Matrix Help Required Please

[Puddsa]

Hi,
I'm sure this is a dumb question, but I've run out of ideas.
I've built a 70x40 pixel matrix.
It's 10 strings of 280 nodes, with 4 strands of 70 nodes per string.
Test mode on f48 lights up the whole board.
When I play through xlights my video does not show the top 5 rows, or the bottom 5 rows.
I'm sure it must be an aspect ratio thing of some sort, but so far have not been able to solve.
I tried recoding the MP4 aspect ratio out of xlights and reloading/rendering, but still get same result.
If anyone has some advice would be greatly appreciated.
Thanks
Colin

 

[AAH]

Does Xlights test mode light up the whole thing? Pop up screenshots will help out if it's either the whole thing working/not working on test or not showing full screen on video output.