JMF Supported Formats

帮朋友调试一个JMF的程序，发现换个格式的文件就不行了，故想找下JMF支持哪些格式的文件。官网有详细的说明，故在此记录下。

 

不能播放的格式一般报如下的错误：

 

Cannot find a Player for: com.sun.media.protocol.file.DataSource

 

 

 

1：官方比较详细的 JMF 2.1.1 - Supported Formats

http://www.oracle.com/technetwork/java/javase/formats-138492.html

 

 

2：官方泛泛的说明

What media types does JMF 2.1.1 support?

http://www.oracle.com/technetwork/java/javase/index-135148.html#jmf2-support

 

 

JMF 2.1.1 supports a wide array of media types, including

• protocols: FILE, HTTP, FTP, RTP
• audio: AIFF, AU, AVI, GSM, MIDI, MP2, MP3*, QT, RMF, WAV
• video: AVI, MPEG-1, QT, H.261, H.263
• other: HotMedia

*MP3 is supported only on the Windows platform.

 

3：通过查看官方JAVA API文档并找源码实现的方式

首先找核心Manager的API文档

http://docs.oracle.com/cd/E17802_01/j2se/javase/technologies/desktop/media/jmf/2.1.1/apidocs/javax/media/Manager.html

然后结合错误并留意到如下一段说明：

 

Finding Players by Content Type

A Player is a MediaHandler. A MediaHandler is a an object that reads data from a DataSource. There are three types of supported MediaHandler: MediaProxy, Player and Processor.
MediaHandlers are identified by the content type that they support. A DataSource identifies the content type of the data it produces with the getContentType method. Manager uses the content type name to find instances of MediaHandler.

To find a MediaHandler using a content type name, Manager constructs a list of class names from the content package-prefix list and the content type name. For each class name in the constructed list a new MediaHandler is instantiated, and the DataSource is attached to the MediaHandler using MediaHandler.setSource.

If the MediaHandler is a Player and the setSource was successful the process is finished and the Player is returned. If the setSource failed, another name in the list is tried.

If the MediaHandler is a MediaProxy then a new DataSource is obtained from the MediaProxy, a new list is created for the content type the DataSource supports and the whole thing is tried again.

If a valid Player is not found then the whole procedure is repeated with "unknown" substituted for the content-type name. The "unknown" content type is supported by generic Players that are capable of handling a large variety of media types, often in a platform dependent way.

The detailed creation algorithm is specified in the methods below.

   找到重点在于 MediaHandlers 这个类的实现类，ok开始在eclipse中看其有哪些实现类，实现类中主要看Parser即可。

ok，代码实现和官方文档基本吻合。