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vlc/modules/video_filter/gaussianblur.c

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/*****************************************************************************
* gaussianblur.c : gaussian blur video filter
*****************************************************************************
* Copyright (C) 2000-2007 VLC authors and VideoLAN
*
* Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_arrays.h>
#include <vlc_configuration.h>
#include <vlc_plugin.h>
#include <vlc_filter.h>
#include <vlc_picture.h>
#include <math.h> /* exp(), sqrt() */
/*****************************************************************************
* Module descriptor
*****************************************************************************/
static int Create ( filter_t * );
#define SIGMA_MIN (0.01)
#define SIGMA_MAX (4096.0)
#define SIGMA_TEXT N_("Gaussian's std deviation")
#define SIGMA_LONGTEXT N_( \
"Gaussian's standard deviation. The blurring will take " \
"into account pixels up to 3*sigma away in any direction.")
#define GAUSSIAN_HELP N_("Add a blurring effect")
#define FILTER_PREFIX "gaussianblur-"
vlc_module_begin ()
set_description( N_("Gaussian blur video filter") )
set_shortname( N_( "Gaussian Blur" ))
set_help(GAUSSIAN_HELP)
set_subcategory( SUBCAT_VIDEO_VFILTER )
add_float_with_range( FILTER_PREFIX "sigma", 2., SIGMA_MIN, SIGMA_MAX,
SIGMA_TEXT, SIGMA_LONGTEXT )
set_callback_video_filter( Create )
vlc_module_end ()
/*****************************************************************************
* Local prototypes
*****************************************************************************/
VIDEO_FILTER_WRAPPER_CLOSE(Filter, Destroy)
static const char *const ppsz_filter_options[] = {
"sigma", NULL
};
/* Comment this to use floats instead of integers (faster for bigger sigma
* values)
* For sigma = 2 ints are faster
* For sigma = 4 floats are faster
*/
#define DONT_USE_FLOATS
#ifdef DONT_USE_FLOATS
# define type_t int
#else
# define type_t float
#endif
typedef struct
{
double f_sigma;
int i_dim;
type_t *pt_distribution;
type_t *pt_buffer;
type_t *pt_scale;
} filter_sys_t;
static void gaussianblur_InitDistribution( filter_sys_t *p_sys )
{
double f_sigma = p_sys->f_sigma;
int i_dim = (int)(3.*f_sigma);
type_t *pt_distribution = xmalloc( (2*i_dim+1) * sizeof( type_t ) );
for( int x = -i_dim; x <= i_dim; x++ )
{
const float f_distribution = sqrt( exp(-(x*x)/(f_sigma*f_sigma) ) / (2.*M_PI*f_sigma*f_sigma) );
#ifdef DONT_USE_FLOATS
const float f_factor = 1 << 8;
#else
const float f_factor = 1;
#endif
pt_distribution[i_dim+x] = (type_t)( f_distribution * f_factor );
//printf("%f\n",(float)pt_distribution[i_dim+x]);
}
p_sys->i_dim = i_dim;
p_sys->pt_distribution = pt_distribution;
}
static int Create( filter_t *p_filter )
{
if( p_filter->fmt_in.video.i_chroma != VLC_CODEC_I420
&& p_filter->fmt_in.video.i_chroma != VLC_CODEC_YV12
&& p_filter->fmt_in.video.i_chroma != VLC_CODEC_I422
)
{
/* We only want planar YUV 4:2:0 or 4:2:2 */
msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
(char*)&(p_filter->fmt_in.video.i_chroma) );
return VLC_EGENERIC;
}
if( !video_format_IsSameChroma( &p_filter->fmt_in.video,
&p_filter->fmt_out.video ) )
{
msg_Err( p_filter, "Input and output chromas don't match" );
return VLC_EGENERIC;
}
filter_sys_t *p_sys = malloc( sizeof( filter_sys_t ) );
if( p_sys == NULL )
return VLC_ENOMEM;
p_filter->p_sys = p_sys;
