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                 service->close = ( mlt_destructor )mlt_transition_close;
  49                 service->close_object = this;
  50
  51                 mlt_properties_set_position( properties, "in", 0 );
  52                 mlt_properties_set_position( properties, "out", 0 );
  53                 mlt_properties_set_int( properties, "a_track", 0 );
  54                 mlt_properties_set_int( properties, "b_track", 1 );
  55
  56                 return 0;
  57         }
  58         return 1;
  59 }
  60
  61 /** Create a new transition.
  62 */
  63
  64 mlt_transition mlt_transition_new( )
  65 {
  66         mlt_transition this = calloc( 1, sizeof( struct mlt_transition_s ) );
  67         if ( this != NULL )
  68                 mlt_transition_init( this, NULL );
  69         return this;
  70 }
  71
  72 /** Get the service associated to the transition.
  73 */
  74
  75 mlt_service mlt_transition_service( mlt_transition this )
  76 {
  77         return this != NULL ? &this->parent : NULL;
  78 }
  79
  80 /** Get the properties interface.
  81 */
  82
  83 mlt_properties mlt_transition_properties( mlt_transition this )
  84 {
  85         return mlt_service_properties( mlt_transition_service( this ) );
  86 }
  87
  88 /** Connect this transition with a producers a and b tracks.
  89 */
  90
  91 int mlt_transition_connect( mlt_transition this, mlt_service producer, int a_track, int b_track )
  92 {
  93         int ret = mlt_service_connect_producer( &this->parent, producer, a_track );
  94         if ( ret == 0 )
  95         {
  96                 mlt_properties properties = mlt_transition_properties( this );
  97                 this->producer = producer;
  98                 mlt_properties_set_int( properties, "a_track", a_track );
  99                 mlt_properties_set_int( properties, "b_track", b_track );
 100         }
 101         return ret;
 102 }
 103
 104 /** Set the in and out points.
 105 */
 106
 107 void mlt_transition_set_in_and_out( mlt_transition this, mlt_position in, mlt_position out )
 108 {
 109         mlt_properties properties = mlt_transition_properties( this );
 110         mlt_properties_set_position( properties, "in", in );
 111         mlt_properties_set_position( properties, "out", out );
 112 }
 113
 114 /** Get the index of the a track.
 115 */
 116
 117 int mlt_transition_get_a_track( mlt_transition this )
 118 {
 119         return mlt_properties_get_int( mlt_transition_properties( this ), "a_track" );
 120 }
 121
 122 /** Get the index of the b track.
 123 */
 124
 125 int mlt_transition_get_b_track( mlt_transition this )
 126 {
 127         return mlt_properties_get_int( mlt_transition_properties( this ), "b_track" );
 128 }
 129
 130 /** Get the in point.
 131 */
 132
 133 mlt_position mlt_transition_get_in( mlt_transition this )
 134 {
 135         return mlt_properties_get_position( mlt_transition_properties( this ), "in" );
 136 }
 137
 138 /** Get the out point.
 139 */
 140
 141 mlt_position mlt_transition_get_out( mlt_transition this )
 142 {
 143         return mlt_properties_get_position( mlt_transition_properties( this ), "out" );
 144 }
 145
 146 /** Process the frame.
 147
 148         If we have no process method (unlikely), we simply return the a_frame unmolested.
 149 */
 150
 151 mlt_frame mlt_transition_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
 152 {
 153         if ( this->process == NULL || b_frame == NULL || ( mlt_frame_is_test_card( b_frame ) && mlt_frame_is_test_audio( b_frame ) ) )
 154                 return a_frame;
 155         else if ( a_frame == NULL || ( mlt_frame_is_test_card( a_frame ) && mlt_frame_is_test_audio( a_frame ) ) )
 156                 return b_frame;
 157         else
 158                 return this->process( this, a_frame, b_frame );
 159 }
 160
 161 /** Get a frame from this filter.
 162
 163         The logic is complex here. A transition is applied to frames on the a and b tracks
 164         specified in the connect method above. Since all frames are obtained via this
 165         method for all tracks, we have to take special care that we only obtain the a and
 166         b frames once - we do this on the first call to get a frame from either a or b.
 167
 168         After that, we have 2 cases to resolve:
 169
 170         1)      if the track is the a_track and we're in the time zone, then we need to call the
 171                 process method to do the effect on the frame and remember we've passed it on
 172                 otherwise, we pass on the a_frame unmolested;
 173         2)      For all other tracks, we get the frames on demand.
 174 */
 175
 176 static int transition_get_frame( mlt_service service, mlt_frame_ptr frame, int index )
 177 {
 178         mlt_transition this = service->child;
 179
 180         mlt_properties properties = mlt_transition_properties( this );
 181
 182         int a_track = mlt_properties_get_int( properties, "a_track" );
 183         int b_track = mlt_properties_get_int( properties, "b_track" );
 184         mlt_position in = mlt_properties_get_position( properties, "in" );
 185         mlt_position out = mlt_properties_get_position( properties, "out" );
 186
 187         if ( ( index == a_track || index == b_track ) && !( this->a_held || this->b_held ) )
 188         {
 189                 mlt_service_get_frame( this->producer, &this->a_frame, a_track );
 190                 mlt_service_get_frame( this->producer, &this->b_frame, b_track );
 191                 this->a_held = 1;
 192                 this->b_held = 1;
 193         }
 194
 195         // Special case track processing
 196         if ( index == a_track )
 197         {
 198                 // Determine if we're in the right time zone
 199                 mlt_position position = mlt_frame_get_position( this->a_frame );
 200                 if ( position >= in && position <= out )
 201                 {
 202                         // Process the transition
 203                         *frame = mlt_transition_process( this, this->a_frame, this->b_frame );
 204                         if ( *frame == this->b_frame )
 205                         {
 206                                 mlt_frame t = this->a_frame;
 207                                 this->a_frame = this->b_frame;
 208                                 this->b_frame = t;
 209                         }
 210                         if ( !mlt_properties_get_int( mlt_frame_properties( this->a_frame ), "test_image" ) )
 211                                 mlt_properties_set_int( mlt_frame_properties( this->b_frame ), "test_image", 1 );
 212                         if ( !mlt_properties_get_int( mlt_frame_properties( this->a_frame ), "test_audio" ) )
 213                                 mlt_properties_set_int( mlt_frame_properties( this->b_frame ), "test_audio", 1 );
 214                         this->a_held = 0;
 215                 }
 216                 else
 217                 {
 218                         // Pass on the 'a frame' and remember that we've done it
 219                         *frame = this->a_frame;
 220                         this->a_held = 0;
 221                 }
 222                 return 0;
 223         }
 224         if ( index == b_track )
 225         {
 226                 // Pass on the 'b frame' and remember that we've done it
 227                 *frame = this->b_frame;
 228                 this->b_held = 0;
 229                 return 0;
 230         }
 231         else
 232         {
 233                 // Pass through
 234                 return mlt_service_get_frame( this->producer, frame, index );
 235         }
 236 }
 237
 238 /** Close the transition.
 239 */
 240
 241 void mlt_transition_close( mlt_transition this )
 242 {
 243         if ( this != NULL && mlt_properties_dec_ref( mlt_transition_properties( this ) ) <= 0 )
 244         {
 245                 this->parent.close = NULL;
 246                 if ( this->close != NULL )
 247                         this->close( this );
 248                 else
 249                         mlt_service_close( &this->parent );
 250         }
 251 }