- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Wed, 6 Jul 2011 22:56:12 +1000
- To: Philip Jägenstedt <philipj@opera.com>
- Cc: public-html@w3.org
On Wed, Jul 6, 2011 at 9:50 PM, Philip Jägenstedt <philipj@opera.com> wrote: > On Wed, 06 Jul 2011 12:47:35 +0200, Silvia Pfeiffer > <silviapfeiffer1@gmail.com> wrote: > >> On Wed, Jul 6, 2011 at 6:33 PM, Philip Jägenstedt <philipj@opera.com> >> wrote: >>> >>> On Fri, 01 Jul 2011 16:29:23 +0200, Silvia Pfeiffer >>> <silviapfeiffer1@gmail.com> wrote: >>> >>>> Hi Paul, all, >>>> >>>> after analyzing this problem thoroughly, which I have documented [1], >>>> I have come to the conclusion that there is no need for introduction >>>> of any normative text into the specification to satisfy this use case. >>>> >>>> Right now, we have a linear navigation means through text tracks of >>>> kind chapter. >>>> >>>> IMO the best means to provide hierarchical navigation, which is >>>> particularly useful to vision-impaired users, is to make it possible >>>> to provide navigation lists inside the cues that make up >>>> kind="chapters" track. As such cues are handed to AT, their markup is >>>> interpreted and made available to AT, including any associated lists. >>>> >>>> My only suggestion would be to potentially add a recommendation to the >>>> specification underneath where "chapters" are introduced [2] >>>> which essentially states that subnaviation within chapter cues should >>>> be provided through list elements (ul,li) inside a chapter's cue. >>> >>> There are no list elements in WebVTT, are you suggesting they be added? >> >> Yes, am. If you look at the examples, I added a <nav> element and am >> using the <time> elements as list elements, since the time markers >> provide the navigation points. > > Oops, I didn't notice you'd linked to > http://www.w3.org/WAI/PF/HTML/wiki/Media_Navigation until now. > >>> To >>> provide a chapter tree, would it not be better to have dedicated syntax >>> for >>> it? Perhaps: >>> >>> 00:00.000 --> 01:00.000 >>> 1. Foo >>> >>> 00:00.000 --> 00:30.000 >>> 1.1. Foo, Part 1 >>> >>> 00:30.000 --> 01:00.000 >>> 1.2. Foo, Part 2 >>> >>> The spec would need to add some parsing for kind=chapters, to deduce the >>> level of nesting from the leading x.y.z... >> >> I've considered this, but with this kind of markup you cannot >> guarantee that the sublevels are temporally within the main level and >> you have to deconstruct the hierarchy. I think parsing something like >> this into a navigation tree is much harder. >> >> Also, navigation currently works in accessibility technology very >> easily through lists, so if we can map whatever we do in WebVTT into a >> list markup, that makes it simple. Therefore, I came up with the list >> markup as given in the wiki page: >> >> <ul> >> <li><? target='timestamp' data='00:00:03.450'>Subchapter 1</li> >> <li><? target='timestamp' data='00:00:04.000'>Subchapter 2</li> >> <ul> >> <li><? target='timestamp' data='00:00:04.000'>Paragraph 1</li> >> <li><? target='timestamp' data='00:00:04.500'>Paragraph 2</li> >> <li><? target='timestamp' data='00:00:05.000'>Paragraph 3</li> >> </li> >> <li><? target='timestamp' data='00:00:06.000'>Subchapter 3</li> >> </ul> >> >> That is using the mapped timestamps from WebVTT to provide the >> navigation points and the list markup to allow making use of >> screenreaders' hierarchical navigation capabilities. > > OK, so the idea is that markup as in > http://www.w3.org/WAI/PF/HTML/wiki/Media_Navigation#Possible_Markup_for_WebVTT > should get converted into a list for getCueAsHTML? That seems a bit funky, > how about just letting it be a HTML <nav> element? If I understand the <nav> element in HTML correctly, then it's just a <div>-like construct that encapsulates an area that contains naviagtion markers, but the navigation itself is still done in a list. I'm looking at http://www.whatwg.org/specs/web-apps/current-work/multipage/sections.html#the-nav-element . We could put the <nav> around the <ul> in the above example, but it's not really necessary. <nav> seemed useful for grouping <timestamp> markers together on a level in WebVTT though. And it's just one element, not two like <ul> and <li>. > The syntax here doesn't seem very important though, so let's discuss that > when the times actually comes to include this in the spec. Agreed. I was just trying to come up with something simple. >>> I'm not convinced this should be added to the spec right away, >> >> Are we talking about adding something to the WebVTT spec or the HTML spec? >> >> For HTML, we don't have to add anything, because IIUC the above markup >> (with <ul> etc) would already be supported. We might add an example, >> if/when we think this is the right way forward. > > I don't understand, HTML doesn't seem involved here except for getCueAsHTML, > right? Yes, that's where it comes in - in getCueAsHTML. >> For WebVTT I am expecting a discussion in the WHATWG, since it's not >> specified in this WG. There is bugs that track this, see >> http://www.w3.org/Bugs/Public/show_bug.cgi?id=12662 . > > OK, thanks. Do you also think this approach of putting hierarchies inside cues is simpler than building hierarchical structures through separate cues, or even with separate tracks? Or do you have a nicer way of dealing with DAISY-like requirements? Cheers, Silvia.
Received on Wednesday, 6 July 2011 12:57:09 UTC