config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
p_filter->p_cfg );
p_filter->ops = &Filter_ops;
p_sys->f_sigma =
var_CreateGetFloat( p_filter, FILTER_PREFIX "sigma" );
if( p_sys->f_sigma <= 0. )
{
msg_Err( p_filter, "sigma must be greater than zero" );
return VLC_EGENERIC;
}
gaussianblur_InitDistribution( p_sys );
msg_Dbg( p_filter, "gaussian distribution is %d pixels wide",
p_sys->i_dim*2+1 );
p_sys->pt_buffer = NULL;
p_sys->pt_scale = NULL;
return VLC_SUCCESS;
}
static void Destroy( filter_t *p_filter )
{
filter_sys_t *p_sys = p_filter->p_sys;
free( p_sys->pt_distribution );
free( p_sys->pt_buffer );
free( p_sys->pt_scale );
free( p_sys );
}
static void Filter( filter_t *p_filter, picture_t *p_pic, picture_t *p_outpic )
{
filter_sys_t *p_sys = p_filter->p_sys;
const int i_dim = p_sys->i_dim;
type_t *pt_buffer;
type_t *pt_scale;
const type_t *pt_distribution = p_sys->pt_distribution;
if( !p_sys->pt_buffer )
{
p_sys->pt_buffer = realloc_or_free( p_sys->pt_buffer,
p_pic->p[Y_PLANE].i_visible_lines *
p_pic->p[Y_PLANE].i_pitch * sizeof( type_t ) );
}
pt_buffer = p_sys->pt_buffer;
if( !p_sys->pt_scale )
{
const int i_visible_lines = p_pic->p[Y_PLANE].i_visible_lines;
const int i_visible_pitch = p_pic->p[Y_PLANE].i_visible_pitch;
const int i_pitch = p_pic->p[Y_PLANE].i_pitch;
p_sys->pt_scale = xmalloc( i_visible_lines * i_pitch * sizeof( type_t ) );
pt_scale = p_sys->pt_scale;
for( int i_line = 0; i_line < i_visible_lines; i_line++ )
{
for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
{
type_t t_value = 0;
for( int y = __MAX( -i_dim, -i_line );
y <= __MIN( i_dim, i_visible_lines - i_line - 1 );
y++ )
{
for( int x = __MAX( -i_dim, -i_col );
x <= __MIN( i_dim, i_visible_pitch - i_col + 1 );
x++ )
{
t_value += pt_distribution[y+i_dim] *
pt_distribution[x+i_dim];
}
}
pt_scale[i_line*i_pitch+i_col] = t_value;
}
}
}
pt_scale = p_sys->pt_scale;
for( int i_plane = 0 ; i_plane < p_pic->i_planes ; i_plane++ )
{
uint8_t *p_in = p_pic->p[i_plane].p_pixels;
uint8_t *p_out = p_outpic->p[i_plane].p_pixels;
const int i_visible_lines = p_pic->p[i_plane].i_visible_lines;
const int i_visible_pitch = p_pic->p[i_plane].i_visible_pitch;
const int i_in_pitch = p_pic->p[i_plane].i_pitch;
const int x_factor = p_pic->p[Y_PLANE].i_visible_pitch/i_visible_pitch-1;
const int y_factor = p_pic->p[Y_PLANE].i_visible_lines/i_visible_lines-1;
for( int i_line = 0; i_line < i_visible_lines; i_line++ )
{
for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
{
type_t t_value = 0;
const int c = i_line*i_in_pitch+i_col;
for( int x = __MAX( -i_dim, -i_col*(x_factor+1) );
x <= __MIN( i_dim, (i_visible_pitch - i_col)*(x_factor+1) + 1 );
x++ )
{
t_value += pt_distribution[x+i_dim] *
p_in[c+(x>>x_factor)];
}
pt_buffer[c] = t_value;
}
}
for( int i_line = 0; i_line < i_visible_lines; i_line++ )
{
for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
{
type_t t_value = 0;
const int c = i_line*i_in_pitch+i_col;
for( int y = __MAX( -i_dim, (-i_line)*(y_factor+1) );
y <= __MIN( i_dim, (i_visible_lines - i_line)*(y_factor+1) - 1 );
y++ )
{
t_value += pt_distribution[y+i_dim] *
pt_buffer[c+(y>>y_factor)*i_in_pitch];
}
const type_t t_scale = pt_scale[(i_line<<y_factor)*(i_in_pitch<<x_factor)+(i_col<<x_factor)];
p_out[i_line * p_outpic->p[i_plane].i_pitch + i_col] = (uint8_t)(t_value / t_scale); // FIXME wouldn't it be better to round instead of trunc ?
}
}
}
}
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