15:55:30 RRSAgent has joined #media 15:55:30 logging to http://www.w3.org/2011/03/20-media-irc 15:55:39 rrsagent, make log public 15:55:44 rrsagent, do not start a new log 15:55:57 meeting: HTML A11Y TF FtF - Media sub-group 15:56:03 chair: Janina_Sajka 15:56:08 Sean has joined #media 15:56:13 silvia has joined #media 15:56:24 Zakim has joined #media 15:56:27 zakim, this will be 21192 15:56:27 ok, MichaelC; I see WAI_(A11YAF2F)11:30AM scheduled to start 26 minutes ago 15:58:07 mkobayas has joined #media 16:22:01 eric_carlson has joined #media 17:38:11 silvia1 has joined #media 17:48:31 MikeSmith has joined #media 17:55:25 JF has joined #media 17:55:48 richardschwerdtfe has joined #media 17:57:02 frankolivier has joined #media 17:57:46 WAI_(A11YAF2F)11:30AM has now started 17:57:53 +??P0 17:58:03 silvia has joined #media 17:58:04 -??P0 17:58:05 WAI_(A11YAF2F)11:30AM has ended 17:58:05 Attendees were 17:58:22 you are back 17:58:50 TOPIC: HTML markup for the JS API that we discussed yesterday 17:58:55 WAI_(A11YAF2F)11:30AM has now started 17:59:01 +??P1 17:59:09 zakim, ??P1 is FtF 17:59:10 +FtF; got it 17:59:19 http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Media_API#.2810.29_HTML_Accessibility_Task_Force_proposal_.28.22The_San_Diego_Solution.22.29 17:59:55 EC: we proposed to extend to media resources, too 18:00:45 EC: we suggest to put inside the element and run the same source selection algorithm on tracks as we run on video 18:02:01 FO: so we have a source and a track selection algorithm 18:02:24 .. and the regular source selection algorithm is also applied to the source elements in the track element 18:02:34 EC: this is similar conceptually to having separate audio and video elements 18:02:39 scribe: silvia 18:04:21 janina has joined #media 18:04:32 Sean has joined #media 18:04:37 zakim, who's on the phone? 18:04:37 On the phone I see FtF 18:05:01 http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Media_API#.2810.29_HTML_Accessibility_Task_Force_proposal_.28.22The_San_Diego_Solution.22.29 18:05:38 FO: what do I do if track links to a resource, but that doesn't load? 18:05:48 EC: you set up all the tracks, but put an error on it 18:06:03 … I would assume that you don't render anything 18:06:21 SP: is it added to the list of available tracks on the menu? 18:06:25 A simple example: 18:06:29 EC: maybe not, or it's shown, but as disabled 18:06:30 18:08:26 SP: this means we probably need to extend the @kind type 18:09:03 and here is an example with multiple caption formats: 18:09:06 18:10:20 SP: this markup is where the formats are different for captions, but the content is identical 18:10:35 … if you wanted them both to appear for user selection, you'd need separate elements 18:11:12 FO: semantics look fine 18:11:29 … I like that we re-use things from the video element 18:11:50 … the track mechanics can basically be read from the JS API 18:12:13 … the supported track @kinds are left to the UA? 18:12:52 … so if e.g. the device doesn't support audio, then audio tracks make no sense 18:13:13 Bug around @kind: http://www.w3.org/Bugs/Public/show_bug.cgi?id=11593 18:14:03 SH: what if we need to replace the video because, e.g. we have extended audio descriptions or an alternative video with a sign language overlay? 18:14:22 … there is no markup way to do that? 18:14:56 EC/SP: you'd have to use script 18:15:16 SH: there is no way for the browser to understand this as an alternative representation? 18:17:26 EC: yes, and this is probably good, because the browser in the case of the sign language video would need to download the audio twice 18:18:01 SH: so the best way to set up your video element in this case would be to have an empty main video with just the timeline and the others as dependent tracks? 18:19:25 EC: yes, that is possible with MP4 - you need some kind of track, but it can e.g. just be a 1x1 pixel image with the duration of the video, since it defines the timeline 18:19:36 … it could also just contain the poster with that duration ;-) 18:21:44 SH: is there a way to attach metadata to a track to define the name of a track? 