- From: David Singer <singer@apple.com>
- Date: Tue, 10 Dec 2013 15:50:20 -0800
- To: Glenn Adams <glenn@chromium.org>
- Cc: Silvia Pfieffer <silviapfeiffer1@gmail.com>, Victor Carbune <vcarbune@chromium.org>, Silvia Pfeiffer <silviapf@chromium.org>, "public-texttracks@w3.org" <public-texttracks@w3.org>, Nigel Megitt <nigel.megitt@bbc.co.uk>
On Dec 10, 2013, at 15:46 , Glenn Adams <glenn@chromium.org> wrote: > Whether or not pixels, SMPTE time codes, frames etc are useful are not is irrelevant to this discussion. TTML supports them. So any discussion of mapping TTML to VTT or HTML or anything else for that matter has to deal with these at some level. > > This thread is not about second guessing or redesigning TTML. Well, one assumes that in a TTML session that could be rendered, along with video that can be, one can work out over time which captions to display at what times. If this is true, then simple NPT timestamps can be derived to express that. If it’s not true, then a TTML renderer has the same problem as a TTML to VTT converter. The same is true of positioning. It is not a goal to replicate (all of) TTML in VTT. It is a goal to enable TTML to be delivered in VTT, just as it was a goal that a captioning session expressed in TTML could be delivered in x08. David Singer Multimedia and Software Standards, Apple Inc.
Received on Tuesday, 10 December 2013 23:50:48 UTC