RE: Tech Discussions on the Multitrack Media (issue-152)

Right, I'm not proposing anything here; just asking.

-----Original Message-----
From: Eric Carlson [mailto:eric.carlson@apple.com] 
Sent: 02 March 2011 17:22
To: Sean Hayes
Cc: David Singer; Silvia Pfeiffer; public-html
Subject: Re: Tech Discussions on the Multitrack Media (issue-152)

Hi Sean -

On Mar 2, 2011, at 5:37 AM, Sean Hayes wrote:

> 
> There seem to be two possible interpretations of 
>     <track kind="descriptions" srclang="en" label="English Audio Description">
>          <source src="audesc.ogg" type="audio/ogg">
>          <source src="audesc.mp3" type="audio/mpeg">
>      </track>
> One is that the audesc media is a complete replacement for the audio in the <source> element with the main soundtrack and descriptions pre-mixed, the second that the audesc is only the descriptions, and is intended to be mixed with the <source> audio at the client. Similar comments apply to the sign language option; and might even, if the captions option were of type video, apply to kind captions too where it is a replacement video with the captions burned in, or a smaller video with burned in captions to be placed PiP.
> 
> Do you intend that the 'kind' attribute be able to distinguish between these cases, or would it be better if there were a separate '@combinator={replace|add}' attribute that allows the author to mark these cases?
> 
  This is an interesting question but it isn't specific to our proposal, it applies to any multi-track solution.

  The UA can't know if an external track augments the main resource or is a replacement for an internal track, so I think the page author must be able to signal it in the markup. I am not wild about "combinator", but I don't have a better suggestion just yet.

eric