2 * \file mlt_multitrack.c
3 * \brief multitrack service class
4 * \see mlt_multitrack_s
6 * Copyright (C) 2003-2009 Ushodaya Enterprises Limited
7 * \author Charles Yates <charles.yates@pandora.be>
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include "mlt_multitrack.h"
25 #include "mlt_playlist.h"
26 #include "mlt_frame.h"
31 /* Forward reference. */
33 static int producer_get_frame( mlt_producer producer, mlt_frame_ptr frame, int index );
35 /** Construct and initialize a new multitrack.
37 * Sets the resource property to "<multitrack>".
39 * \public \memberof mlt_multitrack_s
40 * \return a new multitrack
43 mlt_multitrack mlt_multitrack_init( )
45 // Allocate the multitrack object
46 mlt_multitrack self = calloc( sizeof( struct mlt_multitrack_s ), 1 );
50 mlt_producer producer = &self->parent;
51 if ( mlt_producer_init( producer, self ) == 0 )
53 mlt_properties properties = MLT_MULTITRACK_PROPERTIES( self );
54 producer->get_frame = producer_get_frame;
55 mlt_properties_set_data( properties, "multitrack", self, 0, NULL, NULL );
56 mlt_properties_set( properties, "log_id", "multitrack" );
57 mlt_properties_set( properties, "resource", "<multitrack>" );
58 mlt_properties_set_int( properties, "in", 0 );
59 mlt_properties_set_int( properties, "out", -1 );
60 mlt_properties_set_int( properties, "length", 0 );
61 producer->close = ( mlt_destructor )mlt_multitrack_close;
73 /** Get the producer associated to this multitrack.
75 * \public \memberof mlt_multitrack_s
76 * \param self a multitrack
77 * \return the producer object
78 * \see MLT_MULTITRACK_PRODUCER
81 mlt_producer mlt_multitrack_producer( mlt_multitrack self )
83 return self != NULL ? &self->parent : NULL;
86 /** Get the service associated this multitrack.
88 * \public \memberof mlt_multitrack_s
89 * \param self a multitrack
90 * \return the service object
91 * \see MLT_MULTITRACK_SERVICE
94 mlt_service mlt_multitrack_service( mlt_multitrack self )
96 return MLT_MULTITRACK_SERVICE( self );
99 /** Get the properties associated this multitrack.
101 * \public \memberof mlt_multitrack_s
102 * \param self a multitrack
103 * \return the multitrack's property list
104 * \see MLT_MULTITRACK_PROPERTIES
107 mlt_properties mlt_multitrack_properties( mlt_multitrack self )
109 return MLT_MULTITRACK_PROPERTIES( self );
112 /** Initialize position related information.
114 * \public \memberof mlt_multitrack_s
115 * \param self a multitrack
118 void mlt_multitrack_refresh( mlt_multitrack self )
122 // Obtain the properties of this multitrack
123 mlt_properties properties = MLT_MULTITRACK_PROPERTIES( self );
125 // We need to ensure that the multitrack reports the longest track as its length
126 mlt_position length = 0;
128 // Obtain stats on all connected services
129 for ( i = 0; i < self->count; i ++ )
131 // Get the producer from this index
132 mlt_track track = self->list[ i ];
133 mlt_producer producer = track->producer;
135 // If it's allocated then, update our stats
136 if ( producer != NULL )
138 // If we have more than 1 track, we must be in continue mode
139 if ( self->count > 1 )
140 mlt_properties_set( MLT_PRODUCER_PROPERTIES( producer ), "eof", "continue" );
142 // Determine the longest length
143 //if ( !mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( producer ), "hide" ) )
144 length = mlt_producer_get_playtime( producer ) > length ? mlt_producer_get_playtime( producer ) : length;
148 // Update multitrack properties now - we'll not destroy the in point here
149 mlt_events_block( properties, properties );
150 mlt_properties_set_position( properties, "length", length );
151 mlt_events_unblock( properties, properties );
152 mlt_properties_set_position( properties, "out", length - 1 );
155 /** Listener for producers on the playlist.
157 * \private \memberof mlt_multitrack_s
158 * \param producer a producer
159 * \param self a multitrack
162 static void mlt_multitrack_listener( mlt_producer producer, mlt_multitrack self )
164 mlt_multitrack_refresh( self );
167 /** Connect a producer to a given track.
169 * Note that any producer can be connected here, but see special case treatment
170 * of playlist in clip point determination below.
