- From: Andy Heath <andyheath@axelrod.plus.com>
- Date: Sat, 07 Sep 2013 13:49:32 +0100
- To: Charles McCathie Nevile <chaals@yandex-team.ru>
- CC: "a11y-metadata-project@googlegroups.com" <a11y-metadata-project@googlegroups.com>, "<public-vocabs@w3.org>" <public-vocabs@w3.org>, Gerardo Capiel <gerardoc@benetech.org>, Dan Brickley <danbri@google.com>, Alexander Shubin <ajax@yandex-team.ru>, Egor Antonov <elderos@yandex-team.ru>, Liddy Nevile <liddy@sunriseresearch.org>, Charles Myers <charlesm@benetech.org>, Richard Schwerdtfeger <schwer@us.ibm.com>, George Kerscher <kerscher@montana.com>, Jason Johnson <jasjoh@microsoft.com>, Matt Garrish <matt.garrish@bell.net>
<Lots of snipping> Chaals quoted (and wrote a little bit of): >>> = accessMode = >> >>> It should be possible for a "single resource" to be available with >>> more than one *set* of accessModes. >> >> I agree and this is the design. A single resource can require one or >> more accessMode(s). > > Yes, but... > >> … the accessMode property describes "Human sensory perceptual system >> or cognitive faculty through which a person may process or perceive >> information." […] >> We have also published a best practices and an implementation guide on >> the use of accessMode at: >> <http://www.a11ymetadata.org/wp-content/uploads/2013/04/A11yMetadataProjectBestPracticesGuide_V.6.pdf> >> >> <https://wiki.benetech.org/display/a11ymetadata/Practical+Properties+Guide> >> Chaals wrote: > Yep. But that has an example which I'll use: > > A movie with captions and extended audio description would be encoded as > follows > <div itemscope=”” itemtype=”http://schema.org/Movie”> > <meta itemprop=”accessMode” content=”visual”/> > <meta itemprop=”accessMode” content=”auditory”/> > <meta itemprop=”mediaFeature” content=”audioDescription”/> > <meta itemprop=”mediaFeature” content=”captions”/> > </div> > > My first impression is that if the video has good audio description, > then claiming it has accessMode "visual" seems wrong, since you don't > need to see it. Likewise, since it is captioned, it seems you don't need > to hear it. > > So it doesn't have a single *required* accessMode. On the other hand, > you need to *either* see (clearly enough) or hear, in order to get the > content. The interpretation we had in AfA 3.0 of each property like this was that each specified not "accessMode required" but instead "accessMode available". Did this project take a different interpretation ? I haven't yet read the rest of this because I'm trying to focus on the same ISO meeting Chaals is in (but will do so) - this interpretation is so crucial as to change the whole emphasis so I wanted to reply quickly on this one point. andy axelrod access for all DiversityNet http://axelafa.com >> accessMode is derived from the Access For All (AfA) specification... > >> We chose to leverage this prior work because >> Schema.org<http://Schema.org> is meant to address search use cases, > > Yes, and I think that was the right choice. (Right now I am in an ISO > meeting on this very topic). > >>> Essentially, it is unclear what accessMode really means. At least for >>> the search use case where a user needs to find a suitable resource, I >>> think the only way this can really work is if an accessMode is a set >>> of one or more *required user capabilities*. >> >> Yes, I think that is what we are saying too. In fact, it seems like >> what others have understood on the public vocabs list as evidenced by: >> http://lists.w3.org/Archives/Public/public-vocabs/2013May/0092.html > > Not quite. The example there suggests (based on the documentation of > what accessMode means) that you need both visual and tactile > interactivity to work with the resource. > > But I agree that what people understand in the examples quoted is that > there are multiple ways to access some things. > >> http://lists.w3.org/Archives/Public/public-schemabibex/2013Aug/0049.html > > I'll leave Karen to answer on that one… > >>> To pick some examples: >> >>> Alice In Wonderland is available as a resource which only *requires* >>> the ability to read text. >> >> We happen to have a few versions of Alice in Wonderland in Bookshare > > Yep. > >> If you inspect one of those titles using Yandex's webmaster tools or >> Google's rich snippets tool that lets me just plug in a URL parameter, >> we can see the accessibility microdata on that page: >> http://www.google.com/webmasters/tools/richsnippets?q=https%3A%2F%2Fwww.bookshare.org%2Fbrowse%2Fbook%2F18041<http://www.google.com/webmasters/tools/richsnippets?q=https://www.bookshare.org/browse/book/18041> >> > > I looked at https://www.bookshare.org/browse/book/268061 with > http://webmaster.yandex.ru/microtest.xml > >> As you can see we offer 4 different adaptations of that title, which >> we originally adapted from a physical book that we scanned. For each >> adaptation we describe the accessModes that are used. > > Yes. But > <https://www.bookshare.org/download/book?titleInstanceId=268061&downloadFormat=DAISY_WITH_IMAGES> > doesn't actually *require* visual capability, does it? > > [...] >>> If there is a movie of Alice In Wonderland available with captions, >>> then there are two sets of requirements. One is to be able to watch a >>> movie and listen to the audio, and