research.m1stereo.tv/gitweb/ - melted/blob - src/framework/mlt_service.h

   1 /**
   2  * \file mlt_service.h
   3  * \brief interface declaration for all service classes
   4  *
   5  * Copyright (C) 2003-2008 Ushodaya Enterprises Limited
   6  * \author Charles Yates <charles.yates@pandora.be>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #ifndef _MLT_SERVICE_H_
  24 #define _MLT_SERVICE_H_
  25
  26 #include "mlt_properties.h"
  27 #include "mlt_profile.h"
  28
  29 /** \brief Service abstract base class
  30  *
  31  * \extends mlt_properties
  32  * The service is the base class for all of the interesting classes and
  33  * plugins for MLT. A service can have multiple inputs connections to
  34  * other services called its "producers" but only a single output to another
  35  * service called its "consumer." A service that has both producer and
  36  * consumer connections is called a filter. Any service can have zero or more
  37  * filters "attached" to it. We call any collection of services and their
  38  * connections a "service network," which is similar to what DirectShow calls
  39  * a filter graph or what gstreamer calls an element pipeline.
  40  *
  41  * \event \em service-changed
  42  * \event \em property-changed
  43  * \properties \em mlt_type identifies the subclass
  44  * \properties \em resource is either the stream identifier or grandchild-class
  45  * \properties \em in when to start, what is started is service-specific
  46  * \properties \em out when to stop
  47  * \properties \em _filter_private Set this on a service to ensure that attached filters are handled privately.
  48  * See modules/core/filter_region.c and modules/core/filter_watermark.c for examples.
  49  * \properties \em disable Set this on a filter to disable it while keeping it in the object model.
  50  * \properties \em _profile stores the mlt_profile for a service
  51  */
  52
  53 struct mlt_service_s
  54 {
  55         struct mlt_properties_s parent; /**< \private */
  56
  57         /** Get a frame of data (virtual function).
  58          *
  59          * \param mlt_producer a producer
  60          * \param mlt_frame_ptr a frame pointer by reference
  61          * \param int an index
  62          * \return true if there was an error
  63          */
  64         int ( *get_frame )( mlt_service self, mlt_frame_ptr frame, int index );
  65
  66         /** the destructor virtual function */
  67         mlt_destructor close;
  68         void *close_object; /**< the object supplied to the close virtual function */
  69
  70         void *local; /**< \private instance object */
  71         void *child; /**< \private the object of a subclass */
  72 };
  73
  74 #define MLT_SERVICE_PROPERTIES( service )       ( &( service )->parent )
  75
  76 extern int mlt_service_init( mlt_service self, void *child );
  77 extern void mlt_service_lock( mlt_service self );
  78 extern void mlt_service_unlock( mlt_service self );
  79 extern mlt_service_type mlt_service_identify( mlt_service self );
  80 extern int mlt_service_connect_producer( mlt_service self, mlt_service producer, int index );
  81 extern mlt_service mlt_service_get_producer( mlt_service self );
  82 extern int mlt_service_get_frame( mlt_service self, mlt_frame_ptr frame, int index );
  83 extern mlt_properties mlt_service_properties( mlt_service self );
  84 extern mlt_service mlt_service_consumer( mlt_service self );
  85 extern mlt_service mlt_service_producer( mlt_service self );
  86 extern int mlt_service_attach( mlt_service self, mlt_filter filter );
  87 extern int mlt_service_detach( mlt_service self, mlt_filter filter );
  88 extern void mlt_service_apply_filters( mlt_service self, mlt_frame frame, int index );
  89 extern mlt_filter mlt_service_filter( mlt_service self, int index );
  90 extern mlt_profile mlt_service_profile( mlt_service self );
  91 extern void mlt_service_close( mlt_service self );
  92
  93 #endif
  94