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" );
75 /** Get the producer associated to this multitrack.
78 mlt_producer
mlt_multitrack_producer( mlt_multitrack
this )
83 /** Get the service associated this multitrack.
86 mlt_service
mlt_multitrack_service( mlt_multitrack
this )
88 return mlt_producer_service( mlt_multitrack_producer( this ) );
91 /** Get the properties associated this multitrack.
94 mlt_properties
mlt_multitrack_properties( mlt_multitrack
this )
96 return mlt_service_properties( mlt_multitrack_service( this ) );
99 /** Initialise position related information.
102 void mlt_multitrack_refresh( mlt_multitrack
this )
106 // Obtain the properties of this multitrack
107 mlt_properties properties
= mlt_multitrack_properties( this );
109 // We need to ensure that the multitrack reports the longest track as its length
110 mlt_position length
= 0;
112 // We need to ensure that fps are the same on all services
115 // Obtain stats on all connected services
116 for ( i
= 0; i
< this->count
; i
++ )
118 // Get the producer from this index
119 mlt_producer producer
= this->list
[ i
];
121 // If it's allocated then, update our stats
122 if ( producer
!= NULL
)
124 // If we have more than 1 track, we must be in continue mode
125 if ( this->count
> 1 )
126 mlt_properties_set( mlt_producer_properties( producer
), "eof", "continue" );
128 // Determine the longest length
129 length
= mlt_producer_get_playtime( producer
) > length ?
mlt_producer_get_playtime( producer
) : length
;
134 // This is the first producer, so it controls the fps
135 fps
= mlt_producer_get_fps( producer
);
137 else if ( fps
!= mlt_producer_get_fps( producer
) )
139 // Generate a warning for now - the following attempt to fix may fail
140 fprintf( stderr
, "Warning: fps mismatch on track %d\n", i
);
142 // It should be safe to impose fps on an image producer, but not necessarily safe for video
143 mlt_properties_set_double( mlt_producer_properties( producer
), "fps", fps
);
148 // Update multitrack properties now - we'll not destroy the in point here
149 mlt_properties_set_position( properties
, "length", length
);
150 mlt_properties_set_position( properties
, "out", length
);
151 mlt_properties_set_double( properties
, "fps", fps
);
154 /** Connect a producer to a given track.
156 Note that any producer can be connected here, but see special case treatment
157 of playlist in clip point determination below.
160 int mlt_multitrack_connect( mlt_multitrack
this, mlt_producer producer
, int track
)
162 // Connect to the producer to ourselves at the specified track
163 int result
= mlt_service_connect_producer( mlt_multitrack_service( this ), mlt_producer_service( producer
), track
);
167 // Resize the producer list if need be
168 if ( track
>= this->size
)
171 this->list
= realloc( this->list
, ( track
+ 10 ) * sizeof( mlt_producer
) );
172 for ( i
= this->size
; i
< track
+ 10; i
++ )
173 this->list
[ i
] = NULL
;
174 this->size
= track
+ 10;
177 // Assign the track in our list here
178 this->list
[ track
] = producer
;
180 // Increment the track count if need be
181 if ( track
>= this->count
)
182 this->count
= track
+ 1;
185 mlt_multitrack_refresh( this );
191 /** Determine the clip point.
193 Special case here: a 'producer' has no concept of multiple clips - only the
194 playlist and multitrack producers have clip functionality. Further to that a
195 multitrack determines clip information from any connected tracks that happen
198 Additionally, it must locate clips in the correct order, for example, consider
199 the following track arrangement:
201 playlist1 |0.0 |b0.0 |0.1 |0.1 |0.2 |
202 playlist2 |b1.0 |1.0 |b1.1 |1.1 |
204 Note - b clips represent blanks. They are also reported as clip positions.
206 When extracting clip positions from these playlists, we should get a sequence of:
208 0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
211 mlt_position
mlt_multitrack_clip( mlt_multitrack
this, mlt_whence whence
, int index
)
214 mlt_position position
= 0;
217 // Loop through each of the tracks
218 for ( i
= 0; i
< this->count
; i
++ )
220 // Get the producer for this track
221 mlt_producer producer
= this->list
[ i
];
223 // If it's assigned...
224 if ( producer
!= NULL
)
226 // Get the properties of this producer
227 mlt_properties properties
= mlt_producer_properties( producer
);
229 // Determine if it's a playlist
230 mlt_playlist playlist
= mlt_properties_get_data( properties
, "playlist", NULL
);
232 // We only consider playlists
233 if ( playlist
!= NULL
)
235 // Locate the smallest position
238 // First position found
239 position
= mlt_playlist_clip( playlist
, whence
, index
);
241 // We're no longer first
246 // Obtain the clip position in this playlist
247 //mlt_position position2 = mlt_playlist_clip( playlist, whence, index );
249 // If this position is prior to the first, then use it
250 //if ( position2 < position )
251 //position = position2;
256 fprintf( stderr
, "track %d isn't a playlist\n", index
);
264 /** Get frame method.
266 Special case here: The multitrack must be used in a conjunction with a downstream
267 tractor-type service, ie:
270 Producer2 - multitrack - { filters/transitions } - tractor - consumer
273 The get_frame of a tractor pulls frames from it's connected service on all tracks and
274 will terminate as soon as it receives a test card with a last_track property. The
275 important case here is that the mulitrack does not move to the next frame until all
276 tracks have been pulled.
278 Reasoning: In order to seek on a network such as above, the multitrack needs to ensure
279 that all producers are positioned on the same frame. It uses the 'last track' logic
280 to determine when to move to the next frame.
282 Flaw: if a transition is configured to read from a b-track which happens to trigger
283 the last frame logic (ie: it's configured incorrectly), then things are going to go
286 See playlist logic too.
289 static int producer_get_frame( mlt_producer parent
, mlt_frame_ptr frame
, int index
)
291 // Get the mutiltrack object
292 mlt_multitrack
this = parent
->child
;
294 // Check if we have a track for this index
295 if ( index
< this->count
&& this->list
[ index
] != NULL
)
297 // Get the producer for this track
298 mlt_producer producer
= this->list
[ index
];
300 // Obtain the current position
301 uint64_t position
= mlt_producer_frame( parent
);
303 // Make sure we're at the same point
304 mlt_producer_seek( producer
, position
);
306 // Get the frame from the producer
307 mlt_service_get_frame( mlt_producer_service( producer
), frame
, 0 );
309 // Indicate speed of this producer
310 mlt_properties producer_properties
= mlt_producer_properties( parent
);
311 double speed
= mlt_properties_get_double( producer_properties
, "speed" );
312 mlt_properties properties
= mlt_frame_properties( *frame
);
313 mlt_properties_set_double( properties
, "speed", speed
);
317 // Generate a test frame
318 *frame
= mlt_frame_init( );
320 // Update position on the frame we're creating
321 mlt_frame_set_position( *frame
, mlt_producer_position( parent
) );
323 // Move on to the next frame
324 if ( index
>= this->count
)
326 // Let tractor know if we've reached the end
327 mlt_properties_set_int( mlt_frame_properties( *frame
), "last_track", 1 );
329 // Move to the next frame
330 mlt_producer_prepare_next( parent
);
334 mlt_multitrack_refresh( this );
340 /** Close this instance.
343 void mlt_multitrack_close( mlt_multitrack
this )
345 // Close the producer
346 mlt_producer_close( &this->parent
);