[whatwg] Introduction of media accessibility features

Eric Carlson eric.carlson at apple.com
Tue Apr 13 07:50:11 PDT 2010

On Apr 13, 2010, at 12:28 AM, Jonas Sicking wrote:

> Will implementations want to do the rendering of the subtitles off the
> main thread? I believe many browsers are, or are planning to, render
> the actual video graphics using a separate thread. If that is correct,
> do we want to support rendering of the subtitles on a separate thread
> too?
> Or is it enough to do the rendering on the main thread, but composit
> using a separate thread?
> If rendering is expected to happen on a separate thread, then CSS is
> possibly not the right solution as most CSS engines are
> main-thread-only today.
  It seems to me that the thread subtitles are composed, rendered, and/or composited on is an implementation detail that we should not try to spec. People are extremely sensitive to audio/video sync but we don't mandate how that should be handled, why start with captions?


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