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1 /*
2  *  Copyright (c) 2010 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  *  This code was originally written by: Nathan E. Egge, at the Daala
11  *  project.
12  */
13 #include <assert.h>
14 #include <math.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include "./vpx_config.h"
18 #include "./vpx_dsp_rtcd.h"
19 #include "vpx_dsp/ssim.h"
20 #include "vpx_ports/system_state.h"
21 
22 typedef struct fs_level fs_level;
23 typedef struct fs_ctx fs_ctx;
24 
25 #define SSIM_C1 (255 * 255 * 0.01 * 0.01)
26 #define SSIM_C2 (255 * 255 * 0.03 * 0.03)
27 #if CONFIG_VP9_HIGHBITDEPTH
28 #define SSIM_C1_10 (1023 * 1023 * 0.01 * 0.01)
29 #define SSIM_C1_12 (4095 * 4095 * 0.01 * 0.01)
30 #define SSIM_C2_10 (1023 * 1023 * 0.03 * 0.03)
31 #define SSIM_C2_12 (4095 * 4095 * 0.03 * 0.03)
32 #endif
33 #define FS_MINI(_a, _b) ((_a) < (_b) ? (_a) : (_b))
34 #define FS_MAXI(_a, _b) ((_a) > (_b) ? (_a) : (_b))
35 
36 struct fs_level {
37   uint32_t *im1;
38   uint32_t *im2;
39   double *ssim;
40   int w;
41   int h;
42 };
43 
44 struct fs_ctx {
45   fs_level *level;
46   int nlevels;
47   unsigned *col_buf;
48 };
49 
fs_ctx_init(fs_ctx * _ctx,int _w,int _h,int _nlevels)50 static void fs_ctx_init(fs_ctx *_ctx, int _w, int _h, int _nlevels) {
51   unsigned char *data;
52   size_t data_size;
53   int lw;
54   int lh;
55   int l;
56   lw = (_w + 1) >> 1;
57   lh = (_h + 1) >> 1;
58   data_size =
59       _nlevels * sizeof(fs_level) + 2 * (lw + 8) * 8 * sizeof(*_ctx->col_buf);
60   for (l = 0; l < _nlevels; l++) {
61     size_t im_size;
62     size_t level_size;
63     im_size = lw * (size_t)lh;
64     level_size = 2 * im_size * sizeof(*_ctx->level[l].im1);
65     level_size += sizeof(*_ctx->level[l].ssim) - 1;
66     level_size /= sizeof(*_ctx->level[l].ssim);
67     level_size += im_size;
68     level_size *= sizeof(*_ctx->level[l].ssim);
69     data_size += level_size;
70     lw = (lw + 1) >> 1;
71     lh = (lh + 1) >> 1;
72   }
73   data = (unsigned char *)malloc(data_size);
74   _ctx->level = (fs_level *)data;
75   _ctx->nlevels = _nlevels;
76   data += _nlevels * sizeof(*_ctx->level);
77   lw = (_w + 1) >> 1;
78   lh = (_h + 1) >> 1;
79   for (l = 0; l < _nlevels; l++) {
80     size_t im_size;
81     size_t level_size;
82     _ctx->level[l].w = lw;
83     _ctx->level[l].h = lh;
84     im_size = lw * (size_t)lh;
85     level_size = 2 * im_size * sizeof(*_ctx->level[l].im1);
86     level_size += sizeof(*_ctx->level[l].ssim) - 1;
87     level_size /= sizeof(*_ctx->level[l].ssim);
88     level_size *= sizeof(*_ctx->level[l].ssim);
89     _ctx->level[l].im1 = (uint32_t *)data;
90     _ctx->level[l].im2 = _ctx->level[l].im1 + im_size;
91     data += level_size;
92     _ctx->level[l].ssim = (double *)data;
93     data += im_size * sizeof(*_ctx->level[l].ssim);
94     lw = (lw + 1) >> 1;
95     lh = (lh + 1) >> 1;
96   }
97   _ctx->col_buf = (unsigned *)data;
98 }
99 
fs_ctx_clear(fs_ctx * _ctx)100 static void fs_ctx_clear(fs_ctx *_ctx) { free(_ctx->level); }
101 
fs_downsample_level(fs_ctx * _ctx,int _l)102 static void fs_downsample_level(fs_ctx *_ctx, int _l) {
103   const uint32_t *src1;
104   const uint32_t *src2;
105   uint32_t *dst1;
106   uint32_t *dst2;
107   int w2;
108   int h2;
109   int w;
110   int h;
111   int i;
112   int j;
113   w = _ctx->level[_l].w;
114   h = _ctx->level[_l].h;
115   dst1 = _ctx->level[_l].im1;
116   dst2 = _ctx->level[_l].im2;
117   w2 = _ctx->level[_l - 1].w;
118   h2 = _ctx->level[_l - 1].h;
119   src1 = _ctx->level[_l - 1].im1;
120   src2 = _ctx->level[_l - 1].im2;
121   for (j = 0; j < h; j++) {
122     int j0offs;
123     int j1offs;
124     j0offs = 2 * j * w2;
125     j1offs = FS_MINI(2 * j + 1, h2) * w2;
126     for (i = 0; i < w; i++) {
127       int i0;
128       int i1;
129       i0 = 2 * i;
130       i1 = FS_MINI(i0 + 1, w2);
