2 * mlt_multitrack.c -- multitrack service class
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_multitrack.h"
24 #include "mlt_playlist.h"
25 #include "mlt_frame.h"
30 /** Private definition.
33 struct mlt_multitrack_s
35 // We're extending producer here
36 struct mlt_producer_s parent
;
42 /** Forward reference.
45 static int producer_get_frame( mlt_producer parent
, mlt_frame_ptr frame
, int index
);
50 mlt_multitrack
mlt_multitrack_init( )
52 // Allocate the multitrack object
53 mlt_multitrack
this = calloc( sizeof( struct mlt_multitrack_s
), 1 );
57 mlt_producer producer
= &this->parent
;
58 if ( mlt_producer_init( producer
, this ) == 0 )
60 mlt_properties properties
= mlt_multitrack_properties( this );
61 producer
->get_frame
= producer_get_frame
;
62 mlt_properties_set_data( properties
, "multitrack", this, 0, NULL
, NULL
);
63 mlt_properties_set( properties
, "log_id", "multitrack" );
64 mlt_properties_set( properties
, "resource", "<mulitrack>" );
76 /** Get the producer associated to this multitrack.
79 mlt_producer
mlt_multitrack_producer( mlt_multitrack
this )
84 /** Get the service associated this multitrack.
87 mlt_service
mlt_multitrack_service( mlt_multitrack
this )
89 return mlt_producer_service( mlt_multitrack_producer( this ) );
92 /** Get the properties associated this multitrack.
95 mlt_properties
mlt_multitrack_properties( mlt_multitrack
this )
97 return mlt_service_properties( mlt_multitrack_service( this ) );
100 /** Initialise position related information.
103 void mlt_multitrack_refresh( mlt_multitrack
this )
107 // Obtain the properties of this multitrack
108 mlt_properties properties
= mlt_multitrack_properties( this );
110 // We need to ensure that the multitrack reports the longest track as its length
111 mlt_position length
= 0;
113 // We need to ensure that fps are the same on all services
116 // Obtain stats on all connected services
117 for ( i
= 0; i
< this->count
; i
++ )
119 // Get the producer from this index
120 mlt_producer producer
= this->list
[ i
];
122 // If it's allocated then, update our stats
123 if ( producer
!= NULL
)
125 // If we have more than 1 track, we must be in continue mode
126 if ( this->count
> 1 )
127 mlt_properties_set( mlt_producer_properties( producer
), "eof", "continue" );
129 // Determine the longest length
130 length
= mlt_producer_get_playtime( producer
) > length ?
mlt_producer_get_playtime( producer
) : length
;
135 // This is the first producer, so it controls the fps
136 fps
= mlt_producer_get_fps( producer
);
138 else if ( fps
!= mlt_producer_get_fps( producer
) )
140 // Generate a warning for now - the following attempt to fix may fail
141 fprintf( stderr
, "Warning: fps mismatch on track %d\n", i
);
143 // It should be safe to impose fps on an image producer, but not necessarily safe for video
144 mlt_properties_set_double( mlt_producer_properties( producer
), "fps", fps
);
149 // Update multitrack properties now - we'll not destroy the in point here
150 mlt_properties_set_position( properties
, "length", length
);
151 mlt_properties_set_position( properties
, "out", length
- 1 );
152 mlt_properties_set_double( properties
, "fps", fps
);
155 /** Connect a producer to a given track.
157 Note that any producer can be connected here, but see special case treatment
158 of playlist in clip point determination below.
161 int mlt_multitrack_connect( mlt_multitrack
this, mlt_producer producer
, int track
)
163 // Connect to the producer to ourselves at the specified track
164 int result
= mlt_service_connect_producer( mlt_multitrack_service( this ), mlt_producer_service( producer
), track
);
168 // Resize the producer list if need be
169 if ( track
>= this->size
)
172 this->list
= realloc( this->list
, ( track
+ 10 ) * sizeof( mlt_producer
) );
173 for ( i
= this->size
; i
< track
+ 10; i
++ )
174 this->list
[ i
] = NULL
;
175 this->size
= track
+ 10;
178 // Assign the track in our list here
179 this->list
[ track
] = producer
;
181 // Increment the track count if need be
182 if ( track
>= this->count
)
183 this->count
= track
+ 1;
186 mlt_multitrack_refresh( this );
192 /** Determine the clip point.
