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vf_removelogo.c File Reference

Advanced blur-based logo removing filter. More...

#include "libavutil/imgutils.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#include "bbox.h"
#include "lavfutils.h"
#include "lswsutils.h"

Go to the source code of this file.

Data Structures

struct  RemovelogoContext
 This code implements a filter to remove annoying TV logos and other annoying images placed onto a video stream. More...
 

Macros

#define apply_mask_fudge_factor(x)   (((x) >> 2) + x)
 Choose a slightly larger mask size to improve performance.
 
#define SHOW_LOGO_INFO(mask_type)
 

Functions

static void convert_mask_to_strength_mask (uint8_t *data, int linesize, int w, int h, int min_val, int *max_mask_size)
 Pre-process an image to give distance information.
 
static int query_formats (AVFilterContext *ctx)
 
static int load_mask (uint8_t **mask, int *w, int *h, const char *filename, void *log_ctx)
 
static void generate_half_size_image (const uint8_t *src_data, int src_linesize, uint8_t *dst_data, int dst_linesize, int src_w, int src_h, int *max_mask_size)
 Generate a scaled down image with half width, height, and intensity.
 
static av_cold int init (AVFilterContext *ctx, const char *args)
 
static int config_props_input (AVFilterLink *inlink)
 
static unsigned int blur_pixel (int ***mask, const uint8_t *mask_data, int mask_linesize, uint8_t *image_data, int image_linesize, int w, int h, int x, int y)
 Blur image.
 
static void blur_image (int ***mask, const uint8_t *src_data, int src_linesize, uint8_t *dst_data, int dst_linesize, const uint8_t *mask_data, int mask_linesize, int w, int h, int direct, FFBoundingBox *bbox)
 Blur image plane using a mask.
 
static int filter_frame (AVFilterLink *inlink, AVFilterBufferRef *inpicref)
 
static void uninit (AVFilterContext *ctx)
 

Variables

static const AVFilterPad removelogo_inputs []
 
static const AVFilterPad removelogo_outputs []
 
AVFilter avfilter_vf_removelogo
 

Detailed Description

Advanced blur-based logo removing filter.

This filter loads an image mask file showing where a logo is and uses a blur transform to remove the logo.

Based on the libmpcodecs remove-logo filter by Robert Edele.

Definition in file vf_removelogo.c.

Macro Definition Documentation

#define apply_mask_fudge_factor (   x)    (((x) >> 2) + x)

Choose a slightly larger mask size to improve performance.

This function maps the absolute minimum mask size needed to the mask size we'll actually use. f(x) = x (the smallest that will work) will produce the sharpest results, but will be quite jittery. f(x) = 1.25x (what I'm using) is a good tradeoff in my opinion. This will calculate only at init-time, so you can put a long expression here without effecting performance.

Definition at line 104 of file vf_removelogo.c.

Referenced by convert_mask_to_strength_mask().

#define SHOW_LOGO_INFO (   mask_type)
Value:
av_log(ctx, AV_LOG_VERBOSE, #mask_type " x1:%d x2:%d y1:%d y2:%d max_mask_size:%d\n", \
removelogo->mask_type##_mask_bbox.x1, removelogo->mask_type##_mask_bbox.x2, \
removelogo->mask_type##_mask_bbox.y1, removelogo->mask_type##_mask_bbox.y2, \
mask_type##_max_mask_size);

Referenced by init().

Function Documentation

static void convert_mask_to_strength_mask ( uint8_t data,
int  linesize,
int  w,
int  h,
int  min_val,
int *  max_mask_size 
)
static

Pre-process an image to give distance information.

This function takes a bitmap image and converts it in place into a distance image. A distance image is zero for pixels outside of the logo and is the Manhattan distance (|dx| + |dy|) from the logo edge for pixels inside of the logo. This will overestimate the distance, but that is safe, and is far easier to implement than a proper pythagorean distance since I'm using a modified erosion algorithm to compute the distances.

Parameters
maskimage which will be converted from a greyscale image into a distance image.

Definition at line 120 of file vf_removelogo.c.

