Glossary

broadcast

Transmit a data stream that multiple clients can receive if they choose to.

Buffer

The container for a chunk of media data.

CachingControl

A media control that is used to monitor and display download progress. information.

capture device

A microphone, video capture board, or other source that generates or provides time-based media data. A capture device is represented by a DataSource.

CaptureDeviceControl

A media control that enables the user to control a capture device.

CaptureDeviceInfo

An information object that maintains information about a capture device, such as its name, the formats it supports, and the MediaLocator needed to construct a DataSource for the device.

CaptureDeviceManager

The manager that provides access to the capture devices available to JMF.

Clock

A media object that defines a transformation on a TimeBase.

close

Release all of the resources associated with a Controller.

codec

A compression/decompression engine used to convert media data between compressed and raw formats. The JMF plug-in architecture enables technology providers to supply codecs that can be seamlessly integrated into JMF's media processing.

compositing

Combining multiple sources of media data to form a single finished product.

configured

A Processor state that indicates that the Processor has been connected to its data source and the data format has been determined.

configuring

A Processor state that indicates that configure has been called and the Processor is connecting to the DataSource, demultiplexing the input stream, and accessing information about the data format.

content name

A string that identifies a content type.

content package-prefix

A package prefix in the list of package prefixes that the PackageManager maintains for content extensions such as new DataSource implementations.

content package-prefix list

The list of content package prefixes maintained by the PackageManager.

content type

A multiplexed media data format such as MPEG-1, MPEG-2, QuickTime, AVI, WAV, AU, or MIDI. Content types are usually identified by MIME types.

Control

A JMF construct that can provide access to a user interface component to supports user interaction. JMF controls implement the Control interface.

control-panel component

The user interface component that enables the user to control the media presentation.

Controller

The key construct in the JMF Player/Processor API. The Controller interface defines the basic state and control mechanism for an object that controls, presents, or captures time-based media.

ControllerAdapter

An event adapter that receives ControllerEvents and dispatches them to an appropriate stub-method. Classes that extend this adapter can easily replace only the message handlers they are interested in

ControllerClosedEvent

An event posted by a Controller when it shuts down. A ControllerErrorEvent is a special type of ControllerClosedEvent.

ControllerEvent

The ControllerEvent class is the base class for events posted by a Controller object. To receive ControllerEvents, you implement the ControllerListener interface.

ControllerListener

An object that implements the ControllerListener interface to receive notification whenever a Controller posts a ControllerEvent. See also ControllerAdapter.

data

The actual media data contained by a Buffer object.

DataSink

An object that implements the DataSink interface to read media content from a DataSource and render the media to a destination.

DataSource

An object that implements the DataSource interface to encapsulate the location of media and the protocol and software used to deliver the media.

deallocate

Release any exclusive resources and minimize the use of non-exclusive resources.

decode

Convert a data stream from a compressed type to an uncompressed type.

demultiplex

Extract individual tracks from a multiplexed media stream.

Demultiplexer

A JMF plug-in that parses the input stream. If the stream contains interleaved tracks, they are extracted and output as separate tracks.

duration

The length of time it takes to play the media at the default rate.

Effect

A JMF plug-in that applies and effect algorithm to a track and outputs the modified track in the same format.

encode

Convert a data stream from an uncompressed type to a compressed type.

end of media (eom)

The end of a media stream.

StreamWriterControl

A Control implemented by data sinks and multiplexers that generate output data. This Control enables users to specify a limit on the amount of data generated.

format

A structure for describing a media data type.

frame

One unit of data in a track. For example, one image in a video track.

frame rate

The number of frames that are displayed per second.

GainChangeEvent

An event posted by a GainControl whenever the volume changes.

GainChangeListener

An object that implements the GainChangeListener interface to receive GainChangeEvents from a GainControl.

GainControl

A JMF Control that enables programmatic or interactive control over the playback volume.

JMF (Java Media Framework)

An application programming interface (API) for incorporating media data types into Java applications and applets.

key frame

A frame of video that contains the data for the entire frame rather than just the differences from the previous frame.

latency

See start latency.

managed controller

A Controller that is synchronized with other Controllers through a managing Player. The managing Player drives the operation of each managed Controller--while a Controller is being managed, you should not directly manipulate its state.

