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
  43 #include <vlc_filter.h>
  44 #include "filter_picture.h"
  45
  46 #define SIG_TEXT N_("Sharpen strength (0-2)")
  47 #define SIG_LONGTEXT N_("Set the Sharpen strength, between 0 and 2. Defaults to 0.05.")
  48
  49 /*****************************************************************************
  50  * Local prototypes
  51  *****************************************************************************/
  52 static int  Create    ( vlc_object_t * );
  53 static void Destroy   ( vlc_object_t * );
  54
  55 static picture_t *Filter( filter_t *, picture_t * );
  56 static int SharpenCallback( vlc_object_t *, char const *,
  57                             vlc_value_t, vlc_value_t, void * );
  58
  59 #define SHARPEN_HELP N_("Augment contrast between contours.")
  60 #define FILTER_PREFIX "sharpen-"
  61
  62 /*****************************************************************************
  63  * Module descriptor
  64  *****************************************************************************/
  65 vlc_module_begin ()
  66     set_description( N_("Sharpen video filter") )
  67     set_shortname( N_("Sharpen") )
  68     set_help(SHARPEN_HELP)
  69     set_category( CAT_VIDEO )
  70     set_subcategory( SUBCAT_VIDEO_VFILTER )
  71     set_capability( "video filter2", 0 )
  72     add_float_with_range( "sharpen-sigma", 0.05, 0.0, 2.0, NULL,
  73         SIG_TEXT, SIG_LONGTEXT, false )
  74     add_shortcut( "sharpen" )
  75     set_callbacks( Create, Destroy )
  76 vlc_module_end ()
  77
  78 static const char *const ppsz_filter_options[] = {
  79     "sigma", NULL
  80 };
  81
  82 /*****************************************************************************
  83  * filter_sys_t: Sharpen video filter descriptor
  84  *****************************************************************************
  85  * This structure is part of the video output thread descriptor.
  86  * It describes the Sharpen specific properties of an output thread.
  87  *****************************************************************************/
  88
  89 struct filter_sys_t
  90 {
  91     vlc_mutex_t lock;
  92     int tab_precalc[512];
  93 };
  94
  95 /*****************************************************************************
  96  * clip: avoid negative value and value > 255
  97  *****************************************************************************/
  98 inline static int32_t clip( int32_t a )
  99 {
 100     return (a > 255) ? 255 : (a < 0) ? 0 : a;
 101 }
 102
 103 static void init_precalc_table(filter_sys_t *p_filter, float sigma)
 104 {
 105     for(int i = 0; i < 512; ++i)
 106     {
 107         p_filter->tab_precalc[i] = (i - 256) * sigma;
 108     }
 109 }
 110
 111 /*****************************************************************************
 112  * Create: allocates Sharpen video thread output method
 113  *****************************************************************************
 114  * This function allocates and initializes a Sharpen vout method.
 115  *****************************************************************************/
 116 static int Create( vlc_object_t *p_this )
 117 {
 118     filter_t *p_filter = (filter_t *)p_this;
 119
 120     /* Allocate structure */
 121     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 122     if( p_filter->p_sys == NULL )
 123         return VLC_ENOMEM;
 124
 125     p_filter->pf_video_filter = Filter;
 126
 127     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
 128                    p_filter->p_cfg );
 129
 130     float sigma = var_CreateGetFloatCommand( p_filter, FILTER_PREFIX "sigma" );
 131     init_precalc_table(p_filter->p_sys, sigma);
 132
 133     vlc_mutex_init( &p_filter->p_sys->lock );
 134     var_AddCallback( p_filter, FILTER_PREFIX "sigma",
 135                      SharpenCallback, p_filter->p_sys );
 136
 137     return VLC_SUCCESS;
 138 }
 139
 140
 141 /*****************************************************************************
 142  * Destroy: destroy Sharpen video thread output method
 143  *****************************************************************************
 144  * Terminate an output method created by SharpenCreateOutputMethod
 145  *****************************************************************************/
 146 static void Destroy( vlc_object_t *p_this )
 147 {
 148     filter_t *p_filter = (filter_t *)p_this;
 149     filter_sys_t *p_sys = p_filter->p_sys;
 150
 151     var_DelCallback( p_filter, FILTER_PREFIX "sigma", SharpenCallback, p_sys );
 152     vlc_mutex_destroy( &p_sys->lock );
 153     free( p_sys );
 154 }
 155
 156 /*****************************************************************************
 157  * Render: displays previously rendered output
 158  *****************************************************************************
 159  * This function send the currently rendered image to Invert image, waits
 160  * until it is displayed and switch the two rendering buffers, preparing next
 161  * frame.
