jmfpreface.html

奉献给多媒体java编程者们。JMF2.1.1最新版本的用户指南。JMF是java用于基于实时多媒体的开发工具

  <a name="1004879"> </a><font face="Palatino, Times New Roman, Times, serif">In addition, the <code>MediaPlayer</code> Java Bean has been included with the JMF API in <code>javax.media.bean.playerbean</code>. <code>MediaPlayer</code> can be instantiated directly and used to present one or more media streams. </font>
</p>


<p>
  <a name="1005239"> </a><font face="Palatino, Times New Roman, Times, serif">Future versions of the JMF API will provide additional functionality and enhancements while maintaining compatibility with the current API. </font>
</p>


<h4>
  <a name="999112"> </a><font color="#003366" face="Palatino, Times New Roman, Times, serif">Design Goals for the JMF API</font>
</h4>


<p>
  <a name="999133"> </a><font face="Palatino, Times New Roman, Times, serif">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: </font>
</p>

<ul>
  <li><a name="999532"> </a><font face="Palatino, Times New Roman, Times, serif">Be easy to program </font>
  <li><a name="999138"> </a><font face="Palatino, Times New Roman, Times, serif">Support capturing media data </font>
  <li><a name="999295"> </a><font face="Palatino, Times New Roman, Times, serif">Enable the development of media streaming and conferencing applications in Java</font>
  <li><a name="999541"> </a><font face="Palatino, Times New Roman, Times, serif">Enable advanced developers and technology providers to implement custom solutions based on the existing API and easily integrate new features with the existing framework</font>
  <li><a name="999550"> </a><font face="Palatino, Times New Roman, Times, serif">Provide access to raw media data </font>
  <li><a name="999139"> </a><font face="Palatino, Times New Roman, Times, serif">Enable the development of custom, downloadable demultiplexers, codecs, effects processors, multiplexers, and renderers (JMF <em>plug-ins</em>)</font>
  <li><a name="999559"> </a><font face="Palatino, Times New Roman, Times, serif">Maintain compatibility with JMF 1.0 </font>
</ul>

<h4>
  <a name="1005581"> </a><font color="#003366" face="Palatino, Times New Roman, Times, serif">About the JMF RTP APIs</font>
</h4>


<p>
  <a name="1005582"> </a><font face="Palatino, Times New Roman, Times, serif">The classes in <code>javax.media.rtp, javax.media.rtp.event</code>, and <code>javax.media.rtp.rtcp</code> 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. </font>
</p>


<p>
  <a name="1005583"> </a><font face="Palatino, Times New Roman, Times, serif"><strong>JMF-compliant implementations are not required to support the RTP APIs in</strong><code> </code><strong>javax.media.rtp,</strong><code> </code><strong>javax.media.rtp.event, and javax.media.rtp.rtcp.</strong> The reference implementations of JMF provided by Sun Microsystems, Inc. and IBM Corporation fully support these APIs. </font>
</p>


<p>
  <a name="1005584"> </a><font face="Palatino, Times New Roman, Times, serif">The first 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. </font>
</p>


<p>
  <a name="1005604"> </a><font face="Palatino, Times New Roman, Times, serif">The following RTP classes and interfaces are new in JMF 2.0:

<table border="1" bordercolorlight="#FFFFFF" bordercolordark="#000000"
       cellpadding="5" cellspacing="0">
  <caption><b><i><font face="Palatino, Times New Roman, Times, serif"></font></i></b></caption>
  <tr>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005587"> </a><code>SendStream</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005589"> </a><code>SendStreamListener</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005591"> </a><code>InactiveSendStreamEvent</code></font></td>
  </tr>
  <tr>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005593"> </a><code>ActiveSendStreamEvent</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005595"> </a><code>SendPayloadChangeEvent</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005597"> </a><code>NewSendStreamEvent</code></font></td>
  </tr>
  <tr>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005599"> </a><code>GlobalTransmissionStats</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005601"> </a><code>TransmissionStats</code></font></td>
    <td><font face="Palatino, Times New Roman, Times, serif"><a name="1005603"> </a><code></code></font></td>
  </tr>
</table>



</font>
</p>


<p>
  <a name="1006086"> </a><font face="Palatino, Times New Roman, Times, serif">The RTP packages have been reorganized and some classes, interfaces, and methods have been renamed to make the API easier to use. The package reorganization consists of the following changes:</font>
</p>

<ul>
  <li><a name="1006093"> </a><font face="Palatino, Times New Roman, Times, serif">The RTP event classes that were in<code> javax.media.rtp.session</code> are now in <code>javax.media.rtp.event</code>.</font>
  <li><a name="1006094"> </a><font face="Palatino, Times New Roman, Times, serif">The RTCP-related classes that were in <code>javax.media.rtp.session</code> are now in <code>javax.media.rtp.rtcp</code>.</font>
  <li><a name="1006095"> </a><font face="Palatino, Times New Roman, Times, serif">The rest of the classes in<code> javax.media.rtp.session</code> are now in <code>javax.media.rtp</code> and the <code>javax.media.rtp.session</code> package has been removed.</font>
</ul>

