2 * \file mlt_multitrack.c
3 * \brief multitrack service class
5 * Copyright (C) 2003-2008 Ushodaya Enterprises Limited
6 * \author Charles Yates <charles.yates@pandora.be>
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #include "mlt_multitrack.h"
24 #include "mlt_playlist.h"
25 #include "mlt_frame.h"
30 /* Forward reference. */
32 static int producer_get_frame( mlt_producer producer, mlt_frame_ptr frame, int index );
34 /** Construct and initialize a new multitrack.
36 * Sets the resource property to "<multitrack>".
38 * \public \memberof mlt_multitrack_s
39 * \return a new multitrack
42 mlt_multitrack mlt_multitrack_init( )
44 // Allocate the multitrack object
45 mlt_multitrack this = calloc( sizeof( struct mlt_multitrack_s ), 1 );
49 mlt_producer producer = &this->parent;
50 if ( mlt_producer_init( producer, this ) == 0 )
52 mlt_properties properties = MLT_MULTITRACK_PROPERTIES( this );
53 producer->get_frame = producer_get_frame;
54 mlt_properties_set_data( properties, "multitrack", this, 0, NULL, NULL );
55 mlt_properties_set( properties, "log_id", "multitrack" );
56 mlt_properties_set( properties, "resource", "<multitrack>" );
57 mlt_properties_set_int( properties, "in", 0 );
58 mlt_properties_set_int( properties, "out", -1 );
59 mlt_properties_set_int( properties, "length", 0 );
60 producer->close = ( mlt_destructor )mlt_multitrack_close;
72 /** Get the producer associated to this multitrack.
74 * \public \memberof mlt_multitrack_s
75 * \param this a multitrack
76 * \return the producer object
77 * \see MLT_MULTITRACK_PRODUCER
80 mlt_producer mlt_multitrack_producer( mlt_multitrack this )
82 return this != NULL ? &this->parent : NULL;
85 /** Get the service associated this multitrack.
87 * \public \memberof mlt_multitrack_s
88 * \param this a multitrack
89 * \return the service object
90 * \see MLT_MULTITRACK_SERVICE
93 mlt_service mlt_multitrack_service( mlt_multitrack this )
95 return MLT_MULTITRACK_SERVICE( this );
98 /** Get the properties associated this multitrack.
100 * \public \memberof mlt_multitrack_s
101 * \param this a multitrack
102 * \return the multitrack's property list
103 * \see MLT_MULTITRACK_PROPERTIES
106 mlt_properties mlt_multitrack_properties( mlt_multitrack this )
108 return MLT_MULTITRACK_PROPERTIES( this );
111 /** Initialize position related information.
113 * \public \memberof mlt_multitrack_s
114 * \param this a multitrack
117 void mlt_multitrack_refresh( mlt_multitrack this )
121 // Obtain the properties of this multitrack
122 mlt_properties properties = MLT_MULTITRACK_PROPERTIES( this );
124 // We need to ensure that the multitrack reports the longest track as its length
125 mlt_position length = 0;
127 // Obtain stats on all connected services
128 for ( i = 0; i < this->count; i ++ )
130 // Get the producer from this index
131 mlt_track track = this->list[ i ];
132 mlt_producer producer = track->producer;
134 // If it's allocated then, update our stats
135 if ( producer != NULL )
137 // If we have more than 1 track, we must be in continue mode
138 if ( this->count > 1 )
139 mlt_properties_set( MLT_PRODUCER_PROPERTIES( producer ), "eof", "continue" );
141 // Determine the longest length
142 //if ( !mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( producer ), "hide" ) )
143 length = mlt_producer_get_playtime( producer ) > length ? mlt_producer_get_playtime( producer ) : length;
147 // Update multitrack properties now - we'll not destroy the in point here
148 mlt_events_block( properties, properties );
149 mlt_properties_set_position( properties, "length", length );
150 mlt_events_unblock( properties, properties );
151 mlt_properties_set_position( properties, "out", length - 1 );
154 /** Listener for producers on the playlist.
156 * \private \memberof mlt_multitrack_s
157 * \param producer a producer
158 * \param this a multitrack
161 static void mlt_multitrack_listener( mlt_producer producer, mlt_multitrack this )
163 mlt_multitrack_refresh( this );
166 /** Connect a producer to a given track.
168 * Note that any producer can be connected here, but see special case treatment
169 * of playlist in clip point determination below.
