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html5 longdesc w3c

AAP Provides Longdesc Feedback to W3C

There’s a debate over whether or not the longdesc attribute should be made obsolete in HTML5. I wrote a bit about it a few months ago in the article Longdesc & Other Long Image Description Solutions.

Recently the Association of American Publishers (AAP) submitted feedback on longdesc to the W3C HTML 5 Working Group. It’s very well written and thought it should be shared. I obtained permission to publish the response (thanks Suzanne and Ed). Here is the main part of it:

Use of structured text as a text alternative for an image is supported in HTML through the longdesc attribute. Though there are other options for presenting structured-text, the longdesc attribute provides following benefits:

For User Experience

  • The longdesc attribute is a dedicated mechanism for just this purpose, and it always works in the same way:
    • Students and instructors will find the same user interface throughout all materials, so they will not need to learn new interfaces product-to-product, which takes time and attention away from the learning content.
    • The longdesc attribute can be revealed programmatically through browser extensions, providing access for users who do not use screen readers. Many users benefit from text alternatives, especially users with low vision.
    • The longdesc attribute does not impact the visual design. So, authors do not have to worry about how the text might impact the visual user experience. Authors can, therefore, focus on the experience of students and instructors with visual impairment while they write text alternatives. This focus on the primary audience helps authors create text that is well-suited for its purpose.

For Production Processes and Quality Assurance:

  • The longdesc attribute is easy to code. There is no need for custom scripting.
  • The longdesc attribute works with assistive technology today. If the longdesc attribute continues to be supported, content that works well for users today can be used in future products without editing.
  • The longdesc attribute can be programmatically recognized and tracked, allowing publishers to locate existing long descriptions and to test for the presence of long descriptions.

We are using longdesc increasingly in our products. Unless a different mechanism is created that meets all these requirements, we urge the W3C to keep the longdesc attribute in HTML specifications moving forward.

We do acknowledge that user agent support for the longdesc attribute should be improved. In particular, users who have low vision or who find image descriptions helpful for any reason should be able to set their user agent to reveal the descriptions. The HTML 5 specification should clarify that user agents should provide this functionality in addition to passing information to assistive technologies. In this case, publisher documentation for products with numerous longdesc attributes might include tips about use of these user agent settings.

Evaluating Other Solutions

We discuss the aria-describedby attribute following to illustrate that solutions that at first seem to duplicate the qualities of the longdesc attribute may not actually be as useful when implemented.

The aria-describedby attribute takes the unique indentifier (“ID”) of another object on the same page as its value. In other words, it points to another object (e.g. a paragraph or a link) on the page. This attribute could become an effective way for developers to indicate that the information provided by an image is actually redundant with other information on the page.

Screen reader developers might implement this attribute so that it is silent in screen readers when used on an image by default. They might also allow those who want additional information to set their screen reader to announce aria-describedby and to provide a way to jump to the object indicated by the attribute. An instructor, for example, might choose this setting to be aware of what sighted students will be experiencing.

But, the aria-describedby attribute falls short as a mechanism to link to a separate page of structured text. The aria-describedby attribute could point to a link on the same page as the image, but:

  • Hiding the link visually would require custom CSS or scripting. The mechanism for hiding the link would therefore differ product-to-product, making browser extensions or features to show the links more complex to code and less reliable for users.
  • The link would have to be present on the page for screen reader users, creating redundancy for those users.
  • Since the aria-describedby attribute points to a link or to other content on the same page, its structure implies a two-step process to reach the text alternative. Compared with longdesc, the two step process is more tedious:
    • The user moves to the object that aria-describedby references.
    • If the object is or contains a link or a button, the user interacts with that object to move to the text alternative.

If the issues above are resolved and aria-describedby is used as a way to access descriptions that are otherwise hidden from all users (including screen reader users), another problem emerges. In that case, aria-describedby cannot be silent by default in screen readers when used on images, compromising its use to illustrate that the content of an image is already available on the page. Developers may not realize the distracting and frustratingly circular user experience that this would cause and might use aria-describedby to point to, for example, a paragraph just above the image. Users would then likely follow the aria-describedby announcement, expecting to find additional content, but they would arrive, instead, at a paragraph that they have likely just read.

