/** * \file mlt_multitrack.c * \brief multitrack service class * \see mlt_multitrack_s * * Copyright (C) 2003-2009 Ushodaya Enterprises Limited * \author Charles Yates * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "mlt_multitrack.h" #include "mlt_playlist.h" #include "mlt_frame.h" #include #include /* Forward reference. */ static int producer_get_frame( mlt_producer producer, mlt_frame_ptr frame, int index ); /** Construct and initialize a new multitrack. * * Sets the resource property to "". * * \public \memberof mlt_multitrack_s * \return a new multitrack */ mlt_multitrack mlt_multitrack_init( ) { // Allocate the multitrack object mlt_multitrack this = calloc( sizeof( struct mlt_multitrack_s ), 1 ); if ( this != NULL ) { mlt_producer producer = &this->parent; if ( mlt_producer_init( producer, this ) == 0 ) { mlt_properties properties = MLT_MULTITRACK_PROPERTIES( this ); producer->get_frame = producer_get_frame; mlt_properties_set_data( properties, "multitrack", this, 0, NULL, NULL ); mlt_properties_set( properties, "log_id", "multitrack" ); mlt_properties_set( properties, "resource", "" ); mlt_properties_set_int( properties, "in", 0 ); mlt_properties_set_int( properties, "out", -1 ); mlt_properties_set_int( properties, "length", 0 ); producer->close = ( mlt_destructor )mlt_multitrack_close; } else { free( this ); this = NULL; } } return this; } /** Get the producer associated to this multitrack. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \return the producer object * \see MLT_MULTITRACK_PRODUCER */ mlt_producer mlt_multitrack_producer( mlt_multitrack this ) { return this != NULL ? &this->parent : NULL; } /** Get the service associated this multitrack. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \return the service object * \see MLT_MULTITRACK_SERVICE */ mlt_service mlt_multitrack_service( mlt_multitrack this ) { return MLT_MULTITRACK_SERVICE( this ); } /** Get the properties associated this multitrack. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \return the multitrack's property list * \see MLT_MULTITRACK_PROPERTIES */ mlt_properties mlt_multitrack_properties( mlt_multitrack this ) { return MLT_MULTITRACK_PROPERTIES( this ); } /** Initialize position related information. * * \public \memberof mlt_multitrack_s * \param this a multitrack */ void mlt_multitrack_refresh( mlt_multitrack this ) { int i = 0; // Obtain the properties of this multitrack mlt_properties properties = MLT_MULTITRACK_PROPERTIES( this ); // We need to ensure that the multitrack reports the longest track as its length mlt_position length = 0; // Obtain stats on all connected services for ( i = 0; i < this->count; i ++ ) { // Get the producer from this index mlt_track track = this->list[ i ]; mlt_producer producer = track->producer; // If it's allocated then, update our stats if ( producer != NULL ) { // If we have more than 1 track, we must be in continue mode if ( this->count > 1 ) mlt_properties_set( MLT_PRODUCER_PROPERTIES( producer ), "eof", "continue" ); // Determine the longest length //if ( !mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( producer ), "hide" ) ) length = mlt_producer_get_playtime( producer ) > length ? mlt_producer_get_playtime( producer ) : length; } } // Update multitrack properties now - we'll not destroy the in point here mlt_events_block( properties, properties ); mlt_properties_set_position( properties, "length", length ); mlt_events_unblock( properties, properties ); mlt_properties_set_position( properties, "out", length - 1 ); } /** Listener for producers on the playlist. * * \private \memberof mlt_multitrack_s * \param producer a producer * \param this a multitrack */ static void mlt_multitrack_listener( mlt_producer producer, mlt_multitrack this ) { mlt_multitrack_refresh( this ); } /** Connect a producer to a given track. * * Note that any producer can be connected here, but see special case treatment * of playlist in clip point determination below. