[webrtc-stats] When are "fractionLost", "packetsLost, " "jitter", and other RFC3550-based stats updated?

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

== When are "fractionLost", "packetsLost," "jitter", and other RFC3550-based stats updated? ==
There are a number of stats that are described as "calculated as defined in section 6.4.1. of [RFC3550]", which is the "SR: Sender Report RTCP Packet" section. So my question is: should these stats represent the values from the last generated SR? Or should `getStats` return "live" values?

I'm bringing this up because I found that [Chrome only returns values from the last SR](https://bugs.chromium.org/p/webrtc/issues/detail?id=8804), and it wasn't 100% clear if this is the correct behavior or not; "calculated as defined in section 6.4.1" leaves it a bit ambiguous.

My opinion: for "fractionLost", this makes sense, since it's defined as "the fraction of RTP data packets from source SSRC_n lost since the previous SR or RR packet was sent". It's a somewhat redundant stat anyway, since it can be computed with `packetsReceived` and `packetsLost`. But for the rest of the stats, I don't see any reason why we shouldn't return live values.

Please view or discuss this issue at https://github.com/w3c/webrtc-stats/issues/313 using your GitHub account

Received on Friday, 26 January 2018 19:31:36 UTC