Data Structures
struct	AVRational
	rational number numerator/denominator More...

Enumerations
enum	AVRounding { AV_ROUND_ZERO = 0, AV_ROUND_INF = 1, AV_ROUND_DOWN = 2, AV_ROUND_UP = 3, AV_ROUND_NEAR_INF = 5, AV_ROUND_PASS_MINMAX = 8192 }

Functions
int64_t av_const	av_gcd (int64_t a, int64_t b)
	Return the greatest common divisor of a and b. More...

int64_t	av_rescale (int64_t a, int64_t b, int64_t c) av_const
	Rescale a 64-bit integer with rounding to nearest. More...

int64_t	av_rescale_rnd (int64_t a, int64_t b, int64_t c, enum AVRounding) av_const
	Rescale a 64-bit integer with specified rounding. More...

int64_t	av_rescale_q (int64_t a, AVRational bq, AVRational cq) av_const
	Rescale a 64-bit integer by 2 rational numbers. More...

int64_t	av_rescale_q_rnd (int64_t a, AVRational bq, AVRational cq, enum AVRounding) av_const
	Rescale a 64-bit integer by 2 rational numbers with specified rounding. More...

int	av_compare_ts (int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
	Compare 2 timestamps each in its own timebases. More...

int64_t	av_compare_mod (uint64_t a, uint64_t b, uint64_t mod)
	Compare 2 integers modulo mod. More...

int64_t	av_rescale_delta (AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t *last, AVRational out_tb)
	Rescale a timestamp while preserving known durations. More...

int64_t	av_add_stable (AVRational ts_tb, int64_t ts, AVRational inc_tb, int64_t inc)
	Add a value to a timestamp. More...

static AVRational	av_make_q (int num, int den)
	Create a rational. More...

static int	av_cmp_q (AVRational a, AVRational b)
	Compare two rationals. More...

static double	av_q2d (AVRational a)
	Convert rational to double. More...

int	av_reduce (int dst_num, int dst_den, int64_t num, int64_t den, int64_t max)
	Reduce a fraction. More...

AVRational	av_mul_q (AVRational b, AVRational c) av_const
	Multiply two rationals. More...

AVRational	av_div_q (AVRational b, AVRational c) av_const
	Divide one rational by another. More...

AVRational	av_add_q (AVRational b, AVRational c) av_const
	Add two rationals. More...

AVRational	av_sub_q (AVRational b, AVRational c) av_const
	Subtract one rational from another. More...

static av_always_inline AVRational	av_inv_q (AVRational q)
	Invert a rational. More...

AVRational	av_d2q (double d, int max) av_const
	Convert a double precision floating point number to a rational. More...

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. More...

uint32_t	av_q2intfloat (AVRational q)
	Converts a AVRational to a IEEE 32bit float. More...

Detailed Description

Enumeration Type Documentation

enum AVRounding

Enumerator
AV_ROUND_ZERO	Round toward zero.
AV_ROUND_INF	Round away from zero.
AV_ROUND_DOWN	Round toward -infinity.
AV_ROUND_UP	Round toward +infinity.
AV_ROUND_NEAR_INF	Round to nearest and halfway cases away from zero.
AV_ROUND_PASS_MINMAX	Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE.

Definition at line 70 of file mathematics.h.

Function Documentation

int64_t av_const av_gcd	(	int64_t	a,
		int64_t	b
	)

Return the greatest common divisor of a and b.

If both a and b are 0 or either or both are <0 then behavior is undefined.

int64_t av_rescale	(	int64_t	a,
		int64_t	b,
		int64_t	c
	)		const

Rescale a 64-bit integer with rounding to nearest.

A simple a*b/c isn't possible as it can overflow.

int64_t av_rescale_rnd	(	int64_t	a,
		int64_t	b,
		int64_t	c,
		enum	AVRounding
	)		const

Rescale a 64-bit integer with specified rounding.

A simple a*b/c isn't possible as it can overflow.

Returns: rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is INT64_MIN or INT64_MAX then a is passed through unchanged.

Examples:: muxing.c, and resampling_audio.c.

