If you use audio files, a text transcript should be provided. See Section 508 regulations below for details.
It may be better to use an A tag than an EMBED tag to link to a file. Not all browsers can detect an implement an EMBED tag.
If video files are used, a synchronized text transcript or captions should be provided unless it is not technically feasible. In that case, a text transcript with description of video events can be substituted.
(a) A text equivalent for every non-text element shall be provided.
(b) Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.
(k) A text-only page, with equivalent information or functionality, shall be provided to make a web site comply with the provisions of these standards, when compliance cannot be accomplished in any other way. The content of the text-only page shall be updated whenever the primary page changes.
NOTE: Transcripts are also beneficial for users who may not be able to access audio on their computers. This is a very frequent situation.
The following interview with Director of Education Technology Services, Cole Camplese is captioned. You can access captions by clicking the arrow button on the lower right of the screen
Another Good Example - FMC
iMovie Tutorial
This is accessible because text is reproduced under each video clip.
Popular media editors such as Quicktime Pro, Flash Video (including YouTube), Real Player and Windows
Media include captioning options. In many cases captions are stored in an external text file which can be easily edited.
Note: It is recommended that you do a Google search to determine the latest options.
If you have a script for an audio or video production, this can be the basis for a text transcript. Otherwise you may need to manually transcribe the text.
Avoid automatically playing an audio or video file on a Web page. It can be potentially distracting for different users and could interfere with users who rely on speech recognition software to navigate the Web.
Visually impaired users may need additional information about images in a video.