libavutil/rational.c File Reference

rational numbers More...

#include "avassert.h"
#include <limits.h>
#include "common.h"
#include "mathematics.h"
#include "rational.h"

Go to the source code of this file.

Defines
#define	LOG2   0.69314718055994530941723212145817656807550013436025
Functions
int	av_reduce (int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
	Reduce a fraction.
AVRational	av_mul_q (AVRational b, AVRational c)
	Multiply two rationals.
AVRational	av_div_q (AVRational b, AVRational c)
	Divide one rational by another.
AVRational	av_add_q (AVRational b, AVRational c)
	Add two rationals.
AVRational	av_sub_q (AVRational b, AVRational c)
	Subtract one rational from another.
AVRational	av_d2q (double d, int max)
	Convert a double precision floating point number to a rational.
int	av_nearer_q (AVRational q, AVRational q1, AVRational q2)
int	av_find_nearest_q_idx (AVRational q, const AVRational *q_list)
	Find the nearest value in q_list to q.

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Detailed Description

rational numbers

Author:

Michael Niedermayer <michaelni@gmx.at>

Definition in file rational.c.

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Define Documentation

#define LOG2   0.69314718055994530941723212145817656807550013436025

Referenced by av_d2q().

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Function Documentation

AVRational av_add_q	(	AVRational	b,
		AVRational	c
	)			const

Add two rationals.

Parameters:

	b	first rational
	c	second rational

Returns:

b+c

Definition at line 87 of file rational.c.

Referenced by av_sub_q().

AVRational av_d2q	(	double	d,
		int	max
	)			const

Convert a double precision floating point number to a rational.

inf is expressed as {1,0} or {-1,0} depending on the sign.

Parameters:

	d	double to convert
	max	the maximum allowed numerator and denominator

Returns:

(AVRational) d

Definition at line 96 of file rational.c.

Referenced by av_get_q(), av_opt_set_defaults2(), av_parse_video_rate(), av_set_number2(), config_output_props(), config_props(), init(), matroska_read_header(), microdvd_read_header(), mov_read_tkhd(), mov_read_trak(), mpeg_decode_postinit(), new_video_stream(), nuv_header(), and thp_read_header().

AVRational av_div_q	(	AVRational	b,
		AVRational	c
	)			const

Divide one rational by another.

Parameters:

	b	first rational
	c	second rational

Returns:

b/c

Definition at line 83 of file rational.c.

Referenced by avi_read_header(), config_props_output(), and mpeg_decode_postinit().

int av_find_nearest_q_idx	(	AVRational	q,
		const AVRational *	q_list
	)

Find the nearest value in q_list to q.

Parameters:

q_list

an array of rationals terminated by {0, 0}

Returns:

the index of the nearest value found in the array

Definition at line 127 of file rational.c.

Referenced by transcode().

AVRational av_mul_q	(	AVRational	b,
		AVRational	c
	)			const

Multiply two rationals.

Parameters:

	b	first rational
	c	second rational

Returns:

b*c

Definition at line 78 of file rational.c.

Referenced by av_div_q(), avi_write_header(), config_props(), and mpeg_decode_postinit().

int av_nearer_q	(	AVRational	q,
		AVRational	q1,
		AVRational	q2
	)

Returns:

1 if q1 is nearer to q than q2, -1 if q2 is nearer than q1, 0 if they have the same distance.

Definition at line 112 of file rational.c.

Referenced by av_find_nearest_q_idx().

int av_reduce	(	int *	dst_num,
		int *	dst_den,
		int64_t	num,
		int64_t	den,
		int64_t	max
	)

Reduce a fraction.

This is useful for framerate calculations.

Parameters:

	dst_num	destination numerator
	dst_den	destination denominator
	num	source numerator
	den	source denominator
	max	the maximum allowed for dst_num & dst_den

Returns:

1 if exact, 0 otherwise

Definition at line 36 of file rational.c.

Referenced by asf_read_header(), av_add_q(), av_d2q(), av_mul_q(), av_resample_init(), av_set_pts_info(), avcodec_string(), avformat_find_stream_info(), avi_write_header(), config_output(), decode_frame(), decode_slice_header(), dump_stream_format(), dxa_read_header(), matroska_read_header(), mov_read_trak(), mov_write_pasp_tag(), mpeg_decode_postinit(), MPV_encode_init(), mxf_parse_mpeg2_frame(), parse_source_parameters(), read_fps(), show_stream(), skeleton_header(), smacker_read_header(), start_frame(), tmv_read_header(), transcode(), vmd_read_header(), and yuv4_read_header().

AVRational av_sub_q	(	AVRational	b,
		AVRational	c
	)			const

Subtract one rational from another.

Parameters:

	b	first rational
	c	second rational

Returns:

b-c

Definition at line 92 of file rational.c.