I am using Java Media Framework to transmit video from one computer to another. However I need only a section of each frame to be displayed at the receiver (for example, the top left hand corner of the frame).

I am using a pass-through codec which I set on the data flow path and allows me to access each frame. Using this I can draw on each frame (for example draw a circle overlay on the frame) however when I then try to crop or select a subimage of each frame it does not work. It jus outputs an original, un-altered frame as if the codec wasn't there.

Does anyone have any suggestions as to what could be wrong? Also I would be interested to know if anybody has tried to do anything similar and how you went about it. I was thinking of perhaps using the Robot class to capture a section of a video on screen as a different approach to the problem but not sure how to go about doing that?

Any help is much appreciated.