java media framework
Post on 18-Jul-2015
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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.
States of the Players
Prefetched :Entering the prefetched state, a player issues the
PrefetchCompleteEvent.
Started : When player is started, it enters the started state.
States of the Players
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 followsthe “Observer” design pattern. JMF uses the “Factory” designpattern that simplifies the creation of JMF objects.
The JMF support the reception and transmission of mediastreams using Real-time Transport Protocol (RTP) and JMFsupports 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
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