Multimedia presentations can be inaccessible to people who are unable to hear their audio content and to people who are unable to see critical information that is presented visually. 

• For those with hearing impairment the alternative you provide is a transcript.
• For those who are unable to see all information the alternative you provide is an audio description.
• Additionally, for an audiovisual presentation, a transcript or an audio visual description does not provide an equivalent experience, because the presentation's message is dependent on the simultaneous interaction between its audio and video portions. For this reason, a text alternative and audio description should be synchronized with the multimedia presentation.

Below is a guide for when you should use transcripts, audio descriptions, and more helpful information. 

Media alternative definitions

Audio Description

To be used for video-only and non-live multimedia content.

If a video in question requires Audio Descriptions (if visual information in the video is important to understanding the message of the video), they must be provided as either an alternative audio track or it can be a different, modified version of the original video.  If a different video is created specifically for the purposes of audio descriptions, it should at least be linked next to the regular version of the video. 

Transcript

To be used for audio-only (and non-live multimedia as an option) multimedia content. A text-format transcript must be provided. It can either be below the video or externally linked near the video.  

Transcripts MUST abide by the following guidelines:

• All scripted content must be transcribed verbatim.
• Important background sounds must be conveyed (ideally in brackets or parentheses)
• The identity of the speaker must be included in transcripts.

Captions

To be used for all multimedia (live and non-live). Captions must be included on all multimedia.  

Captions MUST abide by the following guidelines:

• All scripted content must be captioned verbatim.
• Important background sounds must be conveyed (ideally in brackets or parentheses)
• Any speech that is spoken off-screen must be captioned (italics is best practice for this scenario)
• The identity of the speaker must be included in captions.
• Captions must be timed appropriately with the audio.

Type of media format and alternative

Video-only media (non-live)

Video-only media is any non-decorative only video content that has no audio or no audio that is relevant to the content.  The following media alternative is required:

• Audio Description

Audio-only media (non-live)

Audio only media includes podcasts, conference recordings, and pre-recorded radio broadcasts. This includes externally hosted audio-only content on a video streaming service like YouTube (where any visual content is not relevant to the audio content; i.e. a Cornell logo is displayed for the entire video). They must be accompanied by the following media alternative:

• Transcript

Non-live Multimedia (audio + video)

Video content that contains audio, requires the following media alternatives:

• Captions
• Audio Description (read below)
• Transcript ifAudio Description is not required

Live Multimedia functionality (audio + video), Live audio-only

Live multimedia (such as a stream), requires the following media alternative:

• Captions

Note: If an on-demand version of this live multimedia is made, it must then obey the rules for non-live Multimedia.

Live video-only

If streaming live video (such as a livestream of the Cornell Campus without audio) there are no additional media alternatives obligations.

Multimedia accessibility decision matrix for A* and AA* 

*In the matrix table above, A, AA refer to the Web Content Accessibility Guidelines (WCAG) compliance levels.

** When producing a video for the web, the need for audio descriptions can often be avoided. If the video were displaying a list of five important items, the narrator might say, "As you can see, there are five important points." In this case, audio descriptions would be necessary to provide the visual content to those with visual disabilities who cannot 'see' what the important points are. However, if the narrator says, "There are five important points. They are..." and then reads or describes each of the points, then the visual content is being conveyed through audio and there is no additional need for audio descriptions.

Helpful links for media alternatives

• Web Content Accessibility Guidelines WCAG:
  • List of relevant WCAG guideline, success criteria, and techniques in How to Meet WCAG, "Time-based Media: Guideline 1.2"
  • Detailed Understanding WCAG, Time-based Media: Understanding Guideline 1.2- follow the appropriate "Success Criteria for this Guideline" link
• Transcripts on the Web: Getting People to your Podcast and Videos includes the benefits of transcripts, how to get or make transcripts, and best practices for transcripts.
• Guidance on adding captions and descriptions to different forms of multimedia
• Effective Practices for Description of Science Content within Digital Talking Books
• Deafness and the User Experience (explains that written/spoken language is a second language for people who are Deaf)
• WebAIM Captions