.ASX

Introduction

ASX is Microsoft’s metafile format for Windows Media, from the late 1990s. A web page linked to a small .asx file rather than to the stream itself; Windows Media Player opened it and followed the addresses inside to the audio or video. It was widely used for internet radio and live streams. The extensions .wax (audio) and .wvx (video) mark the same format.

Structure

An ASX file is XML-like text, although players accept it loosely: element names are not case-sensitive. The root element is asx with version="3.0". It may hold a title, then one entry per item. Each entry gives one or more ref elements whose href is the stream or file address; a player tries them in order until one works. Entries can also carry their own title, author and copyright.

<asx version="3.0">
  <title>Example Radio</title>
  <entry>
    <title>Live stream</title>
    <ref href="http://radio.example.com/live"/>
    <ref href="http://backup.example.com/live"/>
  </entry>
</asx>

Links