3 * \brief abstraction for all consumer services
6 * Copyright (C) 2003-2010 Ushodaya Enterprises Limited
7 * \author Charles Yates <charles.yates@pandora.be>
8 * \author Dan Dennedy <dan@dennedy.org>
10 * This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with this library; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 #include "mlt_consumer.h"
26 #include "mlt_factory.h"
27 #include "mlt_producer.h"
28 #include "mlt_frame.h"
29 #include "mlt_profile.h"
37 /** Define this if you want an automatic deinterlace (if necessary) when the
38 * consumer's producer is not running at normal speed.
40 #undef DEINTERLACE_ON_NOT_NORMAL_SPEED
42 /** This is not the ideal place for this, but it is needed by VDPAU as well.
44 pthread_mutex_t mlt_sdl_mutex = PTHREAD_MUTEX_INITIALIZER;
46 static void mlt_consumer_frame_render( mlt_listener listener, mlt_properties owner, mlt_service self, void **args );
47 static void mlt_consumer_frame_show( mlt_listener listener, mlt_properties owner, mlt_service self, void **args );
48 static void mlt_consumer_property_changed( mlt_properties owner, mlt_consumer self, char *name );
49 static void apply_profile_properties( mlt_consumer self, mlt_profile profile, mlt_properties properties );
50 static void on_consumer_frame_show( mlt_properties owner, mlt_consumer self, mlt_frame frame );
52 /** Initialize a consumer service.
54 * \public \memberof mlt_consumer_s
55 * \param self the consumer to initialize
56 * \param child a pointer to the object for the subclass
57 * \param profile the \p mlt_profile_s to use (optional but recommended,
58 * uses the environment variable MLT if self is NULL)
59 * \return true if there was an error
62 int mlt_consumer_init( mlt_consumer self, void *child, mlt_profile profile )
65 memset( self, 0, sizeof( struct mlt_consumer_s ) );
67 error = mlt_service_init( &self->parent, self );
70 // Get the properties from the service
71 mlt_properties properties = MLT_SERVICE_PROPERTIES( &self->parent );
73 // Apply profile to properties
74 if ( profile == NULL )
76 // Normally the application creates the profile and controls its lifetime
77 // This is the fallback exception handling
78 profile = mlt_profile_init( NULL );
79 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
80 mlt_properties_set_data( properties, "_profile", profile, 0, (mlt_destructor)mlt_profile_close, NULL );
82 apply_profile_properties( self, profile, properties );
84 // Default rescaler for all consumers
85 mlt_properties_set( properties, "rescale", "bilinear" );
87 // Default read ahead buffer size
88 mlt_properties_set_int( properties, "buffer", 25 );
89 mlt_properties_set_int( properties, "drop_max", 5 );
91 // Default audio frequency and channels
92 mlt_properties_set_int( properties, "frequency", 48000 );
93 mlt_properties_set_int( properties, "channels", 2 );
95 // Default of all consumers is real time
96 mlt_properties_set_int( properties, "real_time", 1 );
98 // Default to environment test card
99 mlt_properties_set( properties, "test_card", mlt_environment( "MLT_TEST_CARD" ) );
101 // Hmm - default all consumers to yuv422 :-/
102 self->format = mlt_image_yuv422;
103 mlt_properties_set( properties, "mlt_image_format", mlt_image_format_name( self->format ) );
104 mlt_properties_set( properties, "mlt_audio_format", mlt_audio_format_name( mlt_audio_s16 ) );
106 mlt_events_register( properties, "consumer-frame-show", ( mlt_transmitter )mlt_consumer_frame_show );
107 mlt_events_register( properties, "consumer-frame-render", ( mlt_transmitter )mlt_consumer_frame_render );
108 mlt_events_register( properties, "consumer-stopped", NULL );
109 mlt_events_listen( properties, self, "consumer-frame-show", ( mlt_listener )on_consumer_frame_show );
111 // Register a property-changed listener to handle the profile property -
112 // subsequent properties can override the profile
113 self->event_listener = mlt_events_listen( properties, self, "property-changed", ( mlt_listener )mlt_consumer_property_changed );
115 // Create the push mutex and condition
116 pthread_mutex_init( &self->put_mutex, NULL );
117 pthread_cond_init( &self->put_cond, NULL );
123 /** Convert the profile into properties on the consumer.
