[whatwg] Video : Slow motion, fast forward effects

Philip Jägenstedt philipj at opera.com
Thu Aug 7 01:57:29 PDT 2008

I suggest that the spec allows raising the NOT_SUPPORTED_ERR exception
in response to any playback rate which it cannot provide for the current
configuration. With a netcast you couldn't support any playback rate
except 1.0 without first buffering all the data you want to play at a
faster rate, so changing the playback rate doesn't make sense. Throwing
NOT_SUPPORTED_ERR must be better than just ignoring it, but the question
is if script authors will remember to check for exceptions when setting
the attribute...


On Thu, 2008-08-07 at 10:28 +0200, Maik Merten wrote:
> Chris Double schrieb:
> > Given that codecs are often highly optimized for forward playback the
> > cost in memory can be excessive to go the other way. Could there be a
> > possibility to say 'reverse playback not supported'?
> This may be needed anyway, given that with streaming media you can't 
> reverse playback, even if the codec would allow it easily (which is not 
> the case for MPEG, VC-1, Theora, Dirac, <your favorite codec here>).
> An interesting case would also be how to handle playback speeds smaller 
> than "1x" in the streaming case, given that you cannot possibly have an 
> infinite buffer of input data. Streaming mostly forces a playback speed 
> of "+1x" in all cases.
> Maik
Philip Jägenstedt
Opera Software

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