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \param producer the producer to connect to the multitrack producer * \param track the 0-based index of the track on which to connect the multitrack * \return true on error */ int mlt_multitrack_connect( mlt_multitrack this, mlt_producer producer, int track ) { // Connect to the producer to ourselves at the specified track int result = mlt_service_connect_producer( MLT_MULTITRACK_SERVICE( this ), MLT_PRODUCER_SERVICE( producer ), track ); if ( result == 0 ) { // Resize the producer list if need be if ( track >= this->size ) { int i; this->list = realloc( this->list, ( track + 10 ) * sizeof( mlt_track ) ); for ( i = this->size; i < track + 10; i ++ ) this->list[ i ] = NULL; this->size = track + 10; } if ( this->list[ track ] != NULL ) { mlt_event_close( this->list[ track ]->event ); mlt_producer_close( this->list[ track ]->producer ); } else { this->list[ track ] = malloc( sizeof( struct mlt_track_s ) ); } // Assign the track in our list here this->list[ track ]->producer = producer; this->list[ track ]->event = mlt_events_listen( MLT_PRODUCER_PROPERTIES( producer ), this, "producer-changed", ( mlt_listener )mlt_multitrack_listener ); mlt_properties_inc_ref( MLT_PRODUCER_PROPERTIES( producer ) ); mlt_event_inc_ref( this->list[ track ]->event ); // Increment the track count if need be if ( track >= this->count ) this->count = track + 1; // Refresh our stats mlt_multitrack_refresh( this ); } return result; } /** Get the number of tracks. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \return the number of tracks */ int mlt_multitrack_count( mlt_multitrack this ) { return this->count; } /** Get an individual track as a producer. * * \public \memberof mlt_multitrack_s * \param this a multitrack * \param track the 0-based index of the producer to get * \return the producer or NULL if not valid */ mlt_producer mlt_multitrack_track( mlt_multitrack this, int track ) { mlt_producer producer = NULL; if ( this->list != NULL && track < this->count ) producer = this->list[ track ]->producer; return producer; } /** Position comparison function for sorting. * * \private \memberof mlt_multitrack_s * \param p1 a position * \param p2 another position * \return <0 if \p p1 is less than \p p2, 0 if equal, >0 if greater */ static int position_compare( const void *p1, const void *p2 ) { return *( mlt_position * )p1 - *( mlt_position * )p2; } /** Add a position to a set. * * \private \memberof mlt_multitrack_s * \param array an array of positions (the set) * \param size the current number of positions in the array (not the capacity of the array) * \param position the position to add * \return the new size of the array */ static int add_unique( mlt_position *array, int size, mlt_position position ) { int i = 0; for ( i = 0; i < size; i ++ ) if ( array[ i ] == position ) break; if ( i == size ) array[ size ++ ] = position; return size; } /** Determine the clip point. * *
 * Special case here: a 'producer' has no concept of multiple clips - only the
 * playlist and multitrack producers have clip functionality. Further to that a
 * multitrack determines clip information from any connected tracks that happen
 * to be playlists.
 *
 * Additionally, it must locate clips in the correct order, for example, consider
 * the following track arrangement:
 *
 * playlist1 |0.0     |b0.0      |0.1          |0.1         |0.2           |
 * playlist2 |b1.0  |1.0           |b1.1     |1.1             |
 *
 * Note - b clips represent blanks. They are also reported as clip positions.
 *
 * When extracting clip positions from these playlists, we should get a sequence of:
 *
 * 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
 * 
* * \public \memberof mlt_multitrack_s * \param this a multitrack * \param whence from where to extract * \param index the 0-based index of which clip to extract * \return the position of clip \p index relative to \p whence */ mlt_position mlt_multitrack_clip( mlt_multitrack this, mlt_whence whence, int index ) { mlt_position position = 0; int i = 0; int j = 0; mlt_position *map = malloc( 1000 * sizeof( mlt_position ) ); int count = 0; for ( i = 0; i < this->count; i ++ ) { // Get the producer for this track mlt_producer producer = this->list[ i ]->producer; // If it's assigned and not a hidden track if ( producer != NULL ) { // Get the properties of this producer mlt_properties properties = MLT_PRODUCER_PROPERTIES( producer ); // Determine if it's a playlist mlt_playlist playlist = mlt_properties_get_data( properties, "playlist", NULL ); // Special case consideration of playlists if ( playlist != NULL ) { for ( j = 0; j < mlt_playlist_count( playlist ); j ++ ) count = add_unique( map, count, mlt_playlist_clip( playlist, mlt_whence_relative_start, j ) ); count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 ); } else { count = add_unique( map, count, 0 ); count = add_unique( map, count, mlt_producer_get_out( producer ) + 1 ); } } } // Now sort the map qsort( map, count, sizeof( mlt_position ), position_compare ); // Now locate the requested index switch( whence ) { case mlt_whence_relative_start: if ( index < count ) position = map[ index ]; else position = map[ count - 1 ]; break; case mlt_whence_relative_current: position = mlt_producer_position( MLT_MULTITRACK_PRODUCER( this ) ); for ( i = 0; i < count - 2; i ++ ) if ( position >= map[ i ] && position < map[ i + 1 ] ) break; index += i; if ( index >= 0 && index < count ) position = map[ index ]; else if ( index < 0 ) position = map[ 0 ]; else position = map[ count - 1 ]; break; case mlt_whence_relative_end: if ( index < count ) position = map[ count - index - 1 ]; else position = map[ 0 ]; break; } // Free the map free( map ); return position; } /** Get frame method. * *
 * Special case here: The multitrack must be used in a conjunction with a downstream
 * tractor-type service, ie:
 *
 * Producer1 \
 * Producer2 - multitrack - { filters/transitions } - tractor - consumer
 * Producer3 /
 *
 * The get_frame of a tractor pulls frames from it's connected service on all tracks and
 * will terminate as soon as it receives a test card with a last_track property. The
 * important case here is that the mulitrack does not move to the next frame until all
 * tracks have been pulled.
 *
 * Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
 * that all producers are positioned on the same frame. It uses the 'last track' logic
 * to determine when to move to the next frame.
 *
 * Flaw: if a transition is configured to read from a b-track which happens to trigger
 * the last frame logic (ie: it's configured incorrectly), then things are going to go
 * out of sync.
 *
 * See playlist logic too.
 * 
* * \private \memberof mlt_multitrack_s * \param parent the producer interface to a mulitrack * \param[out] frame a frame by reference * \param index the 0-based track index * \return true if there was an error */ static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int index ) { // Get the mutiltrack object mlt_multitrack this = parent->child; // Check if we have a track for this index if ( index < this->count && this->list[ index ] != NULL ) { // Get the producer for this track mlt_producer producer = this->list[ index ]->producer; // Get the track hide property int hide = mlt_properties_get_int( MLT_PRODUCER_PROPERTIES( mlt_producer_cut_parent( producer ) ), "hide" ); // Obtain the current position mlt_position position = mlt_producer_frame( parent ); // Get the parent properties mlt_properties producer_properties = MLT_PRODUCER_PROPERTIES( parent ); // Get the speed double speed = mlt_properties_get_double( producer_properties, "_speed" ); // Make sure we're at the same point mlt_producer_seek( producer, position ); // Get the frame from the producer mlt_service_get_frame( MLT_PRODUCER_SERVICE( producer ), frame, 0 ); // Indicate speed of this producer mlt_properties properties = MLT_FRAME_PROPERTIES( *frame ); mlt_properties_set_double( properties, "_speed", speed ); mlt_properties_set_position( properties, "_position", position ); mlt_properties_set_int( properties, "hide", hide ); } else { // Generate a test frame *frame = mlt_frame_init( MLT_PRODUCER_SERVICE( parent ) ); // Update position on the frame we're creating mlt_frame_set_position( *frame, mlt_producer_position( parent ) ); // Move on to the next frame if ( index >= this->count ) { // Let tractor know if we've reached the end mlt_properties_set_int( MLT_FRAME_PROPERTIES( *frame ), "last_track", 1 ); // Move to the next frame mlt_producer_prepare_next( parent ); } } return 0; } /** Close this instance and free its resources. * * \public \memberof mlt_multitrack_s * \param this a multitrack */ void mlt_multitrack_close( mlt_multitrack this ) { if ( this != NULL && mlt_properties_dec_ref( MLT_MULTITRACK_PROPERTIES( this ) ) <= 0 ) { int i = 0; for ( i = 0; i < this->count; i ++ ) { if ( this->list[ i ] != NULL ) { mlt_event_close( this->list[ i ]->event ); mlt_producer_close( this->list[ i ]->producer ); free( this->list[ i ] ); } } // Close the producer this->parent.close = NULL; mlt_producer_close( &this->parent ); // Free the list free( this->list ); // Free the object free( this ); } }