transform.h File Reference

transform input video More...

#include <stdint.h>

Go to the source code of this file.

Macros
#define	INTERPOLATE_DEFAULT   INTERPOLATE_BILINEAR
#define	INTERPOLATE_FAST   INTERPOLATE_NEAREST
#define	INTERPOLATE_BEST   INTERPOLATE_BIQUADRATIC
#define	FILL_DEFAULT   FILL_ORIGINAL

Enumerations
enum	InterpolateMethod { INTERPOLATE_NEAREST, INTERPOLATE_BILINEAR, INTERPOLATE_BIQUADRATIC, INTERPOLATE_COUNT }
enum	FillMethod {   FILL_BLANK, FILL_ORIGINAL, FILL_CLAMP, FILL_MIRROR,   FILL_COUNT }

Functions
void	avfilter_get_matrix (float x_shift, float y_shift, float angle, float zoom, float *matrix)
	Get an affine transformation matrix from a given translation, rotation, and zoom factor.
void	avfilter_add_matrix (const float *m1, const float *m2, float *result)
	Add two matrices together.
void	avfilter_sub_matrix (const float *m1, const float *m2, float *result)
	Subtract one matrix from another.
void	avfilter_mul_matrix (const float *m1, float scalar, float *result)
	Multiply a matrix by a scalar value.
int	avfilter_transform (const uint8_t *src, uint8_t *dst, int src_stride, int dst_stride, int width, int height, const float *matrix, enum InterpolateMethod interpolate, enum FillMethod fill)
	Do an affine transformation with the given interpolation method.

Detailed Description

transform input video

All matrices are defined as a single 9-item block of contiguous memory. For example, the identity matrix would be:

float *matrix = {1, 0, 0,
                 0, 1, 0,
                 0, 0, 1};

Definition in file transform.h.

Macro Definition Documentation

#define INTERPOLATE_DEFAULT   INTERPOLATE_BILINEAR

Definition at line 47 of file transform.h.

#define INTERPOLATE_FAST   INTERPOLATE_NEAREST

Definition at line 48 of file transform.h.

#define INTERPOLATE_BEST   INTERPOLATE_BIQUADRATIC

Definition at line 49 of file transform.h.

#define FILL_DEFAULT   FILL_ORIGINAL

Definition at line 60 of file transform.h.

Enumeration Type Documentation

enum InterpolateMethod

Enumerator:

INTERPOLATE_NEAREST
INTERPOLATE_BILINEAR
INTERPOLATE_BIQUADRATIC
INTERPOLATE_COUNT

Definition at line 39 of file transform.h.

enum FillMethod

Enumerator:

FILL_BLANK
FILL_ORIGINAL
FILL_CLAMP
FILL_MIRROR
FILL_COUNT

Definition at line 51 of file transform.h.

Function Documentation

void avfilter_get_matrix	(	float	x_shift,
		float	y_shift,
		float	angle,
		float	zoom,
		float *	matrix
	)

Get an affine transformation matrix from a given translation, rotation, and zoom factor.

The matrix will look like:

[ zoom * cos(angle), -sin(angle), x_shift, sin(angle), zoom * cos(angle), y_shift, 0, 0, 1 ]

Parameters

x_shift	horizontal translation
y_shift	vertical translation
angle	rotation in radians
zoom	scale percent (1.0 = 100%)
matrix	9-item affine transformation matrix

Definition at line 106 of file transform.c.

Referenced by filter_frame().

void avfilter_add_matrix	(	const float *	m1,
		const float *	m2,
		float *	result
	)

Add two matrices together.

result = m1 + m2.

Parameters

m1	9-item transformation matrix
m2	9-item transformation matrix
result	9-item transformation matrix

Definition at line 118 of file transform.c.

void avfilter_sub_matrix	(	const float *	m1,
		const float *	m2,
		float *	result
	)

Subtract one matrix from another.

result = m1 - m2.

Parameters

m1	9-item transformation matrix
m2	9-item transformation matrix
result	9-item transformation matrix

Definition at line 125 of file transform.c.

void avfilter_mul_matrix	(	const float *	m1,
		float	scalar,
		float *	result
	)

Multiply a matrix by a scalar value.

result = m1 * scalar.

Parameters

m1	9-item transformation matrix
scalar	a number
result	9-item transformation matrix

Definition at line 132 of file transform.c.

int avfilter_transform	(	const uint8_t *	src,
		uint8_t *	dst,
		int	src_stride,
		int	dst_stride,
		int	width,
		int	height,
		const float *	matrix,
		enum InterpolateMethod	interpolate,
		enum FillMethod	fill
	)

Do an affine transformation with the given interpolation method.

This multiplies each vector [x,y,1] by the matrix and then interpolates to get the final value.

Parameters

src	source image
dst	destination image
src_stride	source image line size in bytes
dst_stride	destination image line size in bytes
width	image width in pixels
height	image height in pixels
matrix	9-item affine transformation matrix
interpolate	pixel interpolation method
fill	edge fill method

Returns

negative on error

Definition at line 149 of file transform.c.

Referenced by filter_frame().