The 508 Compliance Resource Team Notes:
In order to make a video file 508 compliant, there are certain areas that must be addressed. There are visual aspects of the video that must be addressed, as well as captioning.
There are 2 types of captions: open captioning and closed captioning. Open captions means the captions are always are in view and cannot be turned off, whereas closed captions can be turned on and off by the viewer. Many popular media players such as Quicktime Pro, Flash Video (including YouTube), Real Player and Windows Media include caption embedding options. In other cases, captions are stored in an external text file, and can pass caption information to a player alongside of a video.
It is important to note that subtitles are different from captions. Subtitles are an internationalization feature, which means their purpose is to make the video available to people who don't understand the spoken language. In other words, you would use captions to watch a video on mute, and you would use subtitles to watch a video in a language that you don't understand. (Note that this terminological distinction holds true in North America, but much of the world does not distinguish between closed captions and subtitles.)
Video captions differ from audio transcripts and usually contain more detailed information than simply a text version of the video's script. For example, comments like "Fred enters the room with a fearful look on his face" are interspersed between the normal, standard audio segments, if and where possible.
You need to also keep in mind that if you are hosting the video on your own website, you need to ensure that the video player itself is 508 compliant. Specific areas of the player must be able to be read by screen readers, such as the play, pause, rewind buttons and volume controls.
For video that is displayed on television sets, special devices called decoders must be available in order to view closed captions. Since 1993, decoders have been required to be built into television sets 13 inches or larger sold for use in the United States.
- Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation (such as captions)
- Any visual information, such as action or expressions, in the video that is necessary to understand the production's content, must be described in an audio file, which also must be synchronized with the video. This can be accomplished within captioning software.
- Videos should not contain flashing, strobing, or flickering elements, as they can cause some people to experience seizures, dizziness, nausea and be distracting for some users with cognitive disabilities.