W3C home > Mailing lists > Public > public-html-a11y@w3.org > June 2012

RE: [media] progress on video transcript discussion

From: John Foliot <john@foliot.ca>
Date: Wed, 6 Jun 2012 14:37:14 -0700
To: "'David MacDonald'" <david100@sympatico.ca>, "'Silvia Pfeiffer'" <silviapfeiffer1@gmail.com>, "'HTML Accessibility Task Force'" <public-html-a11y@w3.org>
Message-ID: <021301cd442c$8bba3ae0$a32eb0a0$@ca>
David MacDonald wrote:
> Good discussion....
> Sylvia's suggested code snip for the use case of embedded video:
> <video src="video.mpg" aria-label="video with transcript below"
> transcript="@this_page#transcript"></video>
> I think this would confuse a blind user... double message..."transcript
> below", and transcript linked from video element... but there is no
> transcript below... just the linked transcript from within the video
> element
> ... maybe the linked version should drop the aria label, or change to
> say
> "video available" or something...

My larger issue is focused on reaching for ARIA every time an accessibility
question comes up. I am a huge fan of ARIA, and rejoice in how much support
we increasingly see from AT tools for ARIA. I am thrilled to see it being
used more and more every day in mainstream development, but we must all
remember that it is designed for (and currently only works with) AT tools,
which only cover a small percentage of people with disabilities.

The programmatic linkage that we require should be one which *all* users
(and developers) can take advantage of. I have held stead-fast on requiring
a solution which would allow developers to expose the presence of a
transcript as part of the common controls associated to the media player. It
can be a button, or a drop-down, or something new and imaginative; the
transcript itself can render in an adjacent div or iframe (or newly minted
transcript element) or separate window or tab, or offer to be downloaded and
saved locally - or any combination of the above. If the browsers vendors
themselves are unsure of exactly how this should look and feel today, then I
can support a period of experimentation in the wild to see what works and
what doesn't - if the linkage is there NOW then that early 'other stuff' can
be scripted experiments. I remain convinced however that the discovery and
switching mechanism needs to be part of the total "user is interacting with
the video (media) experience", and not shunted off elsewhere with nothing
more than a weak ID string, an <a href> and an aria-property tying it back
to the main element. I think we can and should do better than that.

Using ARIA here should almost be a last-resort and not a first choice when
addressing accessibility issues (IMHO) for the simple reason that it *only*
interacts with AT tools - until such time as the Browsers themselves
directly map interaction to aria roles, states and properties and expose
those interactions to all users. HTML5, while adopting all of ARIA as part
of conforming HTML5, also replicates much of ARIA (landmark elements versus
aria-landmark roles), and often with uneven results (just look at the uneven
experience we get with @hidden versus aria-hidden today). I hope for the day
we can use ARIA for all users' user-experiences, but remain skeptical I will
ever see it.


