3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * @file libavutil/rational.h
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #ifndef AVUTIL_RATIONAL_H
29 #define AVUTIL_RATIONAL_H
35 * rational number numerator/denominator
37 typedef struct AVRational
{
38 int num
; ///< numerator
39 int den
; ///< denominator
43 * Compares two rationals.
44 * @param a first rational
45 * @param b second rational
46 * @return 0 if a==b, 1 if a>b and -1 if a<b
48 static inline int av_cmp_q(AVRational a
, AVRational b
){
49 const int64_t tmp
= a
.num
* (int64_t)b
.den
- b
.num
* (int64_t)a
.den
;
51 if(tmp
) return (tmp
>>63)|1;
56 * Converts rational to double.
57 * @param a rational to convert
60 static inline double av_q2d(AVRational a
){
61 return a
.num
/ (double) a
.den
;
66 * This is useful for framerate calculations.
67 * @param dst_num destination numerator
68 * @param dst_den destination denominator
69 * @param num source numerator
70 * @param den source denominator
71 * @param max the maximum allowed for dst_num & dst_den
72 * @return 1 if exact, 0 otherwise
74 int av_reduce(int *dst_num
, int *dst_den
, int64_t num
, int64_t den
, int64_t max
);
77 * Multiplies two rationals.
78 * @param b first rational
79 * @param c second rational
82 AVRational
av_mul_q(AVRational b
, AVRational c
) av_const
;
85 * Divides one rational by another.
86 * @param b first rational
87 * @param c second rational
90 AVRational
av_div_q(AVRational b
, AVRational c
) av_const
;
94 * @param b first rational
95 * @param c second rational
98 AVRational
av_add_q(AVRational b
, AVRational c
) av_const
;
101 * Subtracts one rational from another.
102 * @param b first rational
103 * @param c second rational
106 AVRational
av_sub_q(AVRational b
, AVRational c
) av_const
;
109 * Converts a double precision floating point number to a rational.
110 * @param d double to convert
111 * @param max the maximum allowed numerator and denominator
112 * @return (AVRational) d
114 AVRational
av_d2q(double d
, int max
) av_const
;
117 * @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer
118 * than q1, 0 if they have the same distance.
120 int av_nearer_q(AVRational q
, AVRational q1
, AVRational q2
);
123 * Finds the nearest value in q_list to q.
124 * @param q_list an array of rationals terminated by {0, 0}
125 * @return the index of the nearest value found in the array
127 int av_find_nearest_q_idx(AVRational q
, const AVRational
* q_list
);
129 #endif /* AVUTIL_RATIONAL_H */