- From: Janina Sajka <janina@rednote.net>
- Date: Thu, 7 Oct 2010 21:35:05 -0400
- To: HTML Accessibility Task Force <public-html-a11y@w3.org>
Conversations with the consumers of captions who were in attendance at the Open Subtitles Conference in New York City last week have exposed a potential additional requirement clause for CC-23, and have raised concerns regarding some of our explanatory text in Sec. 2.6 Captioning: http://www.w3.org/WAI/PF/HTML/wiki/Media_Accessibility_Requirements#Captioning 1.) The additional requirement ----- There was great concern about keeping captions synchronized with spoken dialog in primary media resources. Some participants even proposed schemes relying on tracking db variations in the primary media resource audio in order to resync captions. The several participants were in strong agreement that a realtime control to nudge captions forward (and backward) during media play would be very helpful. Their experience is that captions are frequently noticably out of sync, and that this is distracting. They referred to a media player which supports this today, but I've forgotten which--I'll have to grep the conference notes for that datum. PROPOSED ADDITION: Add a clause to CC-23 so that CC-23 would now read: Ascertain that captions are displayed in sync with the media resource. Provide a realtime control to allow users to adjust the caption forward and back against the primary resource. 2.) Explanatory Text Questions a.) Open vs. Closed Captions The relevance of open and closed captioning in an HTML 5 context proved confusing. Indeed, I don't believe we have a mandate to somehow specify either or both. Rather, either can and should be achieved by the consumer using their chosen client browser. If this is correct, the third and fourth sentences in our first paragraph are confusing people. They confused people in NYC last week. SUGGESTION: Rewrite sentences 3 & 4 of our first paragraph in Sec. 2.6 to read: Historically, captions have been either closed or open. Closed captions have been transmitted as data along with the video but were not visible until the user elected to turn them on, usually by invoking an on-screen control or menu selection. Open captions have always been visible; they had been merged with the video track and could not be turned off. b.) Is our 3rd paragraph correct? Our third paragraph currently reads: "The timing of caption text can coincide with the mouth movement of the speaker (where visible), but this is not strictly necessary. For timing purposes, captions may sometimes precede or extend slightly after the audio they represent. Captioning should also use adequate means to distinguish between speakers as turn-taking occurs during conversation; this is commonly done by positioning the text near the speaker, although in some countries color is used to indicate a change in speaker." Do we stand by our assertion that synchronizing captions to spoken dialog is not strictly necessary? Given #1 above, do we still believe this? Is the wider experience of caption users different from what we heard in NYC? Were our NYC consumers unrepresentative of caption users as a whole? Also, our NYC consumers strongly opposed colorizing caption text to identify speakers, and strongly opposed positioning caption text next to the person speaking. Again, did we draw nonrepresentative consumers at the NYC event? Or is our text incorrect? Janina PS: Some useful NYC conference URIs: http://universalsubtitles.org/opensubtitles2010 http://subsummit.universalsubtitles.org/index.php?title=CART-09-29 http://subsummit.universalsubtitles.org/index.php?title=CART-09-30 -- Janina Sajka, Phone: +1.443.300.2200 sip:janina@asterisk.rednote.net Chair, Open Accessibility janina@a11y.org Linux Foundation http://a11y.org Chair, Protocols & Formats Web Accessibility Initiative http://www.w3.org/wai/pf World Wide Web Consortium (W3C)
Received on Friday, 8 October 2010 01:35:36 UTC