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Fix PowerSaveBlocker crash in Android WebView
[chromium-blink-merge.git] / third_party / libwebp / enc / filter.c
blobaae2723d1659166cf5f59f4e962e13b5ccea2398
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 "./vp8enci.h"
15
16 #if defined(__cplusplus) || defined(c_plusplus)
17 extern "C" {
18 #endif
19
20 // NOTE: clip1, tables and InitTables are repeated entries of dsp.c
21 static uint8_t abs0[255 + 255 + 1]; // abs(i)
22 static uint8_t abs1[255 + 255 + 1]; // abs(i)>>1
23 static int8_t sclip1[1020 + 1020 + 1]; // clips [-1020, 1020] to [-128, 127]
24 static int8_t sclip2[112 + 112 + 1]; // clips [-112, 112] to [-16, 15]
25 static uint8_t clip1[255 + 510 + 1]; // clips [-255,510] to [0,255]
26
27 static int tables_ok = 0;
28
29 static void InitTables(void) {
30 if (!tables_ok) {
31 int i;
32 for (i = -255; i <= 255; ++i) {
33 abs0[255 + i] = (i < 0) ? -i : i;
34 abs1[255 + i] = abs0[255 + i] >> 1;
35 }
36 for (i = -1020; i <= 1020; ++i) {
37 sclip1[1020 + i] = (i < -128) ? -128 : (i > 127) ? 127 : i;
38 }
39 for (i = -112; i <= 112; ++i) {
40 sclip2[112 + i] = (i < -16) ? -16 : (i > 15) ? 15 : i;
41 }
42 for (i = -255; i <= 255 + 255; ++i) {
43 clip1[255 + i] = (i < 0) ? 0 : (i > 255) ? 255 : i;
44 }
45 tables_ok = 1;
46 }
47 }
48
49 //------------------------------------------------------------------------------
50 // Edge filtering functions
51
52 // 4 pixels in, 2 pixels out
53 static WEBP_INLINE void do_filter2(uint8_t* p, int step) {
54 const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
55 const int a = 3 * (q0 - p0) + sclip1[1020 + p1 - q1];
56 const int a1 = sclip2[112 + ((a + 4) >> 3)];
57 const int a2 = sclip2[112 + ((a + 3) >> 3)];
58 p[-step] = clip1[255 + p0 + a2];
59 p[ 0] = clip1[255 + q0 - a1];
60 }
61
62 // 4 pixels in, 4 pixels out
63 static WEBP_INLINE void do_filter4(uint8_t* p, int step) {
64 const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
65 const int a = 3 * (q0 - p0);
66 const int a1 = sclip2[112 + ((a + 4) >> 3)];
67 const int a2 = sclip2[112 + ((a + 3) >> 3)];
68 const int a3 = (a1 + 1) >> 1;
69 p[-2*step] = clip1[255 + p1 + a3];
70 p[- step] = clip1[255 + p0 + a2];
71 p[ 0] = clip1[255 + q0 - a1];
72 p[ step] = clip1[255 + q1 - a3];
73 }
74
75 // high edge-variance
76 static WEBP_INLINE int hev(const uint8_t* p, int step, int thresh) {
77 const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
78 return (abs0[255 + p1 - p0] > thresh) || (abs0[255 + q1 - q0] > thresh);
79 }
80
81 static WEBP_INLINE int needs_filter(const uint8_t* p, int step, int thresh) {
82 const int p1 = p[-2*step], p0 = p[-step], q0 = p[0], q1 = p[step];
83 return (2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) <= thresh;
84 }
85
86 static WEBP_INLINE int needs_filter2(const uint8_t* p,
87 int step, int t, int it) {
88 const int p3 = p[-4*step], p2 = p[-3*step], p1 = p[-2*step], p0 = p[-step];
89 const int q0 = p[0], q1 = p[step], q2 = p[2*step], q3 = p[3*step];
90 if ((2 * abs0[255 + p0 - q0] + abs1[255 + p1 - q1]) > t)
91 return 0;
92 return abs0[255 + p3 - p2] <= it && abs0[255 + p2 - p1] <= it &&
