Media Stuff

1
Media Stuff

• JMF Plays wonders

2
Introduction to JMF

• Java Media Framework (JMF) is a large and
  versatile API used to process time-based media.

3
JMF Model

• Consider a Cassette/CD-Player as an example to
  understand JMF objects
• We insert CD/Cassette as media contents, theres
  a player that reads data from this media and
  plays to the speakers
• When recording, a small microphone is a capture
  device that can give data for recording

4
JMF Objects

• Following are the JMF objects you must know about
• Data source
• Capture device
• Player
• Processor
• DataSink
• Format
• Manager

5
DataSource

• A data source encapsulates the media stream much
  like a music CD.
• In JMF, a DataSource object represents the audio
  media, video media, or a combination of the two.
• A DataSource can be a file or an incoming stream
  from the Internet.
• Once created, a DataSource can be fed into a
  Player to be rendered, with the Player
  unconcerned about where the DataSource originated
  or what was its original form.

6
Types of Data Sources

• DataSource type can depend on the nature of the
  source. There are two types of data sources
• Pull data source The client initiates the data
  transfer and controls the data flow from the
  source. HTTP and FILE serve as examples of
  established protocols for this type of data.
• Push data source The server initiates the data
  transfer and controls the data flow from a push
  data source. Push data source examples include
  broadcast media and video on demand.

7
Capture Device

• A capture device represents the hardware you use
  to capture data, such as a microphone, a still
  camera, or a video camera.
• Captured media data can be fed into a Player to
  be rendered, processed to convert the data into
  another format, or stored for future use.

8
Player

• A Player takes as input a stream of audio or
  video data and renders it to a speaker or a
  screen, much like a CD player reads a CD and
  outputs music to the speaker.
• A Player can have states, which exist naturally
  because a Player has to prepare itself and its
  data source before it can start playing the
  media.

9
Player States

• JMF defines six states in a Player
• Unrealized
• Realizing
• Realized
• Prefetching
• Prefetched
• Started

10
Processor

• A Processor is a type of Player.
• In the JMF API, a Processor interface extends
  Player.
• As such, a Processor supports the same
  presentation controls as a Player. Unlike a
  Player, though, a Processor has control over what
  processing is performed on the input media
  stream.
• In addition to rendering a data source, a
  Processor can also output media data through a
  DataSource so it can be presented by another
  Player or Processor, further processed by another
  Processor, or converted to some other format.

11
Processor States

• Besides the six aforementioned Player states, a
  Processor includes two additional states that
  occur before the Processor enters the realizing
  state but after the unrealized state
• Configuring A Processor enters the configuring
  state from the unrealized state when the
  configure() method is called. A Processor exists
  in the configuring state when it connects to the
  DataSource, demultiplexes the input stream, and
  accesses information about the format of the
  input data.
• Configured From the configuring state, a
  Processor moves into the configured state when it
  is connected to the DataSource and the data
  format has been determined.

12
Data Sink

• The DataSink is a base interface for objects that
  read media content delivered by a DataSource and
  render the media to some destination.
• As an example DataSink, consider a file-writer
  object that stores the media in a file.

13
Format

• A Format object represents an object's exact
  media format.
• The format itself carries no encoding-specific
  parameters or global-timing information it
  describes the format's encoding name and the type
  of data the format requires.

14
Subclasses of Format

• Format has following 2 subclasses
• AudioFormat
• VideoFormat.
• VideoFormat contains six direct subclasses
• H261Format
• H263Format
• IndexedColorFormat
• JPEGFormat
• RGBFormat
• YUVFormat

15
Manager

• Manager is the boss object used for management
  (what else?)
• Manager can be used for
• Create players
• Create processors
• Creating Data sources
• Creating data sinks

16
A very simple JMF tasOpeneing and playing a file

• Steps involved are
• Create a Data Source
• Associate it with a Player
• Wait for the right state (Realized)
• Get the visual components of player
• Get the control panel of player
• Add them to a GUI
• Start the player (optional)

17
Code for playing butterfly.mpg

• import java.awt.
• import javax.media.
• import javax.media.protocol.
• import java.io.
• import java.net.

18
Code continues

• class MediaTest implements ControllerListener
• Frame f
• Component v
• Player p
• MediaTest() throws Exception
• String url file/C/media/butterfly.mpg
• URL u new URL(url)
• DataSource ds Manager.createDataSource(u)

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• p Manager.createPlayer( ds )
• p.addControllerListener(this)
• f new Frame()
• f.setSize(400,350)
• f.show()
• p.start()

20

• public void controllerUpdate(
• ControllerEvent e)
• if (e instanceof RealizeCompleteEvent)
• v p.getVisualComponent()
• if(v!null)
• f.add(v ,BorderLayout.CENTER)
• v p.getControlPanelComponent()
• if(v!null)
• f.add(v, BorderLayout.SOUTH)
• f.doLayout()
• // end of method
• // end of class

21
Running the code
Visual Component
Control Panel
22
Creating Data Source

• String url file/C/media/butterfly.mpg
• URL u new URL(url)
• DataSource ds Manager.createDataSource(u)

23
Creating Player

• p Manager.createPlayer( ds )
• p.addControllerListener(this)

24
Getting Adding visual and control panel
components

• v p.getVisualComponent()
• if(v!null)
• f.add(v ,BorderLayout.CENTER)
• v p.getControlPanelComponent()
• if(v!null)
• f.add(v, BorderLayout.SOUTH)

25
Starting a player

• p.start( )
• That was tough !!! ?