/* * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */#include <stdio.h>#include <stdlib.h>#include <inttypes.h>#include <assert.h>#define F 100#define SIZE 2048uint64_t exp16_table[21]={     65537,     65538,     65540,     65544,     65552,     65568,     65600,     65664,     65793,     66050,     66568,     67616,     69763,     74262,     84150,    108051,    178145,    484249,   3578144, 195360063, 582360139072LL,};#if 0// 16.16 fixpoint exp()static unsigned int exp16(unsigned int a){    int i;    int out= 1<<16;    for(i=19;i>=0;i--){        if(a&(1<<i))            out= (out*exp16_table[i] + (1<<15))>>16;    }    return out;}#endif// 16.16 fixpoint log()static int64_t log16(uint64_t a){    int i;    int out=0;    if(a < 1<<16)        return -log16((1LL<<32) / a);    a<<=16;    for(i=20;i>=0;i--){        int64_t b= exp16_table[i];        if(a<(b<<16)) continue;        out |= 1<<i;        a = ((a/b)<<16) + (((a%b)<<16) + b/2)/b;    }    return out;}static uint64_t int_sqrt(uint64_t a){    uint64_t ret=0;    int s;    uint64_t ret_sq=0;    for(s=31; s>=0; s--){        uint64_t b= ret_sq + (1ULL<<(s*2)) + (ret<<s)*2;        if(b<=a){            ret_sq=b;            ret+= 1ULL<<s;        }    }    return ret;}int main(int argc,char* argv[]){    int i, j;    uint64_t sse=0;    uint64_t dev;    FILE *f[2];    uint8_t buf[2][SIZE];    uint64_t psnr;    int len= argc<4 ? 1 : atoi(argv[3]);    int64_t max= (1<<(8*len))-1;    int shift= argc<5 ? 0 : atoi(argv[4]);    int skip_bytes = argc<6 ? 0 : atoi(argv[5]);    if(argc<3){        printf("tiny_psnr <file1> <file2> [<elem size> [<shift> [<skip bytes>]]]\n");        printf("for wav files use the following:\n");        printf("./tiny_psnr file1.wav file2.wav 2 0 44 to skip the header.\n");        return -1;    }    f[0]= fopen(argv[1], "rb");    f[1]= fopen(argv[2], "rb");    fseek(f[shift<0], shift < 0 ? -shift : shift, SEEK_SET);    fseek(f[0],skip_bytes,SEEK_CUR);    fseek(f[1],skip_bytes,SEEK_CUR);    for(i=0;;){        if( fread(buf[0], SIZE, 1, f[0]) != 1) break;        if( fread(buf[1], SIZE, 1, f[1]) != 1) break;        for(j=0; j<SIZE; i++,j++){            int64_t a= buf[0][j];            int64_t b= buf[1][j];            if(len==2){                a= (int16_t)(a | (buf[0][++j]<<8));                b= (int16_t)(b | (buf[1][  j]<<8));            }            sse += (a-b) * (a-b);        }    }    if(!i) i=1;    dev= int_sqrt( ((sse/i)*F*F) + (((sse%i)*F*F) + i/2)/i );    if(sse)        psnr= ((2*log16(max<<16) + log16(i) - log16(sse))*284619LL*F + (1<<31)) / (1LL<<32);    else        psnr= 100*F-1; //floating point free infinity :)    printf("stddev:%3d.%02d PSNR:%2d.%02d bytes:%d\n",        (int)(dev/F), (int)(dev%F),        (int)(psnr/F), (int)(psnr%F),        i*len);    return 0;}