Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application. Developed by University of Strasbourg (France), plus many others.
License: Open Source
Jitsi is primarily focused on video conferencing with strong privacy features, while Ekiga is a versatile VoIP solution that supports multiple protocols but may lack some advanced functionalities. Both are open-source and free, but Jitsi excels in ease of use for video meetings, whereas Ekiga offers broader protocol support for voice and video calls.