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Media: Question about autoplay (video in browsers)

From: Jim Allan <jimallan@tsbvi.edu>
Date: Thu, 27 Jan 2011 10:56:07 -0600
Message-ID: <AANLkTimGieXfF1C0=QWvgm0QG4uXz17aoR8bmiq6PCho@mail.gmail.com>
To: david.bolter@gmail.com, Charles McCathieNevile <chaals@opera.com>, Sean.Hayes@microsoft.com, eric.carlson@apple.com
Cc: WAI-ua <w3c-wai-ua@w3.org>, public-html-a11y@w3.org

The UAWG was discussing how to override autoplay in the browser in
response to a topic in HTML-A11Y telecon [1] last week

We have a success criteria:
2.9.2 Time-Based Media Load-Only:
The user can load time-based media content such that the first frame
is displayed (if video), but the content is not played until explicit
user request. (Level A)

Essentially, autoplay is off, until the user activates 'play'

The question is, a user agent has implemented the ability to turn off
autoplay (as required by UAAG20), but if a script implements autoplay
directly, whose responsibility is it to make sure that autoplay
doesn't happen?

Greg Lowney suggested that whether autoplay is enabled or disabled in
browser, user preferences should be made programmatically available to
scripts as well as extensions and plug-ins, so that they can follow
the user preference.

Is this possible? If possible, will it ever be done?

Jim Allan asked if the browser could simply refuse to play media when
a script attempts to start it on load. This is assuming that the
browser plays the video natively, and the script calls a UA function
that starts the video. But, Greg's not sure that the user agent can
distinguish scripted autostart from attempts to start the media in
response to some explicit user request.

Providing a way for the script to follow the browser's user preference
settings also has the benefit of (if implemented correctly) stopping
autoplay when done using media other than the HTML5 native media (e.g.

Are our assumptions/musings correct? Please enlighten us as to how
this really works in a user agent.

1. http://www.w3.org/2011/01/19-html-a11y-minutes.html

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 Thursday, 27 January 2011 16:56:37 UTC

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