18:22:09 SP: Ogg and Matroska have this functionality FAIK 18:22:59 SH: MP4 can do it, but it's not sure if the MP4 baseline provides it 18:23:11 … might just be a convention 18:23:26 SP: are we happy with this kind of markup? 18:23:44 JF: what @kind attributes do we need now? 18:23:51 … see http://www.w3.org/Bugs/Public/show_bug.cgi?id=11593 18:23:59 I'd like to propose a strawman group='foo' attribute 18:25:17 SP: for audio descriptions we can probably just use the same value @kind=description as for text, because the content type will tell us whether it's audio or text 18:25:39 JS: is it necessary to distinguish between descriptions and extended descriptions? 18:27:34 SH: we have a problem if we specify both text resources and audio descriptions that are in the same 18:28:28 … does the source selection require the same main mime type content to be listed in alternative elements? 18:28:43 EC: no, source selection should continue to work in this situation 18:31:10 JF: what about extended audio descriptions? 18:31:39 SP: that means a change of the timeline and is a bit complicated 18:32:34 EC: the solution that Masatomo provided this morning with pauseOnExit may work if we use text tracks for extending 18:33:24 … seeking would be a problem 18:33:39 .. it's possible with a script - I am not sure we can do it without a script easily 18:33:52 … probably too hard to do it within the last call deadline 18:34:09 SH: we should at least address some mechanism of doing it 18:34:40 … text descriptions on the Web are more useful on the Web with snippets 18:35:09 EC: the requirement to split them into separate files is a bit honorous 18:35:29 SH: media fragments would work with a single audio file 18:35:36 EC: no plans to implement that 18:35:57 SH: you can do it with script 18:37:19 EC: the safest way is to separate them up front 18:37:53 JF: do we need @kind=signing and something for clear audio 18:41:11 18:41:23 18:41:59 18:42:21 SH: I think we need to be able to group tracks into groups where we can do replacements of a track or additions 18:44:23 … we need to give the UA enough information to be able to do the choices 18:44:31 SP: it's up to the user to make that choice 18:45:18 SH: in the case of, e.g. clear audio, we need a toggle control and how would the browser get this information? 18:46:43 SH: I propose we need an attribute called @group in which multiple tracks can be put together and thus marked as alternatives to each other 18:50:10 SP: how do radio buttons work in HTML? 18:50:57 SH: we could do that and use the same @name on all of the track elements that are alternatives to each other 18:53:35 SP: for clear audio, we have two audio tracks being an alternative to one - how would that work? 18:53:39 an example of @name used to specify alternate video tracks: 18:53:41 18:55:14 SP: I don't think that solves the clear audio case yet - show me the markup 18:56:33 an example with a clear-audio alternate: 18:56:37 18:59:02 SP: isn't clear audio a way to separate the foreground speech from the background noise in two different audio resources? 18:59:10 SH: you could do that, but that's not how it's typically done 18:59:50 EC: it only has the foreground speech, so you have the alternative between full audio and speech only 19:00:18 19:00:54 JF: how do we expose the different alternatives to the user? 19:01:05 EC: the @label does this, see the just posted example 19:02:02 MK: how do you do video or sign-language burnt in video and audio and clear audio? 19:04:33 SP: do we need a @kind for clear audio? 19:05:01 SH: we probably do, because right now the default is @kind=subtitles 19:05:20 example with video/video with burned in signing alternates, and audio/clear-audio alternates 19:06:01 SP: we could have just @kind=audio and @kind=video to say that we have alternatives to the main audio/video 19:06:04 because we have alternates for video and audio, we need to include a file as the