On 2/3/14 03:33, Jamie McDonnell wrote:
so I took a look into the stats available currently, and unfortunately
Available Send Bandwidth and Available Receive Bandwidth don't seem to be
exposed, which is what I am using to represent the quality of the call, along
with the jitter value in Chrome.
We're targeting the evolving stats interface that is being discussed in
the W3C, which does not include these metrics (at least, not at the
moment), although we may introduce additional information on an
experimental basis (just like Chrome has with the "bandwidth" stats you
mention):
http://www.w3.org/2011/04/webrtc/wiki/Stats
Basically, if you don't see a stat listed on that page, I'd be very
cautious about using it, as it may be removed or changed significantly,
based on the conversations currently underway at the W3C. (And, even if
something is listed, it might be changed based on those discussions,
although it's less likely.)
What are your thoughts on representing call quality to the end user in a simple
visual way?
The dominating factors in media quality are going to be jitter, packet
loss, and RTT.
* For jitter, we already have an entry in the stats report
* I'll suggest to the working group that we should add packet loss to
the evolving list of stats
* As far as I know, there's no good way to get RTT information out of
RTP and RTCP, so you'll probably want to rig something up with a
DataChannel that basically sends a small message with a sequence
number to the other side, which responds immediately; the time
between sending the message and getting the response is you RTT
From there, I'd try to work out a quality metric by starting with
something like:
(min(6ms - jitter_in_ms, 0) * (100% - packet_loss_in_percent) *
min(200ms - rtt_in_ms, 0))/600
...which should get you a number between 1 and 100. You might want to
tweak things a bit, but that should get you a good first pass estimate.
I'm happy to demo to you in Chrome what we currently have (if that doesn't go
against your morals? ;)
Sure, send me a URL to look at. :)
--
Adam Roach
Principal Platform Engineer
[email protected]
+1 650 903 0800 x863
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