modules/video_filter/sharpen.c

   1 /*****************************************************************************
   2  * sharpen.c: Sharpen video filter
   3  *****************************************************************************
   4  * Copyright (C) 2003-2007 the VideoLAN team
   5  * $Id$
   6  *
   7  * Author: Jérémy DEMEULE <dj_mulder at djduron dot no-ip dot org>
   8  *         Jean-Baptiste Kempf <jb at videolan dot org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /* The sharpen filter. */
  26 /*
  27  * static int filter[] = { -1, -1, -1,
  28  *                         -1,  8, -1,
  29  *                         -1, -1, -1 };
  30  */
  31
  32 /*****************************************************************************
  33  * Preamble
  34  *****************************************************************************/
  35
  36 #ifdef HAVE_CONFIG_H
  37 # include "config.h"
  38 #endif
  39
  40 #include <vlc_common.h>
  41 #include <vlc_plugin.h>
  42 #include <vlc_vout.h>
  43
  44 #include "vlc_filter.h"
  45 #include "filter_picture.h"
  46
  47 #define SIG_TEXT N_("Sharpen strength (0-2)")
  48 #define SIG_LONGTEXT N_("Set the Sharpen strength, between 0 and 2. Defaults to 0.05.")
  49
  50 /*****************************************************************************
  51  * Local prototypes
  52  *****************************************************************************/
  53 static int  Create    ( vlc_object_t * );
  54 static void Destroy   ( vlc_object_t * );
  55
  56 static picture_t *Filter( filter_t *, picture_t * );
  57 static int SharpenCallback( vlc_object_t *, char const *,
  58                             vlc_value_t, vlc_value_t, void * );
  59
  60 #define FILTER_PREFIX "sharpen-"
  61
  62 /*****************************************************************************
  63  * Module descriptor
  64  *****************************************************************************/
  65 vlc_module_begin ()
  66     set_description( N_("Augment contrast between contours.") )
  67     set_shortname( N_("Sharpen video filter") )
  68     set_category( CAT_VIDEO )
  69     set_subcategory( SUBCAT_VIDEO_VFILTER )
  70     set_capability( "video filter2", 0 )
  71     add_float_with_range( "sharpen-sigma", 0.05, 0.0, 2.0, NULL,
  72         SIG_TEXT, SIG_LONGTEXT, false )
  73     add_shortcut( "sharpen" )
  74     set_callbacks( Create, Destroy )
  75 vlc_module_end ()
  76
  77 static const char *const ppsz_filter_options[] = {
  78     "sigma", NULL
  79 };
  80
  81 /*****************************************************************************
  82  * filter_sys_t: Sharpen video filter descriptor
  83  *****************************************************************************
  84  * This structure is part of the video output thread descriptor.
  85  * It describes the Sharpen specific properties of an output thread.
  86  *****************************************************************************/
  87
  88 struct filter_sys_t
  89 {
  90     float f_sigma;
  91     int tab_precalc[512];
  92 };
  93
  94 /*****************************************************************************
  95  * clip: avoid negative value and value > 255
  96  *****************************************************************************/
  97 inline static int32_t clip( int32_t a )
  98 {
  99     return (a > 255) ? 255 : (a < 0) ? 0 : a;
 100 }
 101
 102 static void init_precalc_table(filter_sys_t *p_filter)
 103 {
 104     float sigma = p_filter->f_sigma;
 105
 106     for(int i = 0; i < 512; ++i)
 107     {
 108         p_filter->tab_precalc[i] = (i - 256) * sigma;
 109     }
 110 }
 111
 112 /*****************************************************************************
 113  * Create: allocates Sharpen video thread output method
 114  *****************************************************************************
 115  * This function allocates and initializes a Sharpen vout method.
 116  *****************************************************************************/
 117 static int Create( vlc_object_t *p_this )
 118 {
 119     filter_t *p_filter = (filter_t *)p_this;
 120
 121     /* Allocate structure */
 122     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 123     if( p_filter->p_sys == NULL )
 124         return VLC_ENOMEM;
 125
 126     p_filter->pf_video_filter = Filter;
 127
 128     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
 129                    p_filter->p_cfg );
 130
 131     p_filter->p_sys->f_sigma =
 132         var_CreateGetFloatCommand( p_filter, FILTER_PREFIX "sigma" );
 133     var_AddCallback( p_filter, FILTER_PREFIX "sigma",
 134                      SharpenCallback, p_filter->p_sys );
 135
 136     init_precalc_table(p_filter->p_sys);
 137
 138     return VLC_SUCCESS;
 139 }
 140
 141
 142 /*****************************************************************************
 143  * Destroy: destroy Sharpen video thread output method
 144  *****************************************************************************
 145  * Terminate an output method created by SharpenCreateOutputMethod
 146  *****************************************************************************/
 147 static void Destroy( vlc_object_t *p_this )
 148 {
 149     filter_t *p_filter = (filter_t *)p_this;
 150     free( p_filter->p_sys );
 151 }
 152
 153 /*****************************************************************************
 154  * Render: displays previously rendered output
 155  *****************************************************************************
 156  * This function send the currently rendered image to Invert image, waits
 157  * until it is displayed and switch the two rendering buffers, preparing next
 158  * frame.
