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
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #ifndef AVUTIL_RATIONAL_H
29 #define AVUTIL_RATIONAL_H
33 #include "attributes.h"
36 * @addtogroup lavu_math
41 * rational number numerator/denominator
43 typedef struct AVRational
{
44 int num
; ///< numerator
45 int den
; ///< denominator
50 * Useful for compilers that do not support compound literals.
51 * @note The return value is not reduced.
53 static inline AVRational
av_make_q(int num
, int den
)
55 AVRational r
= { num
, den
};
60 * Compare two rationals.
61 * @param a first rational
62 * @param b second rational
63 * @return 0 if a==b, 1 if a>b, -1 if a<b, and INT_MIN if one of the
64 * values is of the form 0/0
66 static inline int av_cmp_q(AVRational a
, AVRational b
){
67 const int64_t tmp
= a
.num
* (int64_t)b
.den
- b
.num
* (int64_t)a
.den
;
69 if(tmp
) return (int)((tmp
^ a
.den
^ b
.den
)>>63)|1;
70 else if(b
.den
&& a
.den
) return 0;
71 else if(a
.num
&& b
.num
) return (a
.num
>>31) - (b
.num
>>31);
76 * Convert rational to double.
77 * @param a rational to convert
80 static inline double av_q2d(AVRational a
){
81 return a
.num
/ (double) a
.den
;
86 * This is useful for framerate calculations.
87 * @param dst_num destination numerator
88 * @param dst_den destination denominator
89 * @param num source numerator
90 * @param den source denominator
91 * @param max the maximum allowed for dst_num & dst_den
92 * @return 1 if exact, 0 otherwise
94 int av_reduce(int *dst_num
, int *dst_den
, int64_t num
, int64_t den
, int64_t max
);
97 * Multiply two rationals.
98 * @param b first rational
99 * @param c second rational
102 AVRational
av_mul_q(AVRational b
, AVRational c
) av_const
;
105 * Divide one rational by another.
106 * @param b first rational
107 * @param c second rational
110 AVRational
av_div_q(AVRational b
, AVRational c
) av_const
;
114 * @param b first rational
115 * @param c second rational
118 AVRational
av_add_q(AVRational b
, AVRational c
) av_const
;
121 * Subtract one rational from another.
122 * @param b first rational
123 * @param c second rational
126 AVRational
av_sub_q(AVRational b
, AVRational c
) av_const
;
133 static av_always_inline AVRational
av_inv_q(AVRational q
)
135 AVRational r
= { q
.den
, q
.num
};
140 * Convert a double precision floating point number to a rational.
141 * inf is expressed as {1,0} or {-1,0} depending on the sign.
143 * @param d double to convert
144 * @param max the maximum allowed numerator and denominator
145 * @return (AVRational) d
147 AVRational
av_d2q(double d
, int max
) av_const
;
150 * @return 1 if q1 is nearer to q than q2, -1 if q2 is nearer
151 * than q1, 0 if they have the same distance.
153 int av_nearer_q(AVRational q
, AVRational q1
, AVRational q2
);
156 * Find the nearest value in q_list to q.
157 * @param q_list an array of rationals terminated by {0, 0}
158 * @return the index of the nearest value found in the array
160 int av_find_nearest_q_idx(AVRational q
, const AVRational
* q_list
);
166 #endif /* AVUTIL_RATIONAL_H */