Introduction: Audio, video, animation and motion

Four methods

Audio and video accessibility draws on four methods:

Captions: Captions are a text version of the speech and other audio information needed to understand the content. They are synchronized with the audio and usually shown in a media player when users turn them on. Captions benefit users who are deaf, users who are hard of hearing and users who have difficulty processing auditory information.
Transcripts: Basic transcripts are a text version of the speech and non-speech audio information needed to understand the content. “Descriptive transcripts” also include text description of the visual information needed to understand the content. Basic transcripts benefit users who are deaf and users who have difficulty processing auditory information. Descriptive transcripts benefit users who are deaf-blind and users who cannot focus on and comprehend auditory or visual information when there are changing visuals.
Description of visual information: An audio track or descriptive transcript describes the visual information needed to understand video content, (text displayed in the video, facial expressions, actions, etc.). Description benefits users who are blind and others who cannot see the video adequately.
Sign language: Sign languages use hand and arm movements, facial expressions, and body positions to convey meaning. They benefit users who are deaf. Some people who are deaf prefer sign language to text.

ESDC has a team, Creative Services, that offers these services.

Beyond the four methods, there are these additional concerns for audio and video:

Prevent seizures: Ensuring there are no flashing visual effects in videos can prevent seizures in some users.
Prevent dizziness: Removing excessive motion in video or animated content avoids making users with vestibular disorders dizzy, nauseous or disoriented.
Prevent auto-play audio interference with screen readers: Preventing media players from auto-playing avoids chaos for screen reader users. The sound competes with the screen reader’s audio, making it difficult to locate and stop the media player.
Use an accessible media player: Choose a media player that’s keyboard accessible and that communicates the name, role and value(s) of each control.