JMF之API 初识...及JMF 2.0 api与JMF1.0 api的修改注意要点

 (注：本贴只为方便自己快速温故所用，不是文章的全部翻译，只做部份摘要解译，方便自己快速浏览)

About JMF

               JMF1.0只供程序员把实时媒体加到应用中，而JMF2.0则增加了捕获设备多媒体、储存多媒体文件、和播放媒体时的控制功能组件、

               另外，JMF2.0还有plug-in 插件API ，它让高级的JMF开发员可以扩展这些jmf框架api

The JMF 1.0 API (the Java Media Player API) enabled programmers to

develop Java programs that presented time-based media. The JMF 2.0 API

extends the framework to provide support for capturing and storing

media data, controlling the type of processing that is performed during

playback, and performing custom processing on media data streams. In

addition, JMF 2.0 deÞnes a plug-in API that enables advanced developers

and technology providers to more easily customize and extend JMF functionality.

以下是JMF 2.0中新增类和接口：

AudioFormat                                  BitRateControl                                            Buffer

BufferControl                                 BufferToImage                                             BufferTransferHandler

CaptureDevice                              CaptureDeviceInfo                                       CaptureDeviceManager

CloneableDataSource                     Codec                                                           ConfigureCompleteEvent

ConnnectionErrorEvent               DataSink                                                     DataSinkErrorEvent

DataSinkEvent                            DataSinkListener                                        Demultiplexer

Effect                                          EndOfStreamEvent                                     FileTypeDescriptor

Format                                      FormatChangeEvent                                     FormatControl

FrameGrabbingControl               FramePositioningControl                                 FrameProcessingControl

FrameRateControl                     H261Control                                                    H261Format

H263Control                            H263Format                                                 ImageToBuffer

IndexedColorFormat                      InputSourceStream                                KeyFrameControl

MonitorControl                               MpegAudioControl                                   Multiplexer

NoStorageSpaceErrorEvent          PacketSizeControl                                    PlugIn

PlugInManager                             PortControl                                        Processor

ProcessorModel                        PullBufferDataSource                            PullBufferStream

PushBufferDataSource         PushBufferStream                                      QualityControl

Renderer                                 RGBFormat                                        SilenceSuppressionControl

StreamWriterControl                   Track                                                  TrackControl

VideoFormat                           VideoRenderer                                     YUVFormat

 

另外MediaPlayer 这个java bean 已经被加到 javax.media.bean.playerbean包中了。

MediaPlayer 可以被直接实例化对象，用它来展示一个或多个media streams。

（原文）In addition, the "MediaPlayer"  Java Bean has been included with the JMF

API in

javax.media.bean.playerbean.

MediaPlayer  can be instantiated  directly and used to present one or more media streams.

 

Design Goals for the JMF API 2.0

JMF API的设计目标：

          1、更容易编程

           2、支持媒体数据的捕获

           3、让多媒体技术和会议应用技术在java中成为可能

           4、让高级开发者与技术专家可以基于现有的api实现更加客户化的解决方案，以及更加方便集成一些新的技术特点到现有技术框架中。（扩展性）

          5、可以访问媒体原数据

          6、可以开发可以用客户化、可下载、复用、分路、编码、效果处理、与展示、插件等

JMF 2.0 supports media capture and addresses the needs of application

developers who want additional control over media processing and rendering.

It also provides a plug-in architecture that provides direct access

to media data and enables JMF to be more easily customized and

extended. JMF 2.0 is designed to:

¥ Be easy to program

¥ Support capturing media data

¥ Enable the development of media streaming and conferencing

applications in Java

¥ Enable advanced developers and technology providers to implement

custom solutions based on the existing API and easily integrate new

features with the existing framework

¥ Provide access to raw media data

¥ Enable the development of custom, downloadable demultiplexers,

codecs, effects processors, multiplexers, and renderers (JMF

plug-ins

)

¥ Maintain compatibility with JMF 1.0

 

About the JMF RTP APIs

 

在javax.media.rtp javax.media.rtp.event javax.media.rtp.rtcp三个包中包的类和接口就提供了对RTP的支持。

rtp的支持使得多媒体流可以在网络上传输。

The classes in

javax.media.rtp, javax.media.rtp.event

, and

javax.media.rtp.rtcp

provide support for RTP (Real-Time Transport Protocol).

RTP enables the transmission and reception of real-time media

streams across the network. RTP can be used for media-on-demand applications

as well as interactive services such as Internet telephony.

