Install libopal3.10.10 by entering the following commands in the terminal:
sudo apt update sudo apt install libopal3.10.10
Open Phone Abstraction Library - successor of OpenH323
This package contains the shared version of the OPAL library. . The OPAL project aims to create a full featured, interoperable, Open Source implementation of the H.323 and SIP protocols that can be used freely by everybody. These protocols are most used for Voice over IP (VoIP) conferencing. . This package contains the shared version of the OPAL library, together with several audio and video codecs.