Hi Luca, we have exactlly the same problem. The video&audio is fine between two Polycom Trio Realpresence 8800 with Skype for Business, but when a third Skype client joins or we start a multiparty conference from the Trio, the video quality is terrible, with freezing video.
Did you finally got the solution?
welcome to the Polycom Community.
It is always useful to include the currently used UC Software version as issues experienced or a question asked may already be addressed in a newer release.
Please also include if you are using a on premise of off premise Skype for Business server.
This also allows yourself and others to check against current software release notes, Administrator Guides or FAQ post’s.
The above is also stated in the "Must Read First" and is the absolute minimum requirement every new post should include. .
In addition providing us with this basic information gives Polycom an idea what Software Versions are used in the field and avoids wasting time trying to troubleshoot issues which have already been addressed.
Therefore the Polycom VoIP FAQ contains this post here:
Question: How can I find out my SIP or UC Software Version of my Phone?
Resolution: Please check here
As you may notice the post was marked as solved and the discussion is nearly 1.5 years old. Since then we have introduced simulcast so I am not aware of anyone else having this issue.
I suggest you get this to the attention of support.
In order to raise a support ticket you need to work with your Polycom reseller as they need to do this for you. End Customers are usually unable to open a ticket directly with Polycom support.
If this is some sort of an Internet discounter please post either your phone's MAC address or your Polycom devices serial so I can look up who would be able to support you. This may not be who you purchased the Polycom device from.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
If official support is required please check how to phone or open a case here----------------