modules/video_filter/antiflicker.c

   1 /*****************************************************************************
   2  * antiflicker.c : antiflicker video effect plugin for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000-2011 VLC authors and VideoLAN
   5  * $Id:
   6  *
   7  * Authors: Dharani Prabhu <dharani.prabhu.s@gmail.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_filter.h>
  35 #include <vlc_atomic.h>
  36 #include <vlc_picture.h>
  37 #include "filter_picture.h"
  38
  39 /*****************************************************************************
  40  * Local prototypes
  41  *****************************************************************************/
  42 static int GetLuminanceAvg( picture_t * p_pic );
  43 static picture_t *Filter( filter_t *, picture_t * );
  44 static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
  45                            vlc_value_t oldval, vlc_value_t newval,
  46                            void *p_data );
  47
  48 static int  Create    ( vlc_object_t * );
  49 static void Destroy   ( vlc_object_t * );
  50
  51 #define WINDOW_TEXT N_("Window size")
  52 #define WINDOW_LONGTEXT N_("Number of frames (0 to 100)")
  53
  54 #define SFTN_TEXT N_("Softening value")
  55 #define SFTN_LONGTEXT N_("Number of frames consider for smoothening (0 to 30)")
  56
  57 #define FILTER_PREFIX "antiflicker-"
  58
  59 #define MAX_WINDOW_SZ 100
  60 #define MAX_SOFTENING_SZ 31
  61 #define SCENE_CHANGE_THRESHOLD 100
  62
  63 /*****************************************************************************
  64  * Module descriptor
  65  *****************************************************************************/
  66 vlc_module_begin ()
  67     set_description( N_("antiflicker video filter") )
  68     set_shortname( N_( "antiflicker" ))
  69     set_capability( "video filter", 0 )
  70     set_category( CAT_VIDEO )
  71     set_subcategory( SUBCAT_VIDEO_VFILTER )
  72
  73     add_integer_with_range( FILTER_PREFIX "window-size", 10, 0, MAX_WINDOW_SZ,
  74         WINDOW_TEXT, WINDOW_LONGTEXT, false )
  75
  76     add_integer_with_range( FILTER_PREFIX "softening-size", 10, 0, MAX_SOFTENING_SZ,
  77         SFTN_TEXT, SFTN_LONGTEXT, false )
  78
  79     add_shortcut( "antiflicker" )
  80     set_callbacks( Create, Destroy )
  81 vlc_module_end ()
  82
  83 /*****************************************************************************
  84  * filter_sys_t: Distort video output method descriptor
  85  *****************************************************************************
  86  * This structure is part of the video output thread descriptor.
  87  * It describes the Distort specific properties of an output thread.
  88  *****************************************************************************/
  89 struct filter_sys_t
  90 {
  91     atomic_int i_window_size;
  92     atomic_int i_softening;
  93     int ia_luminance_data[MAX_WINDOW_SZ];
  94     uint8_t *p_old_data;
  95 };
  96
  97 /*****************************************************************************
  98  * Create: allocates Distort video thread output method
  99  *****************************************************************************
 100  * This function allocates and initializes a Distort vout method.
