research.m1stereo.tv/gitweb/ - melted/blob - src/framework/mlt_transition.c

   1 /*
   2  * mlt_transition.c -- abstraction for all transition services
   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 "config.h"
  22
  23 #include "mlt_transition.h"
  24 #include "mlt_frame.h"
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 /** Forward references.
  31 */
  32
  33 static int transition_get_frame( mlt_service this, mlt_frame_ptr frame, int index );
  34
  35 /** Constructor.
  36 */
  37
  38 int mlt_transition_init( mlt_transition this, void *child )
  39 {
  40         mlt_service service = &this->parent;
  41         memset( this, 0, sizeof( struct mlt_transition_s ) );
  42         this->child = child;
  43         if ( mlt_service_init( service, this ) == 0 )
  44         {
  45                 mlt_properties properties = mlt_transition_properties( this );
  46
  47                 service->get_frame = transition_get_frame;
  48
  49                 mlt_properties_set_position( properties, "in", 0 );
  50                 mlt_properties_set_position( properties, "out", 0 );
  51                 mlt_properties_set_int( properties, "a_track", 0 );
  52                 mlt_properties_set_int( properties, "b_track", 1 );
  53                 mlt_properties_set( properties, "resource", "<transition>" );
  54
  55                 return 0;
  56         }
  57         return 1;
  58 }
  59
  60 /** Get the service associated to the transition.
  61 */
  62
  63 mlt_service mlt_transition_service( mlt_transition this )
  64 {
  65         return &this->parent;
  66 }
  67
  68 /** Get the properties interface.
  69 */
  70
  71 mlt_properties mlt_transition_properties( mlt_transition this )
  72 {
  73         return mlt_service_properties( mlt_transition_service( this ) );
  74 }
  75
  76 /** Connect this transition with a producers a and b tracks.
  77 */
  78
  79 int mlt_transition_connect( mlt_transition this, mlt_service producer, int a_track, int b_track )
  80 {
  81         int ret = mlt_service_connect_producer( &this->parent, producer, a_track );
  82         if ( ret == 0 )
  83         {
  84                 mlt_properties properties = mlt_transition_properties( this );
  85                 this->producer = producer;
  86                 mlt_properties_set_int( properties, "a_track", a_track );
  87                 mlt_properties_set_int( properties, "b_track", b_track );
  88         }
  89         return ret;
  90 }
  91
  92 /** Set the in and out points.
  93 */
  94
  95 void mlt_transition_set_in_and_out( mlt_transition this, mlt_position in, mlt_position out )
  96 {
  97         mlt_properties properties = mlt_transition_properties( this );
  98         mlt_properties_set_position( properties, "in", in );
  99         mlt_properties_set_position( properties, "out", out );
 100 }
 101
 102 /** Get the index of the a track.
 103 */
 104
 105 int mlt_transition_get_a_track( mlt_transition this )
 106 {
 107         return mlt_properties_get_int( mlt_transition_properties( this ), "a_track" );
 108 }
 109
 110 /** Get the index of the b track.
 111 */
 112
 113 int mlt_transition_get_b_track( mlt_transition this )
 114 {
 115         return mlt_properties_get_int( mlt_transition_properties( this ), "b_track" );
 116 }
 117
 118 /** Get the in point.
 119 */
 120
 121 mlt_position mlt_transition_get_in( mlt_transition this )
 122 {
 123         return mlt_properties_get_position( mlt_transition_properties( this ), "in" );
 124 }
 125
 126 /** Get the out point.
 127 */
 128
 129 mlt_position mlt_transition_get_out( mlt_transition this )
 130 {
 131         return mlt_properties_get_position( mlt_transition_properties( this ), "out" );
 132 }
 133
 134 /** Process the frame.
 135
 136         If we have no process method (unlikely), we simply return the a_frame unmolested.
 137 */
 138
 139 static mlt_frame transition_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
 140 {
 141         if ( this->process == NULL )
 142                 return a_frame;
 143         else
 144                 return this->process( this, a_frame, b_frame );
 145 }
 146
 147 /** Get a frame from this filter.
 148
 149         The logic is complex here. A transition is applied to frames on the a and b tracks
 150         specified in the connect method above. Since all frames are obtained via this
 151         method for all tracks, we have to take special care that we only obtain the a and
 152         b frames once - we do this on the first call to get a frame from either a or b.
 153
 154         After that, we have 2 cases to resolve:
 155
 156         1)      if the track is the a_track and we're in the time zone, then we need to call the
 157                 process method to do the effect on the frame and remember we've passed it on
 158                 otherwise, we pass on the a_frame unmolested;
 159         2)      For all other tracks, we get the frames on demand.
 160 */
 161
 162 static int transition_get_frame( mlt_service service, mlt_frame_ptr frame, int index )
 163 {
 164         mlt_transition this = service->child;
 165
 166         mlt_properties properties = mlt_transition_properties( this );
 167
 168         int a_track = mlt_properties_get_int( properties, "a_track" );
 169         int b_track = mlt_properties_get_int( properties, "b_track" );
 170         mlt_position in = mlt_properties_get_position( properties, "in" );
 171         mlt_position out = mlt_properties_get_position( properties, "out" );
 172
 173         if ( ( index == a_track || index == b_track ) && !( this->a_held || this->b_held ) )
 174         {
 175                 mlt_service_get_frame( this->producer, &this->a_frame, a_track );
 176                 mlt_service_get_frame( this->producer, &this->b_frame, b_track );
 177                 this->a_held = 1;
 178                 this->b_held = 1;
 179         }
 180
 181         // Special case track processing
 182         if ( index == a_track )
 183         {
 184                 // Determine if we're in the right time zone
 185                 mlt_position position = mlt_frame_get_position( this->a_frame );
 186                 if ( position >= in && position <= out )
 187                 {
 188                         // Process the transition
 189                         *frame = transition_process( this, this->a_frame, this->b_frame );
 190                         this->a_held = 0;
 191                 }
 192                 else
 193                 {
 194                         // Pass on the 'a frame' and remember that we've done it
 195                         *frame = this->a_frame;
 196                         this->a_held = 0;
 197                 }
 198                 return 0;
 199         }
 200         if ( index == b_track )
 201         {
 202                 // Pass on the 'b frame' and remember that we've done it
 203                 *frame = this->b_frame;
 204                 this->b_held = 0;
 205                 return 0;
 206         }
 207         else
 208         {
 209                 // Pass through
 210                 return mlt_service_get_frame( this->producer, frame, index );
 211         }
 212 }
 213
 214 /** Close the transition.
 215 */
 216
 217 void mlt_transition_close( mlt_transition this )
 218 {
 219         if ( this->close != NULL )
 220                 this->close( this );
 221         else
 222                 mlt_service_close( &this->parent );
 223 }