171 * \public \memberof mlt_multitrack_s
172 * \param this a multitrack
173 * \param producer the producer to connect to the multitrack producer
174 * \param track the 0-based index of the track on which to connect the multitrack
175 * \return true on error
178 int mlt_multitrack_connect( mlt_multitrack this, mlt_producer producer, int track )
180 // Connect to the producer to ourselves at the specified track
181 int result = mlt_service_connect_producer( MLT_MULTITRACK_SERVICE( this ), MLT_PRODUCER_SERVICE( producer ), track );
185 // Resize the producer list if need be
186 if ( track >= this->size )
189 this->list = realloc( this->list, ( track + 10 ) * sizeof( mlt_track ) );
190 for ( i = this->size; i < track + 10; i ++ )
191 this->list[ i ] = NULL;
192 this->size = track + 10;
195 if ( this->list[ track ] != NULL )
197 mlt_event_close( this->list[ track ]->event );
198 mlt_producer_close( this->list[ track ]->producer );
202 this->list[ track ] = malloc( sizeof( struct mlt_track_s ) );
205 // Assign the track in our list here
206 this->list[ track ]->producer = producer;
207 this->list[ track ]->event = mlt_events_listen( MLT_PRODUCER_PROPERTIES( producer ), this,
208 "producer-changed", ( mlt_listener )mlt_multitrack_listener );
209 mlt_properties_inc_ref( MLT_PRODUCER_PROPERTIES( producer ) );
210 mlt_event_inc_ref( this->list[ track ]->event );
212 // Increment the track count if need be
213 if ( track >= this->count )
214 this->count = track + 1;
217 mlt_multitrack_refresh( this );
223 /** Get the number of tracks.
225 * \public \memberof mlt_multitrack_s
226 * \param this a multitrack
227 * \return the number of tracks
230 int mlt_multitrack_count( mlt_multitrack this )
235 /** Get an individual track as a producer.
237 * \public \memberof mlt_multitrack_s
238 * \param this a multitrack
239 * \param track the 0-based index of the producer to get
240 * \return the producer or NULL if not valid
243 mlt_producer mlt_multitrack_track( mlt_multitrack this, int track )
245 mlt_producer producer = NULL;
247 if ( this->list != NULL && track < this->count )
248 producer = this->list[ track ]->producer;
253 /** Position comparison function for sorting.
255 * \private \memberof mlt_multitrack_s
256 * \param p1 a position
257 * \param p2 another position
258 * \return <0 if \p p1 is less than \p p2, 0 if equal, >0 if greater
261 static int position_compare( const void *p1, const void *p2 )
263 return *( mlt_position * )p1 - *( mlt_position * )p2;
266 /** Add a position to a set.
268 * \private \memberof mlt_multitrack_s
269 * \param array an array of positions (the set)
270 * \param size the current number of positions in the array (not the capacity of the array)
271 * \param position the position to add
272 * \return the new size of the array
275 static int add_unique( mlt_position *array, int size, mlt_position position )
278 for ( i = 0; i < size; i ++ )
279 if ( array[ i ] == position )
282 array[ size ++ ] = position;
286 /** Determine the clip point.
289 * Special case here: a 'producer' has no concept of multiple clips - only the
290 * playlist and multitrack producers have clip functionality. Further to that a
291 * multitrack determines clip information from any connected tracks that happen
294 * Additionally, it must locate clips in the correct order, for example, consider
295 * the following track arrangement:
297 * playlist1 |0.0 |b0.0 |0.1 |0.1 |0.2 |
298 * playlist2 |b1.0 |1.0 |b1.1 |1.1 |
300 * Note - b clips represent blanks. They are also reported as clip positions.
