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RE: ACTION-216 Review video, audio, image, media in HTML5

From: Jim Allan <jimallan@tsbvi.edu>
Date: Thu, 3 Sep 2009 14:10:54 -0500
To: "'Markku Hakkinen'" <markku.hakkinen@gmail.com>, "'Jeanne Spellman'" <jeanne@w3.org>
Cc: "'Kelly Ford'" <Kelly.Ford@microsoft.com>, "'UAWG list'" <w3c-wai-ua@w3.org>
Message-ID: <03b501ca2cca$4316bce0$c94436a0$@edu>
The other item to add is
The User Agent should be required to provide the controls/interface-elements
for media (audio, video, etc.). The author should be able to style or script
for extended functionality. The core functionality - start/stop, pause,
seek, volume, size (full screen), caption track(s)- on/off/fg-bg
color/location, descriptive video(s), should not be written by millions of
authors.

> -----Original Message-----
> From: Markku Hakkinen [mailto:markku.hakkinen@gmail.com]
> Sent: Thursday, September 03, 2009 1:38 PM
> To: Jim Allan; Jeanne Spellman
> Subject: ACTION-216 Review video, audio, image, media in HTML5
> 
> Comments on Video/Audio/Image is HTML5
> Based upon http://www.whatwg.org/specs/web-apps/current-work/
> 
> Note: the comments pertaining to video also apply to audio.
> 
> 4.8.7 Video
> 
> Biggest issue:  Accessibility of the video content left unspecified.
> No mechanism for defining or providing captions as part of the Video
> element.  This is unfortunate, in that W3C's very own proposed DXFP
> [1], and even SMIL Text [2] provide everything needed to create
> accessible video content (assuming the authoring tools and browser
> support were there).
> 
> Given the controversory over video codec support, captioning is
> apparently not being given attention.  The spec says:
> 
> "4.8.10.10 User interface
> 
> The controls attribute is a boolean attribute. If present, it
> indicates that the author has not provided a scripted controller and
> would like the user agent to provide its own set of controls.
> 
> If the attribute is present, or if scripting is disabled for the media
> element, then the user agent should expose a user interface to the
> user. This user interface should include features to begin playback,
> pause playback, seek to an arbitrary position in the content (if the
> content supports arbitrary seeking), change the volume, and show the
> media content in manners more suitable to the user (e.g. full-screen
> video or in an independent resizable window). Other controls may also
> be made available.
> 
> User agents should provide controls to enable or disable the display
> of closed captions associated with the video stream, though such
> features should, again, not interfere with the page's normal
> rendering."
> 
> It is not clear to me that the spec has specified/will specify a
> standard API that would allow a UA to query if media (either audio or
> video) ".hasCaptions", or to otherwise get at the text of the captions
> (or the language, etc).
> 
> If the UA (or AT) is supposed to have the ability to control captions,
> shouldn't the video element have defined the needed properties to
> query and control the caption content in the video being
> loaded/played? This seems very vague and a big gap for such a visible
> feature of the HTML5 spec. Failing any further details in the HTML5
> spec, it is imperative that the UA spec will  address the missing
> details.
> 
> Silvia Pfeiffer [3] has been active in looking at HTML5 video
> accessibility, and has a proposal for iText as a means of integrating
> captioning into HTML5 video.  This is great work, to be lauded, but I
> am still at a loss for the failure to integrate existing W3C work such
> as DXFP for captioning.  I must be missing something.
> 
> No mention of descriptive video or alternate audio tracks.  Again, is
> this something that *may* be in the video source, pr authored using a
> combination of scripting and the audio/video elements? Unclear, and
> should be addressed.
> 
> My take on HTML5 video is that, based on the current spec,
> implementation of captioning/dvs will will primarily occur via
> authored scripting around the video element. Perhaps some browser
> vendor will build it in a non-standard way. It should be defined more
> fully in the HTML5 spec.
> 
> 
> 
> 
> 
> [1] http://www.w3.org/TR/2009/WD-ttaf1-dfxp-20090602/
> [2] http://www.w3.org/TR/SMIL3/smil-text.html
> [3] http://blog.gingertech.net/2009/07/29/first-experiments-with-itext/
Received on Thursday, 3 September 2009 19:12:42 GMT

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