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@google.com (Somnath Banerjee)
13
14#include <assert.h>
15#include "src/enc/vp8i_enc.h"
16#include "src/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
24static 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
59int 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#if !defined(WEBP_REDUCE_SIZE)
69
70static int GetILevel(int sharpness, int level) {
71 if (sharpness > 0) {
72 if (sharpness > 4) {
73 level >>= 2;
74 } else {
75 level >>= 1;
76 }
77 if (level > 9 - sharpness) {
78 level = 9 - sharpness;
79 }
80 }
81 if (level < 1) level = 1;
82 return level;
83}
84
85static void DoFilter(const VP8EncIterator* const it, int level) {
86 const VP8Encoder* const enc = it->enc_;
87 const int ilevel = GetILevel(enc->config_->filter_sharpness, level);
88 const int limit = 2 * level + ilevel;
89
90 uint8_t* const y_dst = it->yuv_out2_ + Y_OFF_ENC;
91 uint8_t* const u_dst = it->yuv_out2_ + U_OFF_ENC;
92 uint8_t* const v_dst = it->yuv_out2_ + V_OFF_ENC;
93
94 // copy current block to yuv_out2_
95 memcpy(y_dst, it->yuv_out_, YUV_SIZE_ENC * sizeof(uint8_t));
96
97 if (enc->filter_hdr_.simple_ == 1) { // simple
98 VP8SimpleHFilter16i(y_dst, BPS, limit);
99 VP8SimpleVFilter16i(y_dst, BPS, limit);
100 } else { // complex
101 const int hev_thresh = (level >= 40) ? 2 : (level >= 15) ? 1 : 0;
102 VP8HFilter16i(y_dst, BPS, limit, ilevel, hev_thresh);
103 VP8HFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh);
104 VP8VFilter16i(y_dst, BPS, limit, ilevel, hev_thresh);
105 VP8VFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh);
106 }
107}
108
109//------------------------------------------------------------------------------
110// SSIM metric for one macroblock
111
112static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) {
113 int x, y;
114 double sum = 0.;
115
116 // compute SSIM in a 10 x 10 window
117 for (y = VP8_SSIM_KERNEL; y < 16 - VP8_SSIM_KERNEL; y++) {
118 for (x = VP8_SSIM_KERNEL; x < 16 - VP8_SSIM_KERNEL; x++) {
119 sum += VP8SSIMGetClipped(yuv1 + Y_OFF_ENC, BPS, yuv2 + Y_OFF_ENC, BPS,
120 x, y, 16, 16);
121 }
122 }
123 for (x = 1; x < 7; x++) {
124 for (y = 1; y < 7; y++) {
125 sum += VP8SSIMGetClipped(yuv1 + U_OFF_ENC, BPS, yuv2 + U_OFF_ENC, BPS,
126 x, y, 8, 8);
127 sum += VP8SSIMGetClipped(yuv1 + V_OFF_ENC, BPS, yuv2 + V_OFF_ENC, BPS,
128 x, y, 8, 8);
129 }
130 }
131 return sum;
132}
133
134#endif // !defined(WEBP_REDUCE_SIZE)
135
136//------------------------------------------------------------------------------
137// Exposed APIs: Encoder should call the following 3 functions to adjust
138// loop filter strength
139
140void VP8InitFilter(VP8EncIterator* const it) {
141#if !defined(WEBP_REDUCE_SIZE)
142 if (it->lf_stats_ != NULL) {
143 int s, i;
144 for (s = 0; s < NUM_MB_SEGMENTS; s++) {
145 for (i = 0; i < MAX_LF_LEVELS; i++) {
146 (*it->lf_stats_)[s][i] = 0;
147 }
148 }
149 VP8SSIMDspInit();
150 }
151#else
152 (void)it;
153#endif
154}
155
156void VP8StoreFilterStats(VP8EncIterator* const it) {
157#if !defined(WEBP_REDUCE_SIZE)
158 int d;
159 VP8Encoder* const enc = it->enc_;
160 const int s = it->mb_->segment_;
161 const int level0 = enc->dqm_[s].fstrength_;
162
163 // explore +/-quant range of values around level0
164 const int delta_min = -enc->dqm_[s].quant_;
165 const int delta_max = enc->dqm_[s].quant_;
166 const int step_size = (delta_max - delta_min >= 4) ? 4 : 1;
167
168 if (it->lf_stats_ == NULL) return;
169
170 // NOTE: Currently we are applying filter only across the sublock edges
171 // There are two reasons for that.
172 // 1. Applying filter on macro block edges will change the pixels in
173 // the left and top macro blocks. That will be hard to restore
174 // 2. Macro Blocks on the bottom and right are not yet compressed. So we
175 // cannot apply filter on the right and bottom macro block edges.
176 if (it->mb_->type_ == 1 && it->mb_->skip_) return;
177
178 // Always try filter level zero
179 (*it->lf_stats_)[s][0] += GetMBSSIM(it->yuv_in_, it->yuv_out_);
180
181 for (d = delta_min; d <= delta_max; d += step_size) {
182 const int level = level0 + d;
183 if (level <= 0 || level >= MAX_LF_LEVELS) {
184 continue;
185 }
186 DoFilter(it, level);
187 (*it->lf_stats_)[s][level] += GetMBSSIM(it->yuv_in_, it->yuv_out2_);
188 }
189#else // defined(WEBP_REDUCE_SIZE)
190 (void)it;
191#endif // !defined(WEBP_REDUCE_SIZE)
192}
193
194void VP8AdjustFilterStrength(VP8EncIterator* const it) {
195 VP8Encoder* const enc = it->enc_;
196#if !defined(WEBP_REDUCE_SIZE)
197 if (it->lf_stats_ != NULL) {
198 int s;
199 for (s = 0; s < NUM_MB_SEGMENTS; s++) {
200 int i, best_level = 0;
201 // Improvement over filter level 0 should be at least 1e-5 (relatively)
202 double best_v = 1.00001 * (*it->lf_stats_)[s][0];
203 for (i = 1; i < MAX_LF_LEVELS; i++) {
204 const double v = (*it->lf_stats_)[s][i];
205 if (v > best_v) {
206 best_v = v;
207 best_level = i;
208 }
209 }
210 enc->dqm_[s].fstrength_ = best_level;
211 }
212 return;
213 }
214#endif // !defined(WEBP_REDUCE_SIZE)
215 if (enc->config_->filter_strength > 0) {
216 int max_level = 0;
217 int s;
218 for (s = 0; s < NUM_MB_SEGMENTS; s++) {
219 VP8SegmentInfo* const dqm = &enc->dqm_[s];
220 // this '>> 3' accounts for some inverse WHT scaling
221 const int delta = (dqm->max_edge_ * dqm->y2_.q_[1]) >> 3;
222 const int level =
223 VP8FilterStrengthFromDelta(enc->filter_hdr_.sharpness_, delta);
224 if (level > dqm->fstrength_) {
225 dqm->fstrength_ = level;
226 }
227 if (max_level < dqm->fstrength_) {
228 max_level = dqm->fstrength_;
229 }
230 }
231 enc->filter_hdr_.level_ = max_level;
232 }
233}
234
235// -----------------------------------------------------------------------------
236