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Diffstat (limited to 'contrib/ffmpeg/libavutil/rational.h')
-rw-r--r-- | contrib/ffmpeg/libavutil/rational.h | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavutil/rational.h b/contrib/ffmpeg/libavutil/rational.h new file mode 100644 index 000000000..63c0b150f --- /dev/null +++ b/contrib/ffmpeg/libavutil/rational.h @@ -0,0 +1,114 @@ +/* + * 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 RATIONAL_H +#define RATIONAL_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. + * returns 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 // RATIONAL_H |