Provide text equivalents for audio - in Windows Media Player

Why this is important

Providing captions enables media that contains spoken or other audio information important to understanding the media's content (on- or off-screen sound effects, or background music) to be accessible to anyone who has difficulty hearing, or is unable to hear, the media soundtrack. Any content intended for playing in Windows Media Player must as a result offer captions to be optimally accessible for these people.

General Principles

Providing captions for a movie to be played in a standalone Windows Media Player involves creating a SAMI caption file and combining it with the media file into an ASX (or WVX or WAX) file. If the captioned media file is to be embedded within a web page, then the SAMI file can be automatically added to the media file without the need for an ASX file. Alternatively, HTML+TIME could be used for embedded media if you can guarantee that your audience will be using Internet Explorer version 5.5 or more recent.

NB: We have provided general advice on captioning in a separate How To: Provide text equivalents for audio - general advice on captions.

Before you continue

The advice on this page helps you avoid introducing a specific accessibility barrier, but it's not a magic formula. To avoid attempting to follow a technical solution that is not appropriate to the resource and its intended purpose, you need to know the context in which the multimedia resource is being used:

  1. The purpose or aim of the multimedia resource in question, and whether it is being used to supplement another resource in the learning environment, or whether its use is required by students.
  2. The target audience, their knowledge and expectations, and the type of browsing and assistive technology that they may be using.
  3. Whether the information and experiences provided by the multimedia technology are already available in an equivalent, alternative form.

For more background on this approach, see our Guide to the use of multimedia in accessible e-learning.

Technique Details

The procedure of creating and making available a captioned Windows Media Player video file (for example an AVI, ASF, MPEG or WAV file) is as follows:

Step 1: Create a SAMI caption file, either using a text editor or a caption authoring program such as MAGpie or HiCaption. The SAMI file contains caption text, timestamp detail, plus formatting information. SAMI supports Cascading Style Sheets as a way of formatting text appearance.

To obtain timestamp detail, you must play the video, pausing and noting the time at which each caption will appear. If you have a transcript file already, the time taken and effort required to create captions is reduced, as you can then focus on splitting the transcript text into appropriate captions, and applying a timestamp to each; if you don't have a transcript you'll have to create this first by playing the video and writing down spoken and non-spoken sound information. Example 1 is a code sample from a SAMI file:

<BODY>

<SYNC Start="0">
  <P ID="Source" Class="Captions">&nbsp;</P>
  <P Class="Captions"><span style="font-family: Verdana;">
    <span style="font-size: 14pt;"><span style="color:#FFFFFF;">
    <span style="background:#000000;"><b>"Access for All" came about 
    <br/>because obviously DDA</b></span></span></span></span></P>
</SYNC>

<SYNC Start="3570">
  <P ID="Source" Class="Captions">&nbsp;</P>
  <P class="Captions"><span style="font-family: Verdana;">
    <span style="font-size:14pt;"><span style="color:#FFFFFF;">
    <span style="background:#000000;"><b>and SENDA were both 
    <br/>introduced and that</b></span></span></span></span></P>
</SYNC>

</BODY>

Example 1: Code sample from SAMI file.

Step 2: Create an ASX file which contains references to both the media file and the SAMI caption file. ASX files can be created in a text editor or using an authoring tool such as MAGpie. ASX files can also contain meta-information about the media file, including author name, title and an abstract of its content.

Example 2 shows code of the ASX file used to combine the SAMI file shown in Example 1 with a Windows Media video clip.

TO ADD!

Example 2: Code of ASX file.

Step 3: Make your captioned Windows Media Player movie available online. For content to be played in a standalone player (the most accessible means of delivery), all that is needed is to provide a link in HTML to the ASX file created in the previous step, using a standard a element.

Clip 1 is an example of a captioned Windows Media video clip, which uses the SAMI and ASX files shown in Examples 1 and 2:

Clip 1: Captioned Windows Media Video

Length : 1 Min 22 Sec

Photograph of interviewee - Ross Little

Watch the Interview
Transcript

For embedded Windows Media Player content, use the object and embed HTML elements, the non-standard embed element being enclosed within the object element. This code provides references to the ASX file; and also specifies which media player controls should be displayed, plus the dimensions of the player window.

While we've given an outline of the process of creating a captioned Windows Media Player movie, the process of creating and providing captioned Windows Media Player content does seem to be fraught with inconsistencies and quirks arising from the way different versions of the player behave. We recommend you use WebAIM's tutorial on Windows Media Player, for a detailed step-by-step process, plus a discussion of the issues surrounding provision of captioned Windows Media Player video.

Testing

To check that your captions are displayed and synchronised appropriately, view the captioned media in as many versions of Windows Media Player as you can. It seems that captions will not automatically show in the standalone version of Windows Media Player - you must actively turn them on. The method of turning on captions varies significantly from version to version of Windows Media Player.

  • Windows Media Player 9 or 10: open the 'Play' menu, choose 'Captions and Subtitles', and select 'On if Available'. If this does not display captions, try opening the 'Tools' menu, selecting 'Options', then the 'Security' tab, and select the 'Show local captions when present' check box. The keyboard shortcut CTRL+Shift+C also toggles captions on or off:

  • Windows Media Player 8: Open the View menu, choose 'Now Playing Tools' and then select 'Captions'.

You should watch the captions while playing the media file with sound on - so that you can detect any clear inaccuracies, missing content or problems with synchronisation. It would also be worthwhile obtaining feedback from end users, particularly people who are deaf or hard of hearing - although they, of course will be unlikely to know whether the captions are a true reflection of the audio content of the media clip.

Related Sites

Captioning for Windows Media (WebAIM)
A detailed tutorial on providing captions for Windows Media Player, including how to create a SAMI file, associate it with a Windows Media clip, and publish the cpationed clip to the web.
Captioning Internet Music Files using SAMI (Caption Central)
Information about SAMI and using SAMI to create captions for Windows Media Player.
Creating Captions for Rich Media (NCAM)
NCAM's tutorial on captoning includes specific advice on captioning for Windows Media Player using SAMI.
Windows Media and SAMI (NCAM)
A list of resources providing information, tutorials and examples on captioning for Windows Media Player.
Windows Media Captioning (Centre for Instructional Technology Accessibility)
A detailed tutorial on creating SAMI caption files, and using them to caption Windows Media clips.

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