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 #define CLAMP( x, min, max ) (x) < (min) ? (min) : (x) > (max) ? (max) : (x)
  29
  30 /** Do it :-).
  31 */
  32
  33 static int filter_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  34 {
  35         // Get the image
  36         int error = mlt_frame_get_image( this, image, format, width, height, 1 );
  37
  38         // Only process if we have no error and a valid colour space
  39         if ( error == 0 && *format == mlt_image_yuv422 )
  40         {
  41                 // Get the brightness level
  42                 double level = mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "brightness" );
  43
  44                 // Only process if level is something other than 1
  45                 if ( level != 1.0 )
  46                 {
  47                         int i = *width * *height + 1;
  48                         uint8_t *p = *image;
  49                         int32_t m = level * ( 1 << 16 );
  50                         int32_t n = 128 * ( ( 1 << 16 ) - m );
  51
  52                         while ( --i )
  53                         {
  54                                 p[0] = CLAMP( (p[0] * m) >> 16, 16, 235 );
  55                                 p[1] = CLAMP( (p[1] * m + n) >> 16, 16, 240 );
  56                                 p += 2;
  57                         }
  58                 }
  59         }
  60
  61         return error;
  62 }
  63
  64 /** Filter processing.
  65 */
  66
  67 static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
  68 {
  69         // Get the starting brightness level
  70         double level = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "start" ) );
  71
  72         // If there is an end adjust gain to the range
  73         if ( mlt_properties_get( MLT_FILTER_PROPERTIES( this ), "end" ) != NULL )
  74         {
  75                 // Determine the time position of this frame in the transition duration
  76                 mlt_position in = mlt_filter_get_in( this );
  77                 mlt_position out = mlt_filter_get_out( this );
  78                 mlt_position time = mlt_frame_get_position( frame );
  79                 double position = ( double )( time - in ) / ( double )( out - in + 1 );
  80                 double end = fabs( mlt_properties_get_double( MLT_FILTER_PROPERTIES( this ), "end" ) );
  81                 level += ( end - level ) * position;
  82         }
  83
  84         // Push the frame filter
  85         mlt_properties_set_double( MLT_FRAME_PROPERTIES( frame ), "brightness", level );
  86         mlt_frame_push_get_image( frame, filter_get_image );
  87
  88         return frame;
  89 }
  90
  91 /** Constructor for the filter.
  92 */
  93
  94 mlt_filter filter_brightness_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
  95 {
  96         mlt_filter this = mlt_filter_new( );
  97         if ( this != NULL )
  98         {
  99                 this->process = filter_process;
 100                 mlt_properties_set( MLT_FILTER_PROPERTIES( this ), "start", arg == NULL ? "1" : arg );
 101         }
 102         return this;
 103 }
 104