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Re: Track kinds

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Fri, 29 Apr 2011 11:07:11 +1000
Message-ID: <BANLkTi=wCGynPYRX-BDN=QvStXZfLs+PhA@mail.gmail.com>
To: Mark Watson <watsonm@netflix.com>
Cc: HTML Accessibility Task Force <public-html-a11y@w3.org>
On Fri, Apr 29, 2011 at 6:52 AM, Mark Watson <watsonm@netflix.com> wrote:
> All,
> I updated the wiki page (http://www.w3.org/WAI/PF/HTML/wiki/Track_Kinds)
> based on our discussion yesterday. There are now three tables, the kinds in
> the current spec, the kinds that have been suggested and the subset that we
> have agreed should be added to the spec (currently just "captions").
> If I understand rightly, the general idea is that we should provide precise,
> container-independent definitions for all the kinds we agree on in a W3C
> document other than the HTML specification and propose that the HTML
> specification just define the text labels to be used with HTML.
> In parallel, various people will work on introducing the same kinds to
> various container specifications.
> We decided to continue the discussion of which ones to propose should be
> added to the specification on the list. To that end the three that Sylvia
> suggested yesterday were:
> - supplementary
> - commentary
> - clear audio
> Comments ?

Thanks for the great work on the wiki page. It is good to pull this together.

I think the list that we have in the spec right now is a good start
and should likely be sufficient for a reply to the 3GPP.

As for further values:

I think adding "supplementary" makes sense, because it states that a
track can be active at the same time as the "main" tracks.

I am not so fussed about any of the others because I think as we
implement this the list will likely grow. I don't mind adding
"captions" and "commentary" because I know there is material that has
in-line captions and there are commentary tracks. Alternatively,
"captions" could be marked as "alternative" and "commentary as
"supplementary" with a description of what it actually is in the

As for "clear audio", I think we first need to clarify what it is
exactly. As I understood from our requirements discussions, a "clear
audio" track is a track that has only the speech part of the video so
that it is possible to turn this sound up through controls in
comparison to the main audio track. If this is the case, then it
compares to the "audio/speech" value of the Ogg roles. If instead it
is as David describes a track which has the speech part amplified in
comparison to the main audio, then it is actually a replacement for
the main audio track and would be covered with "alternative" and a
description in label as "clear audio".

Received on Friday, 29 April 2011 01:07:58 UTC

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