- From: David Singer <singer@apple.com>
- Date: Sun, 06 Apr 2014 11:45:21 +0200
- To: Silvia Pfieffer <silviapfeiffer1@gmail.com>
- Cc: Glenn Adams <glenn@skynav.com>, Jim Ley <jim.ley@gmail.com>, Aaron Colwell <acolwell@google.com>, "<public-html-media@w3.org>" <public-html-media@w3.org>
I think that adding/removing tracks, or reloading the entire video element, are cleaner and more direct ways to get the UA to re-evaluate what it is playing. Switching a track to russian and then saying “oh, I switched you to russian, hope you don’t mind” seems rather roundabout and an un-needed duplication of this functionality. On Apr 6, 2014, at 8:21 , Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote: > On Sun, Apr 6, 2014 at 4:12 PM, Glenn Adams <glenn@skynav.com> wrote: >> >> On Sat, Apr 5, 2014 at 11:55 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> >> wrote: >>> >>> On Thu, Apr 3, 2014 at 12:20 AM, Jim Ley <jim.ley@gmail.com> wrote: >>>> On 2 April 2014 09:26, Silvia Pfeiffer <silviapfeiffer1@gmail.com> >>>> wrote: >>>>> >>>>> On Wed, Apr 2, 2014 at 6:04 PM, Jim Ley <jim.ley@gmail.com> wrote: >>>>>> >>>>>> Isn't the use case for language being mutable simply live subtitles >>>>>> of a >>>>>> live "channel" that has programmes in different languages and >>>>>> therefore >>>>>> has >>>>>> closed captions / subtitles in different languages. >>>>> >>>>> Each one of those subtitle languages would be a different track, so >>>>> there is no need for mutability. >>>> >>>> >>>> No they're not, some shows are in English, some are in Welsh, the >>>> subtitle >>>> track is a single one for the live broadcast, similarly with audio, the >>>> broadcast audio changes languages. >>> >>> Every show should have its own subtitle track. >> >> >> That is an operational policy issue that shouldn't be determined by the >> technology. For example, TTML explicitly supports the presence of multiple >> languages in a single TTML document. The user of TTML decides how to use it: >> whether to create different TTML files for different languages, or whether >> to merge different languages into the same TTML document (allowing selection >> to occur at processing or rendering time). > > You can do that if you just deliver content and leave the rendering to > the application. > > In the discussed case, the user of the technology is the browser user > and there are certain assumptions under which content is consumed. > > I explained the poor consequences that a mid-change of track language > and kind can have on the example of a blind user. Do you disagree with > that example? > > >> It should not be construed to be poor practice of a TTML author merges >> different languages into the same file, > > That may be as is. > >> which translates to a single track >> using HTML5 mechanisms. > > At the point where you hook into HTML5, you have to deal with the > content consumption approach of HTML5. A TTML file with cues of > multiple languages should be converted into as many tracks as there > are languages in use. This is a requirement of the way in which tracks > are consumed in a HTML5 browser. A TTML mapping into HTML5 would need > to provide for this functionality. > > Regards, > Silvia. David Singer Manager, Software Standards, Apple Inc.
Received on Sunday, 6 April 2014 09:45:59 UTC