2 * \file mlt_transition.c
3 * \brief abstraction for all transition services
4 * \see mlt_transition_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_transition.h"
25 #include "mlt_frame.h"
27 #include "mlt_producer.h"
33 /* Forward references */
35 static int transition_get_frame( mlt_service self, mlt_frame_ptr frame, int index );
37 /** Initialize a new transition.
39 * \public \memberof mlt_transition_s
40 * \param self a transition
41 * \param child the object of a subclass
42 * \return true on error
45 int mlt_transition_init( mlt_transition self, void *child )
47 mlt_service service = &self->parent;
48 memset( self, 0, sizeof( struct mlt_transition_s ) );
50 if ( mlt_service_init( service, self ) == 0 )
52 mlt_properties properties = MLT_TRANSITION_PROPERTIES( self );
54 service->get_frame = transition_get_frame;
55 service->close = ( mlt_destructor )mlt_transition_close;
56 service->close_object = self;
58 mlt_properties_set_position( properties, "in", 0 );
59 mlt_properties_set_position( properties, "out", 0 );
60 mlt_properties_set_int( properties, "a_track", 0 );
61 mlt_properties_set_int( properties, "b_track", 1 );
68 /** Create and initialize a new transition.
70 * \public \memberof mlt_transition_s
71 * \return a new transition
74 mlt_transition mlt_transition_new( )
76 mlt_transition self = calloc( 1, sizeof( struct mlt_transition_s ) );
78 mlt_transition_init( self, NULL );
82 /** Get the service class interface.
84 * \public \memberof mlt_transition_s
85 * \param self a transition
86 * \return the service class
87 * \see MLT_TRANSITION_SERVICE
90 mlt_service mlt_transition_service( mlt_transition self )
92 return self != NULL ? &self->parent : NULL;
95 /** Get the properties interface.
97 * \public \memberof mlt_transition_s
98 * \param self a transition
99 * \return the transition's properties
100 * \see MLT_TRANSITION_PROPERTIES
103 mlt_properties mlt_transition_properties( mlt_transition self )
105 return MLT_TRANSITION_PROPERTIES( self );
108 /** Connect a transition with a producer's a and b tracks.
110 * \public \memberof mlt_transition_s
111 * \param self a transition
112 * \param producer a producer
113 * \param a_track the track index of the first input
114 * \param b_track the track index of the second index
115 * \return true on error
118 int mlt_transition_connect( mlt_transition self, mlt_service producer, int a_track, int b_track )
120 int ret = mlt_service_connect_producer( &self->parent, producer, a_track );
123 mlt_properties properties = MLT_TRANSITION_PROPERTIES( self );
124 self->producer = producer;
125 mlt_properties_set_int( properties, "a_track", a_track );
126 mlt_properties_set_int( properties, "b_track", b_track );
131 /** Set the starting and ending time for when the transition is active.
133 * \public \memberof mlt_transition_s
134 * \param self a transition
135 * \param in the starting time
136 * \param out the ending time
139 void mlt_transition_set_in_and_out( mlt_transition self, mlt_position in, mlt_position out )
141 mlt_properties properties = MLT_TRANSITION_PROPERTIES( self );
142 mlt_properties_set_position( properties, "in", in );
143 mlt_properties_set_position( properties, "out", out );
146 /** Get the index of the a track.
148 * \public \memberof mlt_transition_s
149 * \param self a transition
150 * \return the 0-based index of the track of the first producer
153 int mlt_transition_get_a_track( mlt_transition self )
155 return mlt_properties_get_int( MLT_TRANSITION_PROPERTIES( self ), "a_track" );
158 /** Get the index of the b track.
160 * \public \memberof mlt_transition_s
161 * \param self a transition
162 * \return the 0-based index of the track of the second producer
165 int mlt_transition_get_b_track( mlt_transition self )
167 return mlt_properties_get_int( MLT_TRANSITION_PROPERTIES( self ), "b_track" );
170 /** Get the in point.
172 * \public \memberof mlt_transition_s
173 * \param self a transition
174 * \return the starting time
177 mlt_position mlt_transition_get_in( mlt_transition self )
179 return mlt_properties_get_position( MLT_TRANSITION_PROPERTIES( self ), "in" );
182 /** Get the out point.
184 * \public \memberof mlt_transition_s
185 * \param self a transition
186 * \return the ending time
189 mlt_position mlt_transition_get_out( mlt_transition self )
191 return mlt_properties_get_position( MLT_TRANSITION_PROPERTIES( self ), "out" );
194 /** Get the duration.
