git.sesse.net Git - vlc/blob - 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 "filter_picture.h"
  37
  38 /*****************************************************************************
  39  * Local prototypes
  40  *****************************************************************************/
  41 static int GetLuminanceAvg( picture_t * p_pic );
  42 static picture_t *Filter( filter_t *, picture_t * );
  43 static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
  44                            vlc_value_t oldval, vlc_value_t newval,
  45                            void *p_data );
  46
  47 static int  Create    ( vlc_object_t * );
  48 static void Destroy   ( vlc_object_t * );
  49
  50 #define WINDOW_TEXT N_("Window size")
  51 #define WINDOW_LONGTEXT N_("Number of frames (0 to 100)")
  52
  53 #define SFTN_TEXT N_("Softening value")
  54 #define SFTN_LONGTEXT N_("Number of frames consider for smoothening (0 to 30)")
  55
  56 #define FILTER_PREFIX "antiflicker-"
  57
  58 #define MAX_WINDOW_SZ 100
  59 #define MAX_SOFTENING_SZ 31
  60 #define SCENE_CHANGE_THRESHOLD 100
  61
  62 /*****************************************************************************
  63  * Module descriptor
  64  *****************************************************************************/
  65 vlc_module_begin ()
  66     set_description( N_("antiflicker video filter") )
  67     set_shortname( N_( "antiflicker" ))
  68     set_capability( "video filter2", 0 )
  69     set_category( CAT_VIDEO )
  70     set_subcategory( SUBCAT_VIDEO_VFILTER )
  71
  72     add_integer_with_range( FILTER_PREFIX "window-size", 10, 0, MAX_WINDOW_SZ,
  73         WINDOW_TEXT, WINDOW_LONGTEXT, false )
  74
  75     add_integer_with_range( FILTER_PREFIX "softening-size", 10, 0, MAX_SOFTENING_SZ,
  76         SFTN_TEXT, SFTN_LONGTEXT, false )
  77
  78     add_shortcut( "antiflicker" )
  79     set_callbacks( Create, Destroy )
  80 vlc_module_end ()
  81
  82 /*****************************************************************************
  83  * filter_sys_t: Distort video output method descriptor
  84  *****************************************************************************
  85  * This structure is part of the video output thread descriptor.
  86  * It describes the Distort specific properties of an output thread.
  87  *****************************************************************************/
  88 struct filter_sys_t
  89 {
  90     atomic_int i_window_size;
  91     atomic_int i_softening;
  92     int ia_luminance_data[MAX_WINDOW_SZ];
  93     uint8_t *p_old_data;
  94 };
  95
  96 /*****************************************************************************
  97  * Create: allocates Distort video thread output method
  98  *****************************************************************************
  99  * This function allocates and initializes a Distort vout method.
 100  *****************************************************************************/
 101 static int Create( vlc_object_t *p_this )
 102 {
 103     filter_t *p_filter = (filter_t *)p_this;
 104
 105     switch( p_filter->fmt_in.video.i_chroma )
 106     {
 107         CASE_PLANAR_YUV
 108             break;
 109
 110         default:
 111              msg_Err( p_filter, "Unsupported input chroma (%4.4s)",
 112                       (char*)&(p_filter->fmt_in.video.i_chroma) );
 113             return VLC_EGENERIC;
 114     }
 115
 116     /* Allocate structure */
 117     p_filter->p_sys = malloc( sizeof( *p_filter->p_sys ) );
 118     if( p_filter->p_sys == NULL )
 119         return VLC_ENOMEM;
 120
 121     p_filter->pf_video_filter = Filter;
 122
 123     /* Initialize the arguments */
 124     atomic_init( &p_filter->p_sys->i_window_size,
 125                 var_CreateGetIntegerCommand( p_filter,
 126                                              FILTER_PREFIX"window-size" ) );
 127     atomic_init( &p_filter->p_sys->i_softening,
 128                  var_CreateGetIntegerCommand( p_filter,
 129                                              FILTER_PREFIX"softening-size" ) );
 130
 131     p_filter->p_sys->p_old_data = calloc( p_filter->fmt_in.video.i_width *
 132      (p_filter->fmt_in.video.i_height+1),sizeof(*p_filter->p_sys->p_old_data) );
 133
 134     if( p_filter->p_sys->p_old_data == NULL )
 135     {
