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ASX Elements Reference

Advanced Stream Redirector (ASX) files are based on the Extensible Markup Language (XML) syntax, and are made up of various elements with their associated tags and attributes. Each element in an ASX file defines a particular setting or action to the Microsoft® Windows Media® Player control. Some elements must be located in a specific position in the file relative to other elements. Some elements have required tags and attributes that must be defined in the ASX file. Element names and attributes are not case-sensitive.

The most important part of successfully using ASX files is the correct syntax of the ASX elements. Syntax errors in an ASX file can cause anything from a single attribute being overlooked, to the ASX file not being recognized as valid and failing to work at all. Almost as important is the order in which the elements appear in the ASX file. The attributes of some elements temporarily override the attributes of similar elements in different sections of the ASX file.


  • ASX element and attribute tags are not case sensitive. The text used in the ASX file to define an element can be either upper or lower case, or a mix of both. The opening and closing tags used in an element also can be different case.
  • If an element tag 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 in place of a closing tag. If the child elements do not appear between the opening and closing tag for an element, they are not child elements for that element and will be ignored or cause an error in the syntax of the ASX file.

For more information about ASX elements, see the following sections, each of which contains a definition of the element, its attributes and their values, and special conditions related to the element.

Element Description
ABSTRACT Contains text that represents a description of the associated ASX, or ENTRY element.
ASX Defines a file as an ASX file.
AUTHOR Contains a text string representing the name of the author of an ASX file or media clip.
BASE Defines a URL string appended to the front of URLs sent to the WMP control.
COPYRIGHT Defines a text string specifying the copyright information for an ASX or ENTRY element.
DURATION Defines the length of time the WMP control will render a stream.
ENDMARKER Specifies a marker at which the WMP control will stop rendering the stream.
ENTRY Defines a clip.
ENTRYREF Links to the ENTRY elements in an external ASX file.
EVENT Defines a behavior or action taken by the WMP control when it receives a script command labeled as an event.
MOREINFO Specifies a URL to a Web site, e-mail address, or script command associated with a show or clip.
PARAM Defines an custom parameter associated with a clip.
REF Specifies a URL for a piece of media content.
REPEAT Defines the number of times the WMP control repeats one or more ENTRY or ENTRYREF elements.
STARTMARKER Specifies a marker from which the WMP control will start rendering the stream.
STARTTIME Defines a time index from which the WMP control will start rendering the stream.
TITLE Defines a text string specifying the title for an ASX or ENTRY element.

Last updated on Wednesday, April 13, 2005

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