131       dst1[j * w + i] = src1[j0offs + i0] + src1[j0offs + i1] +
132                         src1[j1offs + i0] + src1[j1offs + i1];
133       dst2[j * w + i] = src2[j0offs + i0] + src2[j0offs + i1] +
134                         src2[j1offs + i0] + src2[j1offs + i1];
135     }
136   }
137 }
138 
fs_downsample_level0(fs_ctx * _ctx,const uint8_t * _src1,int _s1ystride,const uint8_t * _src2,int _s2ystride,int _w,int _h,uint32_t bd,uint32_t shift)139 static void fs_downsample_level0(fs_ctx *_ctx, const uint8_t *_src1,
140                                  int _s1ystride, const uint8_t *_src2,
141                                  int _s2ystride, int _w, int _h, uint32_t bd,
142                                  uint32_t shift) {
143   uint32_t *dst1;
144   uint32_t *dst2;
145   int w;
146   int h;
147   int i;
148   int j;
149   w = _ctx->level[0].w;
150   h = _ctx->level[0].h;
151   dst1 = _ctx->level[0].im1;
152   dst2 = _ctx->level[0].im2;
153   for (j = 0; j < h; j++) {
154     int j0;
155     int j1;
156     j0 = 2 * j;
157     j1 = FS_MINI(j0 + 1, _h);
158     for (i = 0; i < w; i++) {
159       int i0;
160       int i1;
161       i0 = 2 * i;
162       i1 = FS_MINI(i0 + 1, _w);
163       if (bd == 8 && shift == 0) {
164         dst1[j * w + i] =
165             _src1[j0 * _s1ystride + i0] + _src1[j0 * _s1ystride + i1] +
166             _src1[j1 * _s1ystride + i0] + _src1[j1 * _s1ystride + i1];
167         dst2[j * w + i] =
168             _src2[j0 * _s2ystride + i0] + _src2[j0 * _s2ystride + i1] +
169             _src2[j1 * _s2ystride + i0] + _src2[j1 * _s2ystride + i1];
170       } else {
171         uint16_t *src1s = CONVERT_TO_SHORTPTR(_src1);
172         uint16_t *src2s = CONVERT_TO_SHORTPTR(_src2);
173         dst1[j * w + i] = (src1s[j0 * _s1ystride + i0] >> shift) +
174                           (src1s[j0 * _s1ystride + i1] >> shift) +
175                           (src1s[j1 * _s1ystride + i0] >> shift) +
176                           (src1s[j1 * _s1ystride + i1] >> shift);
177         dst2[j * w + i] = (src2s[j0 * _s2ystride + i0] >> shift) +
178                           (src2s[j0 * _s2ystride + i1] >> shift) +
179                           (src2s[j1 * _s2ystride + i0] >> shift) +
180                           (src2s[j1 * _s2ystride + i1] >> shift);
181       }
182     }
183   }
184 }
185 
fs_apply_luminance(fs_ctx * _ctx,int _l,int bit_depth)186 static void fs_apply_luminance(fs_ctx *_ctx, int _l, int bit_depth) {
187   unsigned *col_sums_x;
188   unsigned *col_sums_y;
189   uint32_t *im1;
190   uint32_t *im2;
191   double *ssim;
192   double c1;
193   int w;
194   int h;
195   int j0offs;
196   int j1offs;
197   int i;
198   int j;
199   double ssim_c1 = SSIM_C1;
200 #if CONFIG_VP9_HIGHBITDEPTH
201   if (bit_depth == 10) ssim_c1 = SSIM_C1_10;
202   if (bit_depth == 12) ssim_c1 = SSIM_C1_12;
203 #else
204   assert(bit_depth == 8);
205   (void)bit_depth;
206 #endif
207   w = _ctx->level[_l].w;
208   h = _ctx->level[_l].h;
209   col_sums_x = _ctx->col_buf;
210   col_sums_y = col_sums_x + w;
211   im1 = _ctx->level[_l].im1;
212   im2 = _ctx->level[_l].im2;
213   for (i = 0; i < w; i++) col_sums_x[i] = 5 * im1[i];
214   for (i = 0; i < w; i++) col_sums_y[i] = 5 * im2[i];
215   for (j = 1; j < 4; j++) {
216     j1offs = FS_MINI(j, h - 1) * w;
217     for (i = 0; i < w; i++) col_sums_x[i] += im1[j1offs + i];
218     for (i = 0; i < w; i++) col_sums_y[i] += im2[j1offs + i];
219   }
220   ssim = _ctx->level[_l].ssim;
221   c1 = (double)(ssim_c1 * 4096 * (1 << 4 * _l));
222   for (j = 0; j < h; j++) {
223     unsigned mux;
224     unsigned muy;
225     int i0;
226     int i1;
227     mux = 5 * col_sums_x[0];
228     muy = 5 * col_sums_y[0];
229     for (i = 1; i < 4; i++) {
230       i1 = FS_MINI(i, w - 1);
231       mux += col_sums_x[i1];
232       muy += col_sums_y[i1];