Referenced by main(), and write_audio_frame().

int64_t av_rescale_q	(	int64_t	a,
		AVRational	bq,
		AVRational	cq
	)		const

Rescale a 64-bit integer by 2 rational numbers.

Examples:: filtering_video.c, muxing.c, and remuxing.c.

Referenced by display_frame(), main(), and write_audio_frame().

int64_t av_rescale_q_rnd	(	int64_t	a,
		AVRational	bq,
		AVRational	cq,
		enum	AVRounding
	)		const

Rescale a 64-bit integer by 2 rational numbers with specified rounding.

Returns: rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is INT64_MIN or INT64_MAX then a is passed through unchanged.

Examples:: remuxing.c.

Referenced by main().

int av_compare_ts	(	int64_t	ts_a,
		AVRational	tb_a,
		int64_t	ts_b,
		AVRational	tb_b
	)

Compare 2 timestamps each in its own timebases.

The result of the function is undefined if one of the timestamps is outside the int64_t range when represented in the others timebase.

Returns: -1 if ts_a is before ts_b, 1 if ts_a is after ts_b or 0 if they represent the same position

Examples:: muxing.c.

Referenced by get_audio_frame(), get_video_frame(), and main().

int64_t av_compare_mod	(	uint64_t	a,
		uint64_t	b,
		uint64_t	mod
	)

Compare 2 integers modulo mod.

That is we compare integers a and b for which only the least significant log2(mod) bits are known.

Parameters

mod	must be a power of 2

Returns: a negative value if a is smaller than b a positive value if a is greater than b 0 if a equals b

int64_t av_rescale_delta	(	AVRational	in_tb,
		int64_t	in_ts,
		AVRational	fs_tb,
		int	duration,
		int64_t *	last,
		AVRational	out_tb
	)

Rescale a timestamp while preserving known durations.

Parameters

in_ts	Input timestamp
in_tb	Input timebase
fs_tb	Duration and *last timebase
duration	duration till the next call
out_tb	Output timebase

int64_t av_add_stable	(	AVRational	ts_tb,
		int64_t	ts,
		AVRational	inc_tb,
		int64_t	inc
	)

Add a value to a timestamp.

This function guarantees that when the same value is repeatly added that no accumulation of rounding errors occurs.

Parameters

ts	Input timestamp
ts_tb	Input timestamp timebase
inc	value to add to ts
inc_tb	inc timebase

static AVRational av_make_q	(	int	num,
		int	den
	)

inlinestatic

Create a rational.

Useful for compilers that do not support compound literals.

Note: The return value is not reduced.

Definition at line 53 of file rational.h.

static int av_cmp_q	(	AVRational	a,
		AVRational	b
	)

inlinestatic

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 66 of file rational.h.

static double av_q2d ( AVRational a )

inlinestatic

Convert rational to double.

Parameters

a	rational to convert

Returns: (double) a

Definition at line 80 of file rational.h.

Referenced by av_ts_make_time_string().

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

AVRational av_mul_q	(	AVRational	b,
		AVRational	c
	)		const

Multiply two rationals.

Parameters

b	first rational
c	second rational

Returns: b*c

AVRational av_div_q	(	AVRational	b,
		AVRational	c
	)		const

Divide one rational by another.

Parameters

b	first rational
c	second rational

Returns: b/c

AVRational av_add_q	(	AVRational	b,
		AVRational	c
	)		const

Add two rationals.

Parameters

b	first rational
c	second rational

Returns: b+c

AVRational av_sub_q	(	AVRational	b,
		AVRational	c
	)		const

Subtract one rational from another.

Parameters

b	first rational
c	second rational

Returns: b-c

static av_always_inline AVRational av_inv_q ( AVRational q )

static

Invert a rational.

Parameters

q value

Returns: 1 / q

Definition at line 133 of file rational.h.

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

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.

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

uint32_t av_q2intfloat ( AVRational q )

Converts a AVRational to a IEEE 32bit float.

The float is returned in a uint32_t and its value is platform indepenant.

Data Structures

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

Function Documentation