 101  *****************************************************************************/
 102 static int Create( vlc_object_t *p_this )
 103 {
 104     filter_t *p_filter = (filter_t *)p_this;
 105
 106     switch( p_filter->fmt_in.video.i_chroma )
 107     {
 108         CASE_PLANAR_YUV
 109             break;
 110
 111         default:
 112              msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
 113                       (char*)&(p_filter->fmt_in.video.i_chroma) );
 114             return VLC_EGENERIC;
 115     }
 116
 117     /* Allocate structure */
 118     p_filter->p_sys = malloc( sizeof( *p_filter->p_sys ) );
 119     if( p_filter->p_sys == NULL )
 120         return VLC_ENOMEM;
 121
 122     p_filter->pf_video_filter = Filter;
 123
 124     /* Initialize the arguments */
 125     atomic_init( &p_filter->p_sys->i_window_size,
 126                 var_CreateGetIntegerCommand( p_filter,
 127                                              FILTER_PREFIX"window-size" ) );
 128     atomic_init( &p_filter->p_sys->i_softening,
 129                  var_CreateGetIntegerCommand( p_filter,
 130                                              FILTER_PREFIX"softening-size" ) );
 131
 132     p_filter->p_sys->p_old_data = calloc( p_filter->fmt_in.video.i_width *
 133      (p_filter->fmt_in.video.i_height+1),sizeof(*p_filter->p_sys->p_old_data) );
 134
 135     if( p_filter->p_sys->p_old_data == NULL )
 136     {
 137         free( p_filter->p_sys );
 138         return VLC_ENOMEM;
 139     }
 140
 141     memset( p_filter->p_sys->ia_luminance_data, 0,
 142                     sizeof(p_filter->p_sys->ia_luminance_data) );
 143     p_filter->p_sys->ia_luminance_data[p_filter->p_sys->i_window_size - 1] = 256;
 144
 145     var_AddCallback(p_filter,FILTER_PREFIX "window-size",
 146         AntiFlickerCallback, p_filter->p_sys);
 147     var_AddCallback(p_filter,FILTER_PREFIX "softening-size",
 148         AntiFlickerCallback, p_filter->p_sys);
 149
 150     return VLC_SUCCESS;
 151 }
 152
 153 /*****************************************************************************
 154  * Destroy: destroy Distort video thread output method
 155  *****************************************************************************
 156  * Terminate an output method created by DistortCreateOutputMethod
 157  *****************************************************************************/
 158 static void Destroy( vlc_object_t *p_this )
 159 {
 160     filter_t *p_filter = (filter_t *)p_this;
 161
 162     var_DelCallback(p_filter,FILTER_PREFIX "window-size",
 163         AntiFlickerCallback, p_filter->p_sys);
 164     var_DelCallback(p_filter,FILTER_PREFIX "softening-size",
 165         AntiFlickerCallback, p_filter->p_sys);
 166     free(p_filter->p_sys->p_old_data);
 167     free( p_filter->p_sys );
 168 }
 169
 170 /*****************************************************************************
 171  * GetLuminanceAvg : The funtion returns the luminance average for a picture
 172  *****************************************************************************/
 173 static int GetLuminanceAvg( picture_t *p_pic )
 174 {
 175     uint8_t *p_yplane_out = p_pic->p[Y_PLANE].p_pixels;
 176
 177     int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
 178     int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
 179     int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
 180
 181     if( i_num_lines == 0 || i_num_cols == 0 )
 182         return 0;
 183
 184     unsigned lum_sum = 0;
 185     for( int i_line = 0 ; i_line < i_num_lines ; ++i_line )
 186     {
 187         for( int i_col = 0 ; i_col < i_num_cols; ++i_col )
 188         {
 189             lum_sum += p_yplane_out[i_line*i_in_pitch+i_col];
 190         }
 191     }
 192     unsigned div = i_num_lines * i_num_cols;
 193     return (lum_sum + (div>>1)) / div;
 194 }
 195
 196 /*****************************************************************************
 197  * Filter: adjust the luminance value and renders
 198  *****************************************************************************
 199  * The function uses moving average of past frames to adjust the luminance
 200  * of current frame also applies temporaral smoothening if enabled.
 201  *****************************************************************************/
 202 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 203 {
 204     if( !p_pic ) return NULL;
 205
 206     picture_t *p_outpic = filter_NewPicture( p_filter );
 207     if( !p_outpic )
 208     {
 209         picture_Release( p_pic );
 210         return NULL;
 211     }
 212
 213     /****************** Get variables *************************/
 214
 215     int i_window_size = atomic_load( &p_filter->p_sys->i_window_size );
 216     int i_softening = atomic_load( &p_filter->p_sys->i_softening );
 217
 218     uint8_t *p_yplane_in = p_pic->p[Y_PLANE].p_pixels;
 219     uint8_t *p_yplane_out = p_outpic->p[Y_PLANE].p_pixels;
 220     bool scene_changed = false;
 221
 222     int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
