+/** Compute the time difference between now and a time value.
+ *
+ * \private \memberof mlt_consumer_s
+ * \param time1 a time value to be compared against now
+ * \return the difference in microseconds
+ */
+
+static inline long time_difference( struct timeval *time1 )
+{
+ struct timeval time2;
+ time2.tv_sec = time1->tv_sec;
+ time2.tv_usec = time1->tv_usec;
+ gettimeofday( time1, NULL );
+ return time1->tv_sec * 1000000 + time1->tv_usec - time2.tv_sec * 1000000 - time2.tv_usec;
+}
+
+/** The thread procedure for asynchronously pulling frames through the service
+ * network connected to a consumer.
+ *
+ * \private \memberof mlt_consumer_s
+ * \param arg a consumer
+ */
+
+static void *consumer_read_ahead_thread( void *arg )
+{
+ // The argument is the consumer
+ mlt_consumer this = arg;
+
+ // Get the properties of the consumer
+ mlt_properties properties = MLT_CONSUMER_PROPERTIES( this );
+
+ // Get the width and height
+ int width = mlt_properties_get_int( properties, "width" );
+ int height = mlt_properties_get_int( properties, "height" );
+
+ // See if video is turned off
+ int video_off = mlt_properties_get_int( properties, "video_off" );
+ int preview_off = mlt_properties_get_int( properties, "preview_off" );
+ int preview_format = mlt_properties_get_int( properties, "preview_format" );
+
+ // Get the audio settings
+ mlt_audio_format afmt = mlt_audio_pcm;
+ int counter = 0;
+ double fps = mlt_properties_get_double( properties, "fps" );
+ int channels = mlt_properties_get_int( properties, "channels" );
+ int frequency = mlt_properties_get_int( properties, "frequency" );
+ int samples = 0;
+ int16_t *pcm = NULL;
+
+ // See if audio is turned off
+ int audio_off = mlt_properties_get_int( properties, "audio_off" );
+
+ // Get the maximum size of the buffer
+ int buffer = mlt_properties_get_int( properties, "buffer" ) + 1;
+
+ // General frame variable
+ mlt_frame frame = NULL;
+ uint8_t *image = NULL;
+
+ // Time structures
+ struct timeval ante;
+
+ // Average time for get_frame and get_image
+ int count = 1;
+ int skipped = 0;
+ int64_t time_wait = 0;
+ int64_t time_frame = 0;
+ int64_t time_process = 0;
+ int skip_next = 0;
+ mlt_service lock_object = NULL;
+
+ if ( preview_off && preview_format != 0 )
+ this->format = preview_format;
+
+ // Get the first frame
+ frame = mlt_consumer_get_frame( this );
+
+ // Get the lock object
+ lock_object = mlt_properties_get_data( MLT_FRAME_PROPERTIES( frame ), "consumer_lock_service", NULL );
+
+ // Lock it
+ if ( lock_object ) mlt_service_lock( lock_object );
+
+ // Get the image of the first frame
+ if ( !video_off )
+ {
+ mlt_events_fire( MLT_CONSUMER_PROPERTIES( this ), "consumer-frame-render", frame, NULL );
+ mlt_frame_get_image( frame, &image, &this->format, &width, &height, 0 );
+ }
+
+ if ( !audio_off )
+ {
+ samples = mlt_sample_calculator( fps, frequency, counter++ );
+ mlt_frame_get_audio( frame, &pcm, &afmt, &frequency, &channels, &samples );
+ }
+
+ // Unlock the lock object
+ if ( lock_object ) mlt_service_unlock( lock_object );
+
+ // Mark as rendered
+ mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
+
+ // Get the starting time (can ignore the times above)
+ gettimeofday( &ante, NULL );
+
+ // Continue to read ahead
+ while ( this->ahead )
+ {
+ // Fetch width/height again
+ width = mlt_properties_get_int( properties, "width" );
+ height = mlt_properties_get_int( properties, "height" );
+
+ // Put the current frame into the queue
+ pthread_mutex_lock( &this->mutex );
+ while( this->ahead && mlt_deque_count( this->queue ) >= buffer )
+ pthread_cond_wait( &this->cond, &this->mutex );
+ mlt_deque_push_back( this->queue, frame );
+ pthread_cond_broadcast( &this->cond );
+ pthread_mutex_unlock( &this->mutex );
+
+ time_wait += time_difference( &ante );
+
+ // Get the next frame
+ frame = mlt_consumer_get_frame( this );
+ time_frame += time_difference( &ante );
+
+ // If there's no frame, we're probably stopped...
