rtsp into jit.qt.movie output as 160 x 120

All rtsp video streams I read into jit.qt.movie play back are
resized to 160 x 120

However I can read a video stream at its
native resoltion (eg 320 x 240) if I create the stream with jit.qt.broadcast, save the .sdp data file and then open this file
with jit.qt.movie.

But I need to access rtsp video streams from other sources
than jit.qt.broadcast and at a better reloution than 160 x 120.

I'm using

Jitter 1.5.2
Max 4.5.7
OS X 10.4.8
Quicktime 7.1.3

Any ideas?

Many Thanks

Jon