Re: HTML WG Note publication of sourcing in-band media resources

On Mon, May 19, 2014 at 2:46 AM, Silvia Pfeiffer
<silviapfeiffer1@gmail.com> wrote:
>
> On Fri, May 16, 2014 at 8:30 AM, Jerry Smith (WINDOWS)
> <jdsmith@microsoft.com> wrote:
> > The Introduction section of the In-Band Media Resource document implies that subtitles could be a subset of captions and share a single in-band track.  Is there any known example that actually does this?
> >
> > Jerry
>
> I've been told that there are some ISO BMFF files that have both 'SDH'
> and 'Subtitle' kinds associated with a single timed text track, so
> yes.

I think the bit that Jerry referred to is "it is possible that a media
container may encapsulate a subtitle and a caption track in a single
in-band track to save space. In HTML, these tracks will be exposed as
two TextTrack objects."

If such a track in ISO BMFF is to be exposed as two tracks, is there a
way to distinguish which cues should be excluded from the subtitles
track? Having two identical tracks is obviously not useful.

How do existing media players handle such files?

Finally, does ISO BMFF have SDH (subtitles for the deaf or
hard-of-hearing) as a separate flag from the subtitle and captions
kinds, or is possible to assign an arbitrary number of kinds to a
track? Either way it doesn't sound like it maps 1:1 to the HTML track
kinds.

Philip

Received on Monday, 19 May 2014 09:22:38 UTC