The native LED resolution would have been 1536 x 96 pixels...
...it would have been a four row split on a PAL-canvas - would have done that with four mixes on one screen and Offsets.

Catalyst video content on this LED strip was cancelled this morning - so I don´t have to worry about this any longer for now...

I am not an SDI expert but as far as I know every frame in PAL-SD-SDI consists of 864 x 652 pixels total image size.
Depending on your hardware 720 x 576 or 768 x 576 pixels will be used as active picture area...

Olli