = &cpi->rc; |
| 182 CYCLIC_REFRESH *const cr = cpi->cyclic_refresh; |
| 183 struct segmentation *const seg = &cm->seg; |
| 184 unsigned char *const seg_map = cpi->segmentation_map; |
| 185 const int apply_cyclic_refresh = apply_cyclic_refresh_bitrate(cm, rc); |
| 186 // Don't apply refresh on key frame or enhancement layer frames. |
| 187 if (!apply_cyclic_refresh || |
| 188 (cm->frame_type == KEY_FRAME) || |
| 189 (cpi->svc.temporal_layer_id > 0)) { |
| 190 // Set segmentation map to 0 and disable. |
| 191 vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols); |
| 192 vp9_disable_segmentation(&cm->seg); |
| 193 if (cm->frame_type == KEY_FRAME) |
| 194 cr->sb_index = 0; |
| 195 return; |
| 196 } else { |
| 197 int qindex_delta = 0; |
| 198 int i, block_count, bl_index, sb_rows, sb_cols, sbs_in_frame; |
| 199 int xmis, ymis, x, y, qindex2; |
| 200 |
| 201 // Rate target ratio to set q delta. |
| 202 const float rate_ratio_qdelta = 2.0; |
| 203 vp9_clear_system_state(); |
| 204 // Some of these parameters may be set via codec-control function later. |
| 205 cr->max_sbs_perframe = 10; |
| 206 cr->max_qdelta_perc = 50; |
| 207 cr->min_block_size = BLOCK_8X8; |
| 208 cr->time_for_refresh = 1; |
| 209 // Set rate threshold to some fraction of target (and scaled by 256). |
| 210 cr->thresh_rate_sb = (rc->sb64_target_rate * 256) >> 2; |
| 211 // Distortion threshold, quadratic in Q, scale factor to be adjusted. |
| 212 cr->thresh_dist_sb = 8 * (int)(vp9_convert_qindex_to_q(cm->base_qindex) * |
| 213 vp9_convert_qindex_to_q(cm->base_qindex)); |
| 214 if (cpi->sf.use_nonrd_pick_mode) { |
| 215 // May want to be more conservative with thresholds in non-rd mode for now |
| 216 // as rate/distortion are derived from model based on prediction residual. |
| 217 cr->thresh_rate_sb = (rc->sb64_target_rate * 256) >> 3; |
| 218 cr->thresh_dist_sb = 4 * (int)(vp9_convert_qindex_to_q(cm->base_qindex) * |
| 219 vp9_convert_qindex_to_q(cm->base_qindex)); |
| 220 } |
| 221 |
| 222 cr->num_seg_blocks = 0; |
| 223 // Set up segmentation. |
| 224 // Clear down the segment map. |
| 225 vpx_memset(seg_map, 0, cm->mi_rows * cm->mi_cols); |
| 226 vp9_enable_segmentation(&cm->seg); |
| 227 vp9_clearall_segfeatures(seg); |
| 228 // Select delta coding method. |
| 229 seg->abs_delta = SEGMENT_DELTADATA; |
| 230 |
| 231 // Note: setting temporal_update has no effect, as the seg-map coding method |
| 232 // (temporal or spatial) is determined in vp9_choose_segmap_coding_method(), |
| 233 // based on the coding cost of each method. For error_resilient mode on the |
| 234 // last_frame_seg_map is set to 0, so if temporal coding is used, it is |
| 235 // relative to 0 previous map. |
| 236 // seg->temporal_update = 0; |
| 237 |
| 238 // Segment 0 "Q" feature is disabled so it defaults to the baseline Q. |
| 239 vp9_disable_segfeature(seg, 0, SEG_LVL_ALT_Q); |
| 240 // Use segment 1 for in-frame Q adjustment. |
| 241 vp9_enable_segfeature(seg, 1, SEG_LVL_ALT_Q); |
| 242 |
| 243 // Set the q delta for segment 1. |
| 244 qindex_delta = vp9_compute_qdelta_by_rate(rc, cm->frame_type, |
| 245 cm->base_qindex, |
| 246 rate_ratio_qdelta); |
| 247 // TODO(marpan): Incorporate the actual-vs-target rate over/undershoot from |
| 248 // previous encoded frame. |