 136         free( p_filter->p_sys );
 137         return VLC_ENOMEM;
 138     }
 139
 140     memset( p_filter->p_sys->ia_luminance_data, 0,
 141                     sizeof(p_filter->p_sys->ia_luminance_data) );
 142     p_filter->p_sys->ia_luminance_data[p_filter->p_sys->i_window_size - 1] = 256;
 143
 144     var_AddCallback(p_filter,FILTER_PREFIX "window-size",
 145         AntiFlickerCallback, p_filter->p_sys);
 146     var_AddCallback(p_filter,FILTER_PREFIX "softening-size",
 147         AntiFlickerCallback, p_filter->p_sys);
 148
 149     return VLC_SUCCESS;
 150 }
 151
 152 /*****************************************************************************
 153  * Destroy: destroy Distort video thread output method
 154  *****************************************************************************
 155  * Terminate an output method created by DistortCreateOutputMethod
 156  *****************************************************************************/
 157 static void Destroy( vlc_object_t *p_this )
 158 {
 159     filter_t *p_filter = (filter_t *)p_this;
 160
 161     var_DelCallback(p_filter,FILTER_PREFIX "window-size",
 162         AntiFlickerCallback, p_filter->p_sys);
 163     var_DelCallback(p_filter,FILTER_PREFIX "softening-size",
 164         AntiFlickerCallback, p_filter->p_sys);
 165     free(p_filter->p_sys->p_old_data);
 166     free( p_filter->p_sys );
 167 }
 168
 169 /*****************************************************************************
 170  * GetLuminanceAvg : The funtion returns the luminance average for a picture
 171  *****************************************************************************/
 172 static int GetLuminanceAvg( picture_t *p_pic )
 173 {
 174     uint8_t *p_yplane_out = p_pic->p[Y_PLANE].p_pixels;
 175
 176     int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
 177     int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
 178     int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
 179
 180     if( i_num_lines == 0 || i_num_cols == 0 )
 181         return 0;
 182
 183     unsigned lum_sum = 0;
 184     for( int i_line = 0 ; i_line < i_num_lines ; ++i_line )
 185     {
 186         for( int i_col = 0 ; i_col < i_num_cols; ++i_col )
 187         {
 188             lum_sum += p_yplane_out[i_line*i_in_pitch+i_col];
 189         }
 190     }
 191     unsigned div = i_num_lines * i_num_cols;
 192     return (lum_sum + (div>>1)) / div;
 193 }
 194
 195 /*****************************************************************************
 196  * Filter: adjust the luminance value and renders
 197  *****************************************************************************
 198  * The function uses moving average of past frames to adjust the luminance
 199  * of current frame also applies temporaral smoothening if enabled.
 200  *****************************************************************************/
 201 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 202 {
 203     if( !p_pic ) return NULL;
 204
 205     picture_t *p_outpic = filter_NewPicture( p_filter );
 206     if( !p_outpic )
 207     {
 208         picture_Release( p_pic );
 209         return NULL;
 210     }
 211
 212     /****************** Get variables *************************/
 213
 214     int i_window_size = atomic_load( &p_filter->p_sys->i_window_size );
 215     int i_softening = atomic_load( &p_filter->p_sys->i_softening );
 216
 217     uint8_t *p_yplane_in = p_pic->p[Y_PLANE].p_pixels;
 218     uint8_t *p_yplane_out = p_outpic->p[Y_PLANE].p_pixels;
 219     bool scene_changed = false;
 220
 221     int i_num_lines = p_pic->p[Y_PLANE].i_visible_lines;
 222     int i_num_cols = p_pic->p[Y_PLANE].i_visible_pitch;
 223     int i_in_pitch = p_pic->p[Y_PLANE].i_pitch;
 224     int i_out_pitch = p_outpic->p[Y_PLANE].i_pitch;
 225
 226     /******** Get the luminance average for the current picture ********/
 227     int lum_avg = GetLuminanceAvg(p_pic);
 228
 229     /*Identify as scene change if the luminance average deviates
 230      more than the threshold value or if it is the first frame*/
 231
 232     if( abs(lum_avg - p_filter->p_sys->
 233         ia_luminance_data[i_window_size - 1]) > SCENE_CHANGE_THRESHOLD
 234         || p_filter->p_sys->ia_luminance_data[i_window_size - 1] == 256)
 235     {
 236         scene_changed = true;
 237     }
 238
