skip navigation

Docsoft, Incorporated

ASX Captions : How-to

Author: John Miller, Docsoft Inc.
Created: 7.14.2009

The file extension ".asx" stands for Active Stream Redirector for Microsoft’s Media Player. This is one of the files for playing closed captions. We will review a simple example of the .asx file and how to set up your Windows Media Player to show captions. The files used for this example are:

  1. .asx (linking file)
  2. .wmv (video file)
  3. .smi (captions file)

The ASX file:

An ASX file allows you to reference two separate files for play by Windows Media Player. Here’s what it looks like:
<asx version="3.0">
    <ref href="http://server/MyVideo.wmv?SAMI=http://server/MyCaptions.wmv.smi" />

The file path in blue is your video while the file path in red shows your .smi (aka SAMI) file.

The Video File:

Make sure that you can play your video file prior to adding captions. If you have problems viewing the video, a program called a "codec" could be needed to correctly play the video. If your video plays, we are on the right path.

The .smi or SAMI file:

The SAMI file is actually html that allows for formatting of text and timing/display information.

Putting it all together:

Windows Media Player now needs to be set up to allow local captions to play. Here are the steps to set this up.

Allow Local Captions:

  1. If you have a menu in Windows Media Player, click "Tools". If not, right-click then left click "Tools"
  2. Click on the "Security" tab at the top.
  3. We need to check the checkbox that says, "Show local captions when present"
  4. Click "OK"

Turn on Captions:

  1. If you have a menu in Windows Media Player, click "Play." If not, right-click then left-click "Play"
  2. Next select "Lyrics, Captions, and Subtitles"
  3. Then, click "Captions" to play them.

Now click your .asx file and, if the paths to your files are correct, the subtitles should play at the bottom of your movie.

Creating a link on your website:

If you would like to play this file from your website in a stand-alone player, create a webpage and place an anchor tag pointing to the .asx file as shown below:

<a href="http://localhost/myASX.asx">Click here to show your video</a>