233     }
234     for (i = 0; i < w; i++) {
235       ssim[j * w + i] *= (2 * mux * (double)muy + c1) /
236                          (mux * (double)mux + muy * (double)muy + c1);
237       if (i + 1 < w) {
238         i0 = FS_MAXI(0, i - 4);
239         i1 = FS_MINI(i + 4, w - 1);
240         mux += col_sums_x[i1] - col_sums_x[i0];
241         muy += col_sums_x[i1] - col_sums_x[i0];
242       }
243     }
244     if (j + 1 < h) {
245       j0offs = FS_MAXI(0, j - 4) * w;
246       for (i = 0; i < w; i++) col_sums_x[i] -= im1[j0offs + i];
247       for (i = 0; i < w; i++) col_sums_y[i] -= im2[j0offs + i];
248       j1offs = FS_MINI(j + 4, h - 1) * w;
249       for (i = 0; i < w; i++) col_sums_x[i] += im1[j1offs + i];
250       for (i = 0; i < w; i++) col_sums_y[i] += im2[j1offs + i];
251     }
252   }
253 }
254 
255 #define FS_COL_SET(_col, _joffs, _ioffs)                       \
256   do {                                                         \
257     unsigned gx;                                               \
258     unsigned gy;                                               \
259     gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
260     gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
261     col_sums_gx2[(_col)] = gx * (double)gx;                    \
262     col_sums_gy2[(_col)] = gy * (double)gy;                    \
263     col_sums_gxgy[(_col)] = gx * (double)gy;                   \
264   } while (0)
265 
266 #define FS_COL_ADD(_col, _joffs, _ioffs)                       \
267   do {                                                         \
268     unsigned gx;                                               \
269     unsigned gy;                                               \
270     gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
271     gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
272     col_sums_gx2[(_col)] += gx * (double)gx;                   \
273     col_sums_gy2[(_col)] += gy * (double)gy;                   \
274     col_sums_gxgy[(_col)] += gx * (double)gy;                  \
275   } while (0)
276 
277 #define FS_COL_SUB(_col, _joffs, _ioffs)                       \
278   do {                                                         \
279     unsigned gx;                                               \
280     unsigned gy;                                               \
281     gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
282     gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
283     col_sums_gx2[(_col)] -= gx * (double)gx;                   \
284     col_sums_gy2[(_col)] -= gy * (double)gy;                   \
285     col_sums_gxgy[(_col)] -= gx * (double)gy;                  \
286   } while (0)
287 
288 #define FS_COL_COPY(_col1, _col2)                    \
289   do {                                               \
290     col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)];   \
291     col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)];   \
292     col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)]; \
293   } while (0)
294 
295 #define FS_COL_HALVE(_col1, _col2)                         \
296   do {                                                     \
297     col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)] * 0.5;   \
298     col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)] * 0.5;   \
299     col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)] * 0.5; \
300   } while (0)
301 
302 #define FS_COL_DOUBLE(_col1, _col2)                      \
303   do {                                                   \
304     col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)] * 2;   \
305     col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)] * 2;   \
306     col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)] * 2; \
307   } while (0)
308 
