Other options

Debug spot removal

If you check this option, the spots will not be removed but enclosed in rectangles. Red rectangles mark the spots that are subject for removal. Blue rectangles mark the spots that were detected but identified as moving objects. Those spots that were detected but have no perimeter clearance or area fullness are not marked.
Also, this mode will highlight those cells from the motion table where the motion threshold is exceeded.

Preview

When using the Preview button, keep in mind that there is a large time lag between the input frame and the output. It equals ( Kernel-1)/2+5 frames.
Note, that the time lag does not affect the sync to audio in the output file.