From Wiki for iCub and Friends
You may see images that seem to jump back and forth in the following cases:
- If there are multiple connections between two ports. This can happen in mcast or udp connections if the process that owns the target port dies or is killed without closing the port. The easy way to make sure that isn't happening is to call "yarp disconnect /SOURCE /TARGET" before anything else.
- If you are using tcp communication and your machine's buffers are getting filled up. YARP does its best to discard data in such cases, but there's only so much it can do. Try switching to udp or mcast.