93 abs0[255 + p1 - p0] <= it && abs0[255 + q3 - q2] <= it &&
94 abs0[255 + q2 - q1] <= it && abs0[255 + q1 - q0] <= it;
95 }
96
97 //------------------------------------------------------------------------------
98 // Simple In-loop filtering (Paragraph 15.2)
99
100 static void SimpleVFilter16(uint8_t* p, int stride, int thresh) {
101 int i;
102 for (i = 0; i < 16; ++i) {
103 if (needs_filter(p + i, stride, thresh)) {
104 do_filter2(p + i, stride);
105 }
106 }
107 }
108
109 static void SimpleHFilter16(uint8_t* p, int stride, int thresh) {
110 int i;
111 for (i = 0; i < 16; ++i) {
112 if (needs_filter(p + i * stride, 1, thresh)) {
113 do_filter2(p + i * stride, 1);
114 }
115 }
116 }
117
118 static void SimpleVFilter16i(uint8_t* p, int stride, int thresh) {
119 int k;
120 for (k = 3; k > 0; --k) {
121 p += 4 * stride;
122 SimpleVFilter16(p, stride, thresh);
123 }
124 }
125
126 static void SimpleHFilter16i(uint8_t* p, int stride, int thresh) {
127 int k;
128 for (k = 3; k > 0; --k) {
129 p += 4;
130 SimpleHFilter16(p, stride, thresh);
131 }
132 }
133
134 //------------------------------------------------------------------------------
135 // Complex In-loop filtering (Paragraph 15.3)
136
137 static WEBP_INLINE void FilterLoop24(uint8_t* p,
138 int hstride, int vstride, int size,
139 int thresh, int ithresh, int hev_thresh) {
140 while (size-- > 0) {
141 if (needs_filter2(p, hstride, thresh, ithresh)) {
142 if (hev(p, hstride, hev_thresh)) {
143 do_filter2(p, hstride);
144 } else {
145 do_filter4(p, hstride);
146 }
147 }
148 p += vstride;
149 }
150 }
151
152 // on three inner edges
153 static void VFilter16i(uint8_t* p, int stride,
154 int thresh, int ithresh, int hev_thresh) {
155 int k;
156 for (k = 3; k > 0; --k) {
157 p += 4 * stride;
158 FilterLoop24(p, stride, 1, 16, thresh, ithresh, hev_thresh);
159 }
160 }
161
162 static void HFilter16i(uint8_t* p, int stride,
163 int thresh, int ithresh, int hev_thresh) {
164 int k;
165 for (k = 3; k > 0; --k) {
166 p += 4;
167 FilterLoop24(p, 1, stride, 16, thresh, ithresh, hev_thresh);
168 }
169 }
170
171 static void VFilter8i(uint8_t* u, uint8_t* v, int stride,
172 int thresh, int ithresh, int hev_thresh) {
173 FilterLoop24(u + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
174 FilterLoop24(v + 4 * stride, stride, 1, 8, thresh, ithresh, hev_thresh);
175 }
176
177 static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
178 int thresh, int ithresh, int hev_thresh) {
179 FilterLoop24(u + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
180 FilterLoop24(v + 4, 1, stride, 8, thresh, ithresh, hev_thresh);
181 }
182
183 //------------------------------------------------------------------------------
184
185 void (*VP8EncVFilter16i)(uint8_t*, int, int, int, int) = VFilter16i;
186 void (*VP8EncHFilter16i)(uint8_t*, int, int, int, int) = HFilter16i;
187 void (*VP8EncVFilter8i)(uint8_t*, uint8_t*, int, int, int, int) = VFilter8i;
188 void (*VP8EncHFilter8i)(uint8_t*, uint8_t*, int, int, int, int) = HFilter8i;
189
190 void (*VP8EncSimpleVFilter16i)(uint8_t*, int, int) = SimpleVFilter16i;
191 void (*VP8EncSimpleHFilter16i)(uint8_t*, int, int) = SimpleHFilter16i;
192
