Free online ASX to M3U8 converter

Some current players and HLS-based systems do not accept Windows Media playlist files, so an older ASX link list may need to be rewritten as M3U8 for playback or archiving. This usually changes playlist syntax only; it does not convert the referenced audio or video.

What the ASX format is

ASX, or Advanced Stream Redirector, is an XML-based playlist format associated with Windows Media Player and Windows Media Services. It stores references to media in elements such as <ref href="..." />, with optional titles, authors, durations, and other playback metadata.

ASX files were used by older broadcasters, intranet portals, Windows Media applications, and archived media systems. They commonly reference .asf or .wmv files and streaming URLs; the ASX file normally contains pointers rather than the media itself.

What the M3U8 format is

M3U8 is a UTF-8 encoded form of the M3U playlist format. It can be a simple UTF-8 list of media paths or URLs beginning with #EXTM3U, which many modern players can read.

M3U8 is also the playlist format used by HTTP Live Streaming (HLS). An HLS master playlist references variant playlists, while a media playlist references segments such as .ts or fragmented .m4s files. A file renamed with the .m3u8 extension is not automatically an HLS stream: the referenced resource must already be an HLS playlist or the file must contain valid HLS tags and segment references.

How to convert an ASX file to M3U8

First open the ASX file in a text editor and inspect its href attributes. If a reference already points to an HLS playlist ending in .m3u8, you can place that URL in a new M3U8 file. If it points to an MMS, RTSP, Windows Media, or obsolete HTTP stream, changing the playlist extension will not make the source compatible with HLS.

For a conversion without installing software, use the free converter on 101convert.com. Upload the ASX file, select M3U8 as the output format, and download the generated playlist. Open the result in a text editor and test each reference; rewriting XML references cannot restore an offline source or change an incompatible streaming protocol.

For local conversion, extract the ASX references and write them to an UTF-8 M3U8 file. This Python script handles XML namespaces and preserves the URLs without decoding or re-encoding the media:

import sys
import xml.etree.ElementTree as ET
from urllib.parse import urljoin

source, destination = sys.argv[1], sys.argv[2]
tree = ET.parse(source)
root = tree.getroot()
base_url = sys.argv[3] if len(sys.argv) > 3 else ""
urls = []

for element in root.iter():
    name = element.tag.rsplit("}", 1)[-1].lower()
    if name == "base":
        base_url = element.attrib.get("href", element.attrib.get("HREF", base_url))
    elif name == "ref":
        href = element.attrib.get("href", element.attrib.get("HREF"))
        if href:
            urls.append(urljoin(base_url, href) if base_url else href)

with open(destination, "w", encoding="utf-8", newline="\n") as output:
    output.write("#EXTM3U\n")
    output.write("\n".join(urls))
    if urls:
        output.write("\n")

Save the code as asx_to_m3u8.py and run python asx_to_m3u8.py input.asx output.m3u8. If the ASX contains relative web paths, supply the correct base URL as a third argument, for example python asx_to_m3u8.py input.asx output.m3u8 https://example.com/media/. For local Windows paths, replace the extracted references with paths or URLs accessible to the target player; URL resolution does not automatically convert filesystem paths into web URLs.

When a real HLS conversion is required

If the destination application specifically requires HLS rather than a generic M3U8 list, create an HLS package from a playable media source with FFmpeg:

ffmpeg -i input.wmv -c:v libx264 -c:a aac -f hls -hls_time 6 -hls_playlist_type vod output.m3u8

This command decodes and re-encodes the source, writes output.m3u8, and creates HLS segments beside it. Re-encoding can reduce quality and requires enough processing time and storage. Stream copying may be possible with -c copy when the existing codecs and container are valid for the intended HLS output, but it is not suitable for every WMV or ASF source.

Quality and compatibility limits

• Extracting references into M3U8 causes no media quality loss because the audio and video are not processed.
• ASX titles and authors are not automatically retained in a URL-only M3U8 file. Add #EXTINF entries manually if the target player uses playlist metadata.
• Old MMS, RTSP, and Windows Media URLs may work only in legacy software or on the original network. Modern browsers and HLS players generally cannot open them.
• A valid HLS playlist normally includes tags such as #EXT-X-TARGETDURATION and references playable media segments or variant playlists; #EXTM3U alone is insufficient.
• For network playback, the playlist and every referenced segment must be reachable. HLS delivery may also require HTTPS, correct MIME types, and server-side CORS permissions.