Re: TTML2 anonymous inline region creation

On Wed, Oct 21, 2015 at 2:43 AM, John Birch <>

> I believe your proposal is more in line with users expectations.
> Viz: A user probably has the expectation that a region style attribute
> that is specified on a p element has an effect on the region that is
> associated with that p element.

pure speculation, nothing to suggest this in fact

> Changing display align dynamically could be useful in the case of a
> simplistic document using a 'full screen' 'transparent' region. Similarly
> changing writingMode to support mixed Arabic / Latin might be useful.
> Consequently I don't think restricting the scope to specific style
> attributes is necessary... some cases might be somewhat limited in utility,
> but it is probably easier to apply the anonymous set concept to all region
> style attributes.
> Best,
> John
> John Birch | Strategic Partnerships Manager | Screen
> Main Line : +44 1473 831700 | Ext : 2208 | Direct Dial : +44 1473 834532
> Mobile : +44 7919 558380 | Fax : +44 1473 830078
> | |
> Visit us at
> BVE, London Excel, 23-25 February 2016, stand C20
> P Before printing, think about the environment-----Original Message-----
> From: Nigel Megitt []
> Sent: 20 October 2015 15:48
> To: Timed Text Working Group
> Subject: TTML2 anonymous inline region creation
> All,
> Right now in TTML2 if a style attribute is specified on a p element that
> only has an effect on regions then an anonymous inline region is created.
> The style attribute inheritance chain is:
> >initial values -> anonymous region -> body -> div ... -> p -> span ...
> In considering how to fix tts:disparity it occurred to me that this isn't
> always what document authors might want or indeed expect.
> Another idea that I'm considering is: change from creating an anonymous
> inline region to creating an anonymous inline <set> element whose target is
> the region that applies to the element on which it applies and whose timing
> is coincident with the timing of the same element.
> In case of temporally overlapping elements that set the same style
> attributes to different values I would resolve the conflict using a
> begin-time-then-document-order rule, where last one wins.
> This would apply to the following style attributes that only have an
> effect on regions: tts:disparity, tts:extent, tts:origin, tts:position and
> tts:zIndex. I would probably exclude tts:displayAlign, tts:overflow,
> tts:showBackground and tts:writingMode because changing those on the fly
> would be weird.
> I'm just thinking this through right now, not definitively proposing it.
> The main thing I'm worried about is how the current solution interacts
> with issue-341 and issue-368. Even if we do go down the route of creating
> anonymous inline regions I imagine that authors will want a semantic like
> "just like a template region but with the specified style attributes
> differing", where the template region is the one that would have applied in
> the absence of the region-based style attributes on the p. That would also
> require a change to the inheritance chain, which would then be:
> Initial values -> specified region (if any) ... -> anonymous region ->
> body -> div … -> p -> span …
> Any thoughts on this appreciated, even if they're "Aargh don't change it
> now"!
> Nigel
> -----------------------------
> This e-mail (and any attachments) is confidential and may contain personal
> views which are not the views of the BBC unless specifically stated.
> If you have received it in
> error, please delete it from your system.
> Do not use, copy or disclose the
> information in any way nor act in reliance on it and notify the sender
> immediately.
> Please note that the BBC monitors e-mails sent or received.
> Further communication will signify your consent to this.
> -----------------------------
> This message may contain confidential and/or privileged information. If
> you are not the intended recipient you must not use, copy, disclose or take
> any action based on this message or any information herein. If you have
> received this message in error, please advise the sender immediately by
> reply e-mail and delete this message. Thank you for your cooperation.
> Screen Subtitling Systems Ltd. Registered in England No. 2596832.
> Registered Office: The Old Rectory, Claydon Church Lane, Claydon, Ipswich,
> Suffolk, IP6 0EQ

Received on Wednesday, 21 October 2015 09:14:41 UTC