125 * \private \memberof mlt_consumer_s
126 * \param self a consumer
127 * \param profile a profile
128 * \param properties a properties list (typically, the consumer's)
131 static void apply_profile_properties( mlt_consumer self, mlt_profile profile, mlt_properties properties )
133 mlt_event_block( self->event_listener );
134 mlt_properties_set_double( properties, "fps", mlt_profile_fps( profile ) );
135 mlt_properties_set_int( properties, "frame_rate_num", profile->frame_rate_num );
136 mlt_properties_set_int( properties, "frame_rate_den", profile->frame_rate_den );
137 mlt_properties_set_int( properties, "width", profile->width );
138 mlt_properties_set_int( properties, "height", profile->height );
139 mlt_properties_set_int( properties, "progressive", profile->progressive );
140 mlt_properties_set_double( properties, "aspect_ratio", mlt_profile_sar( profile ) );
141 mlt_properties_set_int( properties, "sample_aspect_num", profile->sample_aspect_num );
142 mlt_properties_set_int( properties, "sample_aspect_den", profile->sample_aspect_den );
143 mlt_properties_set_double( properties, "display_ratio", mlt_profile_dar( profile ) );
144 mlt_properties_set_int( properties, "display_aspect_num", profile->display_aspect_num );
145 mlt_properties_set_int( properties, "display_aspect_num", profile->display_aspect_num );
146 mlt_properties_set_int( properties, "colorspace", profile->colorspace );
147 mlt_event_unblock( self->event_listener );
150 /** The property-changed event listener
152 * \private \memberof mlt_consumer_s
153 * \param owner the events object
154 * \param self the consumer
155 * \param name the name of the property that changed
158 static void mlt_consumer_property_changed( mlt_properties owner, mlt_consumer self, char *name )
160 if ( !strcmp( name, "mlt_profile" ) )
163 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
165 // Get the current profile
166 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
168 // Load the new profile
169 mlt_profile new_profile = mlt_profile_init( mlt_properties_get( properties, name ) );
174 if ( profile != NULL )
176 free( profile->description );
177 memcpy( profile, new_profile, sizeof( struct mlt_profile_s ) );
178 profile->description = strdup( new_profile->description );
182 profile = new_profile;
185 // Apply to properties
186 apply_profile_properties( self, profile, properties );
187 mlt_profile_close( new_profile );
190 else if ( !strcmp( name, "frame_rate_num" ) )
192 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
193 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
196 profile->frame_rate_num = mlt_properties_get_int( properties, "frame_rate_num" );
197 mlt_properties_set_double( properties, "fps", mlt_profile_fps( profile ) );
200 else if ( !strcmp( name, "frame_rate_den" ) )
202 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
203 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
206 profile->frame_rate_den = mlt_properties_get_int( properties, "frame_rate_den" );
207 mlt_properties_set_double( properties, "fps", mlt_profile_fps( profile ) );
210 else if ( !strcmp( name, "width" ) )
212 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
213 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
215 profile->width = mlt_properties_get_int( properties, "width" );
217 else if ( !strcmp( name, "height" ) )
219 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
220 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
222 profile->height = mlt_properties_get_int( properties, "height" );
224 else if ( !strcmp( name, "progressive" ) )
226 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
227 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
229 profile->progressive = mlt_properties_get_int( properties, "progressive" );
231 else if ( !strcmp( name, "sample_aspect_num" ) )
233 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
234 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
237 profile->sample_aspect_num = mlt_properties_get_int( properties, "sample_aspect_num" );
238 mlt_properties_set_double( properties, "aspect_ratio", mlt_profile_sar( profile ) );
241 else if ( !strcmp( name, "sample_aspect_den" ) )
243 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
244 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
245 profile->sample_aspect_den = mlt_properties_get_int( properties, "sample_aspect_den" );
247 mlt_properties_set_double( properties, "aspect_ratio", mlt_profile_sar( profile ) );
249 else if ( !strcmp( name, "display_aspect_num" ) )
251 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
252 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
255 profile->display_aspect_num = mlt_properties_get_int( properties, "display_aspect_num" );
256 mlt_properties_set_double( properties, "display_ratio", mlt_profile_dar( profile ) );
259 else if ( !strcmp( name, "display_aspect_den" ) )
261 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
262 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
265 profile->display_aspect_den = mlt_properties_get_int( properties, "display_aspect_den" );
266 mlt_properties_set_double( properties, "display_ratio", mlt_profile_dar( profile ) );
269 else if ( !strcmp( name, "colorspace" ) )
271 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
272 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
274 profile->colorspace = mlt_properties_get_int( properties, "colorspace" );
278 /** The transmitter for the consumer-frame-show event
280 * Invokes the listener.
282 * \private \memberof mlt_consumer_s
283 * \param listener a function pointer that will be invoked
284 * \param owner the events object that will be passed to \p listener
285 * \param self a service that will be passed to \p listener
286 * \param args an array of pointers - the first entry is passed as a string to \p listener
289 static void mlt_consumer_frame_show( mlt_listener listener, mlt_properties owner, mlt_service self, void **args )
291 if ( listener != NULL )
292 listener( owner, self, ( mlt_frame )args[ 0 ] );
295 /** The transmitter for the consumer-frame-render event
297 * Invokes the listener.
299 * \private \memberof mlt_consumer_s
300 * \param listener a function pointer that will be invoked
301 * \param owner the events object that will be passed to \p listener
302 * \param self a service that will be passed to \p listener
303 * \param args an array of pointers - the first entry is passed as a string to \p listener
306 static void mlt_consumer_frame_render( mlt_listener listener, mlt_properties owner, mlt_service self, void **args )
308 if ( listener != NULL )
309 listener( owner, self, ( mlt_frame )args[ 0 ] );
312 /** A listener on the consumer-frame-show event
314 * Saves the position of the frame shown.
316 * \private \memberof mlt_consumer_s
317 * \param owner the events object
318 * \param consumer the consumer on which this event occurred
319 * \param frame the frame that was shown
322 static void on_consumer_frame_show( mlt_properties owner, mlt_consumer consumer, mlt_frame frame )
325 consumer->position = mlt_frame_get_position( frame );
328 /** Create a new consumer.
330 * \public \memberof mlt_consumer_s
331 * \param profile a profile (optional, but recommended)
332 * \return a new consumer
335 mlt_consumer mlt_consumer_new( mlt_profile profile )
337 // Create the memory for the structure
338 mlt_consumer self = malloc( sizeof( struct mlt_consumer_s ) );
341 if ( self != NULL && mlt_consumer_init( self, NULL, profile ) == 0 )
353 /** Get the parent service object.
355 * \public \memberof mlt_consumer_s
356 * \param self a consumer
357 * \return the parent service class
358 * \see MLT_CONSUMER_SERVICE
361 mlt_service mlt_consumer_service( mlt_consumer self )
363 return self != NULL ? &self->parent : NULL;
366 /** Get the consumer properties.
368 * \public \memberof mlt_consumer_s
369 * \param self a consumer
370 * \return the consumer's properties list
371 * \see MLT_CONSUMER_PROPERTIES
374 mlt_properties mlt_consumer_properties( mlt_consumer self )
376 return self != NULL ? MLT_SERVICE_PROPERTIES( &self->parent ) : NULL;
379 /** Connect the consumer to the producer.