172 * \public \memberof mlt_multitrack_s
173 * \param self a multitrack
174 * \param producer the producer to connect to the multitrack producer
175 * \param track the 0-based index of the track on which to connect the multitrack
176 * \return true on error
179 int mlt_multitrack_connect( mlt_multitrack self, mlt_producer producer, int track )
181 // Connect to the producer to ourselves at the specified track
182 int result = mlt_service_connect_producer( MLT_MULTITRACK_SERVICE( self ), MLT_PRODUCER_SERVICE( producer ), track );
186 // Resize the producer list if need be
187 if ( track >= self->size )
190 self->list = realloc( self->list, ( track + 10 ) * sizeof( mlt_track ) );
191 for ( i = self->size; i < track + 10; i ++ )
192 self->list[ i ] = NULL;
193 self->size = track + 10;
196 if ( self->list[ track ] != NULL )
198 mlt_event_close( self->list[ track ]->event );
199 mlt_producer_close( self->list[ track ]->producer );
203 self->list[ track ] = malloc( sizeof( struct mlt_track_s ) );
206 // Assign the track in our list here
207 self->list[ track ]->producer = producer;
208 self->list[ track ]->event = mlt_events_listen( MLT_PRODUCER_PROPERTIES( producer ), self,
209 "producer-changed", ( mlt_listener )mlt_multitrack_listener );
210 mlt_properties_inc_ref( MLT_PRODUCER_PROPERTIES( producer ) );
211 mlt_event_inc_ref( self->list[ track ]->event );
213 // Increment the track count if need be
214 if ( track >= self->count )
215 self->count = track + 1;
218 mlt_multitrack_refresh( self );
224 /** Get the number of tracks.
226 * \public \memberof mlt_multitrack_s
227 * \param self a multitrack
228 * \return the number of tracks
231 int mlt_multitrack_count( mlt_multitrack self )
236 /** Get an individual track as a producer.
238 * \public \memberof mlt_multitrack_s
239 * \param self a multitrack
240 * \param track the 0-based index of the producer to get
241 * \return the producer or NULL if not valid
244 mlt_producer mlt_multitrack_track( mlt_multitrack self, int track )
246 mlt_producer producer = NULL;
248 if ( self->list != NULL && track < self->count )
249 producer = self->list[ track ]->producer;
254 /** Position comparison function for sorting.
256 * \private \memberof mlt_multitrack_s
257 * \param p1 a position
258 * \param p2 another position
259 * \return <0 if \p p1 is less than \p p2, 0 if equal, >0 if greater
262 static int position_compare( const void *p1, const void *p2 )
264 return *( const mlt_position * )p1 - *( const mlt_position * )p2;
267 /** Add a position to a set.
269 * \private \memberof mlt_multitrack_s
270 * \param array an array of positions (the set)
271 * \param size the current number of positions in the array (not the capacity of the array)
272 * \param position the position to add
273 * \return the new size of the array
276 static int add_unique( mlt_position *array, int size, mlt_position position )
279 for ( i = 0; i < size; i ++ )
280 if ( array[ i ] == position )
283 array[ size ++ ] = position;
287 /** Determine the clip point.
290 * Special case here: a 'producer' has no concept of multiple clips - only the
291 * playlist and multitrack producers have clip functionality. Further to that a
292 * multitrack determines clip information from any connected tracks that happen
295 * Additionally, it must locate clips in the correct order, for example, consider
296 * the following track arrangement:
298 * playlist1 |0.0 |b0.0 |0.1 |0.1 |0.2 |
299 * playlist2 |b1.0 |1.0 |b1.1 |1.1 |
301 * Note - b clips represent blanks. They are also reported as clip positions.
