1/*
2 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 <inttypes.h>
24#include <assert.h>
25
26#define FFMIN(a,b) ((a) > (b) ? (b) : (a))
27#define F 100
28#define SIZE 2048
29
30uint64_t exp16_table[21]={
31     65537,
32     65538,
33     65540,
34     65544,
35     65552,
36     65568,
37     65600,
38     65664,
39     65793,
40     66050,
41     66568,
42     67616,
43     69763,
44     74262,
45     84150,
46    108051,
47    178145,
48    484249,
49   3578144,
50 195360063,
51 582360139072LL,
52};
53
54#if 0
55// 16.16 fixpoint exp()
56static unsigned int exp16(unsigned int a){
57    int i;
58    int out= 1<<16;
59
60    for(i=19;i>=0;i--){
61        if(a&(1<<i))
62            out= (out*exp16_table[i] + (1<<15))>>16;
63    }
64
65    return out;
66}
67#endif
68
69// 16.16 fixpoint log()
70static int64_t log16(uint64_t a){
71    int i;
72    int out=0;
73
74    if(a < 1<<16)
75        return -log16((1LL<<32) / a);
76    a<<=16;
77
78    for(i=20;i>=0;i--){
79        int64_t b= exp16_table[i];
80        if(a<(b<<16)) continue;
81        out |= 1<<i;
82        a = ((a/b)<<16) + (((a%b)<<16) + b/2)/b;
83    }
84    return out;
85}
86
87static uint64_t int_sqrt(uint64_t a)
88{
89    uint64_t ret=0;
90    int s;
91    uint64_t ret_sq=0;
92
93    for(s=31; s>=0; s--){
94        uint64_t b= ret_sq + (1ULL<<(s*2)) + (ret<<s)*2;
95        if(b<=a){
96            ret_sq=b;
97            ret+= 1ULL<<s;
98        }
99    }
100    return ret;
101}
102
103int main(int argc,char* argv[]){
104    int i, j;
105    uint64_t sse=0;
106    uint64_t dev;
107    FILE *f[2];
108    uint8_t buf[2][SIZE];
109    uint64_t psnr;
110    int len= argc<4 ? 1 : atoi(argv[3]);
111    int64_t max= (1<<(8*len))-1;
112    int shift= argc<5 ? 0 : atoi(argv[4]);
113    int skip_bytes = argc<6 ? 0 : atoi(argv[5]);
114    int size0=0;
115    int size1=0;
116
117    if(argc<3){
118        printf("tiny_psnr <file1> <file2> [<elem size> [<shift> [<skip bytes>]]]\n");
119        printf("For WAV files use the following:\n");
120        printf("./tiny_psnr file1.wav file2.wav 2 0 44 to skip the header.\n");
121        return -1;
122    }
123
124    f[0]= fopen(argv[1], "rb");
125    f[1]= fopen(argv[2], "rb");
126    if(!f[0] || !f[1]){
127        fprintf(stderr, "Could not open input files.\n");
128        return -1;
129    }
130    fseek(f[shift<0], shift < 0 ? -shift : shift, SEEK_SET);
131
132    fseek(f[0],skip_bytes,SEEK_CUR);
133    fseek(f[1],skip_bytes,SEEK_CUR);
134
135    for(;;){
136        int s0= fread(buf[0], 1, SIZE, f[0]);
137        int s1= fread(buf[1], 1, SIZE, f[1]);
138
139        for(j=0; j<FFMIN(s0,s1); j++){
140            int64_t a= buf[0][j];
141            int64_t b= buf[1][j];
142            if(len==2){
143                a= (int16_t)(a | (buf[0][++j]<<8));
144                b= (int16_t)(b | (buf[1][  j]<<8));
145            }
146            sse += (a-b) * (a-b);
147        }
148        size0 += s0;
149        size1 += s1;
150        if(s0+s1<=0)
151            break;
152    }
153
154    i= FFMIN(size0,size1)/len;
155    if(!i) i=1;
156    dev= int_sqrt( ((sse/i)*F*F) + (((sse%i)*F*F) + i/2)/i );
157    if(sse)
158        psnr= ((2*log16(max<<16) + log16(i) - log16(sse))*284619LL*F + (1<<31)) / (1LL<<32);
159    else
160        psnr= 1000*F-1; //floating point free infinity :)
161
162    printf("stddev:%5d.%02d PSNR:%3d.%02d bytes:%9d/%9d\n",
163        (int)(dev/F), (int)(dev%F),
164        (int)(psnr/F), (int)(psnr%F),
165        size0, size1);
166    return 0;
167}
168
169
170