Windows Media Player 11 SDK Creating Metafile Playlists 

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Creating Metafile Playlists

You can create a playlist using any text editor, such as Microsoft Notepad. Open your text editor. Type the script entries you want to implement. After you have finished typing into Notepad, save the file with an appropriate file name and file name extension. For more information about extensions, see Metafile Extension Guidelines. Typically the file name is the name of the Windows Media file or stream followed by an extension of .wax, .wvx, or .asx. For example, if your media content is a Windows Media audio file that has a .wma extension, use the .wax extension when naming the playlist. Playlists must not include any formatting codes from a word processor, such as Microsoft Word. To be sure no formatting codes are included in the playlist, save the file as a plain text or ASCII file.

Note   Elements and attributes are not case sensitive. The text used in the playlist to define an element or attribute can be either uppercase or lowercase, or a mixture of both.

If an element does not have any child elements (those that modify or are contained within another element), a single slash character (/) can be used at the end of the opening tag, just before the '>', in place of a closing tag. Child elements of an element must appear between the opening and closing tag for that element; otherwise they are not child elements for that element, and are ignored or cause an error in the syntax of the playlist.

The first four characters of a playlist must be "<ASX". The ASX element is used in all playlists whether their extension is .wax, .wvx, or .asx. There must be only one ASX element per playlist. This element identifies the file as a Windows Media metafile playlist. It does not specify the type of playlist.

The ASX element has three possible attributes:

VERSION

The VERSION attribute is required and must follow immediately after the ASX element, for example "<ASX version = "3.0">". The current version number is 3.0. Windows Media Player supports all previous versions. Acceptable values for the VERSION attribute include both 3.0 and 3 (with no decimal point).

PREVIEWMODE

The PREVIEWMODE attribute is optional. It provides another mechanism for specifying how long to render a clip. If the value of the PREVIEWMODE attribute is YES, Windows Media Player will render each clip for the duration specified by the element PREVIEWDURATION. Each clip can have a PREVIEWDURATION specified.

BANNERBAR

The optional BANNERBAR attribute defines whether the Windows Media Player control reserves space for a banner graphic. (Use the BANNER element to specify the graphic to display.) If the value of BANNERBAR is FIXED, Windows Media Player reserves banner space for the show and for every clip, whether or not the metafile playlist specifies a banner for the show or clip. This will keep the size of the Windows Media Player window the same (except when the video size changes) regardless of the absence or presence of a banner graphic. If the show or clip does not have a banner associated with it, the space reserved for one is black. If the value of the BANNERBAR attribute is AUTO, Windows Media Player reserves space for the banner only when the show or clip includes one.

For more information about the three attributes of the ASX element, see the reference entry for the ASX Element.

An ASX element contains ENTRY child elements that define information about the media files to be accessed. Each ENTRY element must contain a REF element that specifies the path to the media file to be streamed. There must be at least one ENTRY or ENTRYREF element within an ASX element.

Other elements defined within the scope of the ASX element, such as TITLE and AUTHOR, are associated with the metadata displayed by Windows Media Player.

The simplest playlists are created by adding multiple ENTRY elements with a single REF element to a metafile. Each ENTRY element in a metafile playlist is rendered in the order it appears in the file as though the user had manually opened each clip.

Example Code

Be sure that the playlist is working by double-clicking it in Windows Explorer. Windows Media Player should open and start streaming the media content. After you have confirmed that the playlist works, save it to your Web server along with your Web pages, and link to it by means of an HREF element, or embed it in a Web page using the Windows Media Player OBJECT element.

The following sections contain more information:

See Also

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