/* * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * * This library 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 of the License, or (at your option) any later version. * * This library 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 this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <stdio.h> #include <inttypes.h> #define F 100 #define SIZE 2048 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]; if(argc!=3){ printf("tiny_psnr <file1> <file2>\n"); return -1; } f[0]= fopen(argv[1], "r"); f[1]= fopen(argv[2], "r"); 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++){ const int a= buf[0][j]; const int b= buf[1][j]; sse += (a-b) * (a-b); } } dev= int_sqrt((sse*F*F)/i); //FIXME someone should write a integer fixpoint log() function for bitexact PSNR scores ... printf("stddev:%3d.%02d bytes:%d\n", (int)(dev/F), (int)(dev%F), i); return 0; }