libavfilter/vf_edgedetect.c File Reference

Edge detection filter. More...

#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"

Go to the source code of this file.

Data Structures
struct	EdgeDetectContext
Defines
#define	OFFSET(x)   offsetof(EdgeDetectContext, x)
#define	FLAGS   AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
#define	COPY_MAXIMA(ay, ax, by, bx)
Enumerations
enum	{ DIRECTION_45UP, DIRECTION_45DOWN, DIRECTION_HORIZONTAL, DIRECTION_VERTICAL }
Functions
	AVFILTER_DEFINE_CLASS (edgedetect)
static av_cold int	init (AVFilterContext *ctx, const char *args)
static int	query_formats (AVFilterContext *ctx)
static int	config_props (AVFilterLink *inlink)
static void	gaussian_blur (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
static int	get_rounded_direction (int gx, int gy)
static void	sobel (AVFilterContext *ctx, int w, int h, uint16_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
static void	non_maximum_suppression (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint16_t *src, int src_linesize)
static void	double_threshold (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
static int	end_frame (AVFilterLink *inlink)
static av_cold void	uninit (AVFilterContext *ctx)
static int	null_draw_slice (AVFilterLink *inlink, int y, int h, int slice_dir)
Variables
static const AVOption	edgedetect_options []
AVFilter	avfilter_vf_edgedetect

---

Detailed Description

Edge detection filter.

See also:

https://en.wikipedia.org/wiki/Canny_edge_detector

Definition in file vf_edgedetect.c.

---

Define Documentation

#define COPY_MAXIMA	(	ay,
		ax,
		by,
		bx		)

Value:

do {                \
    if (src[i] > src[(ay)*src_linesize + i+(ax)] &&     \
        src[i] > src[(by)*src_linesize + i+(bx)])       \
        dst[i] = av_clip_uint8(src[i]);                 \
} while (0)

Referenced by non_maximum_suppression().

#define FLAGS   AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

Definition at line 44 of file vf_edgedetect.c.

#define OFFSET

(

x

)

offsetof(EdgeDetectContext, x)

Definition at line 43 of file vf_edgedetect.c.

---

Enumeration Type Documentation

anonymous enum

Enumerator:

DIRECTION_45UP
DIRECTION_45DOWN
DIRECTION_HORIZONTAL
DIRECTION_VERTICAL

Definition at line 130 of file vf_edgedetect.c.

---

Function Documentation

AVFILTER_DEFINE_CLASS

(

edgedetect

)

static int config_props

(

AVFilterLink *

inlink

)

[static]

Definition at line 76 of file vf_edgedetect.c.

static void double_threshold	(	AVFilterContext *	ctx,
		int	w,
		int	h,
		uint8_t *	dst,
		int	dst_linesize,
		const uint8_t *	src,
		int	src_linesize
	)			[static]

Definition at line 217 of file vf_edgedetect.c.

Referenced by end_frame().

static int end_frame

(

AVFilterLink *

inlink

)

[static]

Definition at line 252 of file vf_edgedetect.c.

static void gaussian_blur	(	AVFilterContext *	ctx,
		int	w,
		int	h,
		uint8_t *	dst,
		int	dst_linesize,
		const uint8_t *	src,
		int	src_linesize
	)			[static]

Definition at line 89 of file vf_edgedetect.c.

Referenced by end_frame().

static int get_rounded_direction	(	int	gx,
		int	gy
	)			[static]

Definition at line 137 of file vf_edgedetect.c.

Referenced by sobel().

static av_cold int init	(	AVFilterContext *	ctx,
		const char *	args
	)			[static]

Definition at line 53 of file vf_edgedetect.c.

static void non_maximum_suppression	(	AVFilterContext *	ctx,
		int	w,
		int	h,
		uint8_t *	dst,
		int	dst_linesize,
		const uint16_t *	src,
		int	src_linesize
	)			[static]

Definition at line 190 of file vf_edgedetect.c.

Referenced by end_frame().

static int null_draw_slice	(	AVFilterLink *	inlink,
		int	y,
		int	h,
		int	slice_dir
	)			[static]

Definition at line 296 of file vf_edgedetect.c.

static int query_formats

(

AVFilterContext *

ctx

)

[static]

Definition at line 69 of file vf_edgedetect.c.

static void sobel	(	AVFilterContext *	ctx,
		int	w,
		int	h,
		uint16_t *	dst,
		int	dst_linesize,
		const uint8_t *	src,
		int	src_linesize
	)			[static]

Definition at line 164 of file vf_edgedetect.c.

Referenced by end_frame().

static av_cold void uninit

(

AVFilterContext *

ctx

)

[static]

Definition at line 288 of file vf_edgedetect.c.

---

Variable Documentation

AVFilter avfilter_vf_edgedetect

Initial value:

 {
    .name          = "edgedetect",
    .description   = NULL_IF_CONFIG_SMALL("Detect and draw edge."),
    .priv_size     = sizeof(EdgeDetectContext),
    .init          = init,
    .uninit        = uninit,
    .query_formats = query_formats,

    .inputs    = (const AVFilterPad[]) {
       {
           .name             = "default",
           .type             = AVMEDIA_TYPE_VIDEO,
           .draw_slice       = null_draw_slice,
           .config_props     = config_props,
           .end_frame        = end_frame,
           .min_perms        = AV_PERM_READ
        },
        { .name = NULL }
    },
    .outputs   = (const AVFilterPad[]) {
        {
            .name            = "default",
            .type            = AVMEDIA_TYPE_VIDEO,
        },
        { .name = NULL }
    },
}

Definition at line 298 of file vf_edgedetect.c.

const AVOption edgedetect_options[] [static]

Initial value:

 {
    { "high", "set high threshold", OFFSET(high), AV_OPT_TYPE_DOUBLE, {.dbl=50/255.}, 0, 1, FLAGS },
    { "low",  "set low threshold",  OFFSET(low),  AV_OPT_TYPE_DOUBLE, {.dbl=20/255.}, 0, 1, FLAGS },
    { NULL },
}

Definition at line 45 of file vf_edgedetect.c.