Audio and Video

Accessibility Techniques for Audio and Video
Topic	Technique	WCAG AA Requirement
Prerecorded Audio-Only	Transcript: Prerecorded audio-only content MUST have a transcript of dialog, narration, and other meaningful sounds. Testing methodology 1.2.1.a	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. Testing methodology 2.2.2.a	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. Testing methodology 1.4.2.a	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 content MUST include a text description. This may be in regular text (e.g. in a paragraph), and it can be short or long, depending on the nature of the video. Testing methodology 1.2.1.a	Required WCAG 1.2.1
	Audio Description: Prerecorded video-only content MUST include an audio description (narrated description) of important visual content. Testing methodology 1.2.5.a	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. Testing methodology 2.2.2.a	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. Testing methodology 2.3.1.a	Required WCAG 2.3.1
Prerecorded Multimedia	Alternative Text: Prerecorded multimedia content SHOULD include a text description of important visual content that is not conveyed through the audio (this can be included in the transcript). Testing methodology 1.2.1.b	Best Practice
	Transcript: Prerecorded multimedia content SHOULD have a text transcript of dialog, narration, and other meaningful sounds. Testing methodology 1.2.1.a	Best Practice
	Captions: Prerecorded multimedia content MUST have synchronized captions. Testing methodology 1.2.2.a	Required WCAG 1.2.2
	Audio Description: Prerecorded multimedia content MUST include an audio description (narrated description) of important visual content. Testing methodology 1.2.5.a	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. Testing methodology 2.2.2.a	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. Testing methodology 1.4.2.a	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. Testing methodology 2.3.1.a	Required WCAG 2.3.1
	Sign Language: Prerecorded multimedia 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. Testing methodology 1.4.2.a	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. Testing methodology 2.2.2.a	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 (and Video-Like Animations)	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. Testing methodology 2.2.2.a	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. Testing methodology 2.3.1.a	Required WCAG 2.3.1
	Alternative Text: Live video-only content MUST include a text description. This may be in regular text (e.g. in a paragraph), and it can be short or long, depending on the nature of the video. Testing methodology 1.2.1.a	Required WCAG 1.2.1
	Audio Description: Live video-only content SHOULD include an audio description (narrated description) of important visual content.	Best Practice
Live Multimedia	Captions: Live multimedia content MUST have synchronized captions. Testing methodology 1.2.4.a	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. Testing methodology 1.4.2.a	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. Testing methodology 2.2.2.a	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. Testing methodology 2.3.1.a	Required WCAG 2.3.1
	Audio Description: Live multimedia content SHOULD include an audio description (narrated 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. Testing methodology 1.4.2.a	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. Testing methodology 2.2.2.a	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. Testing methodology 2.2.2.a	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. Testing methodology 2.3.1.a	Required WCAG 2.3.1
	See the requirements for color contrast (for text and UI elements overlayed on top of video). Testing methodology 1.4.3.a Testing methodology 1.4.3.b	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: Media player keyboard accessibility Media player screen reader accessibility Captions, transcripts, audio descriptions within the media player User customization options within the media player See also the requirements for Form Inputs, Labels, and Instructions See also the requirements for Custom Widgets (JavaScript)	Required Multiple