W3C home > Mailing lists > Public > public-html-a11y@w3.org > April 2011

RE: text track associations

From: Sean Hayes <Sean.Hayes@microsoft.com>
Date: Wed, 13 Apr 2011 15:38:41 +0000
To: Eric Carlson <eric.carlson@apple.com>
CC: Ian Hickson <ian@hixie.ch>, Silvia Pfeiffer <silviapfeiffer1@gmail.com>, Mark Watson <watsonm@netflix.com>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>
Message-ID: <8DEFC0D8B72E054E97DC307774FE4B91442CB4CD@DB3EX14MBXC313.europe.corp.microsoft.com>
Eric >> "Why? Like video, captions are a type of visual media." ... " It never even crossed my mind that a file with only audio samples shouldn't work in a <video> element"

My mistake - my testing was incorrect, it does seem that audio files are implemented across the board.  What I meant was that authors might not, as I did not, immediately grasp that to deliver an audio file with display captions requires using a video element; as captions aren't normally considered video and neither is audio. But I note that logical conclusion of your two statements above is that considering captions as timed visual media means one might expect them to work as a source on a video element, is that what you intended?

Eric >> " If we require the src to a <video> element to contain visual media, what should happen with a file that can change characteristics while it is playing, eg. an adaptive stream that switches to audio-only when the user's bandwidth changes?"

Nobody said anything about requiring video samples, I'm just concerned that the spec reflect reality.

Eric>> " What is the difference between a "video" and a "movie"? How about "A video element is used for playing video or audio files."

Works for me, I don't know why Ian included the term movie, unless he intended it to mean an audio visual resource, where video might be construed as having no audio.

Eric>> " I guess this could go either way, but I think it is more logical for an <audio> element to render only audio samples "

If the only difference between the video and audio element is that one can have a display rectangle and the other cannot, why don't we just say that? Better still get rid of the element and just make display-ability a toggle attribute on <video>.

Anyway, I'm OK with the solution suggested; provided the spec is clear that is allowed, and how its intended to be done.
Received on Wednesday, 13 April 2011 15:39:24 UTC

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