 239     if ( scene_changed )
 240     {
 241         //reset the luminance data
 242         for (int i = 0; i < i_window_size; ++i)
 243             p_filter->p_sys->ia_luminance_data[i] = lum_avg;
 244         plane_CopyPixels( &p_outpic->p[Y_PLANE], &p_pic->p[Y_PLANE] );
 245     }
 246     else
 247     {
 248         /******* Compute the adjustment factor using moving average ********/
 249         for (int i = 0; i < i_window_size-1 ; ++i)
 250             p_filter->p_sys->ia_luminance_data[i] =
 251                            p_filter->p_sys->ia_luminance_data[i+1];
 252
 253         p_filter->p_sys->ia_luminance_data[i_window_size - 1] = lum_avg;
 254
 255         float scale = 1.0;
 256         if (lum_avg > 0)
 257         {
 258              float filt = 0;
 259              for (int i = 0; i < i_window_size; i++)
 260                   filt += (float) p_filter->p_sys->ia_luminance_data[i];
 261              scale = filt/(i_window_size*lum_avg);
 262         }
 263
 264         /******* Apply the adjustment factor to each pixel on Y_PLANE ********/
 265         uint8_t shift = 8;
 266         int scale_num = __MIN(scale,255) * ( 1 << shift );
 267
 268         for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
 269         {
 270             for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
 271             {
 272                 uint8_t pixel_data = p_yplane_in[i_line*i_in_pitch+i_col];
 273                 int pixel_val = ( scale_num * pixel_data +
 274                        (1<<(shift -1)) ) >> shift;
 275                 p_yplane_out[i_line*i_out_pitch+i_col] =
 276                        (pixel_val>255) ? 255:pixel_val;
 277             }
 278         }
 279     }
 280
 281     /***************** Copy the UV plane as such *****************************/
 282     plane_CopyPixels( &p_outpic->p[U_PLANE], &p_pic->p[U_PLANE] );
 283     plane_CopyPixels( &p_outpic->p[V_PLANE], &p_pic->p[V_PLANE] );
 284
 285     if (scene_changed || i_softening == 0)
 286     {
 287        return CopyInfoAndRelease( p_outpic, p_pic );
 288     }
 289
 290     /******* Temporal softening phase. Adapted from code by Steven Don ******/
 291     uint8_t *p_yplane_out_old = p_filter->p_sys->p_old_data;
 292     int i_video_width = p_filter->fmt_in.video.i_width;
 293
 294     for( int i_line = 0 ; i_line < i_num_lines ; i_line++ )
 295     {
 296         for( int i_col = 0; i_col < i_num_cols  ; i_col++ )
 297         {
 298             uint8_t pixel_data = p_yplane_out[i_line*i_out_pitch+i_col];
 299             uint8_t pixel_old = p_yplane_out_old[i_line*i_video_width+i_col];
 300             int diff = abs(pixel_data - pixel_old);
 301             if (diff < i_softening)
 302             {
 303                 if (diff > (i_softening >> 1))
 304                 {
 305                     p_yplane_out_old[i_line*i_video_width+i_col] =
 306                         ((pixel_data * 2) + pixel_old) /3;
 307                 }
 308             }
 309             else
 310             {
 311                 p_yplane_out_old[i_line*i_video_width+i_col] = pixel_data;
 312             }
 313             p_yplane_out[i_line*i_out_pitch+i_col] =
 314                 p_yplane_out_old[i_line*i_video_width+i_col];
 315         }
 316     }
 317
 318     return CopyInfoAndRelease( p_outpic, p_pic );
 319 }
 320
 321 /*****************************************************************************
 322  * Callback function to set the parameters
 323  *****************************************************************************
 324  * This function sets the parameters necesscary for the filter
 325  *****************************************************************************/
 326 static int AntiFlickerCallback( vlc_object_t *p_this, char const *psz_var,
 327                            vlc_value_t oldval, vlc_value_t newval,
 328                            void *p_data )
 329 {
 330     VLC_UNUSED(p_this); VLC_UNUSED(oldval);
 331     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 332
 333     if( !strcmp( psz_var, FILTER_PREFIX "window-size" ) )
 334         atomic_store( &p_sys->i_window_size, newval.i_int );
 335     else if( !strcmp( psz_var, FILTER_PREFIX "softening-size" ) )
 336         atomic_store( &p_sys->i_softening, newval.i_int );
 337
 338     return VLC_SUCCESS;
 339 }