Animation, Motion, and Timed Content
Topic
Technique
WCAG AA Requirement
Prerecorded Audio-Only
Captions: Prerecorded video-only content MUST have synchronized captions.
Transcript: All prerecorded audio MUST have a transcript of dialog, narration, and other meaningful sounds.
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.
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.
Sign Language: Prerecorded audio-only content MAY include sign language interpretation.
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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.
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Prerecorded Video-Only (and video-like animations)
Alternative Text: Prerecorded video-only MUST include a text description.
Captions: Prerecorded video-only content MUST have synchronized captions.
Audio Description: Prerecorded video-only content MUST include an audio description (narrated video description) of important visual content.
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.
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.
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).
Transcript: Prerecorded video-only MUST have a text transcript of dialog, narration, and other meaningful sounds.
Captions: Prerecorded video-only content MUST have synchronized captions.
Audio Description: Prerecorded video-only content MUST include an audio description (narrated video description) of important visual content.
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.
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.
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.
Sign Language: Prerecorded video-only content MAY include sign language interpretation.
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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.
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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.
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.
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.
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Captions: Live audio-only content SHOULD have synchronized captions.
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Live Video-Only
Captions: Live video-only content MUST have synchronized captions.
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.
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.
Alternative Text: Live video-only MUST include a text description.
Audio Description: Live video-only content SHOULD include an audio description (narrated video description) of important visual content.
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Live Multimedia
Captions: Live multimedia content MUST have synchronized captions.
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.
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.
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.
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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.
Audio Description: Live multimedia content SHOULD include an audio description (narrated video description) of important visual content.
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Page Background Sounds
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.
If Informative: If the background sounds contain informative content, all of the requirements for prerecorded audio-only content apply (see above).
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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.
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.
See the requirements for color contrast (for text and UI elements overlayed on top of video).
If Informative: If the background video contains informative content, all of the requirements for prerecorded video-only content apply (see above).
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Media Players
Media players themselves MUST be fully accessible (in particular to keyboard users and screen reader users). See the requirements for:
Required Multiple
Flashing
Flashing: 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.
Parallax Effects (backgrounds or foregrounds that move separately from each other)
Keyboard-Accessible: All content and features within parallax scrolling content MUST be accessible by keyboard.
Text Color Contrast: The contrast of the text against all parts of a moving background MUST be a minimum of 4.5 to 1 for small text or 3 to 1 for large or bold text.
UI Component Color Contrast: The contrast of UI control boundaries compared to adjacent areas SHOULD be 3 to 1 to distinguish the UI control from the adjacent areas.
User Control of Timing
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.
Time Limits: A method MUST be provided to allow users to control time limits by turning them off, adjusting them, or extending them (unless the timing is essential or if the time limit is longer than 20 hours).
Replay Option: A method SHOULD be provided to allow users to replay timed content that is finished or expired (unless replaying the content fundamentally alters its purpose or meaning).
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