- From: Alan Chuter <achuter@technosite.es>
- Date: Wed, 28 Nov 2007 13:29:36 +0100
- To: public-bpwg@w3.org
Dear BPWG participants, In our teleconference agenda for tomorrow, I would like us to discuss the following parts of the updated document concerning the ways that WCAG 2.0 compliance helps ensure a better mobile experience and compliance with MWBPs. Some of what follows has not been published yet, and is cited here from the upcoming version. ** How WCAG Compliance can Benefit All Mobile Web Users The success criteria for multimedia depend to a large extent on support in multimedia players for audio description, full text alternatives and sign language. WCAG gives a definition of audio description [3] and full text alternative [4]. These will only be of use to the general user if they are supported in multimedia players for mobile devices. WCAG 2.0 success criterion 1.1.1 Non-text Content [1] I think this one is not very controversial. WCAG is wider in scope than the MWBP. Please read and comment on it. WCAG 2.0 success criterion 1.2.1 Captions (Prerecorded) [quote]"How does it help mobile users? Mobile devices are often used in situations with significant background noise that makes it difficult to hear the audio track of multimedia content. It public places it may be socially unacceptable to listen to the soundtrack. In these situations captions enable the user to understand the multimedia content."[end quote] Is this realistic? Do mobile user agents (without assistive technology) support captions? Is the screen on a mobile device large enough for captions to be readable? WCAG 2.0 success criterion 1.2.2 Audio Description or Full Text Alternative [quote]"How does it help mobile users? Unlikely to provide any additional benefit (if audio description is supported by device, might conceivably help with understanding video on small screen). Does it give me MWBP compliance?: No."[end quote] This is the basic level and you can choose to provide one alternative or the other (not at issue here). It's unlikely that mobile user agents (without assistive technology) will support audio description, so this probably doesn't give any benefit to the general mobile user. On the other hand a full-text alternative might be usable, except that the volume of text will be unreadable on a small screen especially if there's only one window. If there is therefore no real added benefit, is the above text adequate to say so? WCAG 2.0 success criterion 1.2.3 Captions (Live) This addresses the requirement to provide real-time captioning for live multimedia (like press conference or sporting event). How does it help mobile users? This would be beneficial to mobile users who can not look and listen at the same time. But do mobile multimedia players support closed (optional, turn on turn off) captions? Open (always-visible) captions would be viewable but unacceptable to the general audience. Does it give me MWBP compliance?: No. WCAG 2.0 success criterion 1.2.4 Audio Description Same considerations as for 1.2.2 (but at a higher level you have to provide both Audio Description and Full Text Alternative). WCAG 2.0 success criterion 1.2.5 Sign Language The general mobile user is not likely to be fluent in sign language and so this isn't going to benefit them. Correct? WCAG 2.0 success criterion 1.2.6 (Audio Description (Extended)) Like Audio Description but freezing the video to allow more time. Might benefit the mobile user if supported by mainstream mobile UAs, but in reality probably not. What is the foreseen future level of support? WCAG 2.0 success criterion 1.2.7 Full Text Alternative Same considerations as for 1.2.2. WCAG 2.0 success criterion 1.4.4 Resize text and 1.4.7 Resize and Wrap Read [5]. There is no explicit mention of the WCAG techniques but C12, C13 and C14 do ensure compliance with [MEASURES]. OTOH, "Calculating size and position in a way that scales with text size" using script does not and breaks compliance with [OBJECTS_OR_SCRIPT]. Should this be stated here? (there's no section for "Does it give break MWBP compliance?"). Using only technique "G142: Using a technology that has commonly-available user agents that support zoom" and not using relative measures does not ensure compliance with [MEASURES] and could lead to a difficult user experience on a mobile device. Proposed new text "Some of the WCAG 2.0 Techniques, such as using named font sizes, em units or percentages ensure compliance with [MEASURES] with no further effort. Others such as G142: Using a technology that has commonly-available user agents that support zoom and not using relative units may make it difficult to comply with [MEASURES]". Other updates to the document are described in the changelog [6] that is now linked from the "Status of this Document" section.Important changes include in the "How Mobile Web Best Practices can Benefit Users with Disabilities" section separating out a list of BPs for which there's nothing to say, thereby reducing the amount of text, and making the section headings for BPs, CPs and SCs into links, eliminating a paragraph for each one. best regards, Alan [1] http://www.w3.org/2005/MWI/BPWG/Group/TaskForces/Accessibility/drafts/ED-mwbp-wcag-20071125#wcag20_text-equiv-all [2] http://www.w3.org/2005/MWI/BPWG/Group/TaskForces/Accessibility/drafts/ED-mwbp-wcag-20071125#wcag20_media-equiv-captions [3] http://www.w3.org/TR/2007/WD-WCAG20-20070517/Overview.html#audiodescdef [4] http://www.w3.org/TR/2007/WD-WCAG20-20070517/Overview.html#fullmultaltdef [5] http://www.w3.org/2005/MWI/BPWG/Group/TaskForces/Accessibility/drafts/ED-mwbp-wcag-20071125#wcag20_visual-audio-contrast-scale [6] http://www.w3.org/WAI/EO/changelogs/cl-mwbp-wcag#changelog On 27/11/2007, Jo Rabin <jrabin@mtld.mobi> wrote: > > Hi Folks > > Normal service resumes this week with the following proposed agenda: > > Chair: Jo > Team Contact: tbc > Known Regrets: none > > Agenda: > > 1. Good Standing Discussion > > 2. Reports from Task Forces > > a. CT > b. Checker > c. Results of Poll [1] on mobileOK Pro > > Note that the following answers have been received (corrected for Sean > Owen having appeared to say "yes" by mistake): > > yes 8 > no 3 > concur 4 > abstain 1 > > The poll is open till tomorrow night. > > 3. Alan's Accessibility Document > > As previewed last week, Alan has an updated document [2] which he will > walk us through. > > 4. AOB > > Logistics: > > Date: 2007-11-29T1500Z > > Phone: tel:+16177616200, tel:+33489063499 or tel:+441173706152 > Code 2794 ("BPWG") followed by # > > IRC: irc.w3.org:6665#bpwg > > References > > [1] http://www.w3.org/2002/09/wbs/37584/MobileOK-Pro/ > [2] > http://www.w3.org/2005/MWI/BPWG/Group/TaskForces/Accessibility/drafts/la > test > > > > > -- Email: achuter@technosite.es Blogs http://www.blogger.com/profile/09119760634682340619
Received on Wednesday, 28 November 2007 12:29:49 UTC