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
31uint64_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()
56static 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
75static 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
91int 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}
183