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

   1 /*
   2  * transition_composite.c -- compose one image over another using alpha channel
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Dan Dennedy <dan@dennedy.org>
   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 "transition_composite.h"
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26
  27 /** Get the image.
  28 */
  29
  30 static int transition_get_image( mlt_frame this, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
  31 {
  32         // Get the properties of the a frame
  33         mlt_properties a_props = mlt_frame_properties( this );
  34
  35         // Get the b frame from the stack
  36         mlt_frame b_frame = mlt_frame_pop_frame( this );
  37
  38         if ( b_frame != NULL )
  39         {
  40                 // Get the properties of the b frame
  41                 mlt_properties b_props = mlt_frame_properties( b_frame );
  42
  43                 // Arbitrary composite defaults
  44                 int x = 0;
  45                 int y = 0;
  46                 double mix = 1.0;
  47
  48                 // Override from b frame properties if provided
  49                 if ( mlt_properties_get( b_props, "x" ) != NULL )
  50                         x = mlt_properties_get_int( b_props, "x" );
  51                 if ( mlt_properties_get( b_props, "y" ) != NULL )
  52                         y = mlt_properties_get_int( b_props, "y" );
  53                 if ( mlt_properties_get( b_props, "image.mix" ) != NULL )
  54                         mix = mlt_properties_get_double( b_props, "image.mix" );
  55
  56                 // Composite the b_frame on the a_frame
  57                 mlt_frame_composite_yuv( this, b_frame, x, y, mix );
  58
  59                 // Extract the a_frame image info
  60                 *width = mlt_properties_get_int( a_props, "width" );
  61                 *height = mlt_properties_get_int( a_props, "height" );
  62                 *image = mlt_properties_get_data( a_props, "image", NULL );
  63         }
  64         else if ( a_props != NULL )
  65         {
  66                 // Extract the a_frame image info
  67                 *width = mlt_properties_get_int( a_props, "width" );
  68                 *height = mlt_properties_get_int( a_props, "height" );
  69                 *image = mlt_properties_get_data( a_props, "image", NULL );
  70         }
  71
  72         return 0;
  73 }
  74
  75 /** Composition transition processing.
  76 */
  77
  78 static mlt_frame composite_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
  79 {
  80         // Propogate the transition properties to the b frame
  81         mlt_properties properties = mlt_transition_properties( this );
  82         mlt_properties b_props = mlt_frame_properties( b_frame );
  83
  84         if ( mlt_properties_get( properties, "x" ) != NULL )
  85                 mlt_properties_set_int( b_props, "x", mlt_properties_get_int( properties, "x" ) );
  86         if ( mlt_properties_get( properties, "y" ) != NULL )
  87                 mlt_properties_set_int( b_props, "y", mlt_properties_get_int( properties, "y" ) );
  88
  89         // Only if mix is specified, otherwise a producer may set the mix
  90         if ( mlt_properties_get( properties, "mix" ) != NULL )
  91         {
  92                 // A negative means dissolve
  93                 if ( mlt_properties_get_double( properties, "mix" ) < 0 )
  94                 {
  95                         // Determine the time position of this frame in the transition duration
  96                         mlt_position in = mlt_transition_get_in( this );
  97                         mlt_position out = mlt_transition_get_out( this );
  98                         mlt_position time = mlt_frame_get_position( b_frame );
  99                         double mix = ( double )( time - in ) / ( double )( out - in + 1 );
 100                         mlt_properties_set_double( b_props, "image.mix", mix );
 101                 }
 102                 else
 103                         mlt_properties_set_double( b_props, "image.mix", mlt_properties_get_double( properties, "mix" ) );
 104         }
 105
 106         mlt_frame_push_get_image( a_frame, transition_get_image );
 107         mlt_frame_push_frame( a_frame, b_frame );
 108
 109         return a_frame;
 110 }
 111
 112 /** Constructor for the filter.
 113 */
 114
 115 mlt_transition transition_composite_init( char *arg )
 116 {
 117         mlt_transition this = calloc( sizeof( struct mlt_transition_s ), 1 );
 118         if ( this != NULL && mlt_transition_init( this, NULL ) == 0 )
 119         {
 120                 this->process = composite_process;
 121                 if ( arg != NULL )
 122                         mlt_properties_set_double( mlt_transition_properties( this ), "mix", atof( arg ) );
 123         }
 124         return this;
 125 }
 126