381 * \public \memberof mlt_consumer_s
382 * \param self a consumer
383 * \param producer a producer
384 * \return > 0 warning, == 0 success, < 0 serious error,
385 * 1 = this service does not accept input,
386 * 2 = the producer is invalid,
387 * 3 = the producer is already registered with this consumer
390 int mlt_consumer_connect( mlt_consumer self, mlt_service producer )
392 return mlt_service_connect_producer( &self->parent, producer, 0 );
395 /** Start the consumer.
397 * \public \memberof mlt_consumer_s
398 * \param self a consumer
399 * \return true if there was an error
402 int mlt_consumer_start( mlt_consumer self )
404 if ( !mlt_consumer_is_stopped( self ) )
407 // Stop listening to the property-changed event
408 mlt_event_block( self->event_listener );
411 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
413 // Determine if there's a test card producer
414 char *test_card = mlt_properties_get( properties, "test_card" );
416 // Just to make sure nothing is hanging around...
418 self->put_active = 1;
421 if ( test_card != NULL )
423 if ( mlt_properties_get_data( properties, "test_card_producer", NULL ) == NULL )
425 // Create a test card producer
426 mlt_profile profile = mlt_service_profile( MLT_CONSUMER_SERVICE( self ) );
427 mlt_producer producer = mlt_factory_producer( profile, NULL, test_card );
429 // Do we have a producer
430 if ( producer != NULL )
432 // Test card should loop I guess...
433 mlt_properties_set( MLT_PRODUCER_PROPERTIES( producer ), "eof", "loop" );
434 //mlt_producer_set_speed( producer, 0 );
435 //mlt_producer_set_in_and_out( producer, 0, 0 );
437 // Set the test card on the consumer
438 mlt_properties_set_data( properties, "test_card_producer", producer, 0, ( mlt_destructor )mlt_producer_close, NULL );
444 // Allow the hash table to speed things up
445 mlt_properties_set_data( properties, "test_card_producer", NULL, 0, NULL, NULL );
448 // Set the frame duration in microseconds for the frame-dropping heuristic
449 int frame_duration = 1000000 / mlt_properties_get_int( properties, "frame_rate_num" ) *
450 mlt_properties_get_int( properties, "frame_rate_den" );
451 mlt_properties_set_int( properties, "frame_duration", frame_duration );
453 // Check and run an ante command
454 if ( mlt_properties_get( properties, "ante" ) )
455 if ( system( mlt_properties_get( properties, "ante" ) ) == -1 )
456 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_ERROR, "system(%s) failed!\n", mlt_properties_get( properties, "ante" ) );
458 // Set the real_time preference
459 self->real_time = mlt_properties_get_int( properties, "real_time" );
461 // For worker threads implementation, buffer must be at least # threads
462 if ( abs( self->real_time ) > 1 && mlt_properties_get_int( properties, "buffer" ) <= abs( self->real_time ) )
463 mlt_properties_set_int( properties, "_buffer", abs( self->real_time ) + 1 );
465 // Get the image format to use for rendering threads
466 const char* format = mlt_properties_get( properties, "mlt_image_format" );
469 if ( !strcmp( format, "rgb24" ) )
470 self->format = mlt_image_rgb24;
471 else if ( !strcmp( format, "rgb24a" ) )
472 self->format = mlt_image_rgb24a;
473 else if ( !strcmp( format, "yuv420p" ) )
474 self->format = mlt_image_yuv420p;
475 else if ( !strcmp( format, "none" ) )
476 self->format = mlt_image_none;
478 self->format = mlt_image_yuv422;
482 if ( self->start != NULL )
483 return self->start( self );
488 /** An alternative method to feed frames into the consumer.
490 * Only valid if the consumer itself is not connected.
492 * \public \memberof mlt_consumer_s
493 * \param self a consumer
494 * \param frame a frame
495 * \return true (ignore self for now)
498 int mlt_consumer_put_frame( mlt_consumer self, mlt_frame frame )
502 // Get the service assoicated to the consumer
503 mlt_service service = MLT_CONSUMER_SERVICE( self );
505 if ( mlt_service_producer( service ) == NULL )
509 pthread_mutex_lock( &self->put_mutex );
510 while ( self->put_active && self->put != NULL )
512 gettimeofday( &now, NULL );
513 tm.tv_sec = now.tv_sec + 1;
514 tm.tv_nsec = now.tv_usec * 1000;
515 pthread_cond_timedwait( &self->put_cond, &self->put_mutex, &tm );
517 if ( self->put_active && self->put == NULL )
520 mlt_frame_close( frame );
521 pthread_cond_broadcast( &self->put_cond );
522 pthread_mutex_unlock( &self->put_mutex );
526 mlt_frame_close( frame );
532 /** Protected method for consumer to get frames from connected service
534 * \public \memberof mlt_consumer_s
535 * \param self a consumer
539 mlt_frame mlt_consumer_get_frame( mlt_consumer self )
542 mlt_frame frame = NULL;
544 // Get the service assoicated to the consumer
545 mlt_service service = MLT_CONSUMER_SERVICE( self );
547 // Get the consumer properties
548 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
551 if ( mlt_service_producer( service ) == NULL && mlt_properties_get_int( properties, "put_mode" ) )
555 pthread_mutex_lock( &self->put_mutex );
556 while ( self->put_active && self->put == NULL )
558 gettimeofday( &now, NULL );
559 tm.tv_sec = now.tv_sec + 1;
560 tm.tv_nsec = now.tv_usec * 1000;
561 pthread_cond_timedwait( &self->put_cond, &self->put_mutex, &tm );
565 pthread_cond_broadcast( &self->put_cond );
566 pthread_mutex_unlock( &self->put_mutex );
568 mlt_service_apply_filters( service, frame, 0 );
570 else if ( mlt_service_producer( service ) != NULL )
572 mlt_service_get_frame( service, &frame, 0 );
576 frame = mlt_frame_init( service );
581 // Get the frame properties
582 mlt_properties frame_properties = MLT_FRAME_PROPERTIES( frame );
584 // Get the test card producer
585 mlt_producer test_card = mlt_properties_get_data( properties, "test_card_producer", NULL );
587 // Attach the test frame producer to it.