 223     int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
 224     int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
 225     int i_out_pitch = p_outpic->p[Y_PLANE].i_pitch;
 226
 227     /******** Get the luminance average for the current picture ********/
 228     int lum_avg = GetLuminanceAvg(p_pic);
 229
 230     /*Identify as scene change if the luminance average deviates
 231      more than the threshold value or if it is the first frame*/
 232
 233     if( abs(lum_avg - p_filter->p_sys->
 234         ia_luminance_data[i_window_size - 1]) > SCENE_CHANGE_THRESHOLD
 235         || p_filter->p_sys->ia_luminance_data[i_window_size - 1] == 256)
 236     {
 237         scene_changed = true;
 238     }
 239
 240     if ( scene_changed )
 241     {
 242         //reset the luminance data
 243         for (int i = 0; i < i_window_size; ++i)
 244             p_filter->p_sys->ia_luminance_data[i] = lum_avg;
 245         plane_CopyPixels( &p_outpic->p[Y_PLANE], &p_pic->p[Y_PLANE] );
 246     }
 247     else
 248     {
 249         /******* Compute the adjustment factor using moving average ********/
 250         for (int i = 0; i < i_window_size-1 ; ++i)
 251             p_filter->p_sys->ia_luminance_data[i] =
 252                            p_filter->p_sys->ia_luminance_data[i+1];
 253
 254         p_filter->p_sys->ia_luminance_data[i_window_size - 1] = lum_avg;
 255
 256         float scale = 1.0;
 257         if (lum_avg > 0)
 258         {
 259              float filt = 0;
 260              for (int i = 0; i < i_window_size; i++)
 261                   filt += (float) p_filter->p_sys->ia_luminance_data[i];
 262              scale = filt/(i_window_size*lum_avg);
 263         }
 264
 265         /******* Apply the adjustment factor to each pixel on Y_PLANE ********/
 266         uint8_t shift = 8;
 267         int scale_num = __MIN(scale,255) * ( 1 << shift );
 268
 269         for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
 270         {
 271             for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
 272             {
 273                 uint8_t pixel_data = p_yplane_in[i_line*i_in_pitch+i_col];
 274                 int pixel_val = ( scale_num * pixel_data +
 275                        (1<<(shift -1)) ) >> shift;
 276                 p_yplane_out[i_line*i_out_pitch+i_col] =
 277                        (pixel_val>255) ? 255:pixel_val;
 278             }
 279         }
 280     }
 281
 282     /***************** Copy the UV plane as such *****************************/
 283     plane_CopyPixels( &p_outpic->p[U_PLANE], &p_pic->p[U_PLANE] );
 284     plane_CopyPixels( &p_outpic->p[V_PLANE], &p_pic->p[V_PLANE] );
 285
 286     if (scene_changed || i_softening == 0)
 287     {
 288        return CopyInfoAndRelease( p_outpic, p_pic );
 289     }
 290
 291     /******* Temporal softening phase. Adapted from code by Steven Don ******/
 292     uint8_t *p_yplane_out_old = p_filter->p_sys->p_old_data;
 293     int i_video_width = p_filter->fmt_in.video.i_width;
 294
 295     for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
 296     {
 297         for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
 298         {
 299             uint8_t pixel_data = p_yplane_out[i_line*i_out_pitch+i_col];
 300             uint8_t pixel_old = p_yplane_out_old[i_line*i_video_width+i_col];
 301             int diff = abs(pixel_data - pixel_old);
 302             if (diff < i_softening)
 303             {
 304                 if (diff > (i_softening >> 1))
 305                 {
 306                     p_yplane_out_old[i_line*i_video_width+i_col] =
 307                         ((pixel_data * 2) + pixel_old) /3;
 308                 }
 309             }
 310             else
 311             {
 312                 p_yplane_out_old[i_line*i_video_width+i_col] = pixel_data;
 313             }
 314             p_yplane_out[i_line*i_out_pitch+i_col] =
 315                 p_yplane_out_old[i_line*i_video_width+i_col];
 316         }
 317     }
 318
 319     return CopyInfoAndRelease( p_outpic, p_pic );
 320 }
 321
 322 /*****************************************************************************
 323  * Callback function to set the parameters
 324  *****************************************************************************
 325  * This function sets the parameters necesscary for the filter
 326  *****************************************************************************/
 327 static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
 328                            vlc_value_t oldval, vlc_value_t newval,
 329                            void *p_data )
 330 {
 331     VLC_UNUSED(p_this); VLC_UNUSED(oldval);
 332     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 333
 334     if( !strcmp( psz_var, FILTER_PREFIX "window-size" ) )
 335         atomic_store( &p_sys->i_window_size, newval.i_int );
 336     else if( !strcmp( psz_var, FILTER_PREFIX "softening-size" ) )
 337         atomic_store( &p_sys->i_softening, newval.i_int );
 338
 339     return VLC_SUCCESS;
 340 }