Antisip and Belledonne Communications (company created by the author of linphone) had and have today a strong partnership in the development of mediastreamer2, the multimedia streaming engine of linphone.
In 2006, antisip hugely improved the mediastreamer2:
Antisip is a major SDK provider in the VoIP area: They made and maintain
the well known open source GNU osip and eXtended osip stacks
(osip2/eXosip2). They distribute a commercial full SIP VoIP toolkit based on the osip suite and mediastreamer2.
Antisip currently sells mediastreamer2 commercial licenses and support.