libavfilter/vf_deshake.c File Reference

fast deshake / depan video filter More...

#include "avfilter.h"
#include "formats.h"
#include "video.h"
#include "libavutil/common.h"
#include "libavutil/mem.h"
#include "libavutil/pixdesc.h"
#include "libavcodec/dsputil.h"
#include "transform.h"

Go to the source code of this file.

Data Structures

struct IntMotionVector

struct MotionVector

struct Transform

struct DeshakeContext

Defines

#define CHROMA_WIDTH(link) -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)

#define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)

#define CMP(i, j)

Enumerations

enum SearchMethod { EXHAUSTIVE, SMART_EXHAUSTIVE, SEARCH_COUNT }

Functions

static int cmp (const double *a, const double *b)

static double clean_mean (double *values, int count)

Cleaned mean (cuts off 20% of values to remove outliers and then averages).

static void find_block_motion (DeshakeContext *deshake, uint8_t *src1, uint8_t *src2, int cx, int cy, int stride, IntMotionVector *mv)

Find the most likely shift in motion between two frames for a given macroblock.

static int block_contrast (uint8_t *src, int x, int y, int stride, int blocksize)

Find the contrast of a given block.

static double block_angle (int x, int y, int cx, int cy, IntMotionVector *shift)

Find the rotation for a given block.

static void find_motion (DeshakeContext *deshake, uint8_t *src1, uint8_t *src2, int width, int height, int stride, Transform *t)

Find the estimated global motion for a scene given the most likely shift for each block in the frame.

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

static int query_formats (AVFilterContext *ctx)

static int config_props (AVFilterLink *link)

static av_cold void uninit (AVFilterContext *ctx)

static int end_frame (AVFilterLink *link)

static int draw_slice (AVFilterLink *link, int y, int h, int slice_dir)

Variables

AVFilter avfilter_vf_deshake

Detailed Description

fast deshake / depan video filter

SAD block-matching motion compensation to fix small changes in horizontal and/or vertical shift. This filter helps remove camera shake from hand-holding a camera, bumping a tripod, moving on a vehicle, etc.

Algorithm:

For each frame with one previous reference frame
- For each block in the frame
  - If contrast > threshold then find likely motion vector
- For all found motion vectors
  - Find most common, store as global motion vector
- Find most likely rotation angle
- Transform image along global motion

TODO:

Fill frame edges based on previous/next reference frames
Fill frame edges by stretching image near the edges?
- Can this be done quickly and look decent?

Dark Shikari links to http://wiki.videolan.org/SoC_x264_2010#GPU_Motion_Estimation_2 for an algorithm similar to what could be used here to get the gmv It requires only a couple diamond searches + fast downscaling

Special thanks to Jason Kotenko for his help with the algorithm and my inability to see simple errors in C code.

Definition in file vf_deshake.c.

Define Documentation

#define CHROMA_HEIGHT ( link ) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)

Definition at line 63 of file vf_deshake.c.

Referenced by end_frame().

#define CHROMA_WIDTH ( link ) -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)

Definition at line 62 of file vf_deshake.c.

Referenced by end_frame().

#define CMP	(	i,
		j		)

Value:

deshake->c.sad[0](deshake, src1 + cy * stride + cx, \
                                        src2 + (j) * stride + (i), stride, \
                                        deshake->blocksize)

Referenced by find_block_motion().

Enumeration Type Documentation

enum SearchMethod

Enumerator:

EXHAUSTIVE	Search all possible positions.
SMART_EXHAUSTIVE	Search most possible positions (faster).
SEARCH_COUNT

Definition at line 65 of file vf_deshake.c.

Function Documentation

static double block_angle	(	int	x,
		int	y,
		int	cx,
		int	cy,
		IntMotionVector *	shift
	)			`[static]`

Find the rotation for a given block.

Definition at line 232 of file vf_deshake.c.

Referenced by find_motion().

static int block_contrast	(	uint8_t *	src,
		int	x,
		int	y,
		int	stride,
		int	blocksize
	)			`[static]`

Find the contrast of a given block.

When searching for global motion we really only care about the high contrast blocks, so using this method we can actually skip blocks we don't care much about.

Definition at line 208 of file vf_deshake.c.

