Audio and Video

Accessibility Techniques for Audio and Video
Topic Technique WCAG AA Requirement
Prerecorded Audio-Only Captions: Prerecorded video-only content MUST have synchronized captions. Required
WCAG 1.2.2
Transcript: All prerecorded audio MUST have a transcript of dialog, narration, and other meaningful sounds. Required
WCAG 1.2.1
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Audio Control: A mechanism MUST be provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds. Required
WCAG 1.4.2
Sign Language: Prerecorded audio-only content MAY include sign language interpretation. best practice
Background Sounds: Background sounds in prerecorded audio-only content SHOULD be minimized (20dB lower than foreground sounds, except for occasional sounds of no more than 2 seconds) or eliminated during narration or dialog, or a method must be available to turn off background sounds. best practice
Prerecorded Video-Only (and video-like animations) Alternative Text: Prerecorded video-only MUST include a text description. Required
WCAG 1.2.1
Captions: Prerecorded video-only content MUST have synchronized captions. Required
WCAG 1.2.2
Audio Description: Prerecorded video-only content MUST include an audio description (narrated video description) of important visual content. Required
WCAG 1.2.5
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Flashing Content: A page MUST NOT contain content that flashes more than 3 times per second unless that flashing content is sufficiently small, the flashes are of low contrast, and do not violate general flash thresholds. Required
WCAG 2.3.1
Prerecorded Multimedia Alternative Text: Prerecorded video-only MUST include a text description of important visual content that is not conveyed through the audio (this can be included in the transcript). Required
WCAG 1.2.1
Transcript: Prerecorded video-only MUST have a text transcript of dialog, narration, and other meaningful sounds. Required
WCAG 1.2.1
Captions: Prerecorded video-only content MUST have synchronized captions. Required
WCAG 1.2.2
Audio Description: Prerecorded video-only content MUST include an audio description (narrated video description) of important visual content. Required
WCAG 1.2.5
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Audio Control: A mechanism MUST be provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds. Required
WCAG 1.4.2
Flashing Content: A page MUST NOT contain content that flashes more than 3 times per second unless that flashing content is sufficiently small, the flashes are of low contrast, and do not violate general flash thresholds. Required
WCAG 2.3.1
Sign Language: Prerecorded video-only content MAY include sign language interpretation. best practice
Background Sounds: Background sounds in prerecorded audio-only and prerecorded multimedia content SHOULD be minimized (20dB lower than foreground sounds, except for occasional sounds of no more than 2 seconds) or eliminated during narration or dialog, or a method must be available to turn off background sounds. best practice
Live Audio-Only Audio Control: A mechanism MUST be provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds. Required
WCAG 1.4.2
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Background Sounds: Background sounds in live audio-only content SHOULD be minimized (20dB lower than foreground sounds, except for occasional sounds of no more than 2 seconds) or eliminated during narration or dialog, or a method must be available to turn off background sounds. best practice
Captions: Live audio-only content SHOULD have synchronized captions. best practice
Live Video-Only Captions: Live video-only content MUST have synchronized captions. Required
WCAG 1.2.4
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Flashing Content: Live video-only content MUST NOT contain content that flashes more than 3 times per second unless that flashing content is sufficiently small, the flashes are of low contrast, and do not violate general flash thresholds. Required
WCAG 2.3.1
Alternative Text: Live video-only MUST include a text description. Required
WCAG 1.2.1
Audio Description: Live video-only content SHOULD include an audio description (narrated video description) of important visual content. best practice
Live Multimedia Captions: Live multimedia content MUST have synchronized captions. Required
WCAG 1.2.4
Audio Control: A mechanism MUST be provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds. Required
WCAG 1.4.2
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Background Sounds: Background sounds in live multimedia content SHOULD be minimized (20dB lower than foreground sounds, except for occasional sounds of no more than 2 seconds) or eliminated during narration or dialog, or a method must be available to turn off background sounds. best practice
Flashing Content: A page MUST NOT contain content that flashes more than 3 times per second unless that flashing content is sufficiently small, the flashes are of low contrast, and do not violate general flash thresholds. Required
WCAG 2.3.1
Audio Description: Live multimedia content SHOULD include an audio description (narrated video description) of important visual content. best practice
Page Background Sounds Audio Control: A mechanism MUST be provided to stop, pause, mute, or adjust volume for audio that automatically plays on a page for more than 3 seconds. Required
WCAG 1.4.2
Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
If Informative: If the background sounds contain informative content, all of the requirements for prerecorded audio-only content apply (see above). depends
Page Background Video Autoplay: A method MUST be provided to pause, stop, or hide any media content that begins playing automatically and which lasts 5 seconds or more. Required
WCAG 2.2.2
Flashing Content: A page MUST NOT contain content that flashes more than 3 times per second unless that flashing content is sufficiently small, the flashes are of low contrast, and do not violate general flash thresholds. Required
WCAG 2.3.1
See the requirements for color contrast (for text and UI elements overlayed on top of video). Required
WCAG 1.4.3
If Informative: If the background video contains informative content, all of the requirements for prerecorded video-only content apply (see above). depends
Media Players

Media players themselves MUST be fully accessible (in particular to keyboard users and screen reader users). See the requirements for:

Required
Multiple