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Re: Change Proposal for ISSUE-147

From: Mark Watson <watsonm@netflix.com>
Date: Fri, 18 Mar 2011 08:18:25 -0700
To: Ian Hickson <ian@hixie.ch>
CC: Philip Jägenstedt <philipj@opera.com>, "public-html@w3.org" <public-html@w3.org>
Message-ID: <7990BF01-B664-41F0-919A-2F67571D51CA@netflix.com>
Another possibility would be to define an event fired when the playback rate changes, for example when you are playing at >1.0 and hit the leading edge of a live stream, then playback rate should probably drop to 1.0 (equally, you can be playing at <1.0 and hit the "back" of an availability window for a live stream, meaning again you should switch to 1.0).

...Mark


On Mar 17, 2011, at 1:37 PM, Ian Hickson wrote:

> On Thu, 17 Mar 2011, Philip Jägenstedt wrote:
>> 
>> This CP assumes that the UA knows beforehand which playback rates it can 
>> support. Like many things in media, the only way of knowing for sure may 
>> be to try it, so how should a UA handle a situation like that?
> 
> It also seems like what playback rate is achievable might change in real 
> time, either based on changing stream characteristics, or based on 
> the CPU load varying. Also, some platforms have a limit to how many 
> simultaneous streams they can decode, in which case some streams would be 
> decoding at the actual rate (.playbackRate) and some would be decoding at 
> zero rate.
> 
> What might make sense is to do something like what Silvia proposed, but 
> instead of changing the existing API, just adding an API that returns 
> current playback metrics. That is, have playbackRate and 
> defaultPlaybackRate work as specced now, but add a .metrics object that 
> includes amongst other things an .actualPlaybackRate attribute that gives 
> the actual result. It would make a lot of sense to have this if we add to 
> it the other metrics that browsers are exposing in vendor extensions.
> 
> -- 
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 18 March 2011 15:18:59 UTC

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