Ensure the video is labeled, the user can control playback, and there are alternatives for users who cannot see or hear the video or who need more time to process the information.
Include a label that describes the video. [WCAG 1.1.1 - A]
videoelement's native controls by default. [WCAG 2.1.1 - A]
Include captions for audio content. [WCAG 1.2.2 - A]
Include a transcript or audio alternative for video with no audio. [WCAG 1.2.1 - A]
Ensure users can disable any audio that starts automatically or turn off its volume. [WCAG 1.4.2 - A]
When including video clips, ensure that the native user agent controls are enabled by default (i.e.,
by setting the
controls attribute on the
video element). This practice
ensures that the controls are accessible even if scripting is not available. If you define your own
that do not support scripting.
Providing a label for videos ensures that users can understand the purpose of the video before choosing whether to view it. The poster image that authors can specify to provide a snapshot of the video for visual readers, for example, is not available to users who are blind. The label is the only means of understanding the content without downloading it for these users. For users on mobile devices, especially with high bandwidth costs, this information can save them both time and money.
In terms of providing alternatives, WCAG requires multiple options for video content to address the needs of different user groups:
- Transcripts and/or audio description tracks for users who are blind or have low vision.
- Captions for users who cannot hear the video.
WCAG refers to transcripts as "media alternatives" because they cannot be a simple listing of the spoken dialogue. The transcripts must include descriptions of the actions and any other important events in the video.
Progressing from level A to AA also increases the requirement. Transcripts are not sufficient to for video with audio at level AA, for example, only an audio description track is sufficient.
video element allows child content for fallback purposes, such content is
not intended to serve as an accessible alternative. The user agent only makes this content
available to the user if it does not support the
video element (e.g., in EPUB 2 user
It is also important to consider that users need to be able to hear the audio produced by their assistive technologies (e.g., a screen reader). Automatically playing a video with audio interferes with their ability to hear the text, for example, so unless the clip only plays for three seconds or less, the user must be able to disable playback or mute the volume without also muting their assistive technology (i.e., the system audio control is not sufficient to meet this requirement as it will raise and lower all audio in synchronicity).