1// Copyright 2014 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// WebPPicture tools for measuring distortion
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#include <math.h>
15#include <stdlib.h>
16
17#include "./vp8i_enc.h"
18#include "../utils/utils.h"
19
20typedef double (*AccumulateFunc)(const uint8_t* src, int src_stride,
21                                 const uint8_t* ref, int ref_stride,
22                                 int w, int h);
23
24//------------------------------------------------------------------------------
25// local-min distortion
26//
27// For every pixel in the *reference* picture, we search for the local best
28// match in the compressed image. This is not a symmetrical measure.
29
30#define RADIUS 2  // search radius. Shouldn't be too large.
31
32static double AccumulateLSIM(const uint8_t* src, int src_stride,
33                             const uint8_t* ref, int ref_stride,
34                             int w, int h) {
35  int x, y;
36  double total_sse = 0.;
37  for (y = 0; y < h; ++y) {
38    const int y_0 = (y - RADIUS < 0) ? 0 : y - RADIUS;
39    const int y_1 = (y + RADIUS + 1 >= h) ? h : y + RADIUS + 1;
40    for (x = 0; x < w; ++x) {
41      const int x_0 = (x - RADIUS < 0) ? 0 : x - RADIUS;
42      const int x_1 = (x + RADIUS + 1 >= w) ? w : x + RADIUS + 1;
43      double best_sse = 255. * 255.;
44      const double value = (double)ref[y * ref_stride + x];
45      int i, j;
46      for (j = y_0; j < y_1; ++j) {
47        const uint8_t* const s = src + j * src_stride;
48        for (i = x_0; i < x_1; ++i) {
49          const double diff = s[i] - value;
50          const double sse = diff * diff;
51          if (sse < best_sse) best_sse = sse;
52        }
53      }
54      total_sse += best_sse;
55    }
56  }
57  return total_sse;
58}
59#undef RADIUS
60
61static double AccumulateSSE(const uint8_t* src, int src_stride,
62                            const uint8_t* ref, int ref_stride,
63                            int w, int h) {
64  int y;
65  double total_sse = 0.;
66  for (y = 0; y < h; ++y) {
67    total_sse += VP8AccumulateSSE(src, ref, w);
68    src += src_stride;
69    ref += ref_stride;
70  }
71  return total_sse;
72}
73
74//------------------------------------------------------------------------------
75
76static double AccumulateSSIM(const uint8_t* src, int src_stride,
77                             const uint8_t* ref, int ref_stride,
78                             int w, int h) {
79  const int w0 = (w < VP8_SSIM_KERNEL) ? w : VP8_SSIM_KERNEL;
80  const int w1 = w - VP8_SSIM_KERNEL - 1;
81  const int h0 = (h < VP8_SSIM_KERNEL) ? h : VP8_SSIM_KERNEL;
82  const int h1 = h - VP8_SSIM_KERNEL - 1;
83  int x, y;
84  double sum = 0.;
85  for (y = 0; y < h0; ++y) {
86    for (x = 0; x < w; ++x) {
87      sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
88    }
89  }
90  for (; y < h1; ++y) {
91    for (x = 0; x < w0; ++x) {
92      sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
93    }
94    for (; x < w1; ++x) {
95      const int off1 = x - VP8_SSIM_KERNEL + (y - VP8_SSIM_KERNEL) * src_stride;
96      const int off2 = x - VP8_SSIM_KERNEL + (y - VP8_SSIM_KERNEL) * ref_stride;
97      sum += VP8SSIMGet(src + off1, src_stride, ref + off2, ref_stride);
98    }
99    for (; x < w; ++x) {
100      sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
101    }
102  }
103  for (; y < h; ++y) {
104    for (x = 0; x < w; ++x) {
105      sum += VP8SSIMGetClipped(src, src_stride, ref, ref_stride, x, y, w, h);
106    }
107  }
108  return sum;
109}
110
111//------------------------------------------------------------------------------
112// Distortion
113
114// Max value returned in case of exact similarity.
