[Ccrtp-devel] Jitter calculations are making me jittery

[Silverman, Greg]

I am a newbie, and, when looking at how ccRTP computes jitter I am confused about the way it computes transit time.The RFC calls for

transitTime = arrival_time_in_ts_units-packet_timestamp

However, ccRTP, in IncomingDataQueue::recordReception, is computing arrival_time_in_ts_units as the difference between stack startup time and last packet time. This seems wrong because the first packet could be an RTCP and the first RTP packet could arrive many seconds later, so, the initial jitter value could be huge. Also, SyncSourceLink::lastPacketTime is initialized to (0,0) and never updated.

Greg Silverman
NGC
San Jose, CA