588 if ( test_card != NULL )
589 mlt_properties_set_data( frame_properties, "test_card_producer", test_card, 0, NULL, NULL );
591 // Pass along the interpolation and deinterlace options
592 // TODO: get rid of consumer_deinterlace and use profile.progressive
593 mlt_properties_set( frame_properties, "rescale.interp", mlt_properties_get( properties, "rescale" ) );
594 mlt_properties_set_int( frame_properties, "consumer_deinterlace", mlt_properties_get_int( properties, "progressive" ) | mlt_properties_get_int( properties, "deinterlace" ) );
595 mlt_properties_set( frame_properties, "deinterlace_method", mlt_properties_get( properties, "deinterlace_method" ) );
596 mlt_properties_set_int( frame_properties, "consumer_tff", mlt_properties_get_int( properties, "top_field_first" ) );
603 /** Compute the time difference between now and a time value.
605 * \private \memberof mlt_consumer_s
606 * \param time1 a time value to be compared against now
607 * \return the difference in microseconds
610 static inline long time_difference( struct timeval *time1 )
612 struct timeval time2;
613 time2.tv_sec = time1->tv_sec;
614 time2.tv_usec = time1->tv_usec;
615 gettimeofday( time1, NULL );
616 return time1->tv_sec * 1000000 + time1->tv_usec - time2.tv_sec * 1000000 - time2.tv_usec;
619 /** The thread procedure for asynchronously pulling frames through the service
620 * network connected to a consumer.
622 * \private \memberof mlt_consumer_s
623 * \param arg a consumer
626 static void *consumer_read_ahead_thread( void *arg )
628 // The argument is the consumer
629 mlt_consumer self = arg;
631 // Get the properties of the consumer
632 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
634 // Get the width and height
635 int width = mlt_properties_get_int( properties, "width" );
636 int height = mlt_properties_get_int( properties, "height" );
638 // See if video is turned off
639 int video_off = mlt_properties_get_int( properties, "video_off" );
640 int preview_off = mlt_properties_get_int( properties, "preview_off" );
641 int preview_format = mlt_properties_get_int( properties, "preview_format" );
643 // Get the audio settings
644 mlt_audio_format afmt = mlt_audio_s16;
645 const char *format = mlt_properties_get( properties, "mlt_audio_format" );
648 if ( !strcmp( format, "none" ) )
649 afmt = mlt_audio_none;
650 else if ( !strcmp( format, "s32" ) )
651 afmt = mlt_audio_s32;
652 else if ( !strcmp( format, "s32le" ) )
653 afmt = mlt_audio_s32le;
654 else if ( !strcmp( format, "float" ) )
655 afmt = mlt_audio_float;
656 else if ( !strcmp( format, "f32le" ) )
657 afmt = mlt_audio_f32le;
660 double fps = mlt_properties_get_double( properties, "fps" );
661 int channels = mlt_properties_get_int( properties, "channels" );
662 int frequency = mlt_properties_get_int( properties, "frequency" );
666 // See if audio is turned off
667 int audio_off = mlt_properties_get_int( properties, "audio_off" );
669 // Get the maximum size of the buffer
670 int buffer = mlt_properties_get_int( properties, "buffer" ) + 1;
672 // General frame variable
673 mlt_frame frame = NULL;
674 uint8_t *image = NULL;
679 // Average time for get_frame and get_image
682 int64_t time_process = 0;
684 mlt_position pos = 0;
685 mlt_position start_pos = 0;
686 mlt_position last_pos = 0;
687 int frame_duration = mlt_properties_get_int( properties, "frame_duration" );
688 int drop_max = mlt_properties_get_int( properties, "drop_max" );
690 if ( preview_off && preview_format != 0 )
691 self->format = preview_format;
693 // Get the first frame
694 frame = mlt_consumer_get_frame( self );
698 // Get the image of the first frame
701 mlt_events_fire( MLT_CONSUMER_PROPERTIES( self ), "consumer-frame-render", frame, NULL );
702 mlt_frame_get_image( frame, &image, &self->format, &width, &height, 0 );
707 samples = mlt_sample_calculator( fps, frequency, counter++ );
708 mlt_frame_get_audio( frame, &audio, &afmt, &frequency, &channels, &samples );
712 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
713 last_pos = start_pos = pos = mlt_frame_get_position( frame );
716 // Get the starting time (can ignore the times above)
717 gettimeofday( &ante, NULL );
719 // Continue to read ahead
720 while ( self->ahead )
722 // Put the current frame into the queue
723 pthread_mutex_lock( &self->queue_mutex );
724 while( self->ahead && mlt_deque_count( self->queue ) >= buffer )
725 pthread_cond_wait( &self->queue_cond, &self->queue_mutex );
726 mlt_deque_push_back( self->queue, frame );
727 pthread_cond_broadcast( &self->queue_cond );
728 pthread_mutex_unlock( &self->queue_mutex );
730 // Get the next frame
731 frame = mlt_consumer_get_frame( self );
733 // If there's no frame, we're probably stopped...
736 pos = mlt_frame_get_position( frame );
738 // Increment the counter used for averaging processing cost
741 // All non-normal playback frames should be shown
742 if ( mlt_properties_get_int( MLT_FRAME_PROPERTIES( frame ), "_speed" ) != 1 )
744 #ifdef DEINTERLACE_ON_NOT_NORMAL_SPEED
745 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "consumer_deinterlace", 1 );
747 // Indicate seeking or trick-play
751 // If skip flag not set or frame-dropping disabled
752 if ( !skip_next || self->real_time == -1 )
756 // Reset width/height - could have been changed by previous mlt_frame_get_image
757 width = mlt_properties_get_int( properties, "width" );
758 height = mlt_properties_get_int( properties, "height" );
761 mlt_events_fire( MLT_CONSUMER_PROPERTIES( self ), "consumer-frame-render", frame, NULL );
762 mlt_frame_get_image( frame, &image, &self->format, &width, &height, 0 );
765 // Indicate the rendered image is available.
