- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Thu, 16 Jun 2011 14:55:30 +1000
- To: Mark Watson <watsonm@netflix.com>
- Cc: Bob Lund <B.Lund@cablelabs.com>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Note that I haven't yet seen a use case that absolutely requires us to know if a track is additional or alternative. If we do, we can always use a data-* attribute for this right now. If we see the data-* attribute being required to solve use cases, then we can ask for the introduction of an additional marker. Bob: what was your use case? Cheers, Silvia. On Thu, Jun 16, 2011 at 2:53 PM, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote: > On Thu, Jun 16, 2011 at 1:07 PM, Mark Watson <watsonm@netflix.com> wrote: >> I had a different understanding. >> >> We keep coming back to these cases where we can imagine both "alternative" and "additional" tracks as solutions to some problem. >> >> I've argued at length before that it doesn't work to have a blanket mechanism whereby any track can be labeled as either "alternative" or "additional" - and indeed we have no such mechanism: it's implicit in the track kind - you need to understand the kind to know whether it is alternative or additional. >> >> I actually thought that all our audio kinds were alternatives. I'm no expect, but I would guess that it's hard to create a descriptions track which can be freely mixed with the original audio. > > > I've done so before. It's not hard at all. You listen to the original > track and you speak into the microphone. It is easier to record it in > this way because the quality of the original audio doesn't degrade. It > is also the way in which for example the jwplayer works: > http://www.longtailvideo.com/support/addons/audio-description/15136/audio-description-reference-guide > . > > It would be bad if you have to mix in the original audio because that > both degrades the quality of that track, increases the required > bandwidth (because compressed silence is smaller than compressed > sound), requires re-recording the original content (which might end up > in copyright trouble), and requires switching between tracks rather > than just adding and removing a track. Switching between tracks will > be a lot more perceptible than adding/removing a second track. > > So, I can only see advantages to having an audio description provided > as a separate track. > > >> If both kinds exists (alternative descriptions and additive descriptions), then we need two kind values. Given that it's an accessibility requirement it would be nice for it to be explicit, so I would expect to have two "descriptions" kinds e.g. descriptions-add and descriptions-alt. > > I've only ever seen audio descriptions that come as separate tracks. > In the TV case you would have had to mix it for transmission because > there was only one channel available for transmission, but I believe > that is the artificial case. The more natural case is to have them > separate. > > > Cheers, > Silvia. >
Received on Thursday, 16 June 2011 04:56:18 UTC