1 // Copyright 2011 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Selecting filter level 11 // 12 // Author: somnath (at) google.com (Somnath Banerjee) 13 14 #include <assert.h> 15 #include "./vp8i_enc.h" 16 #include "../dsp/dsp.h" 17 18 // This table gives, for a given sharpness, the filtering strength to be 19 // used (at least) in order to filter a given edge step delta. 20 // This is constructed by brute force inspection: for all delta, we iterate 21 // over all possible filtering strength / thresh until needs_filter() returns 22 // true. 23 #define MAX_DELTA_SIZE 64 24 static const uint8_t kLevelsFromDelta[8][MAX_DELTA_SIZE] = { 25 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 26 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 27 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 28 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 }, 29 { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 30 20, 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 31 44, 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 32 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 33 { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 19, 34 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 35 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 63, 63, 63, 36 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 37 { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 15, 16, 18, 19, 38 21, 22, 24, 25, 27, 28, 30, 31, 33, 34, 36, 37, 39, 40, 42, 43, 39 45, 46, 48, 49, 51, 52, 54, 55, 57, 58, 60, 61, 63, 63, 63, 63, 40 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 41 { 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20, 42 21, 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 43 45, 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 63, 44 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 45 { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 17, 19, 20, 46 22, 23, 25, 26, 28, 29, 31, 32, 34, 35, 37, 38, 40, 41, 43, 44, 47 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 63, 63, 63, 63, 48 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 49 { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 18, 19, 21, 50 22, 24, 25, 27, 28, 30, 31, 33, 34, 36, 37, 39, 40, 42, 43, 45, 51 46, 48, 49, 51, 52, 54, 55, 57, 58, 60, 61, 63, 63, 63, 63, 63, 52 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 }, 53 { 0, 1, 2, 4, 5, 7, 8, 9, 11, 12, 14, 15, 17, 18, 20, 21, 54 23, 24, 26, 27, 29, 30, 32, 33, 35, 36, 38, 39, 41, 42, 44, 45, 55 47, 48, 50, 51, 53, 54, 56, 57, 59, 60, 62, 63, 63, 63, 63, 63, 56 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63, 63 } 57 }; 58 59 int VP8FilterStrengthFromDelta(int sharpness, int delta) { 60 const int pos = (delta < MAX_DELTA_SIZE) ? delta : MAX_DELTA_SIZE - 1; 61 assert(sharpness >= 0 && sharpness <= 7); 62 return kLevelsFromDelta[sharpness][pos]; 63 } 64 65 //------------------------------------------------------------------------------ 66 // Paragraph 15.4: compute the inner-edge filtering strength 67 68 static int GetILevel(int sharpness, int level) { 69 if (sharpness > 0) { 70 if (sharpness > 4) { 71 level >>= 2; 72 } else { 73 level >>= 1; 74 } 75 if (level > 9 - sharpness) { 76 level = 9 - sharpness; 77 } 78 } 79 if (level < 1) level = 1; 80 return level; 81 } 82 83 static void DoFilter(const VP8EncIterator* const it, int level) { 84 const VP8Encoder* const enc = it->enc_; 85 const int ilevel = GetILevel(enc->config_->filter_sharpness, level); 86 const int limit = 2 * level + ilevel; 87 88 uint8_t* const y_dst = it->yuv_out2_ + Y_OFF_ENC; 89 uint8_t* const u_dst = it->yuv_out2_ + U_OFF_ENC; 90 uint8_t* const v_dst = it->yuv_out2_ + V_OFF_ENC; 91 92 // copy current block to yuv_out2_ 93 memcpy(y_dst, it->yuv_out_, YUV_SIZE_ENC * sizeof(uint8_t)); 94 95 if (enc->filter_hdr_.simple_ == 1) { // simple 96 VP8SimpleHFilter16i(y_dst, BPS, limit); 97 VP8SimpleVFilter16i(y_dst, BPS, limit); 98 } else { // complex 99 const int hev_thresh = (level >= 40) ? 2 : (level >= 15) ? 