RIM has been doing everything they can to tear down the walls for BlackBerry 10 developers. Their latest move is to yet again validate the popular PJSIP open source SIP library for BlackBerry 10. This is exactly how TruFone brought their VoIP app to BlackBerry 10 and ported back their work to PJSIP which led to them adding initial support in June.
If you are working on or plan on working on a VoIP or video calling app for BlackBerry 10 you may want to check out RIM’s latest post on PJSIP and its capabilities in BlackBerry 10. TIM even has a sample app setup for developers to tie into the BlackBerry 10 audio subsystem and do things like enable the very important Echo Cancellation.