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Re: DOMHiResTimeStamp

From: Harald Alvestrand <harald@alvestrand.no>
Date: Thu, 07 Feb 2013 20:15:13 +0100
Message-ID: <5113FD41.5020606@alvestrand.no>
To: public-webrtc@w3.org
On 02/07/2013 05:50 PM, Dominique Hazael-Massieux wrote:
> As discussed during the meeting on the way to define stats reports,
> there is a spec that defines a high-resolution timestamp:
> http://www.w3.org/TR/hr-time/ (and it's a recommendation since December!
> )
>
> Dom
Hm - I'm a bit confused about how to convert NTP timestamps into this 
format:

The|DOMHighResTimeStamp| 
<http://www.w3.org/TR/hr-time/#sec-DOMHighResTimeStamp>type is used to 
store a time value measured relative to the|navigationStart| 
<http://www.w3.org/TR/navigation-timing/#dom-performancetiming-navigationstart>attribute 
of the|PerformanceTiming| 
<http://www.w3.org/TR/navigation-timing/#performancetiming>interface[NavigationTiming] 
<http://www.w3.org/TR/hr-time/#NavigationTiming>, the start of 
navigation of the document, or a time value that represents a duration 
between two|DOMHighResTimeStamps| 
<http://www.w3.org/TR/hr-time/#sec-DOMHighResTimeStamp>.

I think we'll have to store the base somewhere and make explicit 
reference to it; Performancetiming.navigationStart doesn't seem terribly 
relevant.

Having the base be different for different objects solves the "NTP clock 
skew" problem (but does raise a few other issues).
Received on Thursday, 7 February 2013 19:16:22 UTC

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