Re: [media] Moving forward with captions / subtitles

Apologies for the delayed response.  Today is a holiday in the US.  Just catching up now on the volley of messages from this morning.

<snip>


Since we all seem to be at least somewhat confused, here's a "common" and
"complex" case expressed in both <track><source> and <trackgroup><track>
markup. <track> in both forms clearly does *not* mean the same thing. Draw
your own conclusions about which is better.

Simple case: two subtitle tracks in two different languages:

In <track><source> markup:

<video src="video.ogv">
   <track role="SUB">
     <source src="subs.en.srt" srclang="en">
     <source src="subs.sv.srt" srclang="sv">
   </track>
</video>

In <trackgroup><track> markup:

<video src="video.ogv">
   <track src="subs.en.srt" role="SUB" srclang="en">
   <track src="subs.sv.srt" role="SUB" srclang="sv">
</video>

<trackgroup> is omitted because it is only needed when some tracks can be
enabled in parallel. If one doesn't like typing role="SUB" twice one can
use <trackgroup role="SUB">. In practice I think role="" will simply be
omitted in simple cases like this, if the selection algorithm we define
allows it.



Complex case: two subtitle tracks and two caption tracks in two different
languages:

In <track><source> markup:

<video src="video.ogv">
   <track role="SUB">
     <source src="subs.en.srt" srclang="en">
     <source src="subs.sv.srt" srclang="sv">
   </track>
   <track role="CC">
     <source src="cc.en.srt" srclang="en">
     <source src="cc.sv.srt" srclang="sv">
   </track>
</video>

In <trackgroup><track> markup:

<video src="video.ogv">
   <trackgroup role="SUB">
     <track src="subs.en.srt" srclang="en">
     <track src="subs.sv.srt" srclang="sv">
   </trackgroup>
   <trackgroup role="CC">
     <track src="cc.en.srt" srclang="en">
     <track src="cc.sv.srt" srclang="sv">
   </trackgroup>
</video>

Personally, I prefer <trackgroup><track> because it matches what I think
of as a "track" and the minimized form caters to the common case.

GF:  I prefer <trackgroup><track> as well--  grouping tracks by role makes the most sense to me. But I'm still confused about one thing after reading today's thread.  From this markup, it looks to me like <trackgroup><track> also would permit multiple tracks of the same role to appear simultaneously.  True?  Playing simultaneous tracks of the same role is still what I'd prefer (in addition to playing simultaneous tracks of differing roles, of course).