193 //------------------------------------------------------------------------------
194 // Paragraph 15.4: compute the inner-edge filtering strength
195
196 static int GetILevel(int sharpness, int level) {
197 if (sharpness > 0) {
198 if (sharpness > 4) {
199 level >>= 2;
200 } else {
201 level >>= 1;
202 }
203 if (level > 9 - sharpness) {
204 level = 9 - sharpness;
205 }
206 }
207 if (level < 1) level = 1;
208 return level;
209 }
210
211 static void DoFilter(const VP8EncIterator* const it, int level) {
212 const VP8Encoder* const enc = it->enc_;
213 const int ilevel = GetILevel(enc->config_->filter_sharpness, level);
214 const int limit = 2 * level + ilevel;
215
216 uint8_t* const y_dst = it->yuv_out2_ + Y_OFF;
217 uint8_t* const u_dst = it->yuv_out2_ + U_OFF;
218 uint8_t* const v_dst = it->yuv_out2_ + V_OFF;
219
220 // copy current block to yuv_out2_
221 memcpy(y_dst, it->yuv_out_, YUV_SIZE * sizeof(uint8_t));
222
223 if (enc->filter_hdr_.simple_ == 1) { // simple
224 VP8EncSimpleHFilter16i(y_dst, BPS, limit);
225 VP8EncSimpleVFilter16i(y_dst, BPS, limit);
226 } else { // complex
227 const int hev_thresh = (level >= 40) ? 2 : (level >= 15) ? 1 : 0;
228 VP8EncHFilter16i(y_dst, BPS, limit, ilevel, hev_thresh);
229 VP8EncHFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh);
230 VP8EncVFilter16i(y_dst, BPS, limit, ilevel, hev_thresh);
231 VP8EncVFilter8i(u_dst, v_dst, BPS, limit, ilevel, hev_thresh);
232 }
233 }
234
235 //------------------------------------------------------------------------------
236 // SSIM metric
237
238 enum { KERNEL = 3 };
239 static const double kMinValue = 1.e-10; // minimal threshold
240
241 void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst) {
242 dst->w += src->w;
243 dst->xm += src->xm;
244 dst->ym += src->ym;
245 dst->xxm += src->xxm;
246 dst->xym += src->xym;
247 dst->yym += src->yym;
248 }
249
250 static void VP8SSIMAccumulate(const uint8_t* src1, int stride1,
251 const uint8_t* src2, int stride2,
252 int xo, int yo, int W, int H,
253 DistoStats* const stats) {
254 const int ymin = (yo - KERNEL < 0) ? 0 : yo - KERNEL;
255 const int ymax = (yo + KERNEL > H - 1) ? H - 1 : yo + KERNEL;
256 const int xmin = (xo - KERNEL < 0) ? 0 : xo - KERNEL;
257 const int xmax = (xo + KERNEL > W - 1) ? W - 1 : xo + KERNEL;
258 int x, y;
259 src1 += ymin * stride1;
260 src2 += ymin * stride2;
261 for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
262 for (x = xmin; x <= xmax; ++x) {
263 const int s1 = src1[x];
264 const int s2 = src2[x];
265 stats->w += 1;
266 stats->xm += s1;
267 stats->ym += s2;
268 stats->xxm += s1 * s1;
269 stats->xym += s1 * s2;
270 stats->yym += s2 * s2;
271 }
272 }
273 }
274
275 double VP8SSIMGet(const DistoStats* const stats) {
276 const double xmxm = stats->xm * stats->xm;
277 const double ymym = stats->ym * stats->ym;
278 const double xmym = stats->xm * stats->ym;
279 const double w2 = stats->w * stats->w;
280 double sxx = stats->xxm * stats->w - xmxm;
281 double syy = stats->yym * stats->w - ymym;
282 double sxy = stats->xym * stats->w - xmym;
283 double C1, C2;
284 double fnum;
285 double fden;
286 // small errors are possible, due to rounding. Clamp to zero.
