libavutil/rational.h File Reference

rational numbers More...

#include <stdint.h>
#include <limits.h>
#include "attributes.h"

Go to the source code of this file.

Data Structures
struct	AVRational
	rational number numerator/denominator More...
Functions
static int	av_cmp_q (AVRational a, AVRational b)
	Compare two rationals.
static double	av_q2d (AVRational a)
	Convert rational to double.
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) av_const
	Multiply two rationals.
AVRational	av_div_q (AVRational b, AVRational c) av_const
	Divide one rational by another.
AVRational	av_add_q (AVRational b, AVRational c) av_const
	Add two rationals.
AVRational	av_sub_q (AVRational b, AVRational c) av_const
	Subtract one rational from another.
AVRational	av_d2q (double d, int max) av_const
	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.

---

Detailed Description

rational numbers

Author:

Michael Niedermayer <michaelni@gmx.at>

Definition in file rational.h.

---

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().

static int av_cmp_q	(	AVRational	a,
		AVRational	b
	)			[inline, static]

Compare two rationals.

Parameters:

	a	first rational
	b	second rational

Returns:

0 if a==b, 1 if a>b, -1 if a<b, and INT_MIN if one of the values is of the form 0/0

Definition at line 50 of file rational.h.

Referenced by av_nearer_q(), avformat_write_header(), decode_slice_header(), dump_stream_format(), ff_h263_aspect_to_info(), mpeg_decode_postinit(), start_frame(), and video_thread().

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().

static double av_q2d

(

AVRational

a

)

[inline, static]

Convert rational to double.

Parameters:

a

rational to convert

Returns:

(double) a

Definition at line 64 of file rational.h.

Referenced by audio_decode_frame(), av_dump_format(), avformat_find_stream_info(), avformat_write_header(), avi_write_header(), config_input(), config_output_props(), config_props(), decode_syncpoint(), do_video_out(), do_video_stats(), dump_stream_format(), dv_write_pack(), end_frame(), fbdev_read_header(), fbdev_read_packet(), ff_rate_control_init(), ff_rate_estimate_qscale(), ff_vbv_update(), flv_write_header(), grab_read_header(), init_pass2(), mkv_write_tracks(), modify_qscale(), mov_write_tkhd_tag(), mov_write_trak_tag(), movie_get_frame(), mpeg1_encode_sequence_header(), MPV_encode_init(), MPV_encode_picture(), mxf_write_header(), pkt_dump_internal(), queue_picture(), read_header(), read_seek(), read_thread(), sdl_write_header(), select_frame(), start_frame(), subtitle_thread(), thp_read_header(), time_value_string(), transcode(), ts_str(), v4l2_read_header(), vf_next_put_image(), video_image_display(), video_thread(), write_trailer(), x11grab_read_header(), and x11grab_read_packet().

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.