 162  *****************************************************************************/
 163 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
 164 {
 165     picture_t *p_outpic;
 166     int i, j;
 167     uint8_t *p_src = NULL;
 168     uint8_t *p_out = NULL;
 169     int i_src_pitch;
 170     int i_out_pitch;
 171     int pix;
 172     const int v1 = -1;
 173     const int v2 = 3; /* 2^3 = 8 */
 174
 175     if( !p_pic ) return NULL;
 176
 177     p_outpic = filter_NewPicture( p_filter );
 178     if( !p_outpic )
 179     {
 180         picture_Release( p_pic );
 181         return NULL;
 182     }
 183
 184     /* process the Y plane */
 185     p_src = p_pic->p[Y_PLANE].p_pixels;
 186     p_out = p_outpic->p[Y_PLANE].p_pixels;
 187     i_src_pitch = p_pic->p[Y_PLANE].i_visible_pitch;
 188     i_out_pitch = p_outpic->p[Y_PLANE].i_visible_pitch;
 189
 190     /* perform convolution only on Y plane. Avoid border line. */
 191     vlc_mutex_lock( &p_filter->p_sys->lock );
 192     for( i = 0; i < p_pic->p[Y_PLANE].i_visible_lines; i++ )
 193     {
 194         if( (i == 0) || (i == p_pic->p[Y_PLANE].i_visible_lines - 1) )
 195         {
 196             for( j = 0; j < p_pic->p[Y_PLANE].i_visible_pitch; j++ )
 197                 p_out[i * i_out_pitch + j] = clip( p_src[i * i_src_pitch + j] );
 198             continue ;
 199         }
 200         for( j = 0; j < p_pic->p[Y_PLANE].i_visible_pitch; j++ )
 201         {
 202             if( (j == 0) || (j == p_pic->p[Y_PLANE].i_visible_pitch - 1) )
 203             {
 204                 p_out[i * i_out_pitch + j] = p_src[i * i_src_pitch + j];
 205                 continue ;
 206             }
 207
 208             pix = (p_src[(i - 1) * i_src_pitch + j - 1] * v1) +
 209                   (p_src[(i - 1) * i_src_pitch + j    ] * v1) +
 210                   (p_src[(i - 1) * i_src_pitch + j + 1] * v1) +
 211                   (p_src[(i    ) * i_src_pitch + j - 1] * v1) +
 212                   (p_src[(i    ) * i_src_pitch + j    ] << v2) +
 213                   (p_src[(i    ) * i_src_pitch + j + 1] * v1) +
 214                   (p_src[(i + 1) * i_src_pitch + j - 1] * v1) +
 215                   (p_src[(i + 1) * i_src_pitch + j    ] * v1) +
 216                   (p_src[(i + 1) * i_src_pitch + j + 1] * v1);
 217
 218            pix = pix >= 0 ? clip(pix) : -clip(pix * -1);
 219            p_out[i * i_out_pitch + j] = clip( p_src[i * i_src_pitch + j] +
 220                p_filter->p_sys->tab_precalc[pix + 256] );
 221         }
 222     }
 223     vlc_mutex_unlock( &p_filter->p_sys->lock );
 224
 225     plane_CopyPixels( &p_outpic->p[U_PLANE], &p_pic->p[U_PLANE] );
 226     plane_CopyPixels( &p_outpic->p[V_PLANE], &p_pic->p[V_PLANE] );
 227
 228     return CopyInfoAndRelease( p_outpic, p_pic );
 229 }
 230
 231 static int SharpenCallback( vlc_object_t *p_this, char const *psz_var,
 232                             vlc_value_t oldval, vlc_value_t newval,
 233                             void *p_data )
 234 {
 235     VLC_UNUSED(p_this); VLC_UNUSED(oldval); VLC_UNUSED(psz_var);
 236     filter_sys_t *p_sys = (filter_sys_t *)p_data;
 237
 238     vlc_mutex_lock( &p_sys->lock );
 239     init_precalc_table(p_sys,  __MIN( 2., __MAX( 0., newval.f_float ) ));
 240     vlc_mutex_unlock( &p_sys->lock );
 241     return VLC_SUCCESS;
 242 }