1 : 0; 100 VP8HFilter16i(y_dst, BPS, limit, ilevel, hev_thresh); 101 VP8HFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh); 102 VP8VFilter16i(y_dst, BPS, limit, ilevel, hev_thresh); 103 VP8VFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh); 104 } 105 } 106 107 //------------------------------------------------------------------------------ 108 // SSIM metric for one macroblock 109 110 static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) { 111 int x, y; 112 double sum = 0.; 113 114 // compute SSIM in a 10 x 10 window 115 for (y = VP8_SSIM_KERNEL; y < 16 - VP8_SSIM_KERNEL; y++) { 116 for (x = VP8_SSIM_KERNEL; x < 16 - VP8_SSIM_KERNEL; x++) { 117 sum += VP8SSIMGetClipped(yuv1 + Y_OFF_ENC, BPS, yuv2 + Y_OFF_ENC, BPS, 118 x, y, 16, 16); 119 } 120 } 121 for (x = 1; x < 7; x++) { 122 for (y = 1; y < 7; y++) { 123 sum += VP8SSIMGetClipped(yuv1 + U_OFF_ENC, BPS, yuv2 + U_OFF_ENC, BPS, 124 x, y, 8, 8); 125 sum += VP8SSIMGetClipped(yuv1 + V_OFF_ENC, BPS, yuv2 + V_OFF_ENC, BPS, 126 x, y, 8, 8); 127 } 128 } 129 return sum; 130 } 131 132 //------------------------------------------------------------------------------ 133 // Exposed APIs: Encoder should call the following 3 functions to adjust 134 // loop filter strength 135 136 void VP8InitFilter(VP8EncIterator* const it) { 137 if (it->lf_stats_ != NULL) { 138 int s, i; 139 for (s = 0; s < NUM_MB_SEGMENTS; s++) { 140 for (i = 0; i < MAX_LF_LEVELS; i++) { 141 (*it->lf_stats_)[s][i] = 0; 142 } 143 } 144 VP8SSIMDspInit(); 145 } 146 } 147 148 void VP8StoreFilterStats(VP8EncIterator* const it) { 149 int d; 150 VP8Encoder* const enc = it->enc_; 151 const int s = it->mb_->segment_; 152 const int level0 = enc->dqm_[s].fstrength_; 153 154 // explore +/-quant range of values around level0 155 const int delta_min = -enc->dqm_[s].quant_; 156 const int delta_max = enc->dqm_[s].quant_; 157 const int step_size = (delta_max - delta_min >= 4) ? 4 : 1; 158 159 if (it->lf_stats_ == NULL) return; 160 161 // NOTE: Currently we are applying filter only across the sublock edges 162 // There are two reasons for that. 163 // 1. Applying filter on macro block edges will change the pixels in 164 // the left and top macro blocks. That will be hard to restore 165 // 2. Macro Blocks on the bottom and right are not yet compressed. So we 166 // cannot apply filter on the right and bottom macro block edges. 167 if (it->mb_->type_ == 1 && it->mb_->skip_) return; 168 169 // Always try filter level zero 170 (*it->lf_stats_)[s][0] += GetMBSSIM(it->yuv_in_, it->yuv_out_); 171 172 for (d = delta_min; d <= delta_max; d += step_size) { 173 const int level = level0 + d; 174 if (level <= 0 || level >= MAX_LF_LEVELS) { 175 continue; 176 } 177 DoFilter(it, level); 178 (*it->lf_stats_)[s][level] += GetMBSSIM(it->yuv_in_, it->yuv_out2_); 179 } 180 } 181 182 void VP8AdjustFilterStrength(VP8EncIterator* const it) { 183 VP8Encoder* const enc = it->enc_; 184 if (it->lf_stats_ != NULL) { 185 int s; 186 for (s = 0; s < NUM_MB_SEGMENTS; s++) { 187 int i, best_level = 0; 188 // Improvement over filter level 0 should be at least 1e-5 (relatively) 189 double best_v = 1.00001 * (*it->lf_stats_)[s][0]; 190 for (i = 1; i < MAX_LF_LEVELS; i++) { 191 const double v = (*it->lf_stats_)[s][i]; 192 if (v > best_v) { 193 best_v = v; 194 best_level = i; 195 } 196 } 197 enc->dqm_[s].fstrength_ = best_level; 198 } 199 } else if (enc->config_->filter_strength > 0) { 200 int max_level = 0; 201 int s; 202 for (s = 0; s < NUM_MB_SEGMENTS; s++) { 203 VP8SegmentInfo* const dqm = &enc->dqm_[s]; 204 // this '>> 3' accounts for some inverse WHT scaling 205 const int delta = (dqm->max_edge_ * dqm->y2_.q_[1]) >> 3; 206 const int level = 207 VP8FilterStrengthFromDelta(enc->filter_hdr_.sharpness_, delta); 208 if (level > dqm->fstrength_) { 209 dqm->fstrength_ = level; 210 } 211 if (max_level < dqm->fstrength_) { 212 max_level = dqm->fstrength_; 213 } 214 } 215 enc->filter_hdr_.level_ = max_level; 216 } 217 } 218 219 // ----------------------------------------------------------------------------- 220