> -----Original Message-----
> From: Silvia Pfeiffer [mailto:silviapfeiffer1@gmail.com]
> Sent: June-05-12 10:27 PM
> To: HTML Accessibility Task Force
> Subject: [media] progress on video transcript discussion
> Hi all,
> I wanted to share what I took out of today's transcript phone
> conference.
> This includes both conclusions that we have come to in the course of
> the
> discussion as well as a proposal of how to progress.
> Some of this is my personal interpretation, so chip in if you disagree
> anywhere, or have any other suggestions.
> Points that we discussed:
> 1. Interactive Transcript
> This was the simplest part of our discussion, so I want to get this out
> of
> the way up front.
> We discussed the need for interactive transcripts in HTML5. Everyone
> agreed
> that it is a very important feature and there are many use cases.
> Examples
> of current solutions include:
> http://wistia.com/product/transcripts
> http://www.3playmedia.com/interactive/
> http://www.protranscript.com/
> http://speakertext.com/captionbox
> http://clickablecaptions.com/captioning-with-instant-search/
> http://dotsub.com/labs/interactiveTranscript
> http://www.subply.com/en/Products/InterActiveTranscript.htm
> The main problem, however, is the timeline that we are given to
> finalize
> HTML5. We do not want to start with a new feature that requires many
> cycles
> to become perfect (e.g. the video element has taken 5 years to be
> sorted
> with all its attributes and elements). So, we want to move this feature
> to
> HTML.next and encourage Web developers to use JavaScript solutions for
> creating more interactive transcript examples so we can learn more
> about the
> needs for features and attributes. We'd in particular like to encourage
> Web
> developers to make use of TextTrack and TextTrackCue objects as their
> source
> for interactive transcripts since it is likely a good way to provide
> the
> information required to render an interactive transcript in the
> browser.
> We'd also like to start the design of a solution in HTML.next and
> continue
> the already fruitful discussions.
> For HTML5, however, we're shelving this issue.
> 2. Programmatic linkage of video and transcript
> The bigger issue - and one which we haven't resolved yet, but have made
> good
> progress on, was the question about the need of programmatic linkage
> between
> the video and its transcript.
> Our discussion started around options of having the transcript tightly
> coupled with the video element, i.e. how to make it part of the video
> element.
> We achieved general agreement that an actual rendering of the
> transcript
> inside the boundaries of the video element (e.g. as an overlay or an
> alternative to the video) doesn't make much sense. The transcript
> itself
> needs to be rendered outside the video element, e.g.
> in a different region on the page or on a different page.
> The second use case for tightly coupling the transcript to the video
> element
> was about the possibility of "activating" the transcript from the video
> element's controls. The idea here is that we would have a button on the
> video controls that when clicked might take us to another Web page with
> the
> transcript on it, or when clicked might unveil a section on the Web
> page
> near the video that shows the transcript, or when clicked might scroll
> us
> down to a page offset where the transcript is displayed. This is a nice
> theory, but is this actually being used this way?
> I personally have been unable to see transcripts used in this way in
> any
> kind of video player on the Web. Where transcripts are displayed, I
> have
> only seen links or text below the video. The only player that was
> different
> is the video player of the Rachel Maddow show, see
> http://www.msnbc.msn.com/id/26315908/vp/47654476#47654476 . This player
> uses
> the transcript button to reveal/hide an interactive transcript.
> Interactive
> transcripts are already tightly linked with the video through their
> synchronized timeline, so having a button to turn an interactive
> transcript
> on/off makes some sense. However, we have already said that we are
> moving
> interactive transcripts to HTML.next, so this is not something we need
> to
> solve now.
> So, I actually believe that neither do we need a solution that renders
> the
> transcript inside the video element, nor do we need a solution that
> creates
> a transcript button of some sort on the video element.
> So, what do we actually need a programmatic linkage between the video
> and
> the transcript for?
> In my mind, we have been mingling up two actual use cases: the first
> one
> where the transcript or a transcript activation button is visible on
> the
> page further down, and the second one where no transcript is visible on
> the
> page with the video and the transcript is actually on a different page
> (possibly because the video was embedded).
> The situation where the transcript is on the page but completely
> invisible
> (including there is no button to make it un-hide) is not one that I
> want to
> entertain here, since it can be satisfied by having a separate Web page
> off-page and thus falls into the second use case.
> (Also, I think it is pretty bad practice and should be discouraged.)
> Note
> that having a button on the page that can hide/unhide the transcript
> text
> makes this fall into the first use case and is not a different use
> case.
> 2.1. First use case: Linkage of video and transcript where the
