Statistics
| Branch: | Revision:

ffmpeg / libavutil / rational.h @ 0b006599

History | View | Annotate | Download (2.84 KB)

1 5ff85f1d Michael Niedermayer
/*
2
 * Rational numbers
3
 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4
 *
5 b78e7197 Diego Biurrun
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8 5ff85f1d Michael Niedermayer
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10 b78e7197 Diego Biurrun
 * version 2.1 of the License, or (at your option) any later version.
11 5ff85f1d Michael Niedermayer
 *
12 b78e7197 Diego Biurrun
 * FFmpeg is distributed in the hope that it will be useful,
13 5ff85f1d Michael Niedermayer
 * 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.
16
 *
17
 * You should have received a copy of the GNU Lesser General Public
18 b78e7197 Diego Biurrun
 * License along with FFmpeg; if not, write to the Free Software
19 5509bffa Diego Biurrun
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 5ff85f1d Michael Niedermayer
 *
21
 */
22 115329f1 Diego Biurrun
23 5ff85f1d Michael Niedermayer
/**
24
 * @file rational.h
25
 * Rational numbers.
26
 * @author Michael Niedermayer <michaelni@gmx.at>
27
 */
28
29
#ifndef RATIONAL_H
30
#define RATIONAL_H
31
32 5c07b9e9 Michael Niedermayer
/**
33
 * Rational number num/den.
34
 */
35 5ff85f1d Michael Niedermayer
typedef struct AVRational{
36 5c07b9e9 Michael Niedermayer
    int num; ///< numerator
37
    int den; ///< denominator
38 5ff85f1d Michael Niedermayer
} AVRational;
39
40 5c07b9e9 Michael Niedermayer
/**
41 1c95ef8b Dujardin Bernard
 * Compare two rationals.
42
 * @param a first rational
43
 * @param b second rational
44
 * @return 0 if a==b, 1 if a>b and -1 if a<b.
45 5c07b9e9 Michael Niedermayer
 */
46 5ff85f1d Michael Niedermayer
static inline int av_cmp_q(AVRational a, AVRational b){
47
    const int64_t tmp= a.num * (int64_t)b.den - b.num * (int64_t)a.den;
48
49 5c07b9e9 Michael Niedermayer
    if(tmp) return (tmp>>63)|1;
50
    else    return 0;
51 5ff85f1d Michael Niedermayer
}
52
53 5c07b9e9 Michael Niedermayer
/**
54 0b006599 Dujardin Bernard
 * Rational to double conversion.
55 1c95ef8b Dujardin Bernard
 * @param a rational to convert
56
 * @return (double) a
57 5c07b9e9 Michael Niedermayer
 */
58 5ff85f1d Michael Niedermayer
static inline double av_q2d(AVRational a){
59
    return a.num / (double) a.den;
60
}
61
62 c11c2bc2 Alexander Strasser
/**
63 1c95ef8b Dujardin Bernard
 * Reduce a fraction.
64 804de96a Diego Biurrun
 * This is useful for framerate calculations.
65 1c95ef8b Dujardin Bernard
 * @param dst_nom destination numerator
66
 * @param dst_den destination denominator
67
 * @param nom source numerator
68
 * @param den source denominator
69 c11c2bc2 Alexander Strasser
 * @param max the maximum allowed for dst_nom & dst_den
70
 * @return 1 if exact, 0 otherwise
71
 */
72
int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max);
73
74 0b006599 Dujardin Bernard
/**
75
 * Multiplies two rationals.
76
 * @param b first rational.
77
 * @param c second rational.
78
 * @return b*c.
79
 */
80 5ff85f1d Michael Niedermayer
AVRational av_mul_q(AVRational b, AVRational c);
81 0b006599 Dujardin Bernard
82
/**
83
 * Divides two rationals.
84
 * @param b first rational.
85
 * @param c second rational.
86
 * @return b/c.
87
 */
88 5ff85f1d Michael Niedermayer
AVRational av_div_q(AVRational b, AVRational c);
89 0b006599 Dujardin Bernard
90
/**
91
 * Adds two rationals.
92
 * @param b first rational.
93
 * @param c second rational.
94
 * @return b+c.
95
 */
96 5ff85f1d Michael Niedermayer
AVRational av_add_q(AVRational b, AVRational c);
97 0b006599 Dujardin Bernard
98
/**
99
 * Substracts two rationals.
100
 * @param b first rational.
101
 * @param c second rational.
102
 * returns b-c.
103
 */
104 5ff85f1d Michael Niedermayer
AVRational av_sub_q(AVRational b, AVRational c);
105 0b006599 Dujardin Bernard
106
/**
107
 * Converts a double precision floating point number to a rational.
108
 * @param d double to convert
109
 * @param max the maximum allowed numerator and denominator
110
 * @return (AVRational) d.
111
 */
112 5ff85f1d Michael Niedermayer
AVRational av_d2q(double d, int max);
113
114
#endif // RATIONAL_H