 

JMF 的实现不是必须包括RTP的支持

(原文)JMF-compliant implementations are not required to support the RTP

APIs in

javax.media.rtp

,

javax.media.rtp.event

, and

javax.media.rtp.rtcp

.

sun 和IBM提供了一些JMF api接口的参考实现

如：RTPSessionMgr等

The reference implementations of JMF provided

by Sun Microsystems, Inc. and IBM Corporation fully support these APIs.

第一个版本中只支持rtp streams的接收和播放，第二版api就增加了rtp streams 的发送。

（原文）The Þrst version of the JMF RTP APIs (referred to as the RTP Session Manager

API) enabled developers to receive RTP streams and play them using

JMF. In JMF 2.0, the RTP APIs also support the transmission of RTP

streams.

以下是RTP的类和接口在2.0中是新增的：

SendStream                                       SendStreamListener                      InactiveSendStreamEvent

ActiveSendStreamEvent                 SendPayloadChangeEvent                    NewSendStreamEvent

GlobalTransmissionStats                TransmissionStats 

RTP包中的一些类和接口已经被重新组织过了，一些方法也被重新命名过。

 The RTP packages have been reorganized and some classes, interfaces,

and methods have been renamed to make the API easier to use.

以下是包重新组织发生的改变

The package reorganization consists of the following changes:

1、The RTP event classes that were in javax.media.rtp.session
are now in  javax.media.rtp.event

2、The RTCP-related classes that were in javax.media.rtp.session are now in javax.media.rtp.rtcp
.

3、The rest of the classes in javax.media.rtp.session are now in
javax.media.rtp and the javax.media.rtp.session package has been removed.

以下是方法重新命名的规则

1、去了方法的rtp、rtcp前缀

The name changes consist primarily of the removal of the RTP and RTCP

preÞxes from class and interface names and the elimination of non-standard

abbreviations. For example,

RTPRecvStreamListener

has been

renamed to

ReceiveStreamListener

. For a complete list of the changes

made to the RTP packages, see the JMF 2.0 Beta release notes.

另外还会做一些修改以兼容jmf2.0对其它方面api的修改

 In addition, changes were made to the RTP APIs to make them compatible

with other changes in JMF 2.0:

 

1、javax.media.rtp.session.io 和javax.media.rtp.session.depacketizer 已经删除，客户化的rtp packetzers 和depacketizers现在通过JMF2.0的plug-in插件体系结构来提供支持。

     原来已存在的depacketizer会被放到现在的插件体系结构中去。

javax.media.rtp.session.io

and

javax.media.rtp.session.depacketizer

have been removed. Custom

RTP packetizers and depacketizers are now supported through the

JMF 2.0 plug-in architecture. Existing depacketizers will need to be

ported to the new plug-in architecture.

2、Buffer 对象实例是SessionManager传送的基本单元，代替来原来 的DePacketizedUnit 和DePacketizedObject传送单元。

     Buffer有自己的数据和头信息格式。

Buffer

is now the basic unit of transfer between the

SessionManager

and other JMF objects, in place of

DePacketizedUnit

and

DePacketizedObject.

RTP-formatted

Buffers

have a specific format

for their data and header objects.

3、 BaseEndcoingInfo已经被JMF的Format对像所代替了。一个rtp特定的Format通过一个特定的encoding字符串标志的。

       编码标志字符串都是“***_RTP格式的” 。如：RAW_RTP 。

        通过在Format中绑定一个动态加载数字来实现动态加载格式信息。

BaseEncodingInfo

has been replaced by the generic JMF

Format

object.

An RTP-specific

Format

is differentiated from other formats by its

encoding string. Encoding strings for RTP-specific

Formats

end in

_RTP

. Dynamic payload information can be provided by associating a

dynamic payload number with a

Format

object.

 

Design Goals for the JMF RTP APIs

// JMF RTP APIs的设计目标：为实现多媒体会议应用。

The RTP APIs in JMF 2.0 support the reception and transmission of RTP

streams and address the needs of application developers who want to use

RTP to implement media streaming and conferencing applications. These

APIs are designed to:

¥ Enable the development of media streaming and conferencing

applications in Java

¥ Support media data reception and transmission using RTP and RTCP

¥ Support custom packetizer and depacketizer plug-ins through the

JMF 2.0 plug-in architecture.

¥ Be easy to program