[Bug 17465] <track> text tracks need to allow a @default attribute per group of @kind tracks

https://www.w3.org/Bugs/Public/show_bug.cgi?id=17465

--- Comment #3 from Philip J <philipj@opera.com> 2012-06-12 13:10:40 UTC ---
(In reply to comment #2)
> (In reply to comment #1)
> > Does it really make sense to enable both a subtitle track and a captions track
> > by default? More sense then enabling two caption tracks?
> 
> We've made them two separate kinds, so: yes. A caption track would be in the
> native language (e.g. in English) and an additional subtitle track would be in
> a different language (e.g. in Swedish), which would be great for deaf people
> that are trying to learn a foreign language.

The site author can't know that the user is learning a language, but even so,
wouldn't it make exactly as much sense for a hearing user to have two subtitle
tracks enabled?

> > I'm not opposed to allowing more than one default track, but how should the
> > automatic track selection be influenced by that?
> 
> I am only asking for a default PER KIND. So, a default caption, a default
> subtitle, a default description, and a default metadata track make complete
> sense to me, in particular since the descriptions are rendered through audio
> and the metadata through script.

With automatic track selection, you'll want to enable the captions or subtitle
track that best matches the user preference, not one captions track and one
subtitle track. In other words, I don't think it makes sense to consider
captions and subtitles separately, they are in the same bucket as far as
automatic selection goes.

Default metadata tracks seems weird, given that scripts are needed to make
sense of them and can enable them by setting .mode = 'hidden'.

> > With only a single track
> > enabled, it's easy to tell that there's another track in a language that the
> > user knows better, but how can one tell which combination of tracks is better
> > than multiple default tracks?
> 
> I don't understand this question. There won't be more than on caption track
> active. In a menu there would be a list of all the available caption tracks, so
> you choose a different one which deactivates the previous one. Same for all the
> other tracks.
> 
> For example, I would author to set (out of a list of tracks of different kinds
> and languages) a default caption track in English and a default descriptions
> track in English. As a browser, I could be even more clever to choose the
> default based on the language settings of the browser - and that default would
> be per kind.

The problem is know how to interpret a page with default captions *and*
subtitles. Should I pick one of them depending on user preference, try to
enable a subtitle and a caption track and fall back to the defaults, or
something else?

> > The simplest thing to do would probably to simply enable all tracks with a
> > default attribute (ignoring their types) and to to disable automatic track
> > selection if there are more than one default tracks.
> 
> How would you do automatic track selection with a single default attribute
> across all track kinds? I think that's actually not do-able/sensible. A default
> per track kind, in contrast, makes sense.

We currently enable the first captions or subtitle track with a default
attribute. The automatic selection we plan to do would consider all captions
and subtitle tracks as a group and pick the one that best matches the user
preference, falling back to the default.

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Received on Tuesday, 12 June 2012 13:10:52 UTC