287 if (sxx < 0.) sxx = 0.;
288 if (syy < 0.) syy = 0.;
289 C1 = 6.5025 * w2;
290 C2 = 58.5225 * w2;
291 fnum = (2 * xmym + C1) * (2 * sxy + C2);
292 fden = (xmxm + ymym + C1) * (sxx + syy + C2);
293 return (fden != 0.) ? fnum / fden : kMinValue;
294 }
295
296 double VP8SSIMGetSquaredError(const DistoStats* const s) {
297 if (s->w > 0.) {
298 const double iw2 = 1. / (s->w * s->w);
299 const double sxx = s->xxm * s->w - s->xm * s->xm;
300 const double syy = s->yym * s->w - s->ym * s->ym;
301 const double sxy = s->xym * s->w - s->xm * s->ym;
302 const double SSE = iw2 * (sxx + syy - 2. * sxy);
303 if (SSE > kMinValue) return SSE;
304 }
305 return kMinValue;
306 }
307
308 void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
309 const uint8_t* src2, int stride2,
310 int W, int H, DistoStats* const stats) {
311 int x, y;
312 for (y = 0; y < H; ++y) {
313 for (x = 0; x < W; ++x) {
314 VP8SSIMAccumulate(src1, stride1, src2, stride2, x, y, W, H, stats);
315 }
316 }
317 }
318
319 static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) {
320 int x, y;
321 DistoStats s = { .0, .0, .0, .0, .0, .0 };
322
323 // compute SSIM in a 10 x 10 window
324 for (x = 3; x < 13; x++) {
325 for (y = 3; y < 13; y++) {
326 VP8SSIMAccumulate(yuv1 + Y_OFF, BPS, yuv2 + Y_OFF, BPS, x, y, 16, 16, &s);
327 }
328 }
329 for (x = 1; x < 7; x++) {
330 for (y = 1; y < 7; y++) {
331 VP8SSIMAccumulate(yuv1 + U_OFF, BPS, yuv2 + U_OFF, BPS, x, y, 8, 8, &s);
332 VP8SSIMAccumulate(yuv1 + V_OFF, BPS, yuv2 + V_OFF, BPS, x, y, 8, 8, &s);
333 }
334 }
335 return VP8SSIMGet(&s);
336 }
337
338 //------------------------------------------------------------------------------
339 // Exposed APIs: Encoder should call the following 3 functions to adjust
340 // loop filter strength
341
342 void VP8InitFilter(VP8EncIterator* const it) {
343 int s, i;
344 if (!it->lf_stats_) return;
345
346 InitTables();
347 for (s = 0; s < NUM_MB_SEGMENTS; s++) {
348 for (i = 0; i < MAX_LF_LEVELS; i++) {
349 (*it->lf_stats_)[s][i] = 0;
350 }
351 }
352 }
353
354 void VP8StoreFilterStats(VP8EncIterator* const it) {
355 int d;
356 const int s = it->mb_->segment_;
357 const int level0 = it->enc_->dqm_[s].fstrength_; // TODO: ref_lf_delta[]
358
359 // explore +/-quant range of values around level0
360 const int delta_min = -it->enc_->dqm_[s].quant_;
361 const int delta_max = it->enc_->dqm_[s].quant_;
362 const int step_size = (delta_max - delta_min >= 4) ? 4 : 1;
363
364 if (!it->lf_stats_) return;
365
366 // NOTE: Currently we are applying filter only across the sublock edges
367 // There are two reasons for that.
368 // 1. Applying filter on macro block edges will change the pixels in
369 // the left and top macro blocks. That will be hard to restore
370 // 2. Macro Blocks on the bottom and right are not yet compressed. So we
371 // cannot apply filter on the right and bottom macro block edges.
372 if (it->mb_->type_ == 1 && it->mb_->skip_) return;
373
374 // Always try filter level zero
375 (*it->lf_stats_)[s][0] += GetMBSSIM(it->yuv_in_, it->yuv_out_);
376
377 for (d = delta_min; d <= delta_max; d += step_size) {
378 const int level = level0 + d;
379 if (level <= 0 || level >= MAX_LF_LEVELS) {
380 continue;
381 }
382 DoFilter(it, level);
383 (*it->lf_stats_)[s][level] += GetMBSSIM(it->yuv_in_, it->yuv_out2_);
384 }
385 }
386
387 void VP8AdjustFilterStrength(VP8EncIterator* const it) {
388 int s;
389 VP8Encoder* const enc = it->enc_;
390
391 if (!it->lf_stats_) {
392 return;
393 }
394 for (s = 0; s < NUM_MB_SEGMENTS; s++) {
395 int i, best_level = 0;
396 // Improvement over filter level 0 should be at least 1e-5 (relatively)
397 double best_v = 1.00001 * (*it->lf_stats_)[s][0];
398 for (i = 1; i < MAX_LF_LEVELS; i++) {
399 const double v = (*it->lf_stats_)[s][i];
400 if (v > best_v) {
401 best_v = v;
402 best_level = i;
403 }
404 }
405 enc->dqm_[s].fstrength_ = best_level;
406 }
407 }
408
409 #if defined(__cplusplus) || defined(c_plusplus)
410 } // extern "C"
411 #endif