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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 
     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 
    100 static void fs_ctx_clear(fs_ctx *_ctx) { free(_ctx->level); }
    101 
    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 
    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 
    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 
    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 
    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 
    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 
    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 
    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