modules/video_filter/gaussianblur.c

   1 /*****************************************************************************
   2  * gaussianblur.c : gaussian blur video filter
   3  *****************************************************************************
   4  * Copyright (C) 2000-2007 VLC authors and VideoLAN
   5  *
   6  * Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 /*****************************************************************************
  24  * Preamble
  25  *****************************************************************************/
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_filter.h>
  34 #include <vlc_picture.h>
  35
  36 #include <math.h>                                          /* exp(), sqrt() */
  37
  38 /*****************************************************************************
  39  * Module descriptor
  40  *****************************************************************************/
  41 static int  Create    ( filter_t * );
  42
  43 #define SIGMA_MIN (0.01)
  44 #define SIGMA_MAX (4096.0)
  45
  46 #define SIGMA_TEXT N_("Gaussian's std deviation")
  47 #define SIGMA_LONGTEXT N_( \
  48     "Gaussian's standard deviation. The blurring will take " \
  49     "into account pixels up to 3*sigma away in any direction.")
  50
  51 #define GAUSSIAN_HELP N_("Add a blurring effect")
  52
  53 #define FILTER_PREFIX "gaussianblur-"
  54
  55 vlc_module_begin ()
  56     set_description( N_("Gaussian blur video filter") )
  57     set_shortname( N_( "Gaussian Blur" ))
  58     set_help(GAUSSIAN_HELP)
  59     set_category( CAT_VIDEO )
  60     set_subcategory( SUBCAT_VIDEO_VFILTER )
  61
  62     add_float_with_range( FILTER_PREFIX "sigma", 2., SIGMA_MIN, SIGMA_MAX,
  63                           SIGMA_TEXT, SIGMA_LONGTEXT,
  64                           false )
  65
  66     set_callback_video_filter( Create )
  67 vlc_module_end ()
  68
  69 /*****************************************************************************
  70  * Local prototypes
  71  *****************************************************************************/
  72 VIDEO_FILTER_WRAPPER_CLOSE(Filter, Destroy)
  73
  74 static const char *const ppsz_filter_options[] = {
  75     "sigma", NULL
  76 };
  77
  78 /* Comment this to use floats instead of integers (faster for bigger sigma
  79  * values)
  80  * For sigma = 2 ints are faster
  81  * For sigma = 4 floats are faster
  82  */
  83 #define DONT_USE_FLOATS
  84
  85 #ifdef DONT_USE_FLOATS
  86 #   define type_t int
  87 #else
  88 #   define type_t float
  89 #endif
  90
  91 typedef struct
  92 {
  93     double f_sigma;
  94     int i_dim;
  95
  96     type_t *pt_distribution;
  97     type_t *pt_buffer;
  98     type_t *pt_scale;
  99 } filter_sys_t;
 100
 101 static void gaussianblur_InitDistribution( filter_sys_t *p_sys )
 102 {
 103     double f_sigma = p_sys->f_sigma;
 104     int i_dim = (int)(3.*f_sigma);
 105     type_t *pt_distribution = xmalloc( (2*i_dim+1) * sizeof( type_t ) );
 106
 107     for( int x = -i_dim; x <= i_dim; x++ )
 108     {
 109         const float f_distribution = sqrt( exp(-(x*x)/(f_sigma*f_sigma) ) / (2.*M_PI*f_sigma*f_sigma) );
 110 #ifdef DONT_USE_FLOATS
 111         const float f_factor = 1 << 8;
 112 #else
 113         const float f_factor = 1;
 114 #endif
 115
 116         pt_distribution[i_dim+x] = (type_t)( f_distribution * f_factor );
 117         //printf("%f\n",(float)pt_distribution[i_dim+x]);
 118     }
 119     p_sys->i_dim = i_dim;
 120     p_sys->pt_distribution = pt_distribution;
 121 }
 122
 123 static int Create( filter_t *p_filter )
 124 {
 125     if(   p_filter->fmt_in.video.i_chroma != VLC_CODEC_I420
 126        && p_filter->fmt_in.video.i_chroma != VLC_CODEC_J420
 127        && p_filter->fmt_in.video.i_chroma != VLC_CODEC_YV12
 128
 129        && p_filter->fmt_in.video.i_chroma != VLC_CODEC_I422
 130        && p_filter->fmt_in.video.i_chroma != VLC_CODEC_J422
 131       )
 132     {
 133         /* We only want planar YUV 4:2:0 or 4:2:2 */
 134         msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
 135                  (char*)&(p_filter->fmt_in.video.i_chroma) );
 136         return VLC_EGENERIC;
 137     }
 138
 139     if( p_filter->fmt_in.video.i_chroma != p_filter->fmt_out.video.i_chroma )
 140     {
 141         msg_Err( p_filter, "Input and output chromas don't match" );
 142         return VLC_EGENERIC;
 143     }
 144
 145     filter_sys_t *p_sys = malloc( sizeof( filter_sys_t ) );
 146     if( p_sys == NULL )
 147         return VLC_ENOMEM;
 148     p_filter->p_sys = p_sys;
 149
 150     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
 151                        p_filter->p_cfg );
 152
 153     p_filter->ops = &Filter_ops;
 154
 155     p_sys->f_sigma =
 156         var_CreateGetFloat( p_filter, FILTER_PREFIX "sigma" );
 157     if( p_sys->f_sigma <= 0. )