+ if ( frame == NULL )
+ continue;
+
+ // Attempt to fetch the lock object
+ lock_object = mlt_properties_get_data( MLT_FRAME_PROPERTIES( frame ), "consumer_lock_service", NULL );
+
+ // Increment the count
+ count ++;
+
+ // Lock if there's a lock object
+ if ( lock_object ) mlt_service_lock( lock_object );
+
+ // All non normal playback frames should be shown
+ if ( mlt_properties_get_int( MLT_FRAME_PROPERTIES( frame ), "_speed" ) != 1 )
+ {
+#ifdef DEINTERLACE_ON_NOT_NORMAL_SPEED
+ mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "consumer_deinterlace", 1 );
+#endif
+ skipped = 0;
+ time_frame = 0;
+ time_process = 0;
+ time_wait = 0;
+ count = 1;
+ skip_next = 0;
+ }
+
+ // Get the image
+ if ( !skip_next || this->real_time == -1 )
+ {
+ // Get the image, mark as rendered and time it
+ if ( !video_off )
+ {
+ mlt_events_fire( MLT_CONSUMER_PROPERTIES( this ), "consumer-frame-render", frame, NULL );
+ mlt_frame_get_image( frame, &image, &this->format, &width, &height, 0 );
+ }
+ mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
+ }
+ else
+ {
+ // Increment the number of sequentially skipped frames
+ skipped ++;
+ skip_next = 0;
+
+ // If we've reached an unacceptable level, reset everything
+ if ( skipped > 5 )
+ {
+ skipped = 0;
+ time_frame = 0;
+ time_process = 0;
+ time_wait = 0;
+ count = 1;
+ }
+ }
+
+ // Always process audio
+ if ( !audio_off )
+ {
+ samples = mlt_sample_calculator( fps, frequency, counter++ );
+ mlt_frame_get_audio( frame, &pcm, &afmt, &frequency, &channels, &samples );
+ }
+
+ // Increment the time take for this frame
+ time_process += time_difference( &ante );
+
+ // Determine if the next frame should be skipped
+ if ( mlt_deque_count( this->queue ) <= 5 )
+ {
+ int frame_duration = mlt_properties_get_int( properties, "frame_duration" );
+ if ( ( ( time_wait + time_frame + time_process ) / count ) > frame_duration )
+ skip_next = 1;
+ }
+
+ // Unlock if there's a lock object
+ if ( lock_object ) mlt_service_unlock( lock_object );
+ }
+
+ // Remove the last frame
+ mlt_frame_close( frame );
+
+ return NULL;
+}
+
+/** Start the read/render thread.
+ *
+ * \private \memberof mlt_consumer_s
+ * \param this a consumer
+ */
+
+static void consumer_read_ahead_start( mlt_consumer this )
+{
+ // We're running now
+ this->ahead = 1;
+
+ // Create the frame queue
+ this->queue = mlt_deque_init( );
+
+ // Create the mutex
+ pthread_mutex_init( &this->mutex, NULL );
+
+ // Create the condition
+ pthread_cond_init( &this->cond, NULL );
+
+ // Create the read ahead
+ if ( mlt_properties_get( MLT_CONSUMER_PROPERTIES( this ), "priority" ) )
+ {
+ struct sched_param priority;
+ priority.sched_priority = mlt_properties_get_int( MLT_CONSUMER_PROPERTIES( this ), "priority" );
+ pthread_attr_t thread_attributes;
+ pthread_attr_init( &thread_attributes );
+ pthread_attr_setschedpolicy( &thread_attributes, SCHED_OTHER );
+ pthread_attr_setschedparam( &thread_attributes, &priority );
+ pthread_attr_setinheritsched( &thread_attributes, PTHREAD_EXPLICIT_SCHED );
+ pthread_attr_setscope( &thread_attributes, PTHREAD_SCOPE_SYSTEM );
+ if ( pthread_create( &this->ahead_thread, &thread_attributes, consumer_read_ahead_thread, this ) < 0 )
+ pthread_create( &this->ahead_thread, NULL, consumer_read_ahead_thread, this );
+ pthread_attr_destroy( &thread_attributes );
+ }
+ else
+ {
+ pthread_create( &this->ahead_thread, NULL, consumer_read_ahead_thread, this );
+ }
+}
+
+/** Stop the read/render thread.
