That is not possible to have a worst image with overscan than without !
The more the overscan is, the bigger are the black borders arround the picture. And the bigger they are, the less you have data to encode. And the less data you have, the higter is the CQ.

when overscan is raised, quality is raised !
Nevertheless, the diff between overlap and resize isn't in the result (they both give an image of 352*480 with a black border of 16 pixels on each side).
The difference is : with overlap, you put the black border ON the image. That means that you can cut the top of the head of the caracter ifor instance.
With resize, the picture is REDUCED to enter between the borders. For instance, 352x480 with overscan 2 (so a border of 16 pixels on each side) means that you the picture is reduced to (352-2*16) x (480 - 2*16). This way you do not cut anything.[/quote]
For the script is simple :
resize
Code:
MPEG2Source(...)
...
GripCrop(352,480,overscan=2)
Gripsize(...)
...
GripBorders()
overlap
Code:
MPEG2Source(...)
...
GripCrop(352,480,overscan=0)
Gripsize(...)
...
GripBorders()
Letterbox(16,16,16,16)
(as you can see, the overlap is obtained with the letterbox function, and the resize is handle inside the gripcrop command)
Note : All this is given automatically by moviestacker. You don't use it ?