Referenced by generate_half_size_image(), and init().

static int query_formats ( AVFilterContext ctx)
static

Definition at line 193 of file vf_removelogo.c.

static int load_mask ( uint8_t **  mask,
int *  w,
int *  h,
const char *  filename,
void log_ctx 
)
static

Definition at line 200 of file vf_removelogo.c.

Referenced by init().

static void generate_half_size_image ( const uint8_t src_data,
int  src_linesize,
uint8_t dst_data,
int  dst_linesize,
int  src_w,
int  src_h,
int *  max_mask_size 
)
static

Generate a scaled down image with half width, height, and intensity.

This function not only scales down an image, but halves the value in each pixel too. The purpose of this is to produce a chroma filter image out of a luma filter image. The pixel values store the distance to the edge of the logo and halving the dimensions halves the distance. This function rounds up, because a downwards rounding error could cause the filter to fail, but an upwards rounding error will only cause a minor amount of excess blur in the chroma planes.

Definition at line 241 of file vf_removelogo.c.

Referenced by init().

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

Definition at line 267 of file vf_removelogo.c.

static int config_props_input ( AVFilterLink inlink)
static

Definition at line 340 of file vf_removelogo.c.

static unsigned int blur_pixel ( int ***  mask,
const uint8_t mask_data,
int  mask_linesize,
uint8_t image_data,
int  image_linesize,
int  w,
int  h,
int  x,
int  y 
)
static

Blur image.

It takes a pixel that is inside the mask and blurs it. It does so by finding the average of all the pixels within the mask and outside of the mask.

Parameters
mask_datathe mask plane to use for averaging
image_datathe image plane to blur
wwidth of the image
hheight of the image
xx-coordinate of the pixel to blur
yy-coordinate of the pixel to blur

Definition at line 369 of file vf_removelogo.c.

Referenced by blur_image().

static void blur_image ( int ***  mask,
const uint8_t src_data,
int  src_linesize,
uint8_t dst_data,
int  dst_linesize,
const uint8_t mask_data,
int  mask_linesize,
int  w,
int  h,
int  direct,
FFBoundingBox bbox 
)
static

Blur image plane using a mask.

Parameters
sourceThe image to have it's logo removed.
destinationWhere the output image will be stored.
source_strideHow far apart (in memory) two consecutive lines are.
destinationSame as source_stride, but for the destination image.
widthWidth of the image. This is the same for source and destination.
heightHeight of the image. This is the same for source and destination.
is_image_directIf the image is direct, then source and destination are the same and we can save a lot of time by not copying pixels that haven't changed.
filterThe image that stores the distance to the edge of the logo for each pixel.
logo_start_xsmallest x-coordinate that contains at least 1 logo pixel.
logo_start_ysmallest y-coordinate that contains at least 1 logo pixel.
logo_end_xlargest x-coordinate that contains at least 1 logo pixel.
logo_end_ylargest y-coordinate that contains at least 1 logo pixel.

This function processes an entire plane. Pixels outside of the logo are copied to the output without change, and pixels inside the logo have the de-blurring function applied.

Definition at line 442 of file vf_removelogo.c.

Referenced by filter_frame().

static int filter_frame ( AVFilterLink inlink,
AVFilterBufferRef inpicref 
)
static

Definition at line 476 of file vf_removelogo.c.

static void uninit ( AVFilterContext ctx)
static

Definition at line 517 of file vf_removelogo.c.

Variable Documentation

const AVFilterPad removelogo_inputs[]
static
Initial value:
= {
{
.name = "default",
.get_video_buffer = ff_null_get_video_buffer,
.config_props = config_props_input,
.filter_frame = filter_frame,
.min_perms = AV_PERM_READ,
},
{ NULL }
}

Definition at line 539 of file vf_removelogo.c.

const AVFilterPad removelogo_outputs[]
static
Initial value:
= {
{
.name = "default",
},
{ NULL }
}

Definition at line 551 of file vf_removelogo.c.

AVFilter avfilter_vf_removelogo
Initial value:
= {
.name = "removelogo",
.description = NULL_IF_CONFIG_SMALL("Remove a TV logo based on a mask image."),
.priv_size = sizeof(RemovelogoContext),
.init = init,
}

Definition at line 559 of file vf_removelogo.c.