766 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
768 // Reset consecutively-skipped counter
771 else // Skip image processing
773 // Increment the number of consecutively-skipped frames
776 // If too many (1 sec) consecutively-skipped frames
777 if ( skipped > drop_max )
779 // Reset cost tracker
782 mlt_log_verbose( self, "too many frames dropped - forcing next frame\n" );
786 // Always process audio
789 samples = mlt_sample_calculator( fps, frequency, counter++ );
790 mlt_frame_get_audio( frame, &audio, &afmt, &frequency, &channels, &samples );
793 // Get the time to process this frame
794 int64_t time_current = time_difference( &ante );
796 // If the current time is not suddenly some large amount
797 if ( time_current < time_process / count * 20 || !time_process || count < 5 )
799 // Accumulate the cost for processing this frame
800 time_process += time_current;
804 mlt_log_debug( self, "current %"PRId64" threshold %"PRId64" count %d\n",
805 time_current, (int64_t) (time_process / count * 20), count );
806 // Ignore the cost of this frame's time
810 // Determine if we started, resumed, or seeked
811 if ( pos != last_pos + 1 )
815 // Do not skip the first 20% of buffer at start, resume, or seek
816 if ( pos - start_pos <= buffer / 5 + 1 )
818 // Reset cost tracker
826 // Only consider skipping if the buffer level is low (or really small)
827 if ( mlt_deque_count( self->queue ) <= buffer / 5 + 1 )
829 // Skip next frame if average cost exceeds frame duration.
830 if ( time_process / count > frame_duration )
833 mlt_log_debug( self, "avg usec %"PRId64" (%"PRId64"/%d) duration %d\n",
834 time_process/count, time_process, count, frame_duration);
838 // Remove the last frame
839 mlt_frame_close( frame );
844 /** Locate the first unprocessed frame in the queue.
846 * When playing with realtime behavior, we do not use the true head, but
847 * rather an adjusted process_head. The process_head is adjusted based on
848 * the rate of frame-dropping or recovery from frame-dropping. The idea is
849 * that as the level of frame-dropping increases to move the process_head
850 * closer to the tail because the frames are not completing processing prior
851 * to their playout! Then, as frames are not dropped the process_head moves
852 * back closer to the head of the queue so that worker threads can work
853 * ahead of the playout point (queue head).
855 * \private \memberof mlt_consumer_s
856 * \param self a consumer
857 * \return an index into the queue
860 static inline int first_unprocessed_frame( mlt_consumer self )
862 int index = self->real_time <= 0 ? 0 : self->process_head;
863 while ( index < mlt_deque_count( self->queue ) && MLT_FRAME( mlt_deque_peek( self->queue, index ) )->is_processing )
868 /** The worker thread procedure for parallel processing frames.
870 * \private \memberof mlt_consumer_s
871 * \param arg a consumer
874 static void *consumer_worker_thread( void *arg )
876 // The argument is the consumer
877 mlt_consumer self = arg;
879 // Get the properties of the consumer
880 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
882 // Get the width and height
883 int width = mlt_properties_get_int( properties, "width" );
884 int height = mlt_properties_get_int( properties, "height" );
885 mlt_image_format format = self->format;
887 // See if video is turned off
888 int video_off = mlt_properties_get_int( properties, "video_off" );
889 int preview_off = mlt_properties_get_int( properties, "preview_off" );
890 int preview_format = mlt_properties_get_int( properties, "preview_format" );
892 // General frame variable
893 mlt_frame frame = NULL;
894 uint8_t *image = NULL;
896 if ( preview_off && preview_format != 0 )
897 format = preview_format;
899 // Continue to read ahead
900 while ( self->ahead )
902 // Get the next unprocessed frame from the work queue
903 pthread_mutex_lock( &self->queue_mutex );
904 int index = first_unprocessed_frame( self );
905 while ( self->ahead && index >= mlt_deque_count( self->queue ) )
907 mlt_log_debug( MLT_CONSUMER_SERVICE(self), "waiting in worker index = %d queue count = %d\n",
908 index, mlt_deque_count( self->queue ) );
909 pthread_cond_wait( &self->queue_cond, &self->queue_mutex );
910 index = first_unprocessed_frame( self );
913 // Mark the frame for processing
914 frame = mlt_deque_peek( self->queue, index );
917 mlt_log_debug( MLT_CONSUMER_SERVICE(self), "worker processing index = %d frame %d queue count = %d\n",
918 index, mlt_frame_get_position(frame), mlt_deque_count( self->queue ) );
919 frame->is_processing = 1;
920 mlt_properties_inc_ref( MLT_FRAME_PROPERTIES( frame ) );
922 pthread_mutex_unlock( &self->queue_mutex );
924 // If there's no frame, we're probably stopped...
928 #ifdef DEINTERLACE_ON_NOT_NORMAL_SPEED
929 // All non normal playback frames should be shown
930 if ( mlt_properties_get_int( MLT_FRAME_PROPERTIES( frame ), "_speed" ) != 1 )
931 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "consumer_deinterlace", 1 );
937 // Fetch width/height again
938 width = mlt_properties_get_int( properties, "width" );
939 height = mlt_properties_get_int( properties, "height" );
940 mlt_events_fire( MLT_CONSUMER_PROPERTIES( self ), "consumer-frame-render", frame, NULL );
941 mlt_frame_get_image( frame, &image, &format, &width, &height, 0 );
943 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
944 mlt_frame_close( frame );
946 // Tell a waiting thread (non-realtime main consumer thread) that we are done.
947 pthread_mutex_lock( &self->done_mutex );
948 pthread_cond_broadcast( &self->done_cond );
949 pthread_mutex_unlock( &self->done_mutex );
955 /** Start the read/render thread.