196 * \public \memberof mlt_transition_s
197 * \param self a transition
198 * \return the duration or zero if unlimited
201 mlt_position mlt_transition_get_length( mlt_transition self )
203 mlt_properties properties = MLT_SERVICE_PROPERTIES( &self->parent );
204 mlt_position in = mlt_properties_get_position( properties, "in" );
205 mlt_position out = mlt_properties_get_position( properties, "out" );
206 return ( out > 0 ) ? ( out - in + 1 ) : 0;
209 /** Get the position within the transition.
211 * The position is relative to the in point.
213 * \public \memberof mlt_transition_s
214 * \param self a transition
215 * \param frame a frame
216 * \return the position
219 mlt_position mlt_transition_get_position( mlt_transition self, mlt_frame frame )
221 mlt_position in = mlt_transition_get_in( self );
222 mlt_position position = mlt_frame_get_position( frame );
223 return position - in;
226 /** Get the percent complete.
228 * \public \memberof mlt_transition_s
229 * \param self a transition
230 * \param frame a frame
231 * \return the progress in the range 0.0 to 1.0
234 double mlt_transition_get_progress( mlt_transition self, mlt_frame frame )
237 mlt_position in = mlt_transition_get_in( self );
238 mlt_position out = mlt_transition_get_out( self );
242 // If always active, use the frame's producer
243 mlt_producer producer = mlt_frame_get_original_producer( frame );
246 in = mlt_producer_get_in( producer );
247 out = mlt_producer_get_out( producer );
252 mlt_position position = mlt_frame_get_position( frame );
253 progress = ( double ) ( position - in ) / ( double ) ( out - in + 1 );
258 /** Get the second field incremental progress.
260 * \public \memberof mlt_transition_s
261 * \param self a transition
262 * \param frame a frame
263 * \return the progress increment in the range 0.0 to 1.0
266 double mlt_transition_get_progress_delta( mlt_transition self, mlt_frame frame )
269 mlt_position in = mlt_transition_get_in( self );
270 mlt_position out = mlt_transition_get_out( self );
274 // If always active, use the frame's producer
275 mlt_producer producer = mlt_frame_get_original_producer( frame );
278 in = mlt_producer_get_in( producer );
279 out = mlt_producer_get_out( producer );
284 mlt_position position = mlt_frame_get_position( frame );
285 double length = out - in + 1;
286 double x = ( double ) ( position - in ) / length;
287 double y = ( double ) ( position + 1 - in ) / length;
288 progress = length * ( y - x ) / 2.0;
293 /** Process the frame.
295 * If we have no process method (unlikely), we simply return the a_frame unmolested.
297 * \public \memberof mlt_transition_s
298 * \param self a transition
299 * \param a_frame a frame from the first producer
300 * \param b_frame a frame from the second producer
304 mlt_frame mlt_transition_process( mlt_transition self, mlt_frame a_frame, mlt_frame b_frame )
306 if ( self->process == NULL )
309 return self->process( self, a_frame, b_frame );
312 /** Get a frame from a transition.
314 The logic is complex here. A transition is typically applied to frames on the a and
315 b tracks specified in the connect method above and only if both contain valid info
316 for the transition type (this is either audio or image).
318 However, the fixed a_track may not always contain data of the correct type, eg:
320 +---------+ +-------+
321 |c1 | |c5 | <-- A(0,1) <-- B(0,2) <-- get frame
322 +---------+ +---------+-+-----+ | |
324 +----------+-----------+-+---------+ |
325 |c2 |c3 | <-----------------+
326 +----------+-------------+
328 During the overlap of c1 and c2, there is nothing for the A transition to do, so this
329 results in a no operation, but B is triggered. During the overlap of c2 and c3, again,
330 the A transition is inactive and because the B transition is pointing at track 0,
331 it too would be inactive. This isn't an ideal situation - it's better if the B
332 transition simply treats the frames from c3 as though they're the a track.
334 For this to work, we cache all frames coming from all tracks between the a and b
335 tracks. Before we process, we determine that the b frame contains someting of the
336 right type and then we determine which frame to use as the a frame (selecting a
337 matching frame from a_track to b_track - 1). If both frames contain data of the
338 correct type, we process the transition.