 159  *****************************************************************************/
 160 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 161 {
 162     picture_t *p_outpic;
 163     int i, j;
 164     uint8_t *p_src = NULL;
 165     uint8_t *p_out = NULL;
 166     int i_src_pitch;
 167     int pix;
 168     const int v1 = -1;
 169     const int v2 = 3; /* 2^3 = 8 */
 170
 171     if( !p_pic ) return NULL;
 172     if( !p_filter ) return NULL;
 173     if( !p_filter->p_sys ) return NULL;
 174
 175     p_outpic = filter_NewPicture( p_filter );
 176     if( !p_outpic )
 177     {
 178         picture_Release( p_pic );
 179         return NULL;
 180     }
 181
 182     /* process the Y plane */
 183     p_src = p_pic->p[Y_PLANE].p_pixels;
 184     p_out = p_outpic->p[Y_PLANE].p_pixels;
 185     if( !p_src || !p_out )
 186     {
 187         msg_Warn( p_filter, "can't get Y plane" );
 188         picture_Release( p_pic );
 189         return NULL;
 190     }
 191
 192     i_src_pitch = p_pic->p[Y_PLANE].i_visible_pitch;
 193
 194     /* perform convolution only on Y plane. Avoid border line. */
 195     for( i = 0; i < p_pic->p[Y_PLANE].i_visible_lines; i++ )
 196     {
 197         if( (i == 0) || (i == p_pic->p[Y_PLANE].i_visible_lines - 1) )
 198         {
 199             for( j = 0; j < p_pic->p[Y_PLANE].i_visible_pitch; j++ )
 200                 p_out[i * i_src_pitch + j] = clip( p_src[i * i_src_pitch + j] );
 201             continue ;
 202         }
 203         for( j = 0; j < p_pic->p[Y_PLANE].i_visible_pitch; j++ )
 204         {
 205             if( (j == 0) || (j == p_pic->p[Y_PLANE].i_visible_pitch - 1) )
 206             {
 207                 p_out[i * i_src_pitch + j] = p_src[i * i_src_pitch + j];
 208                 continue ;
 209             }
 210
 211             pix = (p_src[(i - 1) * i_src_pitch + j - 1] * v1) +
 212                   (p_src[(i - 1) * i_src_pitch + j    ] * v1) +
 213                   (p_src[(i - 1) * i_src_pitch + j + 1] * v1) +
 214                   (p_src[(i    ) * i_src_pitch + j - 1] * v1) +
 215                   (p_src[(i    ) * i_src_pitch + j    ] << v2) +
 216                   (p_src[(i    ) * i_src_pitch + j + 1] * v1) +
 217                   (p_src[(i + 1) * i_src_pitch + j - 1] * v1) +
 218                   (p_src[(i + 1) * i_src_pitch + j    ] * v1) +
 219                   (p_src[(i + 1) * i_src_pitch + j + 1] * v1);
 220
 221         pix = pix >= 0 ? clip(pix) : -clip(pix * -1);
 222         p_out[i * i_src_pitch + j] = clip( p_src[i * i_src_pitch + j] +
 223             p_filter->p_sys->tab_precalc[pix + 256] );
 224         }
 225     }
 226
 227
 228     vlc_memcpy( p_outpic->p[U_PLANE].p_pixels, p_pic->p[U_PLANE].p_pixels,
 229                 p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
 230
 231     vlc_memcpy( p_outpic->p[V_PLANE].p_pixels, p_pic->p[V_PLANE].p_pixels,
 232                 p_outpic->p[V_PLANE].i_lines * p_outpic->p[V_PLANE].i_pitch );
 233
 234
 235     return CopyInfoAndRelease( p_outpic, p_pic );
 236 }
 237
 238 static int SharpenCallback( vlc_object_t *p_this, char const *psz_var,
 239                             vlc_value_t oldval, vlc_value_t newval,
 240                             void *p_data )
 241 {
 242     VLC_UNUSED(p_this); VLC_UNUSED(oldval);
 243     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 244     if( !strcmp( psz_var, FILTER_PREFIX "sigma" ) )
 245         p_sys->f_sigma = __MIN( 2., __MAX( 0., newval.f_float ) );
 246     init_precalc_table(p_sys);
 247     return VLC_SUCCESS;
 248 }