fs_calc_structure(fs_ctx * _ctx,int _l,int bit_depth)309 static void fs_calc_structure(fs_ctx *_ctx, int _l, int bit_depth) {
310   uint32_t *im1;
311   uint32_t *im2;
312   unsigned *gx_buf;
313   unsigned *gy_buf;
314   double *ssim;
315   double col_sums_gx2[8];
316   double col_sums_gy2[8];
317   double col_sums_gxgy[8];
318   double c2;
319   int stride;
320   int w;
321   int h;
322   int i;
323   int j;
324   double ssim_c2 = SSIM_C2;
325 #if CONFIG_VP9_HIGHBITDEPTH
326   if (bit_depth == 10) ssim_c2 = SSIM_C2_10;
327   if (bit_depth == 12) ssim_c2 = SSIM_C2_12;
328 #else
329   assert(bit_depth == 8);
330   (void)bit_depth;
331 #endif
332 
333   w = _ctx->level[_l].w;
334   h = _ctx->level[_l].h;
335   im1 = _ctx->level[_l].im1;
336   im2 = _ctx->level[_l].im2;
337   ssim = _ctx->level[_l].ssim;
338   gx_buf = _ctx->col_buf;
339   stride = w + 8;
340   gy_buf = gx_buf + 8 * stride;
341   memset(gx_buf, 0, 2 * 8 * stride * sizeof(*gx_buf));
342   c2 = ssim_c2 * (1 << 4 * _l) * 16 * 104;
343   for (j = 0; j < h + 4; j++) {
344     if (j < h - 1) {
345       for (i = 0; i < w - 1; i++) {
346         unsigned g1;
347         unsigned g2;
348         unsigned gx;
349         unsigned gy;
350         g1 = abs((int)im1[(j + 1) * w + i + 1] - (int)im1[j * w + i]);
351         g2 = abs((int)im1[(j + 1) * w + i] - (int)im1[j * w + i + 1]);
352         gx = 4 * FS_MAXI(g1, g2) + FS_MINI(g1, g2);
353         g1 = abs((int)im2[(j + 1) * w + i + 1] - (int)im2[j * w + i]);
354         g2 = abs((int)im2[(j + 1) * w + i] - (int)im2[j * w + i + 1]);
355         gy = 4 * FS_MAXI(g1, g2) + FS_MINI(g1, g2);
356         gx_buf[(j & 7) * stride + i + 4] = gx;
357         gy_buf[(j & 7) * stride + i + 4] = gy;
358       }
359     } else {
360       memset(gx_buf + (j & 7) * stride, 0, stride * sizeof(*gx_buf));
361       memset(gy_buf + (j & 7) * stride, 0, stride * sizeof(*gy_buf));
362     }
363     if (j >= 4) {
364       int k;
365       col_sums_gx2[3] = col_sums_gx2[2] = col_sums_gx2[1] = col_sums_gx2[0] = 0;
366       col_sums_gy2[3] = col_sums_gy2[2] = col_sums_gy2[1] = col_sums_gy2[0] = 0;
367       col_sums_gxgy[3] = col_sums_gxgy[2] = col_sums_gxgy[1] =
368           col_sums_gxgy[0] = 0;
369       for (i = 4; i < 8; i++) {
370         FS_COL_SET(i, -1, 0);
371         FS_COL_ADD(i, 0, 0);
372         for (k = 1; k < 8 - i; k++) {
373           FS_COL_DOUBLE(i, i);
374           FS_COL_ADD(i, -k - 1, 0);
375           FS_COL_ADD(i, k, 0);
376         }
377       }
378       for (i = 0; i < w; i++) {
379         double mugx2;
380         double mugy2;
381         double mugxgy;
382         mugx2 = col_sums_gx2[0];
383         for (k = 1; k < 8; k++) mugx2 += col_sums_gx2[k];
384         mugy2 = col_sums_gy2[0];
385         for (k = 1; k < 8; k++) mugy2 += col_sums_gy2[k];
386         mugxgy = col_sums_gxgy[0];
387         for (k = 1; k < 8; k++) mugxgy += col_sums_gxgy[k];
388         ssim[(j - 4) * w + i] = (2 * mugxgy + c2) / (mugx2 + mugy2 + c2);
389         if (i + 1 < w) {
390           FS_COL_SET(0, -1, 1);
391           FS_COL_ADD(0, 0, 1);
392           FS_COL_SUB(2, -3, 2);
393           FS_COL_SUB(2, 2, 2);
394           FS_COL_HALVE(1, 2);
395           FS_COL_SUB(3, -4, 3);
396           FS_COL_SUB(3, 3, 3);
397           FS_COL_HALVE(2, 3);
398           FS_COL_COPY(3, 4);
399           FS_COL_DOUBLE(4, 5);
400           FS_COL_ADD(4, -4, 5);
401           FS_COL_ADD(4, 3, 5);
402           FS_COL_DOUBLE(5, 6);
403           FS_COL_ADD(5, -3, 6);
404           FS_COL_ADD(5, 2, 6);
405           FS_COL_DOUBLE(6, 7);
406           FS_COL_ADD(6, -2, 7);
407           FS_COL_ADD(6, 1, 7);
408           FS_COL_SET(7, -1, 8);
409           FS_COL_ADD(7, 0, 8);
410         }
411       }
412     }
413   }
414 }
415 
416 #define FS_NLEVELS (4)
417 
418 /*These weights were derived from the default weights found in Wang's original
