We have a single Lync 2013 Std server and single Lync 2013 Std edge server.

Clients are Lync 2013 with latest Office updates.

Clients connected via 1Gbps switch ports to each other and the Lync server, all on the same subnet.

Video calls between clients are having a low bandwidth limit applied to them, usually

Applied bandwidth limit:  350 Kbps
 Applied bandwidth source:  PreferenceValue
 

This of course limits the video quality, often to 480x240 15FPS.

Clients are Core i7, 2 cores (4 threads), support H264 acceleration (Intel HD Video 4000) and have WinRSAT Video Encode Score of 7.4

CSMediaConfiguration has MaxVideoRateAllowed set to Hd720p15M, CSConferencingPolicy has VideoRateKb set to 50000

What is the "preference value" and where is it coming from?

Hi,

AppliedBandwidthLimit - This is the actual bandwidth applied to the given send side stream given various policy settings (TURN, API, SDP, Policy Server, and so on). This is not to be confused with the effective bandwidth because there can be a lower effective bandwidth based on the bandwidth estimate. This is basically the maximum bandwidth the send stream can take barring limits imposed by the bandwidth estimate.

More details:

https://technet.microsoft.com/en-us/library/jj721928.aspx

Best Regards,
Eason

Thanks for your reply Eason.

What I'm asking is what is the "PreferenceValue" limit source.

I have seen "StaticMax" which I assume means a maximum hardcoded upper limit, but the source "preferenceValue" is not documented anywhere that I have found.  Does "preferenceValue" mean the guesses that the Lync client makes about the network?