 158     {
 159         msg_Err( p_filter, "sigma must be greater than zero" );
 160         return VLC_EGENERIC;
 161     }
 162     gaussianblur_InitDistribution( p_sys );
 163     msg_Dbg( p_filter, "gaussian distribution is %d pixels wide",
 164              p_sys->i_dim*2+1 );
 165
 166     p_sys->pt_buffer = NULL;
 167     p_sys->pt_scale = NULL;
 168
 169     return VLC_SUCCESS;
 170 }
 171
 172 static void Destroy( filter_t *p_filter )
 173 {
 174     filter_sys_t *p_sys = p_filter->p_sys;
 175
 176     free( p_sys->pt_distribution );
 177     free( p_sys->pt_buffer );
 178     free( p_sys->pt_scale );
 179
 180     free( p_sys );
 181 }
 182
 183 static void Filter( filter_t *p_filter, picture_t *p_pic, picture_t *p_outpic )
 184 {
 185     filter_sys_t *p_sys = p_filter->p_sys;
 186     const int i_dim = p_sys->i_dim;
 187     type_t *pt_buffer;
 188     type_t *pt_scale;
 189     const type_t *pt_distribution = p_sys->pt_distribution;
 190
 191     if( !p_sys->pt_buffer )
 192     {
 193         p_sys->pt_buffer = realloc_or_free( p_sys->pt_buffer,
 194                                p_pic->p[Y_PLANE].i_visible_lines *
 195                                p_pic->p[Y_PLANE].i_pitch * sizeof( type_t ) );
 196     }
 197
 198     pt_buffer = p_sys->pt_buffer;
 199     if( !p_sys->pt_scale )
 200     {
 201         const int i_visible_lines = p_pic->p[Y_PLANE].i_visible_lines;
 202         const int i_visible_pitch = p_pic->p[Y_PLANE].i_visible_pitch;
 203         const int i_pitch = p_pic->p[Y_PLANE].i_pitch;
 204
 205         p_sys->pt_scale = xmalloc( i_visible_lines * i_pitch * sizeof( type_t ) );
 206         pt_scale = p_sys->pt_scale;
 207
 208         for( int i_line = 0; i_line < i_visible_lines; i_line++ )
 209         {
 210             for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
 211             {
 212                 type_t t_value = 0;
 213
 214                 for( int y = __MAX( -i_dim, -i_line );
 215                      y <= __MIN( i_dim, i_visible_lines - i_line - 1 );
 216                      y++ )
 217                 {
 218                     for( int x = __MAX( -i_dim, -i_col );
 219                          x <= __MIN( i_dim, i_visible_pitch - i_col + 1 );
 220                          x++ )
 221                     {
 222                         t_value += pt_distribution[y+i_dim] *
 223                                    pt_distribution[x+i_dim];
 224                     }
 225                 }
 226                 pt_scale[i_line*i_pitch+i_col] = t_value;
 227             }
 228         }
 229     }
 230
 231     pt_scale = p_sys->pt_scale;
 232     for( int i_plane = 0 ; i_plane < p_pic->i_planes ; i_plane++ )
 233     {
 234
 235         uint8_t *p_in = p_pic->p[i_plane].p_pixels;
 236         uint8_t *p_out = p_outpic->p[i_plane].p_pixels;
 237
 238         const int i_visible_lines = p_pic->p[i_plane].i_visible_lines;
 239         const int i_visible_pitch = p_pic->p[i_plane].i_visible_pitch;
 240         const int i_in_pitch = p_pic->p[i_plane].i_pitch;
 241
 242         const int x_factor = p_pic->p[Y_PLANE].i_visible_pitch/i_visible_pitch-1;
 243         const int y_factor = p_pic->p[Y_PLANE].i_visible_lines/i_visible_lines-1;
 244
 245         for( int i_line = 0; i_line < i_visible_lines; i_line++ )
 246         {
 247             for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
 248             {
 249                 type_t t_value = 0;
 250                 const int c = i_line*i_in_pitch+i_col;
 251                 for( int x = __MAX( -i_dim, -i_col*(x_factor+1) );
 252                      x <= __MIN( i_dim, (i_visible_pitch - i_col)*(x_factor+1) + 1 );
 253                      x++ )
 254                 {
 255                     t_value += pt_distribution[x+i_dim] *
 256                                p_in[c+(x>>x_factor)];
 257                 }
 258                 pt_buffer[c] = t_value;
 259             }
 260         }
 261         for( int i_line = 0; i_line < i_visible_lines; i_line++ )
 262         {
 263             for( int i_col = 0; i_col < i_visible_pitch; i_col++ )
 264             {
 265                 type_t t_value = 0;
 266                 const int c = i_line*i_in_pitch+i_col;
 267                 for( int y = __MAX( -i_dim, (-i_line)*(y_factor+1) );
 268                      y <= __MIN( i_dim, (i_visible_lines - i_line)*(y_factor+1) - 1 );
 269                      y++ )
 270                 {
 271                     t_value += pt_distribution[y+i_dim] *
 272                                pt_buffer[c+(y>>y_factor)*i_in_pitch];
 273                 }
 274
 275                 const type_t t_scale = pt_scale[(i_line<<y_factor)*(i_in_pitch<<x_factor)+(i_col<<x_factor)];
 276                 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 ?
 277             }
 278         }
 279     }
 280 }