303 * When extracting clip positions from these playlists, we should get a sequence of:
305 * 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
308 * \public \memberof mlt_multitrack_s
309 * \param self a multitrack
310 * \param whence from where to extract
311 * \param index the 0-based index of which clip to extract
312 * \return the position of clip \p index relative to \p whence
315 mlt_position mlt_multitrack_clip( mlt_multitrack self, mlt_whence whence, int index )
317 mlt_position position = 0;
320 mlt_position *map = malloc( 1000 * sizeof( mlt_position ) );
323 for ( i = 0; i < self->count; i ++ )
325 // Get the producer for this track
326 mlt_producer producer = self->list[ i ]->producer;
328 // If it's assigned and not a hidden track
329 if ( producer != NULL )
331 // Get the properties of this producer
332 mlt_properties properties = MLT_PRODUCER_PROPERTIES( producer );
334 // Determine if it's a playlist
335 mlt_playlist playlist = mlt_properties_get_data( properties, "playlist", NULL );
337 // Special case consideration of playlists
338 if ( playlist != NULL )
340 for ( j = 0; j < mlt_playlist_count( playlist ); j ++ )
341 count = add_unique( map, count, mlt_playlist_clip( playlist, mlt_whence_relative_start, j ) );
342 count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 );
346 count = add_unique( map, count, 0 );
347 count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 );
353 qsort( map, count, sizeof( mlt_position ), position_compare );
355 // Now locate the requested index
358 case mlt_whence_relative_start:
360 position = map[ index ];
362 position = map[ count - 1 ];
365 case mlt_whence_relative_current:
366 position = mlt_producer_position( MLT_MULTITRACK_PRODUCER( self ) );
367 for ( i = 0; i < count - 2; i ++ )
368 if ( position >= map[ i ] && position < map[ i + 1 ] )
371 if ( index >= 0 && index < count )
372 position = map[ index ];
373 else if ( index < 0 )
376 position = map[ count - 1 ];
379 case mlt_whence_relative_end:
381 position = map[ count - index - 1 ];
393 /** Get frame method.
396 * Special case here: The multitrack must be used in a conjunction with a downstream
397 * tractor-type service, ie:
400 * Producer2 - multitrack - { filters/transitions } - tractor - consumer
403 * The get_frame of a tractor pulls frames from it's connected service on all tracks and
404 * will terminate as soon as it receives a test card with a last_track property. The
405 * important case here is that the mulitrack does not move to the next frame until all
406 * tracks have been pulled.
408 * Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
409 * that all producers are positioned on the same frame. It uses the 'last track' logic
410 * to determine when to move to the next frame.
412 * Flaw: if a transition is configured to read from a b-track which happens to trigger
413 * the last frame logic (ie: it's configured incorrectly), then things are going to go
416 * See playlist logic too.
419 * \private \memberof mlt_multitrack_s
420 * \param parent the producer interface to a mulitrack
421 * \param[out] frame a frame by reference
422 * \param index the 0-based track index
423 * \return true if there was an error
426 static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int index )
428 // Get the mutiltrack object
429 mlt_multitrack self = parent->child;
431 // Check if we have a track for this index
432 if ( index < self->count && self->list[ index ] != NULL )
434 // Get the producer for this track
435 mlt_producer producer = self->list[ index ]->producer;
437 // Get the track hide property
438 int hide = mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( mlt_producer_cut_parent( producer ) ), "hide" );
440 // Obtain the current position
441 mlt_position position = mlt_producer_frame( parent );
443 // Get the parent properties
444 mlt_properties producer_properties = MLT_PRODUCER_PROPERTIES( parent );
447 double speed = mlt_properties_get_double( producer_properties, "_speed" );
449 // Make sure we're at the same point
450 mlt_producer_seek( producer, position );
452 // Get the frame from the producer
453 mlt_service_get_frame( MLT_PRODUCER_SERVICE( producer ), frame, 0 );
455 // Indicate speed of this producer
456 mlt_properties properties = MLT_FRAME_PROPERTIES( *frame );
457 mlt_properties_set_double( properties, "_speed", speed );
458 mlt_frame_set_position( *frame, position );
459 mlt_properties_set_int( properties, "hide", hide );
463 // Generate a test frame
464 *frame = mlt_frame_init( MLT_PRODUCER_SERVICE( parent ) );
466 // Update position on the frame we're creating
467 mlt_frame_set_position( *frame, mlt_producer_position( parent ) );
469 // Move on to the next frame
470 if ( index >= self->count )
472 // Let tractor know if we've reached the end
473 mlt_properties_set_int( MLT_FRAME_PROPERTIES( *frame ), "last_track", 1 );
475 // Move to the next frame
476 mlt_producer_prepare_next( parent );
483 /** Close this instance and free its resources.
485 * \public \memberof mlt_multitrack_s
486 * \param self a multitrack
489 void mlt_multitrack_close( mlt_multitrack self )
491 if ( self != NULL && mlt_properties_dec_ref( MLT_MULTITRACK_PROPERTIES( self ) ) <= 0 )
494 for ( i = 0; i < self->count; i ++ )
496 if ( self->list[ i ] != NULL )
498 mlt_event_close( self->list[ i ]->event );
499 mlt_producer_close( self->list[ i ]->producer );
500 free( self->list[ i ] );
504 // Close the producer
505 self->parent.close = NULL;
506 mlt_producer_close( &self->parent );