There are generally recognized recommendations to guide the inclusion of accessible multimedia content in a variety of ways and various situations. In this case, the term multimedia refers to a variety of ways, or media, used to communicate information, such as videos, audio, animations, charts and graphs, and slideshows.
The best way to address accessibility in multimedia is to consider what your audience would get out of your multimedia resource if they were not able to hear the audio portion, or if they had difficulty understanding the spoken word.
Before determining what must happen to make media accessible, you must understand what is required for different types of multimedia. If the multimedia resource includes audio narration or instructions, then a complete transcript of all speech content and relevant non-speech content in the resource should be provided. If it includes audio that is synchronized with a video presentation then captioning should accompany all speech content and relevant non-speech content in the resource. If the data includes contextual visuals such as charts and graphs, audio descriptions of the relevant material should be provided.
These accessibility resources support people who are deaf or hard of hearing, are blind or have low vision and others who might have various forms of cognitive disability. In addition, for those who are not disabled, accessibility features can assist where someone is in a location where they cannot play or hear audio, or possibly they are not native-English speakers and need written-word formats to support understanding. Accessibility for all means just that.
Audio descriptions are very useful for relaying information from many different formats.
They can be very helpful if visual content (e.g., a chart or map) in a video or presentation provides important context that is not available through the audio alone. In addition, many types of multimedia present information in a non-text manner. For individuals who are unable to use the original version, providing text as a transcript, caption, or written description gives everyone access.
A good text transcript provides equivalent information to the audio content in a multimedia resource. There are certain guidelines to employ in order to make sure that it is truly accessible. They include:
All speech content.
Relevant descriptions about the speech, including vocabulary that conveys emotions and mood.
Descriptions of relevant non-speech audio, such as background noises.
Headings and subheadings can be used to great effect when they make a transcript more usable or easy to navigate, especially when the transcript is long.
Captions are text that is synchronized with the audio in a video presentation. Captions should be used when people need to see what’s happening in the video and get the audio information in text at the same time.
The Web Content Accessibility Guidelines (WCAG) has lots of good information about what to do and what not to do when creating accessible content.