internal resolution of jit.qt.grab

Timo Rozendal's icon

hello, I have a question about how jit.qt.grab internally deals with resolution. Is is possible to know if some scaling is happening inside?

I know that for the windows version (jit.dx.grab) it is possible to get the preferrred capure resolution, how does this work with jit.qt.grab?

My main reason for this question at the moment is to check what is happening when I set my dfg1394 to send out odd fields only. Is it reducing the resolution internally (and thus datarate)?