research.m1stereo.tv/gitweb/ - melted/blob - src/modules/core/filter_brightness.c

   1 /*
   2  * filter_brightness.c -- gamma filter
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include "filter_brightness.h"
  22
  23 #include <framework/mlt_frame.h>
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <math.h>
  28
  29 /** Do it :-).
  30 */
  31
  32 static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  33 {
  34         // Get the image
  35         int error = mlt_frame_get_image( this, image, format, width, height, 1 );
  36
  37         // Only process if we have no error and a valid colour space
  38         if ( error == 0 && *format == mlt_image_yuv422 )
  39         {
  40                 // Get the brightness level
  41                 double level = mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "brightness" );
  42
  43                 // Only process if level is something other than 1
  44                 if ( level != 1.0 )
  45                 {
  46                         uint8_t *p = *image;
  47                         uint8_t *q = *image + *width * *height * 2;
  48                         int32_t x = 0;
  49                         int32_t m = level * ( 1 << 16 );
  50
  51                         while ( p != q )
  52                         {
  53                                 x = ( *p * m ) >> 16;
  54                                 *p = x < 16 ? 16 : x > 235 ? 235 : x;
  55                                 p += 2;
  56                         }
  57                 }
  58         }
  59
  60         return error;
  61 }
  62
  63 /** Filter processing.
  64 */
  65
  66 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  67 {
  68         // Get the starting brightness level
  69         double level = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "start" ) );
  70
  71         // If there is an end adjust gain to the range
  72         if ( mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "end" ) != NULL )
  73         {
  74                 // Determine the time position of this frame in the transition duration
  75                 mlt_position in = mlt_filter_get_in( this );
  76                 mlt_position out = mlt_filter_get_out( this );
  77                 mlt_position time = mlt_frame_get_position( frame );
  78                 double position = ( double )( time - in ) / ( double )( out - in + 1 );
  79                 double end = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "end" ) );
  80                 level += ( end - level ) * position;
  81         }
  82
  83         // Push the frame filter
  84         mlt_properties_set_double( MLT_FRAME_PROPERTIES( frame ), "brightness", level );
  85         mlt_frame_push_get_image( frame, filter_get_image );
  86
  87         return frame;
  88 }
  89
  90 /** Constructor for the filter.
  91 */
  92
  93 mlt_filter filter_brightness_init( char *arg )
  94 {
  95         mlt_filter this = mlt_filter_new( );
  96         if ( this != NULL )
  97         {
  98                 this->process = filter_process;
  99                 mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "start", arg == NULL ? "1" : arg );
 100         }
 101         return this;
 102 }
 103