www.pudn.com > ffmpeg-Sdk.rar > mathematics.h

/* 
 * copyright (c) 2005 Michael Niedermayer  
 * 
 * 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 
 */ 
 
#ifndef FFMPEG_MATHEMATICS_H 
#define FFMPEG_MATHEMATICS_H 
 
#include "rational.h" 
 
enum AVRounding { 
    AV_ROUND_ZERO     = 0, ///< round toward zero 
    AV_ROUND_INF      = 1, ///< round away from zero 
    AV_ROUND_DOWN     = 2, ///< round toward -infinity 
    AV_ROUND_UP       = 3, ///< round toward +infinity 
    AV_ROUND_NEAR_INF = 5, ///< round to nearest and halfway cases away from zero 
}; 
 
/** 
 * rescale a 64bit integer with rounding to nearest. 
 * a simple a*b/c isn't possible as it can overflow 
 */ 
int64_t av_rescale(int64_t a, int64_t b, int64_t c); 
 
/** 
 * rescale a 64bit integer with specified rounding. 
 * a simple a*b/c isn't possible as it can overflow 
 */ 
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding); 
 
/** 
 * rescale a 64bit integer by 2 rational numbers. 
 */ 
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq); 
 
#endif /* FFMPEG_MATHEMATICS_H */