115static const double kMinDistortion_dB = 99.;
116
117static double GetPSNR(double v, double size) {
118  return (v > 0. && size > 0.) ? -4.3429448 * log(v / (size * 255 * 255.))
119                               : kMinDistortion_dB;
120}
121
122static double GetLogSSIM(double v, double size) {
123  v = (size > 0.) ? v / size : 1.;
124  return (v < 1.) ? -10.0 * log10(1. - v) : kMinDistortion_dB;
125}
126
127int WebPPlaneDistortion(const uint8_t* src, size_t src_stride,
128                        const uint8_t* ref, size_t ref_stride,
129                        int width, int height, size_t x_step,
130                        int type, float* distortion, float* result) {
131  uint8_t* allocated = NULL;
132  const AccumulateFunc metric = (type == 0) ? AccumulateSSE :
133                                (type == 1) ? AccumulateSSIM :
134                                              AccumulateLSIM;
135  if (src == NULL || ref == NULL ||
136      src_stride < x_step * width || ref_stride < x_step * width ||
137      result == NULL || distortion == NULL) {
138    return 0;
139  }
140
141  VP8SSIMDspInit();
142  if (x_step != 1) {   // extract a packed plane if needed
143    int x, y;
144    uint8_t* tmp1;
145    uint8_t* tmp2;
146    allocated =
147        (uint8_t*)WebPSafeMalloc(2ULL * width * height, sizeof(*allocated));
148    if (allocated == NULL) return 0;
149    tmp1 = allocated;
150    tmp2 = tmp1 + (size_t)width * height;
151    for (y = 0; y < height; ++y) {
152      for (x = 0; x < width; ++x) {
153        tmp1[x + y * width] = src[x * x_step + y * src_stride];
154        tmp2[x + y * width] = ref[x * x_step + y * ref_stride];
155      }
156    }
157    src = tmp1;
158    ref = tmp2;
159  }
160  *distortion = (float)metric(src, width, ref, width, width, height);
161  WebPSafeFree(allocated);
162
163  *result = (type == 1) ? (float)GetLogSSIM(*distortion, (double)width * height)
164                        : (float)GetPSNR(*distortion, (double)width * height);
165  return 1;
166}
167
168int WebPPictureDistortion(const WebPPicture* src, const WebPPicture* ref,
169                          int type, float results[5]) {
170  int w, h, c;
171  int ok = 0;
172  WebPPicture p0, p1;
173  double total_size = 0., total_distortion = 0.;
174  if (src == NULL || ref == NULL ||
175      src->width != ref->width || src->height != ref->height ||
176      results == NULL) {
177    return 0;
178  }
179
180  VP8SSIMDspInit();
181  if (!WebPPictureInit(&p0) || !WebPPictureInit(&p1)) return 0;
182  w = src->width;
183  h = src->height;
184  if (!WebPPictureView(src, 0, 0, w, h, &p0)) goto Error;
185  if (!WebPPictureView(ref, 0, 0, w, h, &p1)) goto Error;
186
187  // We always measure distortion in ARGB space.
188  if (p0.use_argb == 0 && !WebPPictureYUVAToARGB(&p0)) goto Error;
189  if (p1.use_argb == 0 && !WebPPictureYUVAToARGB(&p1)) goto Error;
190  for (c = 0; c < 4; ++c) {
191    float distortion;
192    const size_t stride0 = 4 * (size_t)p0.argb_stride;
193    const size_t stride1 = 4 * (size_t)p1.argb_stride;
194    if (!WebPPlaneDistortion((const uint8_t*)p0.argb + c, stride0,
195                             (const uint8_t*)p1.argb + c, stride1,
196                             w, h, 4, type, &distortion, results + c)) {
197      goto Error;
198    }
199    total_distortion += distortion;
200    total_size += w * h;
201  }
202
203  results[4] = (type == 1) ? (float)GetLogSSIM(total_distortion, total_size)
204                           : (float)GetPSNR(total_distortion, total_size);
205  ok = 1;
206
207 Error:
208  WebPPictureFree(&p0);
209  WebPPictureFree(&p1);
210  return ok;
211}
212
213//------------------------------------------------------------------------------
214