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
X-Lite is a user-friendly VoIP client that excels in audio quality but is limited in video conferencing features, making it suitable for individual calls. In contrast, Jitsi is a robust open-source platform ideal for video conferencing and collaboration, offering more flexibility and features for group communication.