- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Wed, 27 Oct 2010 14:44:27 +1100
- To: Daniel Weck <daniel.weck@gmail.com>
- Cc: public-html-a11y@w3.org, Fabien Cazenave <fabien.cazenave@inria.fr>, Gylling Markus <markus.gylling@gmail.com>, DeMeglio Marisa <marisa.demeglio@gmail.com>
On Wed, Oct 27, 2010 at 2:40 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote: > On Wed, Oct 20, 2010 at 9:34 AM, Daniel Weck <daniel.weck@gmail.com> wrote: >> Hi Silvia, with regards to your proposal [1]: >> >> I think that solution #3 doesn't need to rely on the "par" time container. >> As you know, introducing new markup elements with timing semantics into >> HTML5 is likely to raise the acceptance threshold, so I would like to >> suggest an alternative solution based on a new synchronization attribute. >> >> There is an actively-developed experimental W3C SMIL Timesheet >> implementation [2] that proposes syncMaster (boolean) and mediaSync (IDREF) >> attributes to mark HTML content in order to specify an explicit timebase >> (other than the default one implied by the Timesheet scheduler) for the >> playback of timed continuous media. >> >> Inspired by this mechanism, here is a refactoring of your example (please >> note that I actually prefer "syncMaster" to "mediaSync", but that's merely a >> syntactic sugar issue, so for consistency purposes I'll use the attribute >> just like it is used in the Timesheet implementation proposal): >> >> <video id="v1" controls> <!-- primary content --> >> ...SOURCE(s) and TRACK(s) >> </video> >> <audio controls mediaSync="v1"> <!-- pre-recorded audio descriptions --> >> ...SOURCE(s) >> </audio> >> <video controls mediaSync="v1"> <!-- sign language overlay --> >> ...SOURCE(s) >> </video> >> >> --- Note that the "mediaSync/syncMaster" attribute would modify the playback >> and seeking behavior of the media elements to which it is applied. >> Consequently, I think it would be necessary to specify that the "controls" >> attribute would be overridden (to false) *and* that the JavaScript control >> API would be disabled so that the playback of the supplemental audio and >> video (as per your example) would depend entirely on the "master" media >> object. >> >> Because of the simple nature of this proposal (coarse synchronization), I >> think it would help a great way towards supporting pre-recorded audio >> descriptions (as opposed to textual ones already supported by the track >> element) and sign-language overlay in HTML5. >> >> Let me know what you think. >> Cheers, Dan >> >> [1] >> http://lists.w3.org/Archives/Public/public-html-a11y/2010Oct/0520.html >> >> [2] >> http://labs.kompozer.net/timesheets/audio.html#htmlMarkup >> http://labs.kompozer.net/timesheets/video.html#htmlMarkup >> > > I've just checked the specification of SMIL Timesheets [1] and wasn't > able to find either a mediaSync or a syncMaster attribute. Is that > something that Kompozer introduces or is that specified somewhere > else, too? > > Thanks, > Silvia. > > [1] http://www.w3.org/TR/timesheets/ > Gah, just some more googling and I found it: http://www.w3.org/TR/SMIL3/smil-timing.html#Timing-ControllingRuntimeSync has syncMaster, but not mediaSync. Is mediaSync introduced to avoid the use of <par> ? Cheers, Silvia.
Received on Wednesday, 27 October 2010 03:45:20 UTC