[whatwg] HTML5 video seeking

Philip Jägenstedt philipj at opera.com
Tue Nov 15 01:30:23 PST 2011

On Tue, 15 Nov 2011 00:49:32 +0100, Aaron Colwell <acolwell at chromium.org>  

> Hi,
> I was looking at the seeking
> algorithm<http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#seeking>
> and
> had a question about step 10.
> 10. Wait until the user agent has established whether or not the media
> data for the new playback position is available, and, if it is, until it
> has decoded enough data to play back that position.
> Does this mean the user agent must resume playback at the exact location
> specified?
> What if the nearest keyframe is several seconds away?
> Is the UA expected to decode and toss the frames instead of starting
> playback at the nearest keyframe?
> On desktop machines I don't think this would be a problem, but on mobile
> devices it might be since the hardware may not be able to decode
> significantly faster than realtime. What is the intended behavior for  
> such
> constrained devices?
> Aaron

This was last discussed in the huge thread "HTML5 video: frame accuracy /  
SMPTE" where I made the suggestions [1] to introduce a seek() function to  
allow both frame-accurate and fast seeking. If you like that idea maybe we  
can just spec and implement it?


Philip Jägenstedt
Core Developer
Opera Software

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