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

Macros
#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)
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	filter_frame (AVFilterLink *inlink, AVFrame *in)
static av_cold void	uninit (AVFilterContext *ctx)

Variables
static const AVOption	edgedetect_options []
static const AVFilterPad	edgedetect_inputs []
static const AVFilterPad	edgedetect_outputs []
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.

Macro Definition Documentation

#define OFFSET

(

x

)

offsetof(EdgeDetectContext, x)

Definition at line 43 of file vf_edgedetect.c.

#define FLAGS   AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

Definition at line 44 of file vf_edgedetect.c.

#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().

Enumeration Type Documentation

anonymous enum

Enumerator:

DIRECTION_45UP
DIRECTION_45DOWN
DIRECTION_HORIZONTAL
DIRECTION_VERTICAL

Definition at line 123 of file vf_edgedetect.c.

Function Documentation

AVFILTER_DEFINE_CLASS

(

edgedetect

)

static av_cold int init ( AVFilterContext *  ctx )

static

Definition at line 53 of file vf_edgedetect.c.

static int query_formats ( AVFilterContext *  ctx )

static

Definition at line 62 of file vf_edgedetect.c.

static int config_props ( AVFilterLink *  inlink )

static

Definition at line 69 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 82 of file vf_edgedetect.c.

Referenced by filter_frame().

static int get_rounded_direction ( int  gx, int  gy  )

static

Definition at line 130 of file vf_edgedetect.c.

Referenced by sobel().

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 157 of file vf_edgedetect.c.

Referenced by filter_frame().

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 183 of file vf_edgedetect.c.

Referenced by filter_frame().

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 210 of file vf_edgedetect.c.

Referenced by filter_frame().

static int filter_frame ( AVFilterLink *  inlink, AVFrame *  in  )

static

Definition at line 245 of file vf_edgedetect.c.

static av_cold void uninit ( AVFilterContext *  ctx )

static

Definition at line 294 of file vf_edgedetect.c.

Variable Documentation

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.

const AVFilterPad edgedetect_inputs[]

static

Initial value:

= {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .config_props = config_props,
        .filter_frame = filter_frame,
     },
     { NULL }
}

Definition at line 302 of file vf_edgedetect.c.

const AVFilterPad edgedetect_outputs[]

static

Initial value:

= {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
}

Definition at line 312 of file vf_edgedetect.c.

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        = edgedetect_inputs,
    .outputs       = edgedetect_outputs,
    .priv_class    = &edgedetect_class,
    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
}

Definition at line 320 of file vf_edgedetect.c.