340 This method is invoked for each track and we return the cached frames as needed.
341 We clear the cache only when the requested frame is flagged as a 'last_track' frame.
343 * \private \memberof mlt_transition_s
344 * \param service a service
345 * \param[out] frame a frame by reference
346 * \param index 0-based track index
347 * \return true on error
350 static int transition_get_frame( mlt_service service, mlt_frame_ptr frame, int index )
353 mlt_transition self = service->child;
355 mlt_properties properties = MLT_TRANSITION_PROPERTIES( self );
357 int accepts_blanks = mlt_properties_get_int( properties, "accepts_blanks" );
358 int a_track = mlt_properties_get_int( properties, "a_track" );
359 int b_track = mlt_properties_get_int( properties, "b_track" );
360 mlt_position in = mlt_properties_get_position( properties, "in" );
361 mlt_position out = mlt_properties_get_position( properties, "out" );
362 int always_active = mlt_properties_get_int( properties, "always_active" );
363 int type = mlt_properties_get_int( properties, "_transition_type" );
364 int reverse_order = 0;
366 // Ensure that we have the correct order
367 if ( a_track > b_track )
371 b_track = mlt_properties_get_int( properties, "a_track" );
374 // Only act on this operation once per multitrack iteration from the tractor
379 int a_frame = a_track;
380 int b_frame = b_track;
381 mlt_position position;
382 int ( *invalid )( mlt_frame ) = type == 1 ? mlt_frame_is_test_card : mlt_frame_is_test_audio;
384 // Initialise temporary store
385 if ( self->frames == NULL )
386 self->frames = calloc( sizeof( mlt_frame ), b_track + 1 );
388 // Get all frames between a and b
389 for( i = a_track; i <= b_track; i ++ )
390 mlt_service_get_frame( self->producer, &self->frames[ i ], i );
392 // We're holding these frames until the last_track frame property is received
395 // When we need to locate the a_frame
400 // Some transitions (esp. audio) may accept blank frames
401 active = accepts_blanks;
403 // If we're not active then...
406 // Hunt for the a_frame
407 while( a_frame <= b_frame && invalid( self->frames[ a_frame ] ) )
410 // Determine if we're active now
411 active = a_frame != b_frame && !invalid( self->frames[ b_frame ] );
416 mlt_log( service, MLT_LOG_ERROR, "invalid transition type\n" );
420 // Now handle the non-always active case
421 if ( active && !always_active )
423 // For non-always-active transitions, we need the current position of the a frame
424 position = mlt_frame_get_position( self->frames[ a_frame ] );
426 // If a is in range, we're active
427 active = position >= in && ( out == 0 || position <= out );
430 // Finally, process the a and b frames
433 mlt_frame a_frame_ptr = self->frames[ !reverse_order ? a_frame : b_frame ];
434 mlt_frame b_frame_ptr = self->frames[ !reverse_order ? b_frame : a_frame ];
435 int a_hide = mlt_properties_get_int( MLT_FRAME_PROPERTIES( a_frame_ptr ), "hide" );
436 int b_hide = mlt_properties_get_int( MLT_FRAME_PROPERTIES( b_frame_ptr ), "hide" );
437 if ( !( a_hide & type ) && !( b_hide & type ) )
439 // Process the transition
440 *frame = mlt_transition_process( self, a_frame_ptr, b_frame_ptr );
442 // We need to ensure that the tractor doesn't consider this frame for output
443 if ( *frame == a_frame_ptr )
448 mlt_properties_set_int( MLT_FRAME_PROPERTIES( a_frame_ptr ), "hide", a_hide );
449 mlt_properties_set_int( MLT_FRAME_PROPERTIES( b_frame_ptr ), "hide", b_hide );
454 // Obtain the frame from the cache or the producer we're attached to
455 if ( index >= a_track && index <= b_track )
456 *frame = self->frames[ index ];
458 error = mlt_service_get_frame( self->producer, frame, index );
460 // Determine if that was the last track
461 self->held = !mlt_properties_get_int( MLT_FRAME_PROPERTIES( *frame ), "last_track" );
466 /** Close and destroy the transition.
468 * \public \memberof mlt_transition_s
469 * \param self a transition
472 void mlt_transition_close( mlt_transition self )
474 if ( self != NULL && mlt_properties_dec_ref( MLT_TRANSITION_PROPERTIES( self ) ) <= 0 )
476 self->parent.close = NULL;
477 if ( self->close != NULL )
483 mlt_service_close( &self->parent );
484 free( self->frames );