tiny_psnr.c
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1 /*
2  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of Libav.
5  *
6  * Libav is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * Libav is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with Libav; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <inttypes.h>
25 #include <assert.h>
26 
27 #define FFMIN(a, b) ((a) > (b) ? (b) : (a))
28 #define F 100
29 #define SIZE 2048
30 
31 uint64_t exp16_table[21] = {
32  65537,
33  65538,
34  65540,
35  65544,
36  65552,
37  65568,
38  65600,
39  65664,
40  65793,
41  66050,
42  66568,
43  67616,
44  69763,
45  74262,
46  84150,
47  108051,
48  178145,
49  484249,
50  3578144,
51  195360063,
52  582360139072LL,
53 };
54 
55 // 16.16 fixpoint log()
56 static int64_t log16(uint64_t a)
57 {
58  int i;
59  int out = 0;
60 
61  if (a < 1 << 16)
62  return -log16((1LL << 32) / a);
63  a <<= 16;
64 
65  for (i = 20; i >= 0; i--) {
66  int64_t b = exp16_table[i];
67  if (a < (b << 16))
68  continue;
69  out |= 1 << i;
70  a = ((a / b) << 16) + (((a % b) << 16) + b / 2) / b;
71  }
72  return out;
73 }
74 
75 static uint64_t int_sqrt(uint64_t a)
76 {
77  uint64_t ret = 0;
78  uint64_t ret_sq = 0;
79  int s;
80 
81  for (s = 31; s >= 0; s--) {
82  uint64_t b = ret_sq + (1ULL << (s * 2)) + (ret << s) * 2;
83  if (b <= a) {
84  ret_sq = b;
85  ret += 1ULL << s;
86  }
87  }
88  return ret;
89 }
90 
91 int main(int argc, char *argv[])
92 {
93  int i, j;
94  uint64_t sse = 0;
95  uint64_t dev;
96  FILE *f[2];
97  uint8_t buf[2][SIZE];
98  uint64_t psnr;
99  int len = argc < 4 ? 1 : atoi(argv[3]);
100  int64_t max = (1 << (8 * len)) - 1;
101  int shift = argc < 5 ? 0 : atoi(argv[4]);
102  int skip_bytes = argc < 6 ? 0 : atoi(argv[5]);
103  int size0 = 0;
104  int size1 = 0;
105  int maxdist = 0;
106 
107  if (argc < 3) {
108  printf("tiny_psnr <file1> <file2> [<elem size> [<shift> [<skip bytes>]]]\n");
109  printf("WAV headers are skipped automatically.\n");
110  return 1;
111  }
112 
113  f[0] = fopen(argv[1], "rb");
114  f[1] = fopen(argv[2], "rb");
115  if (!f[0] || !f[1]) {
116  fprintf(stderr, "Could not open input files.\n");
117  return 1;
118  }
119 
120  for (i = 0; i < 2; i++) {
121  uint8_t *p = buf[i];
122  if (fread(p, 1, 12, f[i]) != 12)
123  return 1;
124  if (!memcmp(p, "RIFF", 4) &&
125  !memcmp(p + 8, "WAVE", 4)) {
126  if (fread(p, 1, 8, f[i]) != 8)
127  return 1;
128  while (memcmp(p, "data", 4)) {
129  int s = p[4] | p[5] << 8 | p[6] << 16 | p[7] << 24;
130  fseek(f[i], s, SEEK_CUR);
131  if (fread(p, 1, 8, f[i]) != 8)
132  return 1;
133  }
134  } else {
135  fseek(f[i], -12, SEEK_CUR);
136  }
137  }
138 
139  fseek(f[shift < 0], abs(shift), SEEK_CUR);
140 
141  fseek(f[0], skip_bytes, SEEK_CUR);
142  fseek(f[1], skip_bytes, SEEK_CUR);
143 
144  for (;;) {
145  int s0 = fread(buf[0], 1, SIZE, f[0]);
146  int s1 = fread(buf[1], 1, SIZE, f[1]);
147 
148  for (j = 0; j < FFMIN(s0, s1); j++) {
149  int64_t a = buf[0][j];
150  int64_t b = buf[1][j];
151  int dist;
152  if (len == 2) {
153  a = (int16_t)(a | (buf[0][++j] << 8));
154  b = (int16_t)(b | (buf[1][ j] << 8));
155  }
156  sse += (a - b) * (a - b);
157  dist = abs(a - b);
158  if (dist > maxdist)
159  maxdist = dist;
160  }
161  size0 += s0;
162  size1 += s1;
163  if (s0 + s1 <= 0)
164  break;
165  }
166 
167  i = FFMIN(size0, size1) / len;
168  if (!i)
169  i = 1;
170  dev = int_sqrt(((sse / i) * F * F) + (((sse % i) * F * F) + i / 2) / i);
171  if (sse)
172  psnr = ((2 * log16(max << 16) + log16(i) - log16(sse)) *
173  284619LL * F + (1LL << 31)) / (1LL << 32);
174  else
175  psnr = 1000 * F - 1; // floating point free infinity :)
176 
177  printf("stddev:%5d.%02d PSNR:%3d.%02d MAXDIFF:%5d bytes:%9d/%9d\n",
178  (int)(dev / F), (int)(dev % F),
179  (int)(psnr / F), (int)(psnr % F),
180  maxdist, size0, size1);
181  return 0;
182 }