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UMMS Architecture
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UMMS Architecture
Introduction
This page describes the architecture of umms-0.1, you can get the code from: git://gitorious.org:meego-middleware/umms.git
UMMS general description can found on its main page
Class Diagram
- UmmsAudioManager
Class to implement com.UMMS.AudioManager interface which provide client with audio output control service.
- UmmsVideoOutput
Class to implement com.UMMS.VideoOutput interface which provide client with video output control service.
- UmmsPlayingContentMetadataViewer
Class to implement com.UMMS.PlayingContentMetadataViewer interface which allow the client to query the current playing content on server side.
- UmmsObjectManager
Class to manage MediaPlayer objects, including create/destory, register/unregister MediaPlayer objects.
- UmmsMediaPlayer
Class to implement the com.UMMS.MediaPlayer interface which provide media playback service for client.
- UmmsPlayerBackend
A base class which defined internal interface for media playback. UmmsMediaPlayer uses this class to handle the service request. Backend developer need to subclass it.
- UmmsAudioManagerBackend
A base class which defined internal interface for controlling audio output. UmmsAudioManager uses this class to handle the service request. Backend developer need to subclass it.
- UmmsVideoOutputBackend
A base class which defined internal interface for controlling video output. UmmsVideoOutput uses this class to handle the service request. Backend developer need to subclass it.
- UmmsPlugin
A class which defined the plugin mechanism. All backend should be implemented as a UmmsPlugin.
- Player
An implementation of UmmsPlayerBackend.
- AudioManger
An implementation of UmmsAudioBackend.
- VideoOutput
An implementation of UmmsVideoOutput.
Note that, Player,AudioManger,VideoOutput are plugins and will not provide by umms-1.0.
How to develop a backend
- Step 1: Implement MediaPlayerControl interface
The MediaPlayerControl is internal interface to abstract all the media playback control. Backend developer should create a class and implement this interface. Of cause, you can just implement a subset of the virtual methods defined by the interface, e.g. The DvbPlayerControlBase doesn't implement the "pause" method. If you want to add time-shifting feature for DVB playback, implementing "pause" method is a choice.
- Step 2: Modify PlayerControlFactory
All the backend selection logic is contained in PlayerControlFactory class. For now, PlayerControlFactory creates the appropriate backend(named "engine" in the source code) according to platform information and the URI. The Developer should modify the function pointer array(in player-control-factory.c) to contain his custom backend:
MediaPlayerControl* (*engine_factory[PLATFORM_INVALID][N_PLAYER_CONTROL_FACTORY_ENGINE_TYPE])(void)