the second set is to be able to >>> watch a movie and read the captions. (If it had descriptive audio, a >>> third would be being able to hear the descriptive audio and the main >>> audio…) > > (See also the movie example mentioned earlier) > >> That is the purpose of mediaFeature. A movie typically has >> accessModes of visual and auditory. If it has captions, we simply add >> a mediaFeature of captions and/or a mediaFeature of audioDescription. >> You can find an example in our Practical Properties Guide: >> >> https://wiki.benetech.org/display/a11ymetadata/Practical+Properties+Guide#PracticalPropertiesGuide-Video >> > > Yes, but I don't think that is actually correct. If the movie has > captions, you *don't* necessarily need auditory capacity anymore. > However, in order to watch the movie without auditory capability, you > may need the ability to read images of text (this also depends on the > format used for captioning...) > >>> It might be that this assumption is already made in the proposal, > > It certainly seems to be an assumption. > >>> but it is not explicit, and the proposal doesn't explain how to deal >>> with a single version that can be used with different sets of >>> capabilities (whereas it includes a way to point to other versions) > >> Schema.org<http://Schema.org> allows for multiple values for the same >> property. For example, take a look at the example properties for >> ingredients at the bottom of this page: http://schema.org/Recipe > > Sure. But while the data about Alice in Wonderland shows how to include > multiple alternative books, each with a *set* or properties, I am not > sure the accessMode definition works for including different > combinations that are "mutually exclusive". > > To continue the captioned, audio described movie example, I think we > should be saying it has an accessMode which requires the ability to see > and hear, a different accessMode that requires the ability to hear, and > a third one that requires the ability to see and to read text on images. > > Any *one* of these is sufficient for a user to successfully use the > video resource, no? > >>> == details in accessMode == >> >>> the top-level accessMode is only useful for "most" cases. Knowing >>> that I am physically capable of watching and listening to a video is >>> great, unless it is only available in a format I cannot use such as >>> "flash for my iPhone 3", "ogg theora/vorbis"…. >> >> Schema.org<http://Schema.org> already has a properties for formats >> (e.g., http://schema.org/encodingFormat , >> http://schema.org/BookFormatType ) > > Yep. So we should be expecting those to be used, right? > >>> Similarly if I have more detailed requirements. For example although >>> I can watch and hear a video tutorial, being red-green colourblind or >>> requiring very high contrast may mean I can't actually understand it >>> in practice. >> >> For those use cases, we have accessMode = colorDependent > > Yes. But this assumes that users who require white-on-black, users who > use a common high-contrast mode, and users who are unable to distinguish > light blue from white have the same requirements. > >> and mediaFeature = > > Something missing here. > >> = accessFeature = > >>> Are these just cataloguing information, similar to noting that a >>> physical book has 5 pages of color photographs, or a guarantee that >>> e.g. each image has alternative text, or a longer description is >>> provided as necessary? >> >> We thought that implementing AfA or ISO 24751 verbatim for the >> purposes of web search and for use by web masters would be too >> complicated: it needed to be a small set of properties that a user >> could deal with. > > Hmmm. It needs to be as simple as possible - and no simpler... > >> We decided to combine various ideas into mediaFeature. > > Which I think makes sense. > >> mediaFeature simply states that the author/publisher or someone who >> modified that book, tried to take advantage the stated accessibility >> features. > > Right. > >> For example we make no promise that every image was described >> appropriately, > > But is best practice to use mediaFeature: textAlternative when there is > at least one image with an alternative, or when all the images have one? > > (We can't guarantee that everyone does everything perfectly, but it is > important to explain what we think people should be trying to do as well > as they can). > >>> It isn't clear, for example, how to classify a resource that assumes >>> the ability to touch several points of a screen at once, which is now >>> a common feature on devices but poses an obvious potential problem to >>> some users such as those who don't have very many fingers. >> >> In this use case, the resource that needs to be described is an >> application, not the content. > > Hmm. I don't understand the difference between applications and content. > I can see there are some things I would call one, and some that I would > call the other, but resources identified by schema.org seem hard to > classify into one or the other. > > For example, is an interactive map an application or content? What about > a document that allows structured navigation, a la DAISY? > > I don't know of a clear way to determine the difference. But then, I am > not