> transcript is
> visible on the page
> Sighted users need no programmatic linkage in this case, since they can
> clearly see the transcript (or transcript link) further down on the
> page.
> However, blind users may find it difficult to discover that a
> transcript is
> available when they directly go to the video element.
> So, we need to make sure the availability of the transcript is
> announced
> when reaching the video element, and possibly provide a means to
> directly
> jump to the transcript (to avoid dealing with other DOM clutter).
> (Note: at one stage I thought @aria-describedby will solve this
> problem, but
> when it refers to an <a> element, it just renders flattened text, and
> when
> it reads a full text transcript, it can't be navigated since it's all
> just a
> single AccDescription of the element.
> So, I'm dropping this suggestion. So here are some new thoughts.)
> The announcement can likely be made using @aria-label.
> The linkage could be made by introducing a new @role attribute value of
> "transcript" so it is possible to gain it as a navigation landmark.
> This role would then go onto the element that contains the transcript,
> which
> could be an <a>, <div>, <p>, <iframe> or anything else really
> (including
> <button> or <textarea>).
> There are many knowledgeable people on this list about aria, so maybe
> you
> can chip in here.
> 2.2 Linkage of video and transcript where the transcript is not visible
> on
> the page
> At first sight this is a non-usecase: if we can't see the transcript,
> why
> would we need to link to it from the video, in particular since we
> don't
> want to put buttons into the video?
> It took me a while to understand this myself: when you publish a video
> on
> your page, you have control and you can put the transcript (or
> transcript
> link) below the video and announce it in the screen reader etc. But
> once
> this video is embedded somewhere else, you need a link to discover the
> transcript's availability and jump back to the original page. (This is
> actually the same for full-screen video, but it's easy to exit
> fullscreen to
> get back to the transcript.)
> One solution that needs no new markup is: the Web developer creates a
> snippet of embed text (in an iframe) that includes a visible link back
> to
> the original page and gives it a @role=transcript so it's discoverable
> by
> blind users. That reduces this use case back to the previous use case
> (transcript is visible). However, the problem with this is that the
> page
> that embeds the video may not want to show such a link and may only
> want the
> video, thus removing the extra link.
> This is a problem both for sighted and non-sighted users. They may find
> themselves on a page that has a video and there is a transcript
> available
> for this video, but they have no means of discovering the availability
> of
> the transcript or navigating to it. Sighted users may never find out
> that a
> transcript actually exists. For non-sighted users it's even worse -
> they
> could be misled into believing there is a "transcript available below"
> when
> the @aria-label attribute has been copied, but then search for it in
> vain.
> So, my suggestion here would be to introduce a @transcript attribute on
> the
> video that requires a full URL (we should discourage the use of
> relative
> URLs since they don't work when embedding which is the main use case
> here).
> Browsers would display this URL in the context menu of the video
> element, so
> sighted users can discover them. Web developers can be clever, create
> their
> own video controls and include the link there if they like. And blind
> users
> will be told that there is a "transcript available" and have some means
> of
> activating the linkage.
> This would be the markup:
> <video src="video.mpg" aria-label="video with transcript below"
> transcript="@this_page#transcript"></video>
> <div id="transcript" role="transcript">
> <h4>This is a transcript</h4>
> <p>blah blah blah</p>
> </div>
> And the embed would have:
> <video src="video.mpg" aria-label="video with transcript below"
> transcript="@this_page#transcript"></video>
> Here is another example markup with an off-page link:
> <video src="video.mpg" aria-label="video with transcript below"
> transcript="@this_page#transcript"></video>
> <a id="transcript" role="transcript"
> href="transcript.html">Transcript</a>
> Now, it is possible that publishers may want to shorten this to
> <video src="video.mpg" aria-label="video with transcript below"
> transcript="@base_url/transcript.html"></video>
> <a id="transcript" role="transcript"
> href="transcript.html">Transcript</a>
> and this would essentially mean duplicating the link. I don't see that
> as a
> problem, however, since they satisfy two different use cases.
> I'm fully aware that this is somewhat related to the @longdesc
> discussion.
> This use case could, therefore, also be solved by using @aria-
> describedAt
> containing a link to the transcript (as in fact I have suggested
> before).
> >From what I've learnt in previous discussions, we want the extra
> semantics
> of it being a transcript and not just a random long description, so
> introducing a new attribute for this seems right. If we can make it
> always
> have a full URL! ;-)
> Hope this all helps to make progress.
> Cheers,
> Silvia.
Received on Wednesday, 6 June 2012 21:37:55 UTC

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