302 * When extracting clip positions from these playlists, we should get a sequence of:
304 * 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
307 * \public \memberof mlt_multitrack_s
308 * \param this a multitrack
309 * \param whence from where to extract
310 * \param index the 0-based index of which clip to extract
311 * \return the position of clip \p index relative to \p whence
314 mlt_position mlt_multitrack_clip( mlt_multitrack this, mlt_whence whence, int index )
316 mlt_position position = 0;
319 mlt_position *map = malloc( 1000 * sizeof( mlt_position ) );
322 for ( i = 0; i < this->count; i ++ )
324 // Get the producer for this track
325 mlt_producer producer = this->list[ i ]->producer;
327 // If it's assigned and not a hidden track
328 if ( producer != NULL )
330 // Get the properties of this producer
331 mlt_properties properties = MLT_PRODUCER_PROPERTIES( producer );
333 // Determine if it's a playlist
334 mlt_playlist playlist = mlt_properties_get_data( properties, "playlist", NULL );
336 // Special case consideration of playlists
337 if ( playlist != NULL )
339 for ( j = 0; j < mlt_playlist_count( playlist ); j ++ )
340 count = add_unique( map, count, mlt_playlist_clip( playlist, mlt_whence_relative_start, j ) );
341 count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 );
345 count = add_unique( map, count, 0 );
346 count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 );
352 qsort( map, count, sizeof( mlt_position ), position_compare );
354 // Now locate the requested index
357 case mlt_whence_relative_start:
359 position = map[ index ];
361 position = map[ count - 1 ];
364 case mlt_whence_relative_current:
365 position = mlt_producer_position( MLT_MULTITRACK_PRODUCER( this ) );
366 for ( i = 0; i < count - 2; i ++ )
367 if ( position >= map[ i ] && position < map[ i + 1 ] )
370 if ( index >= 0 && index < count )
371 position = map[ index ];
372 else if ( index < 0 )
375 position = map[ count - 1 ];
378 case mlt_whence_relative_end:
380 position = map[ count - index - 1 ];
392 /** Get frame method.
395 * Special case here: The multitrack must be used in a conjunction with a downstream
396 * tractor-type service, ie:
399 * Producer2 - multitrack - { filters/transitions } - tractor - consumer
402 * The get_frame of a tractor pulls frames from it's connected service on all tracks and
403 * will terminate as soon as it receives a test card with a last_track property. The
404 * important case here is that the mulitrack does not move to the next frame until all
405 * tracks have been pulled.
407 * Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
408 * that all producers are positioned on the same frame. It uses the 'last track' logic
409 * to determine when to move to the next frame.
411 * Flaw: if a transition is configured to read from a b-track which happens to trigger
412 * the last frame logic (ie: it's configured incorrectly), then things are going to go
415 * See playlist logic too.
418 * \private \memberof mlt_multitrack_s
419 * \param parent the producer interface to a mulitrack
420 * \param[out] frame a frame by reference
421 * \param index the 0-based track index
422 * \return true if there was an error
425 static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int index )
427 // Get the mutiltrack object
428 mlt_multitrack this = parent->child;
430 // Check if we have a track for this index
431 if ( index < this->count && this->list[ index ] != NULL )
433 // Get the producer for this track
434 mlt_producer producer = this->list[ index ]->producer;
436 // Get the track hide property
437 int hide = mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( mlt_producer_cut_parent( producer ) ), "hide" );
439 // Obtain the current position
440 mlt_position position = mlt_producer_frame( parent );
442 // Get the parent properties
443 mlt_properties producer_properties = MLT_PRODUCER_PROPERTIES( parent );
446 double speed = mlt_properties_get_double( producer_properties, "_speed" );
448 // Make sure we're at the same point
449 mlt_producer_seek( producer, position );
451 // Get the frame from the producer
452 mlt_service_get_frame( MLT_PRODUCER_SERVICE( producer ), frame, 0 );
454 // Indicate speed of this producer
455 mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
456 mlt_properties_set_double( properties, "_speed", speed );
457 mlt_properties_set_position( properties, "_position", position );
458 mlt_properties_set_int( properties, "hide", hide );
462 // Generate a test frame
463 *frame = mlt_frame_init( MLT_PRODUCER_SERVICE( parent ) );
465 // Update position on the frame we're creating
466 mlt_frame_set_position( *frame, mlt_producer_position( parent ) );
468 // Move on to the next frame
469 if ( index >= this->count )
471 // Let tractor know if we've reached the end
472 mlt_properties_set_int( MLT_FRAME_PROPERTIES( *frame ), "last_track", 1 );
474 // Move to the next frame
475 mlt_producer_prepare_next( parent );
482 /** Close this instance and free its resources.
484 * \public \memberof mlt_multitrack_s
485 * \param this a multitrack
488 void mlt_multitrack_close( mlt_multitrack this )
490 if ( this != NULL && mlt_properties_dec_ref( MLT_MULTITRACK_PROPERTIES( this ) ) <= 0 )
493 for ( i = 0; i < this->count; i ++ )
495 if ( this->list[ i ] != NULL )
497 mlt_event_close( this->list[ i ]->event );
498 mlt_producer_close( this->list[ i ]->producer );
499 free( this->list[ i ] );
503 // Close the producer
504 this->parent.close = NULL;
505 mlt_producer_close( &this->parent );