This sounds like a problem that has been introduced by Apple in iOS6, relating to MJPEG streams. Various manufacturers and software developers have reported the same. Here is one direct reference in the Apple Forums: http://discussions.apple.com/thread/4347848?start=0&tstart=0

Some integrators have had mixed results by reducing the frame-rate and resolution of the video stream.

At this time, we have no workaround within TPControl. We also anticipate the issue will be resolved by Apple in an update to iOS.