What Is an ASX File? Playlists, Streams and How to Open One

1 What Is an ASX File? A short text playlist that points to a stream

Picture a friend who emails you a file called radio.asx and says it is a live station. You double-click it. Nothing plays, or the wrong app opens. You open it in Notepad and find eight lines of tags and no sound. Most ASX file questions start right there.

An ASX file works like a link you paste in a chat. The link is a few characters, and the video lives somewhere else. Your ASX file adds a title, an author and sometimes a few extra details. Windows Media Player reads those lines and plays what the address points to.

Microsoft built the format so web pages could link to streams. The page links to a small ASX file, the browser downloads it and the player takes over. Internet radio stations used this route. One of our sample files is a stream list from SomaFM, an online radio station.

Two other things share the letters. ASX is also the Australian Securities Exchange, which has nothing to do with this file. And Alpha Five, a tool for web apps, once used the .asx ending for temporary index files. The section on other meanings covers both.

ASX file facts at a glance

Wrong page? A shortcut that ends in .lnk is covered in the LNK shortcut file guide. A Java launcher that ends in .jnlp is covered in the JNLP Java launcher file guide.

3 What Are the ASX, WAX and WVX Endings? One format, three endings and a reserved fourth

Think of the ending as a hint to the player and a note to you. A radio list gets .wax and a video list gets .wvx. Inside, the three look alike. They use the same tags and the same version number.

The table follows the Microsoft list of Windows Media file name extensions and the extension guidelines for metafiles. Microsoft also advises naming the metafile after the media file. A song called night.wma gets a metafile called night.wax.

VLC treats the three alike. The VLC playlist module opens .asx, .wax and .wvx files with one piece of code, and it has done so since version 0.5.0.

We found no WAX, WVX or WMX file in the public projects we searched. Every file in the samples section ends in .asx.

4 What Do 4 Public ASX Files Show? Where we found them and how three tools read them

The samples come from the test folders of Clementine, Kodi and Apache Tika. The first two are media players and the third is a content-extraction toolkit. We searched nine well-known open-source media and content projects and found ASX files in three. We downloaded the files in October 2026.

Four files is a small set, because public ASX files are rare. The format is old, and few projects keep samples of it. Treat the counts as a sketch and not as statistics. We read every file in Python and tested it in three tools.

What the four ASX files contain

All four files use version 3.0. Two start with the capital tag <ASX and two with <asx. The Kodi file mixes both styles inside one file. It also has two made-up tags, TEST and SOMETHING. They look like a check that a reader skips tags it does not know.

Where the nine addresses point

Eight of the nine addresses start with http:// and one starts with mms://. The mms:// address belongs to the Tika sample, a city council video from April 2009. The SomaFM list names four servers for the same radio station. One address is an MP3 file, so an ASX file is not limited to Windows Media files.

How the four files behave in three tools

The one that failed is the SomaFM list. Its tag <Abstract> ends with </abstract>, and strict XML readers need the two to match. Microsoft says tag names are not case sensitive, so Windows Media Player may accept the file. We could not test the player here, so we say nothing about how it handles it.

Eight ASX files we wrote to test a strict reader

We also wrote eight tiny ASX files and gave every one a single change. Then we tried to parse them with the Python XML reader. Three parsed and five did not.

The pattern is simple. Matching tags, quoted values and an escaped & parse every time. Players may accept some of the rejected files, and we did not test that. A clean file works in every reader, so write it clean.

What the counts say about ASX files

Check your own ASX file

Python reads any ASX file in a few lines. Replace radio.asx with your file name. The code prints the first five bytes and then the addresses it finds. If the ASX file is not strict, it prints the XML error.

import xml.etree.ElementTree as ET
raw = open("radio.asx", "rb").read()
print(raw[:5])
try:
    root = ET.fromstring(raw)
    print([e.get("href") or e.get("HREF") for e in root.iter() if e.tag.lower() == "ref"])
except ET.ParseError as err:
    print("not strict XML:", err)

A healthy ASX file prints b'<ASX ' or b'<asx ' first. Anything else at the start means the file is not a Windows Media playlist.

5 What Does Our Expert Say About ASX Files? A note from Neeraj Singh on why they fail to play

Expert insight

“An ASX file is a short note, not a video. That is why it so rarely breaks and so often fails to play. In our four public samples, every file was under 1.4 KB, and ffprobe could not read any of them as media. When one will not play, I open it in Notepad before I test a player. I copy the address inside it and try that address alone. If the address is dead, no player can fix it.”

Neeraj Singh Manager, Tech Support & Operations · 19+ years fixing Windows and system errors

What an old address looks like

The Tika sample is a good example. Its title names a council video from April 2009, and its address starts with mms://. Microsoft deprecated that protocol in 2003 and dropped it from Windows Media Services 2008, according to the Wikipedia entry on Microsoft Media Server.

We could not test whether that address still answers, because a normal web fetch cannot reach an mms:// address. So we do not say it is dead. The point is the age. An ASX file keeps its address long after the stream may have moved.

Frequently Asked Questions About ASX Files