modules/video_filter/noise.c

   1 /*****************************************************************************
   2  * noise.c : "add noise to image" video filter
   3  *****************************************************************************
   4  * Copyright (C) 2000-2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 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 General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, 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_rand.h>
  35
  36 #include <vlc_filter.h>
  37 #include "filter_picture.h"
  38
  39 /*****************************************************************************
  40  * Local prototypes
  41  *****************************************************************************/
  42 static int  Create    ( vlc_object_t * );
  43 static picture_t *Filter( filter_t *, picture_t * );
  44
  45 #define FILTER_PREFIX "noise-"
  46
  47 /*****************************************************************************
  48  * Module descriptor
  49  *****************************************************************************/
  50 vlc_module_begin ()
  51     set_description( N_("Noise video filter") )
  52     set_shortname( N_( "Noise" ))
  53     set_capability( "video filter2", 0 )
  54     set_category( CAT_VIDEO )
  55     set_subcategory( SUBCAT_VIDEO_VFILTER )
  56
  57     add_shortcut( "noise" )
  58     set_callbacks( Create, NULL )
  59 vlc_module_end ()
  60
  61 /*****************************************************************************
  62  * Create: allocates Distort video thread output method
  63  *****************************************************************************
  64  * This function allocates and initializes a Distort vout method.
  65  *****************************************************************************/
  66 static int Create( vlc_object_t *p_this )
  67 {
  68     filter_t *p_filter = (filter_t *)p_this;
  69     p_filter->pf_video_filter = Filter;
  70
  71     return VLC_SUCCESS;
  72 }
  73
  74 /*****************************************************************************
  75  * Render: displays previously rendered output
  76  *****************************************************************************
  77  * This function send the currently rendered image to Distort image, waits
  78  * until it is displayed and switch the two rendering buffers, preparing next
  79  * frame.
  80  *****************************************************************************/
  81 static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
  82 {
  83     picture_t *p_outpic;
  84     int i_index;
  85
  86     if( !p_pic ) return NULL;
  87
  88     p_outpic = filter_NewPicture( p_filter );
  89     if( !p_outpic )
  90     {
  91         msg_Warn( p_filter, "can't get output picture" );
  92         picture_Release( p_pic );
  93         return NULL;
  94     }
  95
  96     for( i_index = 0 ; i_index < p_pic->i_planes ; i_index++ )
  97     {
  98         uint8_t *p_in = p_pic->p[i_index].p_pixels;
  99         uint8_t *p_out = p_outpic->p[i_index].p_pixels;
 100
 101         const int i_num_lines = p_pic->p[i_index].i_visible_lines;
 102         const int i_num_cols = p_pic->p[i_index].i_visible_pitch;
 103         const int i_in_pitch = p_pic->p[i_index].i_pitch;
 104         const int i_out_pitch = p_outpic->p[i_index].i_pitch;
 105
 106         int i_line, i_col;
 107
 108         for( i_line = 0 ; i_line < i_num_lines ; i_line++ )
 109         {
 110             if( vlc_mrand48()&7 )
 111             {
 112                 /* line isn't noisy */
 113                 vlc_memcpy( p_out+i_line*i_out_pitch, p_in+i_line*i_in_pitch,
 114                             i_num_cols );
 115             }
 116             else
 117             {
 118                 /* this line is noisy */
 119                 unsigned noise_level = (vlc_mrand48()&7)+2;
 120                 for( i_col = 0; i_col < i_num_cols ; i_col++ )
 121                 {
 122                     if( ((unsigned)vlc_mrand48())%noise_level )
 123                     {
 124                         p_out[i_line*i_out_pitch+i_col] =
 125                             p_in[i_line*i_in_pitch+i_col];
 126                     }
 127                     else
 128                     {
 129                         p_out[i_line*i_out_pitch+i_col] = (vlc_mrand48()&3)*0x7f;
 130                     }
 131                 }
 132             }
 133         }
 134     }
 135
 136     return CopyInfoAndRelease( p_outpic, p_pic );
 137 }