Last year I posted an article about Mac Messenger 7 reporting that it supported H.263 in the SDP when it actually didn’t have that codec in the client. This was before Lync and at the time we didn’t know how it would be fixed in future releases. Now that the Lync for Mac 2011 client was out I thought I’d give a quick, though anticlimatic, update. In a nutshell the newest client still only supports RTV. The good news is that it advertises it properly in the SDP now:
m=video 51263 RTP/AVP 121 (note the absence of 34 after 121, which would indicate H.263)
a=rtpmap:121 x-rtvc1/90000 (no more a=rtpmap 34 H263)
However, the video landscape has changed quite a bit since I wrote that article last March. Most of the major video vendors support RTV either natively in their endpoints and bridges (Polycom) or via a gateway architecture (all other vendors as of this writing). Because of this shift support for the legacy H.263 codec is far less important than it was even a year ago. And that’s a good thing since the resolution of H.263 is too low to be really useful in many cases and it lacks the resiliency and flexibility of RTV. On a related video topic, stay tuned for some info on Polycom’s upcoming CX7000 room video system.
Thanks to Jeff Schertz for providing a Snooper log of the Lync for Mac 2011 call.