When one tries to display a frame using XV of 2048 pixels (the maximum height on this card according to xvinfo). It gets squashed in the vertical direction. When displaying the same frame but then with a height of 2047 pixels everything works fine. This only happens with the traditional overlay, the textured overlay seems to handle a height of 2048 pixels just fine.
The video card in this machine is a:
01:00.1 Display controller: ATI Technologies Inc RV380 [Radeon X600]
fixed in 0f575984594e6977b4a7cb794dad8c6e56c850f1