+ *
+ * \private \memberof mlt_consumer_s
+ * \param this a consumer
+ */
+
+static void consumer_read_ahead_stop( mlt_consumer this )
+{
+ // Make sure we're running
+ if ( this->ahead )
+ {
+ // Inform thread to stop
+ this->ahead = 0;
+
+ // Broadcast to the condition in case it's waiting
+ pthread_mutex_lock( &this->mutex );
+ pthread_cond_broadcast( &this->cond );
+ pthread_mutex_unlock( &this->mutex );
+
+ // Broadcast to the put condition in case it's waiting
+ pthread_mutex_lock( &this->put_mutex );
+ pthread_cond_broadcast( &this->put_cond );
+ pthread_mutex_unlock( &this->put_mutex );
+
+ // Join the thread
+ pthread_join( this->ahead_thread, NULL );
+
+ // Destroy the mutex
+ pthread_mutex_destroy( &this->mutex );
+
+ // Destroy the condition
+ pthread_cond_destroy( &this->cond );
+
+ // Wipe the queue
+ while ( mlt_deque_count( this->queue ) )
+ mlt_frame_close( mlt_deque_pop_back( this->queue ) );
+
+ // Close the queue
+ mlt_deque_close( this->queue );
+ }
+}
+
+/** Flush the read/render thread's buffer.
+ *
+ * \public \memberof mlt_consumer_s
+ * \param this a consumer
+ */
+
+void mlt_consumer_purge( mlt_consumer this )
+{
+ if ( this->ahead )
+ {
+ pthread_mutex_lock( &this->mutex );
+ while ( mlt_deque_count( this->queue ) )
+ mlt_frame_close( mlt_deque_pop_back( this->queue ) );
+ pthread_cond_broadcast( &this->cond );
+ pthread_mutex_unlock( &this->mutex );
+ }
+}
+
+/** Get the next frame from the producer connected to a consumer.
+ *
+ * Typically, one uses this instead of \p mlt_consumer_get_frame to make
+ * the asynchronous/real-time behavior configurable at runtime.
+ * You should close the frame returned from this when you are done with it.
+ *
+ * \public \memberof mlt_consumer_s
+ * \param this a consumer
+ * \return a frame
+ */
+
+mlt_frame mlt_consumer_rt_frame( mlt_consumer this )
+{
+ // Frame to return
+ mlt_frame frame = NULL;
+
+ // Get the properties
+ mlt_properties properties = MLT_CONSUMER_PROPERTIES( this );
+
+ // Check if the user has requested real time or not
+ if ( this->real_time )
+ {
+ int size = 1;
+
+ // Is the read ahead running?
+ if ( this->ahead == 0 )
+ {
+ int buffer = mlt_properties_get_int( properties, "buffer" );
+ int prefill = mlt_properties_get_int( properties, "prefill" );
+ consumer_read_ahead_start( this );
+ if ( buffer > 1 )
+ size = prefill > 0 && prefill < buffer ? prefill : buffer;
+ }
+
+ // Get frame from queue
+ pthread_mutex_lock( &this->mutex );
+ while( this->ahead && mlt_deque_count( this->queue ) < size )
+ pthread_cond_wait( &this->cond, &this->mutex );
+ frame = mlt_deque_pop_front( this->queue );
+ pthread_cond_broadcast( &this->cond );
+ pthread_mutex_unlock( &this->mutex );
+ }
+ else
+ {
+ // Get the frame in non real time
+ frame = mlt_consumer_get_frame( this );
+
+ // This isn't true, but from the consumers perspective it is
+ if ( frame != NULL )
+ mlt_properties_set_int( MLT_FRAME_PROPERTIES( frame ), "rendered", 1 );
+ }
+
+ return frame;
+}
+
+/** Callback for the implementation to indicate a stopped condition.
+ *
+ * \public \memberof mlt_consumer_s
+ * \param this a consumer
+ */
+
+void mlt_consumer_stopped( mlt_consumer this )
+{
+ mlt_properties_set_int( MLT_CONSUMER_PROPERTIES( this ), "running", 0 );
+ mlt_events_fire( MLT_CONSUMER_PROPERTIES( this ), "consumer-stopped", NULL );
+ mlt_event_unblock( this->event_listener );
+}
+