Java media framework

JAVA MEDIA FRAMEWORK
Ms. Vishwakarma Payal Rambali Shailkumari
M.Sc.-II (Computer Science)
Roll No: 05

Outline
 What is Java Media Framework?
 Creating Media Player .
 Prefetching the Media .
 Adding the Player to your Application .
 Registering the Applet as a Listener .
 Starting the Player .
 Cleaning up and Stopping the Player .
 The States of the Player .
 Adding Controls to the Player .
 Setting the Media Time and Changing Rate .
 Features of JMF .

What is Java Media Framework ?
 The java media framework provides the means to present all
kinds of interesting media type.
 The java media framework is an API for integrating
advanced media formats into java, such as video and
sound.
 The media framework has several components, including
media players, media capture, and conferencing .
 A key to any of these topics is in providing a timing
mechanism, which determines when the next part of the
media should be played. It is important to have a
mechanism to keep a video stream playing at the same
speed as accompanying sound stream.

Creating a Media Player
 By creating an applet that uses a media player. Putting the
media into applet involve a few basic steps:
1. Create the URL for media file.
2. Create the player for the media.
3. Tell the player to prefetch .
4. Add the player to the applet.
5. Start the player.

Creating a Media Player
 To create the player you utilize the Manager class. The
Manager class is actually the hub for getting both the
timebase and the players.
 The first task is to create an URL for file then to create the
player.
 Example : In the BasicPlayer class, following are happens in
the init() method.

Creating a Player and it’s
associated URL
try
{
mediaURL =new URL(getDocumentBase(),mediafile);
Player=Manager.createPlayer(mediaURL);
}
catch(IOException e)
{
System.out.println(“URL for “+ mediafile” is invalid);
}

Prefetching the Media
 Prefetching causes two things:
1. The player goes through a process called realization.
2. It then starts to download the media file so that some of it
can be cached.
 This reduces the latency time before the player can start
actually playing the media.
 Example : In the BasicPlayer class, following are happens in
the start() method.

 In the start method ,we prefetch the media we are going to
play.
Example:
public void start()
{
if(player!=null)
{
//prefetch starts the player .
player.prefetch();
}
}
Prefetching the Media

Adding Player to your Application
 Adding the player to application is actually kind of tricky .
 The player itself is not an AWT component. So you don’t add
the player it self ,but it’s visual representation.
 To get the visual component ,player has a method called
getVisualComponent().
 Player has a method called getState() that returns the state of
the current player .
 ControllerListener has one method-
ControllerUpdate(ControllerEvent).

 We can use the ControllerUpdate method to know when the
media has been fetched.
 ControllerUpdate() method is called each time the state of the
controller changes.
Example:
Adding Player to your Application
public synchronized void control update(ControllerEvent event)
{
if(event instanceof RealizeCompleteEvent)
{
if((VisualComponent = player.getVisualCompent())!=null)
add(“center”,visualComponent);
validate();
}
}

Registering the Applet
as a Listener
 To have the player call ControllerUpdate() you must first
register your application with the player.
 Just like all java.awt.event listener after a component has
been registered as listener ,it’s the method will be call any
time an event occurs.
 For the current purposes you will add the
addControllerListener code to the init() method of the applet.

Public void init()
{
String mediaFile =null;
URL mediaURL=null;
setLayout(new BorderLayout());
If((mediaFile=getParameter(“file”))==null)
{
System.err.print(“Media file not present”);
System.err.print(“Required parameter is ‘file’ ”);
}
else
{
try
{
mediaURL = new URL(getDocumentBase(),mediafile);
player=manager.createPlayer(mediaURL);
}
}
Registering the Applet
as a Listener

Starting the Player
 start() which tells player to start. The more fundamental
methods allows to start the player and specify when it will
actually display it’s media.
 The syncstart() method is the method that actually causes
the player to start.
Example :
If(event instanceof PrefetchCompleteEvent)
{
player.start();
}

Cleaning Up and Stopping the
Player
 stop() method must be used to stop the media player and
clean up.
 The stop() method is called when browser leaves the current
web pages. After browser leaves the page, we should stop
playing the current media.
 One addition step we should take-removing the media from
memory. The player has deallocate() method. As soon as you
know that you no longer need a media ,you should tell the
player to deallocate it so that it can be garbage collected.

 Using both the player’s stop() and deallcoate() methods, you
can create the applets stop method.
Example:
Public void stop()
{
if(player!=null)
{
player.deallocate();
}
}
Cleaning Up and Stopping the
Player

States of the Players
 There are different states that player goes through during
normal operation.
Unrealized
realize()
Realizing
Realized
Prefetch()
Prefetching
Prefetch
Start()/deallocate()
Start
deallocate()

 Unrealized: At this stage, the player does not know anything
about the media except what the URL to the media is.
 Realizing: In the realizing state, the player acquired all of
resources that are non-exclusive.
 Realized: When the player enters the realized state, the
RealizeCompleteEvent is issued.
 Prefetching: To get the player to move into the prefetching
state, you can use the prefetch() method.

 Prefetched :Entering the prefetched state, a player issues the
PrefetchCompleteEvent.
 Started : When player is started, it enters the started state.

Adding Controls to the Players
Example:
Public synchronized void controllerUpdate(ControllerEvent event)
{
if(event isnstaceofRealizeCompleteEvent)
{
if((visualComponent =player.getVisualComponent())!=null)
if(visualComponent!=null)
add(“South”,controlComponent);
else
add(“Center”,controlComponent);
}}
 Each type of the player has the capability to give you a set of
controls using the ControlPanelComponent() method.
 Like the getVisualComponent() method, the
getControlPanelComponent() cannot be used until after the
player has been realized.

Setting the media time and
Changing rate
 The setMediaTime() method takes long parameter and that
number represents the time in nanoseconds.
 The setRate() method returns to you the actual rate that has
been applied.
Example :
if(event isnstaceofPrefetchCompleteEvent)
{
System.out.println(“Prefetching : ” + newDate());
player.setRate((float)2.0);
player.start();
}

Features of JMF
 JMF supports many popular media formats such as JPEG,
MPEG-1, MPEG-2, QuickTime, AVI, WAV, MP3, GSM, G723,
H263, and MIDI.
 JMF supports popular media access protocols such as file,
HTTP, HTTPS, FTP, RTP, and RTSP.
 JMF uses a well-defined event reporting mechanism that follows
the “Observer” design pattern. JMF uses the “Factory” design
pattern that simplifies the creation of JMF objects.
 The JMF support the reception and transmission of media
streams using Real-time Transport Protocol (RTP) and JMF
supports management of RTP sessions.

References
 Book:
Advanced JAVA
 Websites:
 http://www.programming.com/GepBook/Chapter7/M3L1.p
pt
 https://web.cs.dal.ca/~mheywood/CSCI6506/HandOuts/N
04-Deception.pdf

Java media framework

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