- From: Jim Allan <jimallan@tsbvi.edu>
- Date: Wed, 9 Mar 2011 17:33:44 -0600
- To: WAI-ua <w3c-wai-ua@w3.org>
2.9.2 Time-Based Media Load-Only: The user can override the play on load of recognized time-based media content such that the content is not played until explicit user request. (Level A) Intent As an opt-in user setting, autoplay for media is off/paused, until the user activates 'play'. The user agent provides a global control that sets a state equivalent to "paused waiting for user interaction" for all recognized media when a page loads.This prevents media from playing without explicit request from the user. This helps users who need to avoid signals that may trigger seizures, users who are easily distracted, and users who have difficulty interacting with the controls provided for playing media. The user agent provides a visual or auditory (as appropriate) indicator that the video is in paused state and needs user interaction to start. There may times when media doesn't have a native control in the page. That is, the media is not in the actual document, but rather has simply been created with document.createElement('audio'). Here, the user agent does not recognize that the media exists. The user agent cannot give a visual indication by default, as it wouldn't be clear where that indication should appear in the page. At that stage, it will be up to the author to provide the controls See WCAG in resources below. Examples 1. Stuart, a screen reader user, opens a page with an audio element that starts playing immediately. He cannot hear the screen reader because of the noise from the audio element, and must search through the page to find the 'noisy' element to pause or turn it off. Once the screen reader is the sole source of audio the he can read the page and determine if the audio is important and choose to play it. 2. Using similar techniques that are used for pop-up blockers, the user agent checks to see if the play() request was from user interaction or a background script. If it isn't from direct user interaction, the user agent could ask the user to explicitly allow the media to play, perhaps remembering the choice for the site. 3. Playback of a <video> or <audio> element can only be triggered in response to a user gesture on a touch screen device with no keyboard (like pop-up blockers). 4. The user agent provides a global control that calls "paused for user interaction" for all media when a page loads. Resources HTML5 4.8.10.8 Playing the media resource (http://dev.w3.org/html5/spec/Overview.html#playing-the-media-resource) WCAG 2.0 - 1.4.2 Audio Control http://www.w3.org/TR/WCAG20/#visual-audio-contrast -- Jim Allan, Accessibility Coordinator & Webmaster Texas School for the Blind and Visually Impaired 1100 W. 45th St., Austin, Texas 78756 voice 512.206.9315 fax: 512.206.9264 http://www.tsbvi.edu/ "We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Wednesday, 9 March 2011 23:34:18 UTC