Constness changes

[melted] / src / framework / mlt_multitrack.c

/**
 * \file mlt_multitrack.c
 * \brief multitrack service class
 * \see mlt_multitrack_s
 *
 * Copyright (C) 2003-2009 Ushodaya Enterprises Limited
 * \author Charles Yates <charles.yates@pandora.be>
 *
 * 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 <stdio.h>
#include <stdlib.h>

/* 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 "<multitrack>".
 *
 * \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", "<multitrack>" );
                        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.
 *
 * <pre>
 * 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]
 * </pre>
 *
 * \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.
 *
 * <pre>
 * 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.
 * </pre>
 *
 * \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 );
        }
}