Manager

The JMF access point for obtaining system dependent resources such as Players, Processors, DataSources and the system TimeBase.

managing player

A Player that is driving the operation of other Controllers in order to synchronize them. The addController method is used to place Controllers under the control of a managing Player.

maximum start latency

The maximum length of time before a Player will be ready to present media data.

media capture

The process of acquiring media data from a source such as a microphone or a video capture card that's connected to a camera.

media data

The media information contained in a media stream.

media event

An event posted by a GainControl, DataSink, or a Controller to notify listeners that the status of the object posting the event has changed.

media processing

Manipulating media data to apply effect algorithms, convert the data to a different format, or present it.

media stream

A data stream that contains time-based media information.

media time

The current position in a media stream.

MediaHandler

An object that implements the MediaHandler interface, which defines how the media source that the handler uses to obtain content is selected. There are currently three supported types of MediaHandlers: Player (including Processor), MediaProxy, and DataSink.

MediaLocator

An object that describes the media that a Player presents. A MediaLocator is similar to a URL and can be constructed from a URL. In the Java programming language, a URL can only be constructed if the corresponding protocol handler is installed on the system. MediaLocator doesn't have this restriction.

MediaProxy

An object that processes content from one DataSource to create another. Typically, a MediaProxy reads a text configuration file that contains all of the information needed to make a connection to a server and obtain media data.

MIME type

A standardized content type description based on the Multipurpose Internet Mail Extensions (MIME) specification.

MonitorControl

A Control that provides a way to display the capture monitor for a particular capture device.

multicast

Transmit a data stream to a select group of participants. See also broadcast, unicast.

multiplex

Merge separate tracks into one multiplexed media stream.

multiplexed media stream

A media stream that contains multiple channels of media data.

Multiplexer

A JMF plug-in that combines multiple tracks of input data into a single interleaved output stream and delivers the resulting stream as an output DataSource.

output data source

A DataSource that encapsulates a Processor object's output.

package prefix

An identifier for your code that you register with the JMF PackageManager. For example, COM.yourbiz. The PackageManager maintains separate lists of package prefixes for content and protocol extensions. See also content package-prefix, protocol package-prefix.

participant

In RTP, an application participating in an RTP session

payload

In RTP, the data transported by RTP in a packet, such as audio samples or compressed video data.

Player

An object that implements the Player interface to processes a stream of data as time passes, reading data from a DataSource and rendering it at a precise time.

Player state

One of the six states that a Player can be in: Unrealized, Realizing, Realized, Prefetching, Prefetched, and Started. In normal operation, a Player steps through each state until it reaches the Started state.

playback

The process of presenting time-based media to the user.

plug-in

A media processing component that implements the JMF PlugIn interface.

PlugInManager

A manager object that maintains a registry of installed plug-ins and is used to search the available plug-ins.

Positionable

An object that supports changing the media position within the stream and implements the Positionable interface.

post-process

Apply an effect algorithm after the media stream has been decoded.

pre-process

Apply an effect algorithm before the media stream is encoded.

prefetch

Prepare a Player to present its media. During this phase, the Player preloads its media data, obtains exclusive-use resources, and anything else it needs to do to prepare itself to play.

prefetched

A Player state in which the Player is ready to be started.

prefetching

A Player state in which the Player is in the process of preparing itself to play.

Processor

A special type of JMF Player that can provide control over how the media data is processed before it is presented.

Processor state

One of the eight states that a Processor can be in. A Processor has two more Stopped states than a Player: Configuring and Configured. See also Player state.

ProcessorModel

An object that defines the input and output requirements for a Processor. When a Processor is created using a ProcessorModel, the Manager does its best to create a Processor that meets these requirements.

progress bar component

The user interface component that can be retrieved from a CachingControl to display download progress to the user.

protocol

A data delivery mechanism such as HTTP, RTP, FILE.

protocol package-prefix

A package prefix in the list of package prefixes that the PackageManager maintains for protocol extensions such as new MediaHandlers.

protocol package-prefix list

The list of protocol package prefixes maintained by the PackageManager.

pull

Initiate the data transfer and control the flow of data from the client side.

