Types of Alternate Media
| Alternative Media | File Formats | Details | Use |
|---|---|---|---|
| Descriptive Transcripts. Text version of the audio track and descriptions of essential visual content. | Web page / HTML is the most accessible option. Accessible text file, Word document, or PDF. | Includes dialog, names of speakers, and essential sounds. Can be displayed on the same page as the video or as a link to a webpage or document. | Pre-recorded audio or video. |
| Open Captions. Text overlay in the video. | The text is permanently embedded in the video. | Includes dialog, names of speakers, and essential sounds. Can’t be turned on or off. Can’t be edited. | Pre-recorded video. |
| Closed Captions. Text overlay in the video or displayed in a separate window. | SRT or WebVTT files. Must use a video player that supports captioning files. | Includes dialog, names of speakers, and essential sounds. Can be turned on or off in the player. Can be edited. | Pre-recorded audio or video. |
| Live Captions. Text overlay in the video or displayed in a separate window. | CART. Must use a video player that supports live captioning. | Includes dialog, names of speakers, and essential sounds. A captioner transcribes captions in real time. | Live audio or video stream. |
| Audio Descriptions (Open). Voiceover that briefly describes visual content. | The description voiceover is included in the main audio track. | Includes descriptions of essential visuals. The video length is not modified to accommodate audio descriptions. Can be turned on or off in the player. Can be edited. | Pre-recorded video. |
| Audio Descriptions (Closed). Voiceover that briefly describes visual content. | WebVTT file or a second audio track. | Must use a video player that supports WebVTT or additional audio tracks. Some players support turning audio descriptions on or off. Video length is not modified to accommodate audio descriptions. | Pre-recorded video. |
| Extended Audio Descriptions. Voiceover with detailed descriptions of all visual content. | Voiceover included in the main audio track of a video. | Extended audio is often produced as a second video with pauses when the description plays. | Pre-recorded video. |
Accessible Alternatives for Video
| Media | Accessible Alternative | WCAG 2.x, Level AA Compliance |
|---|---|---|
| Pre-recorded Video with no Audio. | Descriptive transcript and audio descriptions. | Audio descriptions. |
| Pre-recorded Video with Audio. | Captions and descriptive transcript. Include audio descriptions or extended audio descriptions if needed. | Captions. Audio Descriptions if needed. |
| Live Video. | CART captions. Include audio descriptions if needed. | Captions. |
Accessible Alternatives for Audio
| Media | Accessible Alternatives | WCAG 2.x, Level AA |
|---|---|---|
| Audio Only Pre-recorded. | Descriptive transcript | Descriptive transcript. |
| Audio Only Live. | CART captioning | No level AA requirement. |