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Because you cannot link directly from a Web page to a streaming media server, you use metafile playlists. The metafile playlists contain the information needed by Windows Media Player and are stored on a Web server. You can then link from the Web document to a metafile playlist. When a metafile playlist is opened, control transfers to Windows Media Player, which processes the file, connects to the streaming media server, and plays the specified content.
The browser first downloads the metafile playlist to the user's cache directory. Because the metafile playlist is small, this is a very quick step. The user's computer then finds in its file associations table the association of the metafile playlist with Windows Media Player. Windows Media Player opens and interprets the scripting in the metafile playlist, which contains, among other things, the URL of the streaming content. Windows Media Player uses the URL to locate the content and initiate the stream. The metafile playlist scripting then controls the streaming experience.
When a metafile playlist is opened by Windows Media Player version 6.4, the entire file is parsed and all Uniform Resource Locators (URLs) resolved before any content is played. If referenced content includes associated graphics, all referenced graphic files are downloaded before the content is played. This prevents long pauses between pieces of content while a graphic is being downloaded, but can also cause a long delay before the first piece of content plays. For Windows Media Player version 7 or later, each URL is resolved as it is encountered.
Because metafile playlists work through a helper application associated with the ASXMIME type (application/mplayer2 or video/x-ms-asf), they are compatible with any browser that supports helper applications. The examples shown in this document will work with Internet Explorer 4.0 and later, and with Netscape Navigator 4.0 and later on Win32 and MAC platforms. In all examples, you will have to be sure that any media files referenced have valid paths and file names for your environment.
See Also
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