RE: ISSUE-446: Should be a subset of IMSC1 [TTML WebVTT mapping note]

Please see my replies in the parallel thread that should help clear up (I think) some misunderstandings. In short, by all means please forge ahead!  The dragons lay ahead :-)

 Mike

-----Original Message-----
From: singer@apple.com [mailto:singer@apple.com] 
Sent: Wednesday, September 23, 2015 3:50 PM
To: Nigel Megitt <nigel.megitt@bbc.co.uk>
Cc: Timed Text Working Group <public-tt@w3.org>
Subject: Re: ISSUE-446: Should be a subset of IMSC1 [TTML WebVTT mapping note]


> On Sep 23, 2015, at 4:10 , Nigel Megitt <nigel.megitt@bbc.co.uk> wrote:
> 
> I disagree that the T2VP profile should be deliberately constrained to 
> be a subset of IMSC1, because it would be too limiting and wasn't 
> specified in the charter description of this Note.

I’m with Nigel.  Well, mostly. No, no, I support him.

Let’s work out the best mapping, and then if the mapped part of TTML is not cleanly part of a current profile, think about how to handle that case. So I am sort of with both of you: I don’t want to constrain the mapping work a priori, but I also don’t want to emerge with a needless mismatch a posteriori.

> 
> I do agree that if there are significant things that prevent IMSC 1 
> from being mappable to WebVTT then we should look at the discrepancies 
> and try to reconcile them. I also would not object to an additional 
> set of constraints that explain what limitations would apply to WebVTT 
> in order to convert it to IMSC 1, extra to what could be done if 
> mapping to TTML1 more generally.
> 
> Some obvious things that aren't in WebVTT but are constraints of IMSC 
> 1 that I do not think we need to carry over are the reference fonts, 
> the simultaneously active region limit and the HRM.

Yup.

> 
> Nigel
> 
> 
> On 23/09/2015 05:51, "Timed Text Working Group Issue Tracker"
> <sysbot+tracker@w3.org> wrote:
> 
>> ISSUE-446: Should be a subset of IMSC1 [TTML WebVTT mapping note]
>> 
>> http://www.w3.org/AudioVideo/TT/tracker/issues/446
>> 
>> Raised by: Pierre-Anthony Lemieux
>> On product: TTML WebVTT mapping note
>> 
>> The profile/authoring guidelines specified in the document should be 
>> a subset of IMSC1:
>> 
>> - it helps narrow down the set of features to be supported, e.g. no 
>> need to support #markerMode
>> - it simplifies the job of implementers who are already supporting 
>> IMSC1
>> 
>> Features have been deemed necessary but are not in IMSC1 should be 
>> considered for addition there.
>> 
>> 
>> 
> 
> 
> 
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David Singer
Manager, Software Standards, Apple Inc.

Received on Wednesday, 23 September 2015 23:05:11 UTC