[webrtc-stats] RTCStats.timestamp - fingerprinting and since epoch (#786)

hamishwillee has just created a new issue for https://github.com/w3c/webrtc-stats:

== RTCStats.timestamp - fingerprinting and since epoch ==
The MDN docs for [RTCStats.timestamp](https://developer.mozilla.org/en-US/docs/Web/API/RTCIceCandidatePairStats/timestamp) say this for the value:

> A [DOMHighResTimeStamp](https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp) value indicating the time at which the activity described by the statistics in this object was recorded, in milliseconds elapsed since the beginning of January 1, 1970, UTC.
> 
> The value should be accurate to within a few milliseconds but may not be entirely precise, either because of hardware or operating system limitations or because of [fingerprinting](https://developer.mozilla.org/en-US/docs/Glossary/Fingerprinting) protection in the form of reduced clock precision or accuracy.

Is this correct. Looking at the [spec for the timestamp](https://w3c.github.io/webrtc-stats/#dom-rtcstats) it just says 

> Timestamps are expressed with [DOMHighResTimeStamp](https://www.w3.org/TR/hr-time-3/#dom-domhighrestimestamp) [[HIGHRES-TIME](https://w3c.github.io/webrtc-stats/#bib-highres-time)], and are defined as [Performance](https://www.w3.org/TR/hr-time-3/#dom-performance).[timeOrigin](https://www.w3.org/TR/hr-time-3/#dom-performance-timeorigin) + [Performance](https://www.w3.org/TR/hr-time-3/#dom-performance).[now](https://www.w3.org/TR/hr-time-3/#dom-performance-now)() at the time the information is collected.

It isn't clear that this is relative to the Unix epoch (to me) ("milliseconds elapsed since the beginning of January 1, 1970").

I also can't find anything that talks about the accuracy of this value, and how it is affected by fingerprinting. 

Can you confirm either point/the accuracy of the MDN docs?



Please view or discuss this issue at https://github.com/w3c/webrtc-stats/issues/786 using your GitHub account


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Received on Friday, 8 March 2024 04:03:29 UTC