957 * \private \memberof mlt_consumer_s
958 * \param self a consumer
961 static void consumer_read_ahead_start( mlt_consumer self )
966 // Create the frame queue
967 self->queue = mlt_deque_init( );
969 // Create the queue mutex
970 pthread_mutex_init( &self->queue_mutex, NULL );
972 // Create the condition
973 pthread_cond_init( &self->queue_cond, NULL );
975 // Create the read ahead
976 if ( mlt_properties_get( MLT_CONSUMER_PROPERTIES( self ), "priority" ) )
978 struct sched_param priority;
979 priority.sched_priority = mlt_properties_get_int( MLT_CONSUMER_PROPERTIES( self ), "priority" );
980 pthread_attr_t thread_attributes;
981 pthread_attr_init( &thread_attributes );
982 pthread_attr_setschedpolicy( &thread_attributes, SCHED_OTHER );
983 pthread_attr_setschedparam( &thread_attributes, &priority );
984 pthread_attr_setinheritsched( &thread_attributes, PTHREAD_EXPLICIT_SCHED );
985 pthread_attr_setscope( &thread_attributes, PTHREAD_SCOPE_SYSTEM );
986 if ( pthread_create( &self->ahead_thread, &thread_attributes, consumer_read_ahead_thread, self ) < 0 )
987 pthread_create( &self->ahead_thread, NULL, consumer_read_ahead_thread, self );
988 pthread_attr_destroy( &thread_attributes );
992 pthread_create( &self->ahead_thread, NULL, consumer_read_ahead_thread, self );
997 /** Start the worker threads.
999 * \private \memberof mlt_consumer_s
1000 * \param self a consumer
1003 static void consumer_work_start( mlt_consumer self )
1005 int n = abs( self->real_time );
1006 pthread_t *thread = calloc( 1, sizeof( pthread_t ) * n );
1008 // We're running now
1010 self->threads = thread;
1012 // These keep track of the accelleration of frame dropping or recovery.
1013 self->consecutive_dropped = 0;
1014 self->consecutive_rendered = 0;
1016 // This is the position in the queue from which to look for a frame to process.
1017 // If we always start from the head, then we may likely not complete processing
1018 // before the frame is played out.
1019 self->process_head = 0;
1021 // Create the queues
1022 self->queue = mlt_deque_init();
1023 self->worker_threads = mlt_deque_init();
1025 // Create the mutexes
1026 pthread_mutex_init( &self->queue_mutex, NULL );
1027 pthread_mutex_init( &self->done_mutex, NULL );
1029 // Create the conditions
1030 pthread_cond_init( &self->queue_cond, NULL );
1031 pthread_cond_init( &self->done_cond, NULL );
1033 // Create the read ahead
1034 if ( mlt_properties_get( MLT_CONSUMER_PROPERTIES( self ), "priority" ) )
1037 struct sched_param priority;
1038 pthread_attr_t thread_attributes;
1040 priority.sched_priority = mlt_properties_get_int( MLT_CONSUMER_PROPERTIES( self ), "priority" );
1041 pthread_attr_init( &thread_attributes );
1042 pthread_attr_setschedpolicy( &thread_attributes, SCHED_OTHER );
1043 pthread_attr_setschedparam( &thread_attributes, &priority );
1044 pthread_attr_setinheritsched( &thread_attributes, PTHREAD_EXPLICIT_SCHED );
1045 pthread_attr_setscope( &thread_attributes, PTHREAD_SCOPE_SYSTEM );
1049 if ( pthread_create( thread, &thread_attributes, consumer_worker_thread, self ) < 0 )
1050 if ( pthread_create( thread, NULL, consumer_worker_thread, self ) == 0 )
1051 mlt_deque_push_back( self->worker_threads, thread );
1054 pthread_attr_destroy( &thread_attributes );
1061 if ( pthread_create( thread, NULL, consumer_worker_thread, self ) == 0 )
1062 mlt_deque_push_back( self->worker_threads, thread );
1069 /** Stop the read/render thread.
1071 * \private \memberof mlt_consumer_s
1072 * \param self a consumer
1075 static void consumer_read_ahead_stop( mlt_consumer self )
1077 // Make sure we're running
1078 if ( self->started )
1080 // Inform thread to stop
1083 // Broadcast to the condition in case it's waiting
1084 pthread_mutex_lock( &self->queue_mutex );
1085 pthread_cond_broadcast( &self->queue_cond );
1086 pthread_mutex_unlock( &self->queue_mutex );
1088 // Broadcast to the put condition in case it's waiting
1089 pthread_mutex_lock( &self->put_mutex );
1090 pthread_cond_broadcast( &self->put_cond );
1091 pthread_mutex_unlock( &self->put_mutex );
1094 pthread_join( self->ahead_thread, NULL );
1097 // Destroy the frame queue mutex
1098 pthread_mutex_destroy( &self->queue_mutex );
1100 // Destroy the condition
1101 pthread_cond_destroy( &self->queue_cond );
1104 while ( mlt_deque_count( self->queue ) )
1105 mlt_frame_close( mlt_deque_pop_back( self->queue ) );
1108 mlt_deque_close( self->queue );
1112 /** Stop the worker threads.
