- From: Lachlan Hunt <lachlan.hunt@lachy.id.au>
- Date: Wed, 01 Aug 2007 01:12:25 +1000
- To: Sander Tekelenburg <st@isoc.nl>
- CC: public-html@w3.org
Sander Tekelenburg wrote: > At 12:10 +1000 UTC, on 2007-07-29, Lachlan Hunt wrote: >> <http://accessites.org/site/2006/10/the-great-accessibility-camp-out/> >> >> I fit into Camp 2, as described in that article. The term web >> accessibility refers to issues relating to disabilities. That doesn't >> mean I don't care about other types of issues, just that I don't group >> them under that term. > > OK, so to you "accessibility" means making content accessable to specific > groups with specific physical/mental disabilities. And "universaility" means > making content accessable to any user. > > Is that correct? Yes. > We can allow for universaility by designing HTML such that [1] all non-text > can be authored with a textual equivalent, [2] that textual equivalent can > contain markup and [3] the techniques to provide that marked up textual > equivalent and its relation to other alternates are as unified as possible > (because that's the easiest for authors and thus likelier that they will > bother). > > Such universaility would provide at least basic accessibility. Next would be > to develop ways to allow authors to provide better accessibility by targeting > specific groups. Your example of captioned text for example, but also things > like @scope or @headers. That sounds reasonable. > My point is that going at it the other way around makes no sense. If we > concentrate on accessibility features to allow authors to cater to specific > groups, we automaticaly ignore other groups. I didn't want to ignore other groups, I initially thought the issue being discussed was about addressing accessibility needs, instead of the more general universality needs, and hence didn't want to conflate the issue with non-accessibility related issues. > I completely agree though that both should be available to users. In fact, > that's what I am arguing for when I say that UAs must make equivalents > discoverable and accessible to users. Seems to me we agree. I agree in principle. It seems we just disagree about the way to do it. >> Here's an example of a presentation I >> published earlier this year. >> >> http://lachy.id.au/dev/presentation/future-of-html/ >> >> Both the audio and the transcript are available to everyone, and are >> complimentary for several reasons. > > (I haven't looked at the PowerPoint file.) The audio file is obviously an > equivalent of the text. The only reason to mark them up as if they are > instead complimentary is that currently neither HTML nor UAs allow you to > mark them up for what they are, equivalents, and let users easily discover > and access both. > > Those limitations result in a situation where the only way to determine that > the audio and text are equivalents is for a *human* to examine both. For me, > who can both see and hear pretty well, that means having to listen to the > entire audio file, while reading along with the text. Pretty intensive labour > to find out if I would miss some content by consuming only the text or the > audio file. Would you have any reason to assume there were any significant differences? I just don't understand why you think natural language is incapable of expressing that they are alternatives. Although perhaps there may have been some minor ambiguity, I think the revised text (as explained in a previous post) is now sufficient. > So your example just confirms the need for what I'm arguing for: that authors > need a (simple) mechanism to mark up equivalents as being equivalents, and > that UAs need to ensure that users can easily access equivalents. In what way exactly, are you imagining that your user agent could expose the fact that they are alternatives, any better than could be expressed using natural language in the document? >> But with multimedia, there >> are a variety of reasons why a user would choose the alternative format >> even if they could access the media. > > Well, even assuming that indeed with multimeda that need is more widespread, > we seem to agree that there is a need to allow users to discover and access > equivalents easily. And I suspect that we also agree that ideally the way to > author that would be as unified as possible across elements. Agreed. >> Consider how difficult it is for a user to access the alternative >> content nested within <object>. AFAIK, the only way to do so in most >> graphical browsers is to view the source. > > I think for <object> the main difficulty is that it can contain so many > different types. If an object contains an image, the user can reload the page > with auto-image loadin switched off. If it contains Flash, he can disable > Flash to get the fallback. Etc. A better UA would perhaps allow the user to > one-click disable all non-text. If we look at the way alternatives are often provided for flash based sites, there are so many that place a link to an HTML only version of the site below the flash. I've rarely seen authors place fallback content for flash within the object element itself. Here are a few examples of the kind of alternate content provided. * http://www.jkrowling.com/ The JK Rowling site provides links to alternative formats and languages on the home page. Includes HTML versions as well as flash using accessibility features. * http://www.nevermorethemovie.com/ When JavaScript is disabled or, presumably, if it cannot detect Flash, a link to the HTML only version of the site appears at the bottom of the page. Unfortunately, the HTML only version of the site is extremely poor quality. * http://www.kamasutracollection.com/ The home page has an "Enter Site" link that leads the flash based site, followed by a "Basic Version" link that leads to the HTML only version. Although, those are image links without alt text provided. I also noticed elsewhere on the site that they sometimes use alt text on other image links that is clearly intended for displaying as a tooltip. * http://h41111.www4.hp.com/mh41111/cannes/index.html Contains a small flash component that lets the user play 2 short videos. It links to the HTML version from within the flash movie, in the bottom left corner. However, it appears that the flash has simply been replaced with a static image and the videos are nowhere to be found. * http://www.rushhourmovie.com/ Provides some alternative text on the page that is covered with flash. Unfortunately, when JavaScript is disabled and the flash is not inserted, it uses black text on black background, so it's fairly useless to many people. It seems to be aimed more at search engines. * http://cleanishappy.com/ * http://www.beowulfmovie.com/ * http://www.noendinsightmovie.com/ These don't provide any alternative content for users, but their use of the meta element for descriptions indicates that SEO is an incentive to providing textual alternatives. It's unfortunate that it has been provided in a way that is completely useless to anyone else. Those are just a few examples that I could find, and not really sufficient to draw any real conclusions from yet. We certainly need to find more. However, for the ones were actually trying to provide alternative content for users, there does appear to be a tendency to use visible links on the page to the alternate version, rather than nesting the alternative within. It would be really good if we could find more examples of embedded content where alternatives have been provided, particularly for videos. I couldn't find any, though I checked a couple of news related sites that offer videos and they didn't provide any alternatives. >> So, if an audio file was embedded using <object> (or <audio>) and >> the transcript was nested within, that would make it difficult for >> users without assistive technology to access it. > > What makes you think that that problem is caused by that markup structure? > Looks more like a UA functionality issue to me. By embedding alternates, all > the author does is [1] provide equivalents and [2] define the order of the > default fallback cascade. It doesn't prohibit UAs from accessing any of the > equivalents. We can't ignore existing user agent behaviour in this regard. There are no existing graphical UAs that allow the user to easily switch between the embedded content and its fallback. It seems unrealistic to expect user agents to introduce this functionality, for authors to significantly change their authoring practices in regards to providing fallback, and for users to adapt to the new way of accessing content. -- Lachlan Hunt http://lachy.id.au/
Received on Tuesday, 31 July 2007 15:12:37 UTC