| 249 if (-qindex_delta > cr->max_qdelta_perc * cm->base_qindex / 100) |
| 250 qindex_delta = -cr->max_qdelta_perc * cm->base_qindex / 100; |
| 251 |
| 252 // Compute rd-mult for segment 1. |
| 253 qindex2 = clamp(cm->base_qindex + cm->y_dc_delta_q + qindex_delta, 0, MAXQ); |
| 254 cr->rdmult = vp9_compute_rd_mult(cpi, qindex2); |
| 255 |
| 256 vp9_set_segdata(seg, 1, SEG_LVL_ALT_Q, qindex_delta); |
| 257 |
| 258 sb_cols = (cm->mi_cols + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE; |
| 259 sb_rows = (cm->mi_rows + MI_BLOCK_SIZE - 1) / MI_BLOCK_SIZE; |
| 260 sbs_in_frame = sb_cols * sb_rows; |
| 261 // Number of target superblocks to get the q delta (segment 1). |
| 262 block_count = cr->max_sbs_perframe * sbs_in_frame / 100; |
| 263 // Set the segmentation map: cycle through the superblocks, starting at |
| 264 // cr->mb_index, and stopping when either block_count blocks have been found |
| 265 // to be refreshed, or we have passed through whole frame. |
| 266 assert(cr->sb_index < sbs_in_frame); |
| 267 i = cr->sb_index; |
| 268 do { |
| 269 int sum_map = 0; |
| 270 // Get the mi_row/mi_col corresponding to superblock index i. |
| 271 int sb_row_index = (i / sb_cols); |
| 272 int sb_col_index = i - sb_row_index * sb_cols; |
| 273 int mi_row = sb_row_index * MI_BLOCK_SIZE; |
| 274 int mi_col = sb_col_index * MI_BLOCK_SIZE; |
| 275 assert(mi_row >= 0 && mi_row < cm->mi_rows); |
| 276 assert(mi_col >= 0 && mi_col < cm->mi_cols); |
| 277 bl_index = mi_row * cm->mi_cols + mi_col; |
| 278 // Loop through all 8x8 blocks in superblock and update map. |
| 279 xmis = MIN(cm->mi_cols - mi_col, |
| 280 num_8x8_blocks_wide_lookup[BLOCK_64X64]); |
| 281 ymis = MIN(cm->mi_rows - mi_row, |
| 282 num_8x8_blocks_high_lookup[BLOCK_64X64]); |
| 283 for (y = 0; y < ymis; y++) { |
| 284 for (x = 0; x < xmis; x++) { |
| 285 const int bl_index2 = bl_index + y * cm->mi_cols + x; |
| 286 // If the block is as a candidate for clean up then mark it |
| 287 // for possible boost/refresh (segment 1). The segment id may get |
| 288 // reset to 0 later if block gets coded anything other than ZEROMV. |
| 289 if (cr->map[bl_index2] == 0) { |
| 290 seg_map[bl_index2] = 1; |
| 291 sum_map++; |
| 292 } else if (cr->map[bl_index2] < 0) { |
| 293 cr->map[bl_index2]++; |
| 294 } |
| 295 } |
| 296 } |
| 297 // Enforce constant segment over superblock. |
| 298 // If segment is partial over superblock, reset to either all 1 or 0. |
| 299 if (sum_map > 0 && sum_map < xmis * ymis) { |
| 300 const int new_value = (sum_map >= xmis * ymis / 2); |
| 301 for (y = 0; y < ymis; y++) |
| 302 for (x = 0; x < xmis; x++) |
| 303 seg_map[bl_index + y * cm->mi_cols + x] = new_value; |
| 304 } |
| 305 i++; |
| 306 if (i == sbs_in_frame) { |
| 307 i = 0; |
| 308 } |
| 309 if (sum_map >= xmis * ymis /2) |
| 310 block_count--; |
| 311 } while (block_count && i != cr->sb_index); |
| 312 cr->sb_index = i; |
| 313 } |
| 314 } |
| 315 |
| 316 void vp9_cyclic_refresh_set_rate_and_dist_sb(CYCLIC_REFRESH *cr, |
| 317 int64_t rate_sb, int64_t dist_sb) { |
| 318 cr->projected_rate_sb = rate_sb; |
| 319 cr->projected_dist_sb = dist_sb; |
| 320 } |
| 321 |
| 322 int vp9_cyclic_refresh_get_rdmult(const CYCLIC_REFRESH *cr) { |
| 323 return cr->rdmult; |
| 324 } |
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