- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Wed, 17 Nov 2010 21:21:54 +1100
- To: "HTML Accessibility Task Force (public-html-a11y@w3.org)" <public-html-a11y@w3.org>
- Cc: Frank Olivier <Frank.Olivier@microsoft.com>, "public-html@w3.org" <public-html@w3.org>
The spec classifications as proposed by Frank and discussed in this thread have now found entry into the checklist at http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Checklist . Cheers, Silvia. On Fri, Nov 5, 2010 at 11:17 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote: > On Fri, Nov 5, 2010 at 8:25 PM, Maciej Stachowiak <mjs@apple.com> wrote: >> >> >> On Nov 5, 2010, at 8:50 AM, Maciej Stachowiak wrote: >> >>> >>> (1) What are the kinds of changes needed to the HTML5 spec to support this requirement? >> >> Here is my attempt to answer this question for the following items, based on our discussions yesterday: >> >>> >>> On Nov 4, 2010, at 5:55 PM, Frank Olivier wrote: >>> >>>> SPECNEW, SPECCED: (SL-1) Support sign-language video either as a track as part of a media resource or as an external file. >> >> The <track> element currently only supports textual formats; would need to support video format and an appropriate value for the kind attribute. Another possibility is a mechanism to associate two <video> elements to play in sync. > > > We have bug 9452 for that: > http://www.w3.org/Bugs/Public/show_bug.cgi?id=9452 > > > >>>> SPECNEW, SPECCED: (SL-2) Support the synchronized playback of the sign-language video with the media resource. >> >> Ditto above. > > > Ditto bug 9452. > > >>>> SPECNEW, TRACK: (CC-5) Support positioning in all parts of the screen - either inside the media viewport but also possibly in a determined space next to the media viewport. This is particularly important when multiple captions are on screen at the same time and relate to different speakers, or when in-picture text is avoided. >> >> Timed track rendering section does not seem to have provision for positioning timed text outside the media element or its controls. > > > Doesn't look like we've got a bug for this yet, but I have raised it > in discussion threads on WHATWG. > > >>>> SPECNEW, TRACK: (CN-1) Provide a means to structure media resources so that users can navigate them by semantic content structure. >> >> We were not sure whether this is provided for, however, using a <track> element with kind=chapters seems to address this requirement. > > > Yes, it does, but not hierarchically. We can, however, introduce some > sort of level marker into the chapter tracks to make them hierarchical > with time-overlapping cues. I've been thinking about proposing that. > > >>>> SPECNEW, UX: (CC-25) Support edited and verbatim captions, if available. >> >> We thought the <track> element lacked a way to distinguish verbatim and edited captions in the same language, however, it seems like the label attribute may be sufficient to identify caption tracks as edited or verbatim. > > > The @label is just a user-readable string. Do we need a > machine-readable means to distinguish between edited and verbatim > copies or just user readable? If the latter, then it will indeed be > sufficient. (I'd be happy with that, btw.) > > >>>> SPECNEW, UX: (DV-8) Allow the author to provide fade and pan controls to be accurately synchronized with the original soundtrack. >> >> HTML5 does have volume control, but not the ability to pan a soundtrack. > > > This was identified as a "should" level requirement. My suggestion > would be to not solve this within HTML5 LC, but keep this for a future > version. > > >>>> SPECNEW: (DAC-5) Non-synchronized alternatives (e.g., short text alternatives, long descriptions) can be rendered as replacements for the original rendered content (UAAG 2.0 3.1.3). >> >> HTML5 spec doesn't seem to have specific provision for a textual alternative (as opposed to captions or a transcript) for a video. > > > I think a simple text or hyperlink to a longer text right next to the > video or audio element will be sufficient to fulfill this need - it's > what WCAG suggests, too. I don't actually think we need some new > markup for this. > > >> Also, looking closer at the spec, I believe the following items marked SPECCED are actually *not* yet provided for: >> >>>> SPECCED: (CA-1) Support clear audio as a separate, alternative audio track from other audio-based alternative media resources. >> >> >> There is no provision for the <track> element to reference audio, nor is there an appropriate kind value for clear audio. > > > No, but this could be solved with the same multitrack solution as > earlier and bug 9452. If we are careful, we will introduce a means to > directly change the volume on different audio tracks through > JavaScript, so we can satisfy this. > > >>>> SPECCED: (DV-4) Support recordings of real human speech as a track of the media resource, or as an external file. >> >> >> The HTML5 draft has no provision for a video description track in the form of audio rather than text in the <track> element. > > > Agreed. And again, this can be solved with the same multitrack support > that bug 9452 is asking for. > > >> And I believe the following 4 items may not actually have HTML5 spec impact: >> >>>> SPECNEW: (CN-6) Support direct access to any structural element, possibly through URIs. [Media fragment-like issue] >> >> Seems addressable through Media Fragments URI: <http://www.w3.org/TR/media-frags/> >> Does HTML5 need any changes to adopt this? > > > There is some recommendation necessary around the visual display of a > media fragment in a video or audio element's @src, possibly the > introduction of some new controls (e.g. loop fragment / loop whole, or > rewind fragment / rewind whole). And then there is the whole question > of addressing named fragments over timed fragments. The media > fragments WG is looking into these issues and preparing a > recommendation. This is all part of bug 10723 > http://www.w3.org/Bugs/Public/show_bug.cgi?id=10723. > > >>>> SPECNEW: (CN-3) Support both global navigation by the larger structural elements of a media work, and also the most localized atomic structures of that work, even though authors may not have marked-up all levels of navigational granularity. >> >> (I don't fully understand this requirement; sounds like maybe it should be in the UX category.) > > > I'm not sure how navigation is possible without having marked-up > navigation points. Other that that, it is clearly related to the above > discussion of CN-1 and chapter cues. > > >>>> SPECNEW: (CNS-1) All identified structures, including ancillary content as defined in "Content Navigation" above, must be accessible with the use of "next" and "previous," as refined by the granularity control. [May be handled with cue ranges] >> >> (I don't recall why this is a spec requirement rather than UX) > > > It's more an accessibility API requirement than anything else, really. > > >>>> SPECNEW: (DAC-2) The user has a global option to specify which types of alternative content by default and, in cases where the alternative content has different dimensions than the original content, how the layout/reflow of the document should be handled. (UAAG 2.0 3.1.2). [Probably minimal spec text required: Media queries would work nicely here; also UX issue (user sets media query to match)] >> >> Seems like this would be an issue for a spec to extend Media Queries; not clear if there is actual HTML5 impact. > > > I almost think this is a case for user preferences, so UX. I'm not > clear how media queries can help here. > > > Cheers, > Silvia. >
Received on Wednesday, 17 November 2010 10:22:49 UTC