[whatwg] Implementation difficulties for MediaController

Ian Hickson ian at hixie.ch
Sun Mar 27 20:01:51 PDT 2011

It's been brought to my attention that there are aspects of the 
MediaController design that are hard to implement; in particular around 
the ability to synchronise or desynchronise media while it is playing 

To help with this, I propose to put in some blocks on the API on the short 
term so that things that are hard to implement today will simply throw 
exceptions or otherwise fail in detectable and predictable ways.

However, to do that I need a better idea of what exactly is hard to 

It would be helpful if you could describe exactly what is easy and what is 
hard (that is, glitchy or simply unsupported by common media frameworks) 
in terms of media synchronisation, in particular along the following axes:

 * multiple in-band tracks vs multiple independent files
 * playing tracks synchronised at different offsets
 * playing tracks at different rates
 * changing any of the above while media is playing vs when it is stopped
 * adding or removing tracks while media is playing vs when it is stopped
 * changing overall playback rate while a synced set of media is playing

Based on this I can then limit the API accordingly.

(Any other feedback you may have on this proposed API is of course also 
very welcome.)

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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