mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-11-26 19:01:44 +02:00
116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
/*
|
|
* Rational numbers
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file rational.h
|
|
* Rational numbers.
|
|
* @author Michael Niedermayer <michaelni@gmx.at>
|
|
*/
|
|
|
|
#ifndef FFMPEG_RATIONAL_H
|
|
#define FFMPEG_RATIONAL_H
|
|
|
|
#include <stdint.h>
|
|
|
|
/**
|
|
* Rational number num/den.
|
|
*/
|
|
typedef struct AVRational{
|
|
int num; ///< numerator
|
|
int den; ///< denominator
|
|
} AVRational;
|
|
|
|
/**
|
|
* Compare two rationals.
|
|
* @param a first rational
|
|
* @param b second rational
|
|
* @return 0 if a==b, 1 if a>b and -1 if a<b.
|
|
*/
|
|
static inline int av_cmp_q(AVRational a, AVRational b){
|
|
const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den;
|
|
|
|
if(tmp) return (tmp>>63)|1;
|
|
else return 0;
|
|
}
|
|
|
|
/**
|
|
* Rational to double conversion.
|
|
* @param a rational to convert
|
|
* @return (double) a
|
|
*/
|
|
static inline double av_q2d(AVRational a){
|
|
return a.num / (double) a.den;
|
|
}
|
|
|
|
/**
|
|
* Reduce a fraction.
|
|
* This is useful for framerate calculations.
|
|
* @param dst_nom destination numerator
|
|
* @param dst_den destination denominator
|
|
* @param nom source numerator
|
|
* @param den source denominator
|
|
* @param max the maximum allowed for dst_nom & dst_den
|
|
* @return 1 if exact, 0 otherwise
|
|
*/
|
|
int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max);
|
|
|
|
/**
|
|
* Multiplies two rationals.
|
|
* @param b first rational.
|
|
* @param c second rational.
|
|
* @return b*c.
|
|
*/
|
|
AVRational av_mul_q(AVRational b, AVRational c);
|
|
|
|
/**
|
|
* Divides one rational by another.
|
|
* @param b first rational.
|
|
* @param c second rational.
|
|
* @return b/c.
|
|
*/
|
|
AVRational av_div_q(AVRational b, AVRational c);
|
|
|
|
/**
|
|
* Adds two rationals.
|
|
* @param b first rational.
|
|
* @param c second rational.
|
|
* @return b+c.
|
|
*/
|
|
AVRational av_add_q(AVRational b, AVRational c);
|
|
|
|
/**
|
|
* Subtracts one rational from another.
|
|
* @param b first rational.
|
|
* @param c second rational.
|
|
* @return b-c.
|
|
*/
|
|
AVRational av_sub_q(AVRational b, AVRational c);
|
|
|
|
/**
|
|
* Converts a double precision floating point number to a rational.
|
|
* @param d double to convert
|
|
* @param max the maximum allowed numerator and denominator
|
|
* @return (AVRational) d.
|
|
*/
|
|
AVRational av_d2q(double d, int max);
|
|
|
|
#endif /* FFMPEG_RATIONAL_H */
|