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Re: Are developers responsible for video full screen mode (Success Criteria 2.3.1)

From: Gregg C Vanderheiden <greggvan@umd.edu>
Date: Thu, 11 May 2017 22:31:29 -0400
Message-Id: <4B0D20CD-FFE8-4BD2-9C3B-DCB6F37DAC3F@umd.edu>
Cc: IG - WAI Interest Group List list <w3c-wai-ig@w3.org>
To: Brian Stevens <bstevens@ilsworld.com>
Question 1:  Does your site fail if the image is at Full Screen?     If not — then of course you are ok. 

If it DOES fail at full screen — and full screen viewing is an option on your page — then the safe thing to do is to place a warning above the video that says    "CAUTION: When viewed full screen this video may trigger seizures in people who are photosensitive” 

[To not put up such a warning is a bit like leaving an open manhole cover without warning barriers -  for people who have photosensitive seizure disorders. ]

There was the famous incident in Japan where a cartoon sent about ~300 children to the hospital.   They then showed the video on the evening news and sent another ~300 to the hospital. 

And then there was the London Olympics Promotion video... 

Question 2:  If it does fail at full screen - what is it that fails?   The Trace R&D Center Photosensitive Epilepsy Analysis Tool will show you exactly where it fails.    There are a number of things that can be done to a video that fails - so that it will not fail. 

But it usually is hard to fail the test - and there are ways to change a video very subtly to fix them. 


Gregg C Vanderheiden

> On May 11, 2017, at 9:54 PM, Brian Stevens <bstevens@ilsworld.com> wrote:
> Hello,
> Some of my company's animated videos fail Success Criteria 2.3.1, but only in the optional full screen mode (as provided automatically
>  with HTML5 video). At the default size, as they are presented, the videos pass.
> We're using the Trace Center Photosensitive Epilepsy Analysis Tool ( PEAT ) (Version 1.6). The PEAT User Guide says to "Test
>  out multimedia at the size that it will appear on your web site. E.g., if a video will be presented in a small window rather than a full screen mode, then test it at the smaller size."
> I just wanted to be sure, would this mean developers are not responsible for full screen
>  mode for 2.3.1?
> The only related documentation in the WCAG I could find that mentions viewing modes
>  is in Technique G176, where it says "Users with lower resolution displays or that enlarge or view their screens closely would have a higher risk depending
>  on the viewing distance. To address the needs of this group, G19:
>  Ensuring that no component of the content flashes more than three times in any 1-second period <https://www.w3.org/TR/2016/NOTE-WCAG20-TECHS-20161007/G19.html> should be used since it is independent of screen
>  resolution or viewing distance."
> This is basically almost saying that accommodating unpredictable resizing is covered
>  by Success Criteria 2.3.2 instead, which is Level AAA. Does that include a full screen mode offered by the site itself?
> Sorry if I am answering my own questions, I just wanted to know definitively. Thanks!!
> Brian Stevens
Received on Friday, 12 May 2017 02:32:09 UTC

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