- From: Maciej Stachowiak <mjs@apple.com>
- Date: Thu, 21 Apr 2011 21:47:37 -0700
- To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Cc: HTML Accessibility Task Force <public-html-a11y@w3.org>, Eric Carlson <eric.carlson@apple.com>
Hi Silvia, Could you please also post these messages to public-html so the whole WG is aware? Thanks, Maciej On Apr 21, 2011, at 9:20 PM, Silvia Pfeiffer wrote: > This is a reply by Eric and myself. > > Eric and I hereby confirm that we withdraw our change proposal 3 > http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Change_Proposal > since we are in amicable consensus with change proposal 4, even if the > 5 changes listed below are not applied immediately, but registered as > bugs on the spec and dealt with post LC. > > Best Regards, > Silvia & Eric. > > > On Fri, Apr 22, 2011 at 2:12 PM, Silvia Pfeiffer > <silviapfeiffer1@gmail.com> wrote: >> (sending this on behalf of the accessibility task force) >> >> Dear HTML WG chairs, >> >> The undersigned members of the media subgroup of the accessibility >> task force have come to a consensus on ISSUE-152, which we'd like to >> share with the larger group through this email. >> >> We appreciate the extra time provided to us by the chairs to further >> discuss the submitted four change proposals and come to an agreement. >> There have indeed been lengthy discussions during the provided time >> frame and we have made great progress. >> >> The group has come to a consensus on which proposal to support. While >> some of our feedback on that change proposal has already been taken on >> board, there is still a list of 5 outstanding changes that need to be >> addressed for the specification text to be complete. >> >> The four proposals on the table are as follows: >> >> 1. Audio Track Selecction for Media Element >> submitted by: Frank Olivier >> http://lists.w3.org/Archives/Public/public-html/2011Feb/att-0363/CP_Issue152.htm >> >> 2. Media Multitrack Change Proposal 2: Synchronize separate media >> elements through attributes >> submitted by: Sean Hayes >> http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Change_Proposal_2 >> >> 3. Media Multitrack Change Proposal: Synchronize separate media >> elements through attributes >> submitted by: Silvia Pfeiffer and Eric Carlson >> http://www.w3.org/WAI/PF/HTML/wiki/Media_Multitrack_Change_Proposal >> >> 4. Proposal for Audio and Video Track Selection and Synchronisation >> for Media Elements >> submitted by: Ian Hickson >> http://lists.w3.org/Archives/Public/public-html/2011Mar/0436.html >> >> >> CONSENSUS >> The undersigned members of the media subgroup of the accessibility >> task force have agreed to withdraw proposals 1-3 in favor of proposal >> 4 with the following additions to be made to the proposal: >> >> (1) track kind for in-band tracks: >> >> At this point, it is also not possible to discover the functionality >> that a in-band track provides through script. A similar problem was >> solved for the TextTrack object by introduction of a kind attribute. >> This is also necessary for the TrackList object, in particular to >> introduce a standard naming scheme across different media container >> formats for exposing the kind of data that their tracks provide. >> >> Therefore, we request addition of a getKind(in unsigned long index) >> function to the TrackList object, or something of equivalent >> functionality. >> >> The proposed list of values that kind should understand are: >> for video: >> * sign language video (in different sign languages as provided through >> getLanguage()) >> * captions (as in: burnt-in video that may just be overlays) >> * different camera angles >> * video mosaic >> for audio: >> * audio descriptions >> * language dub >> * commentary (such as director's commentary) >> * clear audio (see >> http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Requirements#Clear_audio) >> >> >> (2) loop attribute for grouped multitrack: >> >> The MediaController object currently does not allow for looping of the >> grouped resource. This is inconsistent with what is possible on >> individual media elements and also inconsistent with what is possible >> on in-band multitrack media resources. The same behavior that an >> in-band multitrack resource exposes on looping needs to also be >> possible on a grouped multitrack resource. >> >> Therefore, we request addition of a loop IDL attribute on the >> MediaController object. >> When it is set to true, playback on the grouped multitrack must >> restart after all slave elements have ended. >> >> It is set to true when at least one of the media elements in the group >> have a loop IDL attribute that is set to true, false otherwise. >> Alternatively, it would also be acceptable to set it to true only when >> all of the media elements in the group have a loop IDL attribute that >> is set to true, though that seems overly verbose. >> >> >> (3) autoplay attribute for grouped multitrack: >> >> The MediaController object currently always autoplay without a means >> to control this autoplay behaviour and without consistent autoplay >> across all the slave elements. This is inconsistent with in-band >> multitrack media resources. One of the main use cases for the >> introduction of autoplay attributes was that this allows the UA to >> expose a user setting that disables autoplay behaviour, which is >> particularly useful to vision-impaired users who cannot easily locate >> autoplaying media elements. >> >> Therefore, we request addition of a autoplay IDL attribute on the >> MediaController object. >> When it is set to true, playback of the grouped multitrack must start >> once all slave elements have reached a readyState of HAVE_ENOUGH_DATA >> and can play through. >> >> It is set to true when at least one of the media elements in the group >> have a autoplay IDL attribute that is set to true, false otherwise. >> Alternatively, it would also be acceptable to set it to true only when >> all of the media elements in the group have a autoplay IDL attribute >> that is set to true, though that seems overly verbose. >> >> >> (4) readyState for grouped multitrack: >> >> The MediaController object currently does not expose an aggregate view >> of the readyState of the slave media elements. It is, however, >> impossible for a developer to reliably aggregate the readyState from >> the individual slave media elements, since their states may continue >> to change. The media framework inside the UA is the only place where >> such aggregation is sensibly possible. >> >> Therefore, we request addition of a readyState IDL attribute on the >> MediaController object. >> It must represent the minimum state that all the slave media elements >> have achieved. >> >> >> (5) onended event: >> >> The MediaController object currently does not expose an onended event. >> This is inconsistent with in-band multitrack media resources and a >> convenience event that is useful when reacting to the situation of all >> slave elements being finished. This would for example be the case for >> a grouped multitrack resource with an ordinary video track and a sign >> language track, where the ordinary video track should get a display of >> further related videos once all tracks have finished playing. It would >> e.g. wait until the sign language track is finished before it >> displayed further information. >> >> Therefore, we request addition of a onended event to the MediaController object. >> >> >> Best Regards, >> >> Media Subgroup of the Accessibility Task force >> >> Judy Brewer >> Janina Sajka >> John Foliot >> Sean Hayes >> Frank Olivier >> Eric Carlson >> Mark Watson >> Bob Lund >> Silvia Pfeiffer >> >
Received on Friday, 22 April 2011 04:48:11 UTC