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 library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <framework/mlt_filter.h>
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <math.h>
  27
  28 /** Do it :-).
  29 */
  30
  31 static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  32 {
  33         // Get the image
  34         int error = mlt_frame_get_image( this, image, format, width, height, 1 );
  35
  36         // Only process if we have no error and a valid colour space
  37         if ( error == 0 && *format == mlt_image_yuv422 )
  38         {
  39                 // Get the brightness level
  40                 double level = mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "brightness" );
  41
  42                 // Only process if level is something other than 1
  43                 if ( level != 1.0 )
  44                 {
  45                         uint8_t *p = *image;
  46                         uint8_t *q = *image + *width * *height * 2;
  47                         int32_t x = 0;
  48                         int32_t m = level * ( 1 << 16 );
  49
  50                         while ( p != q )
  51                         {
  52                                 x = ( *p * m ) >> 16;
  53                                 *p = x < 16 ? 16 : x > 235 ? 235 : x;
  54                                 p += 2;
  55                         }
  56                 }
  57         }
  58
  59         return error;
  60 }
  61
  62 /** Filter processing.
  63 */
  64
  65 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  66 {
  67         // Get the starting brightness level
  68         double level = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "start" ) );
  69
  70         // If there is an end adjust gain to the range
  71         if ( mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "end" ) != NULL )
  72         {
  73                 // Determine the time position of this frame in the transition duration
  74                 mlt_position in = mlt_filter_get_in( this );
  75                 mlt_position out = mlt_filter_get_out( this );
  76                 mlt_position time = mlt_frame_get_position( frame );
  77                 double position = ( double )( time - in ) / ( double )( out - in + 1 );
  78                 double end = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "end" ) );
  79                 level += ( end - level ) * position;
  80         }
  81
  82         // Push the frame filter
  83         mlt_properties_set_double( MLT_FRAME_PROPERTIES( frame ), "brightness", level );
  84         mlt_frame_push_get_image( frame, filter_get_image );
  85
  86         return frame;
  87 }
  88
  89 /** Constructor for the filter.
  90 */
  91
  92 mlt_filter filter_brightness_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
  93 {
  94         mlt_filter this = mlt_filter_new( );
  95         if ( this != NULL )
  96         {
  97                 this->process = filter_process;
  98                 mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "start", arg == NULL ? "1" : arg );
  99         }
 100         return this;
 101 }
 102