- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Mon, 7 Apr 2014 17:51:45 +1000
- To: Aaron Colwell <acolwell@google.com>
- Cc: "<public-html-media@w3.org>" <public-html-media@w3.org>
On Mon, Apr 7, 2014 at 5:05 PM, Aaron Colwell <acolwell@google.com> wrote: > In the interest of trying to move forward on the MSE bug 24370, I'm going to > try to provide a high level summary of the "Resolving Bug 24370" thread and > propose a way forward. Please forgive me if I accidentally misrepresent > something. > > Summary: > 1. Changes in languages are allowed during the course of a presentation, but > there is some debate about how these should be represented in HTML5. The > majority opinion in the thread appears to prefer immutable language & kind > attributes and track objects being added & removed to reflect language > changes. > > 2. Currently track kind can't be signalled in ISO-BMFF content. A new > box/atom needs to be defined to signal this information. > > 3. No argument or example has been given that requires Javascript to > explicitly change the language or kind of a track. My interpretation of Jim > Ley's comment is that the application only wants to be notified of changes > in the media and does not need to be able to change the values on the > tracks. > > 4. Bob Lund and David Singer appear to explicitly support removing the > mutable attribute definitions. I believe Silvia Pfeiffer implicitly supports > their removal based on the arguments she has made in the thread. I also > support removal of the mutable attribute definitions. I thought I was quite explicit about that. ;-) > Proposed Next Steps: > 1. Remove the mutable attribute definitions for language and kind. I'm > unclear about the process around this sort of change since this is not an > "at risk" feature. I'd hate to have to go through a long Last Call process > again for this. > > 2. Work with David Singer and other MPEG savy folks to define a new box/atom > for ISO-BMFF to carry track kind information. This definition could > initially live in the ISO-BMFF byte stream format spec while it is waiting > to be officially standardized by MPEG. > > 3. Silvia and/or Hixie update the HTML specs to reflect the expected > behavior for language & kind changes. I don't have concrete proposals for > this at the moment, but it seems like there has been confusion around the > intended behavior when track changes occur mid-playback and whether or not > the track attributes can change value during playback. I think two things should be done in the HTML spec: * explain that language & kind changes have no effect * recommend, possibly even require that in-band tracks with cues of several languages should be exposed to HTML as multiple text tracks I think taking this back to the open bug in the WHATWG would be a good way to continue the discussion with Hixie. > Please indicate your support or opposition to the summary and proposed next > steps. You have my support. Cheers, Silvia.
Received on Monday, 7 April 2014 07:52:33 UTC