PullBufferDataSource

A pull DataSource that uses a Buffer object as its unit of transfer.

PullDataSource

A DataSource that enables the client to initiate the data transfer and control the flow of data.

PullBufferStream

A SourceStream managed by a PullBufferDataSource.

PullSourceStream

A SourceStream managed by a PullDataSource.

push

Initiate the data transfer and control the flow of data from the server side.

PushBufferDataSource

A push DataSource that uses a Buffer object as its unit of transfer.

PushDataSource

A DataSource that enables the server to initiate the data transfer and control the flow of data.

PushBufferStream

A SourceStream managed by a PushBufferDataSource.

PushSourceStream

A SourceStream managed by a PushDataSource.

rate

A temporal scale factor that determines how media time changes with respect to time-base time. A Player object's rate defines how many media time units advance for every unit of time-base time.

raw media format

A format that can be directly rendered by standard media rendering devices without the need for decompression. For audio, a PCM sample representation is one example of a raw media format.

realize

Determine resource requirements and acquire the resources that the Player only needs to acquire once.

realized

The Player state in which the Player knows what resources it needs and information about the type of media it is to present. A Realized Player knows how to render its data and can provide visual components and controls. Its connections to other objects in the system are in place, but it doesn't own any resources that would prevent another Player from starting.

realizing

The Player state in which the Player is determining what resources it needs and gathering information about the type of media it is to present.

render

Deliver media data to some destination, such as a monitor or speaker.

Renderer

A JMF plug-in that delivers media data to some destination, such as a monitor or speaker.

RTCP

RTP Control Protocol.

RTP

Real-time Transfer Protocol.

session

In RTP, the association among a set of participants communicating with RTP. A session is defined by a network address plus a port pair for RTP and RTCP.

source

A provider of a stream of media data.

SourceStream

A single stream of media data.

SSRC

See synchronization source.

start

Activate a Player. A Started Player's time-base time and media time are mapped and its clock is running, though the Player might be waiting for a particular time to begin presenting its media data.

start latency

The time it takes before a Player can begin presenting media data.

started

One of the two fundamental Clock states. (The other is Stopped.) Controller breaks the Started state down into several resource allocation phases: Unrealized, Realizing, Realized, Prefetching, and Prefetched.

status change events

Controller events such as RateChangeEvent, SizeChangeEvent StopTimeChangeEvent that indicate that the status of a Controller has changed.

stop

Halt a Player's presentation of media data.

stop time

The media time at which a Player should halt.

synchronization source

The source of a stream of RTP packets, identified by a 32-bit numeric SSRC identifier carried in the RTP header.

synchronize

Coordinate two or more Controller's so that they can present media data together. Synchronized Controller's use the same TimeBase.

target state

The state that a Player is heading toward. For example, when a Player is in the Realizing state, its target state is Realized.

time-based media

Media such as audio, video, MIDI, and animations that change with respect to time.

TimeBase

An object that defines the flow of time for a Controller. A TimeBase is a constantly ticking source of time, much like a crystal.

time-base time

The current time returned by a TimeBase.

track

A channel in a multiplexed media stream that contains media or control data. For example, a multiplexed media stream might contain an audio track and a video track.

TrackControl

A Control used to query, control and manipulate the data of individual media tracks.

track format

The format associated with a particular track.

transcode

Convert a data stream from an uncompressed type to a compressed type or vice-versa.

transition events

ControllerEvents posted by a Controller as its state changes.

unicast

Transmit a data stream to a single recipient.

unrealized

The initial state of a Player. A Player in the Unrealized state has been instantiated, but does not yet know anything about its media.

URL

Universal Resource Locator.

user-interface component

An instance of a class that implements the Component interface. JMF Players have two types of default user-interface components, a ControlPanelComponent and a VisualComponent.

visual component

The user interface component that displays the media or information about the media.

VOD

Video on Demand.