- From: David Singer <singer@apple.com>
- Date: Wed, 11 May 2011 15:48:30 -0700
- To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Cc: John Foliot <jfoliot@stanford.edu>, HTML Accessibility Task Force <public-html-a11y@w3.org>, James Craig <jcraig@apple.com>, Michael Cooper <cooper@w3.org>
On May 11, 2011, at 6:50 , Silvia Pfeiffer wrote: >>> >>> 1. To satisfy use case 1: @aria-label >> (http://www.w3.org/WAI/PF/HTML/wiki/Media_Alt_Technologies#Example_1:_A_Cl >> ockwork_Orange) >> >> <video poster="media/ClockworkOrangetrailer.jpg" controls >> aria-label="A Clockwork Orange movie poster"> >> <source src="media/ClockworkOrangetrailer.mp4"> >> <source src="media/ClockworkOrangetrailer.webm"> >> <source src="media/ClockworkOrangetrailer.ogv"> >> </video> >> >> RESPONSE: >> This is a mistaken use of aria-label: this <video> (object) is not a >> poster, it is the entire media offering - a multi-media resource that deaf >> users, blind users, and deaf/blind users will consume differently based >> upon the additional resources that the author provides. > > I have come to this text by discussion with several people, including > several blind developers of screen readers, so I don't think this is a > mistaken use of aria-label. In fact, my examples actually had longer > text in @aria-label and I was told to make them shorter because blind > users don't want to have to wait until the end of reading-out of the > label before being told additional information about the element. > > Note how my proposal clearly states that this text is only relevant > when the video is not on autoplay. This is because in this situation > the video is represented by the placeholder image, which in this case > is the Clockwork Orange movie poster. When the video plays, the alt > text is not relevant because we have an audio track playing and audio > descriptions. So, when autoplay is turned off and a screenreader moves > onto this element, the screenreader needs to share with the blind user > exactly what the sighted users are seeing, which is the placeholder > image. > > Also, note how I am deliberately not talking about a poster frame, > because we are not providing accessibility information to the user > about the markup, but about the rendering. Since there is no > difference to the sighted user when looking at the video element > whether the frame is extracted from the video file or from a separate > resource, this is not something that a blind user needs to be told > about either. I think the point is that the poster and the aria-label are both about the video (they are peers) so it might be better to say <video poster="media/ClockworkOrangetrailer.jpg" controls aria-label="A Clockwork Orange movie trailer"> <source src="media/ClockworkOrangetrailer.mp4"> <source src="media/ClockworkOrangetrailer.webm"> <source src="media/ClockworkOrangetrailer.ogv"> </video> > > It's a label for the video element, which in the instance of > non-autoplay is simply the content of the placeholder frame. So, it's > completely correct. > I think it should be thought of as a label for the video in the element, whether or not it's playing. So saying it's a poster is not true; that would be the correct description of an image. David Singer Multimedia and Software Standards, Apple Inc.
Received on Wednesday, 11 May 2011 23:53:17 UTC