[Bug 26923] [InbandTracks] Number of HTML tracks from DASH

https://www.w3.org/Bugs/Public/show_bug.cgi?id=26923

--- Comment #6 from Bob Lund <b.lund@cablelabs.com> ---
(In reply to Bob Lund from comment #5)
> (In reply to Cyril Concolato from comment #4)
> > (In reply to Bob Lund from comment #3)
> > > OK. Then this bug should be closed and marked as a duplicate of bug 26921.
> > Part of this bug is a duplicate. Not all (see below). I don't want to close
> > it.
> > 
> > > > > > Also, it is not clear which AS
> > > > > > should be exposed ? All including those for which the mime type is not
> > > > > > supported?
> > > 
> > > This question did not get addressed. It seems to make sense that the UA
> > > should only create audio, video and non-metadata text tracks for media
> > > streams it can render.
> > Why would you only expose those tracks? Those tracks will be rendered. I
> > agree standardization will help for interoperability in the UI. But
> > standardization is even more important for the other tracks. The tracks that
> > the browser cannot render. 
> 
> Those would be metadata text tracks. The spec already has language for which
> AdaptationSet and ContentComponents result in the creation of metadata
> tracks.
> 
> As it stands now, the latest version [1] states exactly what constitutes an
> HTML track based on AS or CC MIME type. We could add a note stating that
> that the UA does not need to create tracks for audio/video MIME types that
> it cannot render.

[1] http://rawgit.com/w3c/HTMLSourcingInbandTracks/master/index.html#mpegdash
> 
> > Those are interesting to expose to JS so that JS
> > app do something with them. That's also mentioned by Silvia in [3]
> > "Exposing cues to JavaScript enables a Web developer to create all
> > sorts of interesting presentations around it, such as interactive
> > transcripts rendered next to the video."
> > [3] http://lists.w3.org/Archives/Public/public-inbandtracks/2014Sep/0014.html
> > 
> > 
> > > This bug was about creating tracks from the DASH MPD. Script created tracks
> > > is another topic.
> > I disagree.
> 
> The bug you submitted refers to UA.
> 
> > Scripts can be used to create tracks from the MPD. For the
> > tracks that are known to be supported, rely on MSE, for others do it by hand.
> > 
> 
> By hand, I assume you mean script. Yes, script can create text tracks.
> 
> > 
> > > > Why? Informative specs are not really useful. It should be normative. UA
> > > > don't have to implement it, but if they decide to implement it, it should be
> > > > done in a normative way. The MSE follows that approach for instance, it says:
> > > > "If an implementation claims to support a MIME type listed in the registry,
> > > > its SourceBuffer implementation must conform to the byte stream format
> > > > specification listed in the registry entry."
> > > 
> > > Feel free to go down that path.
> > Fine. Thanks.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.

Received on Tuesday, 14 October 2014 18:57:47 UTC