419  Matlab implementation: {0.0448, 0.2856, 0.2363, 0.1333}.
420  We drop the finest scale and renormalize the rest to sum to 1.*/
421 
422 static const double FS_WEIGHTS[FS_NLEVELS] = {
423   0.2989654541015625, 0.3141326904296875, 0.2473602294921875, 0.1395416259765625
424 };
425 
fs_average(fs_ctx * _ctx,int _l)426 static double fs_average(fs_ctx *_ctx, int _l) {
427   double *ssim;
428   double ret;
429   int w;
430   int h;
431   int i;
432   int j;
433   w = _ctx->level[_l].w;
434   h = _ctx->level[_l].h;
435   ssim = _ctx->level[_l].ssim;
436   ret = 0;
437   for (j = 0; j < h; j++)
438     for (i = 0; i < w; i++) ret += ssim[j * w + i];
439   return pow(ret / (w * h), FS_WEIGHTS[_l]);
440 }
441 
convert_ssim_db(double _ssim,double _weight)442 static double convert_ssim_db(double _ssim, double _weight) {
443   assert(_weight >= _ssim);
444   if ((_weight - _ssim) < 1e-10) return MAX_SSIM_DB;
445   return 10 * (log10(_weight) - log10(_weight - _ssim));
446 }
447 
calc_ssim(const uint8_t * _src,int _systride,const uint8_t * _dst,int _dystride,int _w,int _h,uint32_t _bd,uint32_t _shift)448 static double calc_ssim(const uint8_t *_src, int _systride, const uint8_t *_dst,
449                         int _dystride, int _w, int _h, uint32_t _bd,
450                         uint32_t _shift) {
451   fs_ctx ctx;
452   double ret;
453   int l;
454   ret = 1;
455   fs_ctx_init(&ctx, _w, _h, FS_NLEVELS);
456   fs_downsample_level0(&ctx, _src, _systride, _dst, _dystride, _w, _h, _bd,
457                        _shift);
458   for (l = 0; l < FS_NLEVELS - 1; l++) {
459     fs_calc_structure(&ctx, l, _bd);
460     ret *= fs_average(&ctx, l);
461     fs_downsample_level(&ctx, l + 1);
462   }
463   fs_calc_structure(&ctx, l, _bd);
464   fs_apply_luminance(&ctx, l, _bd);
465   ret *= fs_average(&ctx, l);
466   fs_ctx_clear(&ctx);
467   return ret;
468 }
469 
vpx_calc_fastssim(const YV12_BUFFER_CONFIG * source,const YV12_BUFFER_CONFIG * dest,double * ssim_y,double * ssim_u,double * ssim_v,uint32_t bd,uint32_t in_bd)470 double vpx_calc_fastssim(const YV12_BUFFER_CONFIG *source,
471                          const YV12_BUFFER_CONFIG *dest, double *ssim_y,
472                          double *ssim_u, double *ssim_v, uint32_t bd,
473                          uint32_t in_bd) {
474   double ssimv;
475   uint32_t bd_shift = 0;
476   vpx_clear_system_state();
477   assert(bd >= in_bd);
478   bd_shift = bd - in_bd;
479 
480   *ssim_y = calc_ssim(source->y_buffer, source->y_stride, dest->y_buffer,
481                       dest->y_stride, source->y_crop_width,
482                       source->y_crop_height, in_bd, bd_shift);
483   *ssim_u = calc_ssim(source->u_buffer, source->uv_stride, dest->u_buffer,
484                       dest->uv_stride, source->uv_crop_width,
485                       source->uv_crop_height, in_bd, bd_shift);
486   *ssim_v = calc_ssim(source->v_buffer, source->uv_stride, dest->v_buffer,
487                       dest->uv_stride, source->uv_crop_width,
488                       source->uv_crop_height, in_bd, bd_shift);
489 
490   ssimv = (*ssim_y) * .8 + .1 * ((*ssim_u) + (*ssim_v));
491   return convert_ssim_db(ssimv, 1.0);
492 }
493