<p>
  <a name="1006096"> </a><font face="Palatino, Times New Roman, Times, serif">The name changes consist primarily of the removal of the RTP and RTCP prefixes from class and interface names and the elimination of non-standard abbreviations. For example, <code>RTPRecvStreamListener</code> has been renamed to <code>ReceiveStreamListener</code>. For a complete list of the changes made to the RTP packages, see the JMF 2.0 Beta release notes.</font>
</p>


<p>
  <a name="1006092"> </a><font face="Palatino, Times New Roman, Times, serif">In addition, changes were made to the RTP APIs to make them compatible with other changes in JMF 2.0:</font>
</p>

<ul>
  <li><a name="1006087"> </a><font face="Palatino, Times New Roman, Times, serif"><code>javax.media.rtp.session.io</code> and <code>javax.media.rtp.session.depacketizer</code> 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.</font>
  <li><a name="1005607"> </a><font face="Palatino, Times New Roman, Times, serif"><code>Buffer </code>is now the basic unit of transfer between the <code>SessionManager</code> and other JMF objects, in place of <code>DePacketizedUnit</code> and <code>DePacketizedObject.</code> RTP-formatted <code>Buffers</code> have a specific format for their data and header objects.</font>
  <li><a name="1005608"> </a><font face="Palatino, Times New Roman, Times, serif"><code>BaseEncodingInfo</code> has been replaced by the generic JMF <code>Format</code> object. An RTP-specific <code>Format</code> is differentiated from other formats by its encoding string. Encoding strings for RTP-specific <code>Formats</code> end in  <code>_RTP</code>. Dynamic payload information can be provided by associating a dynamic payload number with a <code>Format</code> object.</font>
</ul>

<h5>
  <a name="1005609"> </a><i><font color="#003366" face="Palatino, Times New Roman, Times, serif">Design Goals for the JMF RTP APIs</font></i>
</h5>


<p>
  <a name="1005610"> </a><font face="Palatino, Times New Roman, Times, serif">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: </font>
</p>

<ul>
  <li><a name="1005611"> </a><font face="Palatino, Times New Roman, Times, serif">Enable the development of media streaming and conferencing applications in Java</font>
  <li><a name="1005612"> </a><font face="Palatino, Times New Roman, Times, serif">Support media data reception and transmission using RTP and RTCP</font>
  <li><a name="1005613"> </a><font face="Palatino, Times New Roman, Times, serif">Support custom packetizer and depacketizer plug-ins through the JMF 2.0 plug-in architecture.</font>
  <li><a name="1005614"> </a><font face="Palatino, Times New Roman, Times, serif">Be easy to program</font>
</ul>

<h4>
  <a name="999260"> </a><font color="#003366" face="Palatino, Times New Roman, Times, serif">Partners in the Development of the JMF API</font>
</h4>


<p>
  <a name="999261"> </a><font face="Palatino, Times New Roman, Times, serif">The JMF 2.0 API is being jointly designed by Sun Microsystems, Inc. and IBM Corporation.</font>
</p>


<p>
  <a name="999385"> </a><font face="Palatino, Times New Roman, Times, serif">The JMF 1.0 API was jointly developed by Sun Microsystems Inc., Intel Corporation, and Silicon Graphics, Inc.</font>
</p>


<h4>
  <a name="999263"> </a><font color="#003366" face="Palatino, Times New Roman, Times, serif">Contact Information</font>
</h4>


<p>
  <a name="1004147"> </a><font face="Palatino, Times New Roman, Times, serif">For the latest information about JMF, visit the Sun Microsystems, Inc. website at:</font>
</p>

<pre>
<a name="1004148"> </a>http://java.sun.com/products/java-media/jmf/
</pre>

<p>
  <a name="999266"> </a><font face="Palatino, Times New Roman, Times, serif">Additional information about JMF can be found on the IBM Corporation website at:</font>
</p>

<pre>
<a name="999267"> </a>http://www.software.ibm.com/net.media/
</pre>

<h3>
  <a name="998529"> </a><font color="#003366" face="Palatino, Times New Roman, Times, serif">About this Document</font>
</h3>


<p>
  <a name="999128"> </a><font face="Palatino, Times New Roman, Times, serif">This document describes the architecture and use of the JMF 2.0 API. It replaces the Java Media Player Guide distributed in conjunction with the JMF 1.0 releases. </font>
</p>


<p>
  <a name="1006323"> </a><font face="Palatino, Times New Roman, Times, serif">Except where noted, the information in this book is not implementation specific. For examples specific to the JMF reference implementation developed by Sun Microsystems and IBM corporation, see the sample code and solutions available from Sun's JMF website (<code>http://java.sun.com/products/java-media/jmf/index.html</code>).</font>