1114 * \private \memberof mlt_consumer_s
1115 * \param self a consumer
1118 static void consumer_work_stop( mlt_consumer self )
1120 // Make sure we're running
1121 if ( self->started )
1123 // Inform thread to stop
1126 // Broadcast to the queue condition in case it's waiting
1127 pthread_mutex_lock( &self->queue_mutex );
1128 pthread_cond_broadcast( &self->queue_cond );
1129 pthread_mutex_unlock( &self->queue_mutex );
1131 // Broadcast to the put condition in case it's waiting
1132 pthread_mutex_lock( &self->put_mutex );
1133 pthread_cond_broadcast( &self->put_cond );
1134 pthread_mutex_unlock( &self->put_mutex );
1136 // Broadcast to the done condition in case it's waiting
1137 pthread_mutex_lock( &self->done_mutex );
1138 pthread_cond_broadcast( &self->done_cond );
1139 pthread_mutex_unlock( &self->done_mutex );
1143 while ( ( thread = mlt_deque_pop_back( self->worker_threads ) ) )
1144 pthread_join( *thread, NULL );
1146 // Deallocate the array of threads
1147 if ( self->threads )
1148 free( self->threads );
1150 // Indicate that worker threads no longer running
1153 // Destroy the mutexes
1154 pthread_mutex_destroy( &self->queue_mutex );
1155 pthread_mutex_destroy( &self->done_mutex );
1157 // Destroy the conditions
1158 pthread_cond_destroy( &self->queue_cond );
1159 pthread_cond_destroy( &self->done_cond );
1162 while ( mlt_deque_count( self->queue ) )
1163 mlt_frame_close( mlt_deque_pop_back( self->queue ) );
1166 mlt_deque_close( self->queue );
1167 mlt_deque_close( self->worker_threads );
1171 /** Flush the read/render thread's buffer.
1173 * \public \memberof mlt_consumer_s
1174 * \param self a consumer
1177 void mlt_consumer_purge( mlt_consumer self )
1181 pthread_mutex_lock( &self->queue_mutex );
1182 while ( mlt_deque_count( self->queue ) )
1183 mlt_frame_close( mlt_deque_pop_back( self->queue ) );
1184 pthread_cond_broadcast( &self->queue_cond );
1185 pthread_mutex_unlock( &self->queue_mutex );
1189 /** Use multiple worker threads and a work queue.
1192 static mlt_frame worker_get_frame( mlt_consumer self, mlt_properties properties )
1195 mlt_frame frame = NULL;
1197 double fps = mlt_properties_get_double( properties, "fps" );
1198 int threads = abs( self->real_time );
1199 int buffer = mlt_properties_get_int( properties, "_buffer" );
1200 buffer = buffer > 0 ? buffer : mlt_properties_get_int( properties, "buffer" );
1201 // This is a heuristic to determine a suitable minimum buffer size for the number of threads.
1202 int headroom = 2 + threads * threads;
1203 buffer = buffer < headroom ? headroom : buffer;
1205 // Start worker threads if not already started.
1206 if ( ! self->ahead )
1208 int prefill = mlt_properties_get_int( properties, "prefill" );
1209 prefill = prefill > 0 && prefill < buffer ? prefill : buffer;
1211 consumer_work_start( self );
1213 // Fill the work queue.
1215 while ( self->ahead && i-- )
1217 frame = mlt_consumer_get_frame( self );
1220 pthread_mutex_lock( &self->queue_mutex );
1221 mlt_deque_push_back( self->queue, frame );
1222 pthread_cond_signal( &self->queue_cond );
1223 pthread_mutex_unlock( &self->queue_mutex );
1228 while ( self->ahead && first_unprocessed_frame( self ) < prefill )
1230 pthread_mutex_lock( &self->done_mutex );
1231 pthread_cond_wait( &self->done_cond, &self->done_mutex );
1232 pthread_mutex_unlock( &self->done_mutex );
1234 self->process_head = threads;
1237 // mlt_log_verbose( MLT_CONSUMER_SERVICE(self), "size %d done count %d work count %d process_head %d\n",
1238 // threads, first_unprocessed_frame( self ), mlt_deque_count( self->queue ), self->process_head );
1240 // Feed the work queue
1241 while ( self->ahead && mlt_deque_count( self->queue ) < buffer )
1243 frame = mlt_consumer_get_frame( self );
1246 pthread_mutex_lock( &self->queue_mutex );
1247 mlt_deque_push_back( self->queue, frame );
1248 pthread_cond_signal( &self->queue_cond );
1249 pthread_mutex_unlock( &self->queue_mutex );
1252 // Wait if not realtime.
1253 mlt_frame head_frame = MLT_FRAME( mlt_deque_peek_front( self->queue ) );
1254 while ( self->ahead && self->real_time < 0 &&
1255 !( head_frame && mlt_properties_get_int( MLT_FRAME_PROPERTIES( head_frame ), "rendered" ) ) )
1257 pthread_mutex_lock( &self->done_mutex );
1258 pthread_cond_wait( &self->done_cond, &self->done_mutex );
1259 pthread_mutex_unlock( &self->done_mutex );
1262 // Get the frame from the queue.
1263 pthread_mutex_lock( &self->queue_mutex );
1264 frame = mlt_deque_pop_front( self->queue );
1265 pthread_mutex_unlock( &self->queue_mutex );
1267 // Adapt the worker process head to the runtime conditions.
1268 if ( self->real_time > 0 )
1270 if ( frame && mlt_properties_get_int( MLT_FRAME_PROPERTIES( frame ), "rendered" ) )
1272 self->consecutive_dropped = 0;
1273 if ( self->process_head > threads && self->consecutive_rendered >= self->process_head )
1274 self->process_head--;
1276 self->consecutive_rendered++;
1280 self->consecutive_rendered = 0;
1281 if ( self->process_head < buffer - threads && self->consecutive_dropped > threads )
1282 self->process_head++;
1284 self->consecutive_dropped++;
1286 // mlt_log_verbose( MLT_CONSUMER_SERVICE(self), "dropped %d rendered %d process_head %d\n",
1287 // self->consecutive_dropped, self->consecutive_rendered, self->process_head );
1289 // Check for too many consecutively dropped frames
1290 if ( self->consecutive_dropped > mlt_properties_get_int( properties, "drop_max" ) )
1292 int orig_buffer = mlt_properties_get_int( properties, "buffer" );
1293 int prefill = mlt_properties_get_int( properties, "prefill" );
1294 mlt_log_verbose( self, "too many frames dropped - " );
1296 // If using a default low-latency buffer level (SDL) and below the limit
1297 if ( ( orig_buffer == 1 || prefill == 1 ) && buffer < (threads + 1) * 10 )
1299 // Auto-scale the buffer to compensate
1300 mlt_log_verbose( self, "increasing buffer to %d\n", buffer + threads );
1301 mlt_properties_set_int( properties, "_buffer", buffer + threads );
1302 self->consecutive_dropped = fps / 2;
1306 // Tell the consumer to render it
1307 mlt_log_verbose( self, "forcing next frame\n" );
1308 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
1309 self->consecutive_dropped = 0;
1317 /** Get the next frame from the producer connected to a consumer.