194 Special case here: a 'producer' has no concept of multiple clips - only the
195 playlist and multitrack producers have clip functionality. Further to that a
196 multitrack determines clip information from any connected tracks that happen
199 Additionally, it must locate clips in the correct order, for example, consider
200 the following track arrangement:
202 playlist1 |0.0 |b0.0 |0.1 |0.1 |0.2 |
203 playlist2 |b1.0 |1.0 |b1.1 |1.1 |
205 Note - b clips represent blanks. They are also reported as clip positions.
207 When extracting clip positions from these playlists, we should get a sequence of:
209 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
212 mlt_position
mlt_multitrack_clip( mlt_multitrack
this, mlt_whence whence
, int index
)
215 mlt_position position
= 0;
218 // Loop through each of the tracks
219 for ( i
= 0; i
< this->count
; i
++ )
221 // Get the producer for this track
222 mlt_producer producer
= this->list
[ i
];
224 // If it's assigned...
225 if ( producer
!= NULL
)
227 // Get the properties of this producer
228 mlt_properties properties
= mlt_producer_properties( producer
);
230 // Determine if it's a playlist
231 mlt_playlist playlist
= mlt_properties_get_data( properties
, "playlist", NULL
);
233 // We only consider playlists
234 if ( playlist
!= NULL
)
236 // Locate the smallest position
239 // First position found
240 position
= mlt_playlist_clip( playlist
, whence
, index
);
242 // We're no longer first
247 // Obtain the clip position in this playlist
248 //mlt_position position2 = mlt_playlist_clip( playlist, whence, index );
250 // If this position is prior to the first, then use it
251 //if ( position2 < position )
252 //position = position2;
257 fprintf( stderr
, "track %d isn't a playlist\n", index
);
265 /** Get frame method.
267 Special case here: The multitrack must be used in a conjunction with a downstream
268 tractor-type service, ie:
271 Producer2 - multitrack - { filters/transitions } - tractor - consumer
274 The get_frame of a tractor pulls frames from it's connected service on all tracks and
275 will terminate as soon as it receives a test card with a last_track property. The
276 important case here is that the mulitrack does not move to the next frame until all
277 tracks have been pulled.
279 Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
280 that all producers are positioned on the same frame. It uses the 'last track' logic
281 to determine when to move to the next frame.
283 Flaw: if a transition is configured to read from a b-track which happens to trigger
284 the last frame logic (ie: it's configured incorrectly), then things are going to go
287 See playlist logic too.
290 static int producer_get_frame( mlt_producer parent
, mlt_frame_ptr frame
, int index
)
292 // Get the mutiltrack object
293 mlt_multitrack
this = parent
->child
;
295 // Check if we have a track for this index
296 if ( index
< this->count
&& this->list
[ index
] != NULL
)
298 // Get the producer for this track
299 mlt_producer producer
= this->list
[ index
];
301 // Obtain the current position
302 mlt_position position
= mlt_producer_frame( parent
);
304 // Make sure we're at the same point
305 mlt_producer_seek( producer
, position
);
307 // Get the frame from the producer
308 mlt_service_get_frame( mlt_producer_service( producer
), frame
, 0 );
310 // Indicate speed of this producer
311 mlt_properties producer_properties
= mlt_producer_properties( parent
);
312 double speed
= mlt_properties_get_double( producer_properties
, "speed" );
313 mlt_properties properties
= mlt_frame_properties( *frame
);
314 mlt_properties_set_double( properties
, "speed", speed
);
318 // Generate a test frame
319 *frame
= mlt_frame_init( );
321 // Update position on the frame we're creating
322 mlt_frame_set_position( *frame
, mlt_producer_position( parent
) );
324 // Move on to the next frame
325 if ( index
>= this->count
)
327 // Let tractor know if we've reached the end
328 mlt_properties_set_int( mlt_frame_properties( *frame
), "last_track", 1 );
330 // Move to the next frame
331 mlt_producer_prepare_next( parent
);
335 mlt_multitrack_refresh( this );
341 /** Close this instance.
344 void mlt_multitrack_close( mlt_multitrack
this )
346 // Close the producer
347 mlt_producer_close( &this->parent
);