Re: [media] a first draft JavaScript API for multitrack media

On 2/16/10 10:44 PM, "Silvia Pfeiffer" <silviapfeiffer1@gmail.com> wrote:

Hi all, and in particular media subgroup,

Today we had a phone discussion about the JavaScript API spec and we
realised that we haven't actually specified the list of roles that the
@roles attribute should accept.

So, I wanted to start a discussion on this with the goal of eventually
reaching a list that we can all agree on to cover the known use cases.

Let me start by stating that in today's call everyone agreed that we
need to come up with a determined list of values for the roles, so if
you disagree with that, you should speak up now.

So, let me start proposing a list of track roles:

Video track roles:
* "main"
* "alternate" (e.g. different camera angle; happy to stick with Apple
terminology ;-)
* "sign" (for sign language)

Audio track roles:
* "main"
* "alternate" (probably linked to an alternate video track)
* "dub"
* "audesc" (audio description)
GF:  audiodesc (or audioDesc) would be more descriptive

* "music"
* "sfx" (sound effects)

Text track roles:
* "caption"
* "subtitle"
* "textaudesc" (textual audio descriptions; to be used as braille or
through TTS)
GF:  despite its length, textaudiodesc (or textAudioDesc) would be more descriptive, I think.

* "karaoke"
* "chapters"
* "ticker text"
* "lyrics"

We could most certainly also think about abbreviating them, e.g. "CC",
"SUB", "AD", so I wonder what everyone's preferences are here.

GF:  My preference would be for not abbreviating them:  it makes them immediately obvious, plus it conforms to other usages of @role (http://www.w3.org/TR/wai-aria/roles#role_definitions; http://www.w3.org/TR/ttaf1-dfxp/#metadata-attribute-role are two examples).

So, shoot away with your own preferred track types! What conventions
are you used to from MPEG?

GF:  Speaking of conventions, we should probably settle on a naming convention:  camelCase (e.g., role="tickerText"), all lowercase (e.g., role="tickertext") or spaces (e.g., role="ticker text").  My preference would be for camelCase.