Referenced by find_motion().

static double clean_mean	(	double *	values,
		int	count
	)			`[static]`

Cleaned mean (cuts off 20% of values to remove outliers and then averages).

Definition at line 116 of file vf_deshake.c.

Referenced by find_motion().

static int cmp	(	const double *	a,
		const double *	b
	)			`[static]`

Definition at line 108 of file vf_deshake.c.

static int config_props ( AVFilterLink * link ) [static]

Definition at line 400 of file vf_deshake.c.

static int draw_slice	(	AVFilterLink *	link,
		int	y,
		int	h,
		int	slice_dir
	)			`[static]`

Definition at line 536 of file vf_deshake.c.

static int end_frame ( AVFilterLink * link ) [static]

Definition at line 428 of file vf_deshake.c.

static void find_block_motion	(	DeshakeContext *	deshake,
		uint8_t *	src1,
		uint8_t *	src2,
		int	cx,
		int	cy,
		int	stride,
		IntMotionVector *	mv
	)			`[static]`

Find the most likely shift in motion between two frames for a given macroblock.

Test each block against several shifts given by the rx and ry attributes. Searches using a simple matrix of those shifts and chooses the most likely shift by the smallest difference in blocks.

Definition at line 137 of file vf_deshake.c.

Referenced by find_motion().

static void find_motion	(	DeshakeContext *	deshake,
		uint8_t *	src1,
		uint8_t *	src2,
		int	width,
		int	height,
		int	stride,
		Transform *	t
	)			`[static]`

Find the estimated global motion for a scene given the most likely shift for each block in the frame.

The global motion is estimated to be the same as the motion from most blocks in the frame, so if most blocks move one pixel to the right and two pixels down, this would yield a motion vector (1, -2).

Definition at line 253 of file vf_deshake.c.

Referenced by end_frame().

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

Definition at line 334 of file vf_deshake.c.

static int query_formats ( AVFilterContext * ctx ) [static]

Definition at line 387 of file vf_deshake.c.

static av_cold void uninit ( AVFilterContext * ctx ) [static]

Definition at line 416 of file vf_deshake.c.

Variable Documentation

AVFilter avfilter_vf_deshake

Initial value:

 {
    .name      = "deshake",
    .description = NULL_IF_CONFIG_SMALL("Stabilize shaky video."),

    .priv_size = sizeof(DeshakeContext),

    .init = init,
    .uninit = uninit,
    .query_formats = query_formats,

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

    .outputs   = (const AVFilterPad[]) {{ .name       = "default",
                                    .type             = AVMEDIA_TYPE_VIDEO, },
                                  { .name = NULL}},
}

Definition at line 541 of file vf_deshake.c.


Data Structures
struct	IntMotionVector
struct	MotionVector
struct	Transform
struct	DeshakeContext
Defines
#define	CHROMA_WIDTH(link) -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)
#define	CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)
#define	CMP(i, j)
Enumerations
enum	SearchMethod { EXHAUSTIVE, SMART_EXHAUSTIVE, SEARCH_COUNT }
Functions
static int	cmp (const double a, const double b)
static double	clean_mean (double *values, int count)
	Cleaned mean (cuts off 20% of values to remove outliers and then averages).
static void	find_block_motion (DeshakeContext deshake, uint8_t src1, uint8_t src2, int cx, int cy, int stride, IntMotionVector mv)
	Find the most likely shift in motion between two frames for a given macroblock.
static int	block_contrast (uint8_t *src, int x, int y, int stride, int blocksize)
	Find the contrast of a given block.
static double	block_angle (int x, int y, int cx, int cy, IntMotionVector *shift)
	Find the rotation for a given block.
static void	find_motion (DeshakeContext deshake, uint8_t src1, uint8_t src2, int width, int height, int stride, Transform t)
	Find the estimated global motion for a scene given the most likely shift for each block in the frame.
static av_cold int	init (AVFilterContext ctx, const char args)
static int	query_formats (AVFilterContext *ctx)
static int	config_props (AVFilterLink *link)
static av_cold void	uninit (AVFilterContext *ctx)
static int	end_frame (AVFilterLink *link)
static int	draw_slice (AVFilterLink *link, int y, int h, int slice_dir)
Variables
AVFilter	avfilter_vf_deshake