We urge the W3C HTML Working Group to write out the expected implementation and user experience details of any proposed replacements for the longdesc attribute to be sure that they will be at least as effective as the longdesc attribute in practice.

Categories
conference google html5 mobile visual

Accessibility at Google IO 2011

So I attended the first day of Google I/O 2011, my first time at a Google event. I was glad to hear a fair amount of talk about accessibility. There were at least 3 sessions focusing on the topic (see below) and a breakout area where you can talk with developers.

There was even an accessibility “Developer Sandbox” area which was great. I tried out the ChromeVox screen reader on a Chromebook with help from Google’s Rachel Shearer. I got a quick demo of the built-in TalkBack screen reader on an Android mobile device. Mika Pyyhkala and I were shown the LevelStar braille device running Android. The University of Washington showed off their mobile ASL Android project which used video chat technology.

Some tips for Android development from the sessions are:

  • In Android code, ensure images, especially ImageButtons, are labeled with contentDescription.
  • Use standard controls.
  • Stick with standard or modified views; custom very complex to make accessible.
  • Ensure all controls reachable with D-pad and Trackball.
  • Test with screen reader using D-Pad. To turn on, enable accessibility under Settings/Accessibility, then enable Talkback.
  • Take advantage of device’s “many eyes and ears” for alternative input/output (microphone, speaker, touch screen, camera, GPS)

The sessions specific to accessibility were:

More resources:


Tim Credo, Charles Chen, and T.V. Raman on stage at Google I/O.

Categories
html5 keyboard video

Accessible YouTube & HTML5 Video

YouTube is obviously a great site for video, but not for everyone as it contains various accessibility challenges, particularly keyboard access. The use of Flash itself to play the video can be problematic, not be mention requiring support of the Flash plugin. HTML5 is a pending solution (HTML5 video is available on YouTube as a “trial”), but in its infancy, HTML5 video has accessibility issues that still need to be resolved, as does HTML5 itself.

In the meantime, here are a few alternatives to the YouTube website which provide more accessible controls and a much cleaner interface.

If you still don’t have what you need or want, why not build your own interface?! The following are tools and resources for building more accessible YouTube videos including captioning:

Further reading:

If you developed an accessible YouTube solution, or know of another not listed, please leave a comment.

YouTube logo

Categories
aria html5 video

HTML5 Sanity Check

Most of us are excited about HTML5 and all the benefits it will bring. Overly excited maybe is a more accurate term, which includes myself. We as a community need a “sanity check” about the readiness of HTML5 and its accessibility because:

  1. The spec isn’t complete (2012 for Candidate Recommendation) thus requirements may still change.
  2. The browsers are in the middle of implementation and much accessibility support isn’t provided yet.
  3. There are many accessibility issues remaining such as Canvas in general; no semantic information to assistive technology for many elements; keyboard access lacking in audio & video controls in most conditions.

The web site HTML5Accessibility.com is a great place to learn about these issues for each major web browser. Along with that is a presentation by Steve Faulkner (@stevefaulkner) of the Paciello Group: HTML5 Accessibility – Is It Ready Yet? presentation by Steve Faulkner and and Hans Hillen (SlideShare).

Because of this intermediate stage, we developers must implement more complex code as desired, including fallback methods for user agents which don’t yet support the HTML5 features. Here are some great resources on doing so:

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audio conference html5 podcast review

Podcast #86: EDUCAUSE Review, AHG Preview, HTML5 Audio with Terrill Thompson

Head shot of Terrill Thompson Dennis speaks with Terrill Thompson about a variety of topics including a summary of the EDUCAUSE conference; a preview of the Accessing Higher Ground (AHG) conference; community efforts to fix the web; HTML5 audio, video, and controls; and captioning.

Download Web Axe Episode 86 (Educause review, AHG preview, HTML5 audio with Terrill Thompson)

[Transcript of podcast 86]

Mentioned links

More on the EDUCAUSE Twitter backchannel

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