Videoconferencing software that uses GTK

Ekiga (formerly called GnomeMeeting) was a VoIP and video conferencing application for GNOME and Microsoft Windows. It was distributed as free software under the terms of the GNU GPL-2.0-or-later. It was the default VoIP client in Ubuntu until October 2009, when it was replaced by Empathy. Ekiga supports both the SIP and H.323 (based on OPAL) protocols and is fully interoperable with any other SIP compliant application and with Microsoft NetMeeting. It supports many high-quality audio and video codecs.