convinced that we need one. > >> If the accessibility API of this application supports multi-touch with >> the user’s AT, then the proposed ATCompatible and accessAPI properties >> should be relevant. Furthermore, we also have a property called >> controlFlexibility, which also should provide information about whether >> the application can be fully controlled either via audio, mouse, >> keyboard, touch or video/gestures. > > Yes. > >>> = adaptations, other versions, ... = >>> >>> Liddy has pointed out that the concept of "the original" is only >>> sometimes interesting, and that it isn't an accessibility concept but >>> a more general one related to creative works. >> >> Actually to a teacher, the “original” is important if they are trying >> to find a resource for a disabled student that is an adaptation of the >> “original” resource used by the rest of the students in the classroom >> who don’t have a disability. > > I don't think so, I believe they are happy to know that two things are > versions of each other without caring which was the original. > >> Similarly a publisher or book seller wants to make it easy for consumers >> with specialized needs to find resources that have been adapted or “made >> accessible.” > > But again, the publisher doesn't really care which is the "original" - > and in the case of modern electronic works, the concept may not have a > real meaning. > >> These adaptations properties are also derived from AfA and >> ISO 24751 and I think it’s worthwhile reading their specifications to >> understand their reasoning. We did simplify the terms (removing partial >> adaptation and the like) to simplify this for search purposes. > > There is a lot of literature, and there are a number of standards, > describing how instances of a CreativeWork relate to each other. I don't > think we *need*, for accessibility, anything more than the super-simple > "this is a version of that". If people need to describe the relationship > for other reasons, they should use something that can support the things > they may need - i.e. the stuff that got removed (and probably stuff that > was never in AfA but is in Bibex, or FRBR…) > >>> This isn't high priority, except that I think we should quickly >>> decide we want to avoid dealing with defining stuff that others have >>> spent decades on, and instead try to use their work... > > This isn't high priority, except that I think we should quickly decide > we want to avoid dealing with defining stuff that others have spent > decades on, and instead try to use their work... > >>> = ATCompatible = >> >>> being a boolean seems a bit naive. I can think of lots of resources >>> that work with specific assistive technologies, but fail with others >>> (my instant example is http://cookiecrook.com/longdesc/iframe/ which >>> works great on VoiceOver but as far as I can tell does nothing to >>> work effectively with the built-in MacOS magnifier - two assistive >>> technologies I have readily available…). >> >> In the case of content, we once again, we tried to simplify the work >> for web masters and searchers. Since we can always expand the vocabulary, > > This is why I think fixing this bit is not the first priority. > >> we decided to err on simplicity, and to just have the focus on whether >> accessible technology was considered; > > Yes, but > >> enumerating WCAG sections would be overly daunting in a search. > > Well, it would be a fairly unfriendly way to define things. > >> In the case of applications, we did provide greater granularity with the >> accessAPI property, which would differentiate what accessibility API, >> such as VoiceOver, the application is compatible with. > > Yes. Because for an actual user, it doesn't matter that the developer > considered assistive technology in general, only whether they can use a > resource with their particular setup. This is analagous to the reason > why knowing the format of a resource is important. > >> I don't think ATCompatible is the first priority for fixing. But I do >> think it should be replaced with something because I don't think it is >> very useful. >> >>> = Evolution = >> >>> Who looks after the terms, and how do they get extended? >> >> This is probably the problem with any Schema.org<http://Schema.org> >> proposal. > > Sure. Which is why I ask the question in this particular case :) > >> By basing this proposal on existing standards, such as AfA and ISO >> 24751, it will be easier to evolve these terms as more people and >> organizations (e.g., IMS, GPII, IDPF) will be invested in keeping >> these terms synchronized with other standards and technologies. > > My experience suggests that this will actually make it harderif the > different standards aren't already evolving in lock-step, unless we have > a clear story for what triggers changes in the schema.org version. > >> We believe that there are some efforts with 24751 to have a registry >> to assist in this process. > > There are efforts in 24751 to have a registry, but I am not sure that > its purpose is to facilitate keeping schema.org as useful as possible in > the face of the evolving world. > andy andyheath@axelrod.plus.com -- __________________ Andy Heath http://axelafa.com
Received on Saturday, 7 September 2013 12:50:03 UTC