1319 * Typically, one uses this instead of \p mlt_consumer_get_frame to make
1320 * the asynchronous/real-time behavior configurable at runtime.
1321 * You should close the frame returned from this when you are done with it.
1323 * \public \memberof mlt_consumer_s
1324 * \param self a consumer
1328 mlt_frame mlt_consumer_rt_frame( mlt_consumer self )
1331 mlt_frame frame = NULL;
1333 // Get the properties
1334 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
1336 // Check if the user has requested real time or not
1337 if ( self->real_time > 1 || self->real_time < -1 )
1340 return worker_get_frame( self, properties );
1342 else if ( self->real_time == 1 || self->real_time == -1 )
1346 // Is the read ahead running?
1347 if ( self->ahead == 0 )
1349 int buffer = mlt_properties_get_int( properties, "buffer" );
1350 int prefill = mlt_properties_get_int( properties, "prefill" );
1351 consumer_read_ahead_start( self );
1353 size = prefill > 0 && prefill < buffer ? prefill : buffer;
1356 // Get frame from queue
1357 pthread_mutex_lock( &self->queue_mutex );
1358 while( self->ahead && mlt_deque_count( self->queue ) < size )
1359 pthread_cond_wait( &self->queue_cond, &self->queue_mutex );
1360 frame = mlt_deque_pop_front( self->queue );
1361 pthread_cond_broadcast( &self->queue_cond );
1362 pthread_mutex_unlock( &self->queue_mutex );
1364 else // real_time == 0
1366 // Get the frame in non real time
1367 frame = mlt_consumer_get_frame( self );
1369 // This isn't true, but from the consumers perspective it is
1370 if ( frame != NULL )
1371 mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
1377 /** Callback for the implementation to indicate a stopped condition.
1379 * \public \memberof mlt_consumer_s
1380 * \param self a consumer
1383 void mlt_consumer_stopped( mlt_consumer self )
1385 mlt_properties_set_int( MLT_CONSUMER_PROPERTIES( self ), "running", 0 );
1386 mlt_events_fire( MLT_CONSUMER_PROPERTIES( self ), "consumer-stopped", NULL );
1387 mlt_event_unblock( self->event_listener );
1390 /** Stop the consumer.
1392 * \public \memberof mlt_consumer_s
1393 * \param self a consumer
1394 * \return true if there was an error
1397 int mlt_consumer_stop( mlt_consumer self )
1399 // Get the properies
1400 mlt_properties properties = MLT_CONSUMER_PROPERTIES( self );
1403 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_DEBUG, "stopping put waiting\n" );
1404 pthread_mutex_lock( &self->put_mutex );
1405 self->put_active = 0;
1406 pthread_cond_broadcast( &self->put_cond );
1407 pthread_mutex_unlock( &self->put_mutex );
1409 // Stop the consumer
1410 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_DEBUG, "stopping consumer\n" );
1412 // Cancel the read ahead threads
1414 if ( self->started )
1416 // Unblock the consumer calling mlt_consumer_rt_frame
1417 pthread_mutex_lock( &self->queue_mutex );
1418 pthread_cond_broadcast( &self->queue_cond );
1419 pthread_mutex_unlock( &self->queue_mutex );
1422 // Invoke the child callback
1423 if ( self->stop != NULL )
1426 // Check if the user has requested real time or not and stop if necessary
1427 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_DEBUG, "stopping read_ahead\n" );
1428 if ( abs( self->real_time ) == 1 )
1429 consumer_read_ahead_stop( self );
1430 else if ( abs( self->real_time ) > 1 )
1431 consumer_work_stop( self );
1433 // Kill the test card
1434 mlt_properties_set_data( properties, "test_card_producer", NULL, 0, NULL, NULL );
1436 // Check and run a post command
1437 if ( mlt_properties_get( properties, "post" ) )
1438 if (system( mlt_properties_get( properties, "post" ) ) == -1 )
1439 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_ERROR, "system(%s) failed!\n", mlt_properties_get( properties, "post" ) );
1441 mlt_log( MLT_CONSUMER_SERVICE( self ), MLT_LOG_DEBUG, "stopped\n" );
1446 /** Determine if the consumer is stopped.
1448 * \public \memberof mlt_consumer_s
1449 * \param self a consumer
1450 * \return true if the consumer is stopped
1453 int mlt_consumer_is_stopped( mlt_consumer self )
1455 // Check if the consumer is stopped
1456 if ( self->is_stopped != NULL )
1457 return self->is_stopped( self );
1462 /** Close and destroy the consumer.
1464 * \public \memberof mlt_consumer_s
1465 * \param self a consumer
1468 void mlt_consumer_close( mlt_consumer self )
1470 if ( self != NULL && mlt_properties_dec_ref( MLT_CONSUMER_PROPERTIES( self ) ) <= 0 )
1472 // Get the childs close function
1473 void ( *consumer_close )( ) = self->close;
1475 if ( consumer_close )
1478 //mlt_consumer_stop( self );
1481 consumer_close( self );
1485 // Make sure it only gets called once
1486 self->parent.close = NULL;
1488 // Destroy the push mutex and condition
1489 pthread_mutex_destroy( &self->put_mutex );
1490 pthread_cond_destroy( &self->put_cond );
1492 mlt_service_close( &self->parent );
1497 /** Get the position of the last frame shown.
1499 * \public \memberof mlt_consumer_s
1500 * \param consumer a consumer
1501 * \return the position
1504 mlt_position mlt_consumer_position( mlt_consumer consumer )
1506 return consumer->position;