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>
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.
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.
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.
23 #include "mlt_transition.h"
24 #include "mlt_frame.h"
30 /** Forward references.
33 static int transition_get_frame( mlt_service
this, mlt_frame_ptr frame
, int index
);
38 int mlt_transition_init( mlt_transition
this, void *child
)
40 mlt_service service
= &this->parent
;
41 memset( this, 0, sizeof( struct mlt_transition_s
) );
43 if ( mlt_service_init( service
, this ) == 0 )
45 mlt_properties properties
= mlt_transition_properties( this );
47 service
->get_frame
= transition_get_frame
;
49 mlt_properties_set_position( properties
, "in", 0 );
50 mlt_properties_set_position( properties
, "out", 0 );
51 mlt_properties_set_int( properties
, "a_track", 0 );
52 mlt_properties_set_int( properties
, "b_track", 1 );
59 /** Get the service associated to the transition.
62 mlt_service
mlt_transition_service( mlt_transition
this )
67 /** Get the properties interface.
70 mlt_properties
mlt_transition_properties( mlt_transition
this )
72 return mlt_service_properties( mlt_transition_service( this ) );
75 /** Connect this transition with a producers a and b tracks.
78 int mlt_transition_connect( mlt_transition
this, mlt_service producer
, int a_track
, int b_track
)
80 int ret
= mlt_service_connect_producer( &this->parent
, producer
, a_track
);
83 mlt_properties properties
= mlt_transition_properties( this );
84 this->producer
= producer
;
85 mlt_properties_set_int( properties
, "a_track", a_track
);
86 mlt_properties_set_int( properties
, "b_track", b_track
);
91 /** Set the in and out points.
94 void mlt_transition_set_in_and_out( mlt_transition
this, mlt_position in
, mlt_position out
)
96 mlt_properties properties
= mlt_transition_properties( this );
97 mlt_properties_set_position( properties
, "in", in
);
98 mlt_properties_set_position( properties
, "out", out
);
101 /** Get the index of the a track.
104 int mlt_transition_get_a_track( mlt_transition
this )
106 return mlt_properties_get_int( mlt_transition_properties( this ), "a_track" );
109 /** Get the index of the b track.
112 int mlt_transition_get_b_track( mlt_transition
this )
114 return mlt_properties_get_int( mlt_transition_properties( this ), "b_track" );
117 /** Get the in point.
120 mlt_position
mlt_transition_get_in( mlt_transition
this )
122 return mlt_properties_get_position( mlt_transition_properties( this ), "in" );
125 /** Get the out point.
128 mlt_position
mlt_transition_get_out( mlt_transition
this )
130 return mlt_properties_get_position( mlt_transition_properties( this ), "out" );
133 /** Process the frame.
135 If we have no process method (unlikely), we simply return the a_frame unmolested.
138 static mlt_frame
transition_process( mlt_transition
this, mlt_frame a_frame
, mlt_frame b_frame
)
140 if ( this->process
== NULL
)
143 return this->process( this, a_frame
, b_frame
);
146 /** Get a frame from this filter.
148 The logic is complex here. A transition is applied to frames on the a and b tracks
149 specified in the connect method above. Since all frames are obtained via this
150 method for all tracks, we have to take special care that we only obtain the a and
151 b frames once - we do this on the first call to get a frame from either a or b.
153 After that, we have 2 cases to resolve:
155 1) if the track is the a_track and we're in the time zone, then we need to call the
156 process method to do the effect on the frame and remember we've passed it on
157 otherwise, we pass on the a_frame unmolested;
158 2) For all other tracks, we get the frames on demand.
161 static int transition_get_frame( mlt_service service
, mlt_frame_ptr frame
, int index
)
163 mlt_transition
this = service
->child
;
165 mlt_properties properties
= mlt_transition_properties( this );
167 int a_track
= mlt_properties_get_int( properties
, "a_track" );
168 int b_track
= mlt_properties_get_int( properties
, "b_track" );
169 mlt_position in
= mlt_properties_get_position( properties
, "in" );
170 mlt_position out
= mlt_properties_get_position( properties
, "out" );
172 // Fetch a and b frames together...
173 if ( ( index
== a_track
|| index
== b_track
) && !( this->a_held
|| this->b_held
) )
175 mlt_service_get_frame( this->producer
, &this->a_frame
, a_track
);
176 mlt_service_get_frame( this->producer
, &this->b_frame
, b_track
);
181 // Special case track processing
182 if ( index
== a_track
)
184 // Determine if we're in the right time zone
185 mlt_position position
= mlt_frame_get_position( this->a_frame
);
186 if ( position
>= in
&& position
<= out
)
188 // Process the transition
189 *frame
= transition_process( this, this->a_frame
, this->b_frame
);
194 // Pass on the 'a frame' and remember that we've done it
195 *frame
= this->a_frame
;
200 if ( index
== b_track
)
202 // Pass on the 'b frame' and remember that we've done it
203 *frame
= this->b_frame
;
210 return mlt_service_get_frame( this->producer
, frame
, index
);
214 /** Close the transition.
217 void mlt_transition_close( mlt_transition
this )
219 if ( this->close
!= NULL
)
222 mlt_service_close( &this->parent
);