- From: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Date: Tue, 6 May 2014 14:45:48 +0000
- To: Philip Jägenstedt <philipj@opera.com>
- CC: Silvia Pfeiffer <silviapfeiffer1@gmail.com>, "public-texttracks@w3.org" <public-texttracks@w3.org>
On 06/05/2014 14:17, "Philip Jägenstedt" <philipj@opera.com> wrote: >On Tue, May 6, 2014 at 12:19 PM, Nigel Megitt <nigel.megitt@bbc.co.uk> >wrote: >> >> On 05/05/2014 15:14, "Philip Jägenstedt" <philipj@opera.com> wrote: >> >>>On Mon, May 5, 2014 at 2:50 PM, Silvia Pfeiffer >>><silviapfeiffer1@gmail.com> wrote: >>> >>>> NB: Incidentally, following CEA708 rendering as exactly as possible is >>>> inline with what the US law prescribes, namely identical rendering >>>> between TV and Online. Though, to be honest, there is a line of "rough >>>> identity" that I am prepared to accept and I would call overlap >>>> avoidance an optimisation of sorts, which is why I'm not really >>>> accepting this as an argument. >>> >>>What will we do if the European Union introduces similar legislation >>>and broadcasters say that their existing content is EBU-TT, a TTML >>>flavor? Should the TTML model be added to WebVTT? >> >> I don't know about adding the TTML model precisely but I do think it >>would >> be worth considering the logical semantics encapsulated in TTML for >>region >> definition and overlap processing, which has an accepted mapping from >> CEA708 already, and has therefore tackled these questions. Given that >> WebVTT is on Rec track in the TTWG and one of the deliverables is a VTT >> <--> TTML mapping it would make everyones' lives easier in creating that >> deliverable if the regions models are as closely coincident as we can >>make >> them, accepting the differences in rendering approach and syntax between >> the two formats. >> >> I haven't seen anything in the discussion so far that looks like a >>CEA708 >> requirement that can not already be met using TTML regions. If you want >> region overlap avoidance that would be different, but I suspect that >>isn't >> actually needed, and in any case would be a separate case from the >>z-index >> overlap order definition: I can't see how both approaches could apply to >> the same content simultaneously. > >So, my question was actually rhetorical. I don't think it should be a >goal in itself to map other formats to WebVTT, or for WebVTT to be one >format to rule them all. Sorry I didn't spot the <rhetorical> tag! In any case there is a point to discuss there. I agree that format mapping isn't an end in itself, but in this case we know that some form of mapping will be generated and we can aim to make life easier by reducing the size of the task. To be clear, there is a TTWG goal to map between WebVTT and TTML - it is in the group's charter. >If other formats have features that address common use cases that >WebVTT is missing then we should consider supporting those use cases, >of course. I get the impression this is about FCC-mandated requirements rather than usage frequency. It makes sense to do as little as possible to meet those requirements and expand & enhance later if people want to use it in new ways. Lifting the existing region model from TTML would probably fit that description. Nigel ----------------------------- http://www.bbc.co.uk 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. -----------------------------
Received on Tuesday, 6 May 2014 14:47:21 UTC