The scanline option is not scanlines at all. It is a grid. Picture in attachments.
-Thanks in advance
we know. this is on purpose for a complicated reason. do you want a scanlines filter? bearing in mind that the hardware has a grid, and not scanlines? if so, then issue
--scanline-filter-a=0 --scanline-filter-b=0 --scanline-filter-c=4 --scanline-filter-d=4
on the commandline. is this unsatisfactory? if so, this should be turned into a feature request for an actual scanlines filter.