Purple/Green line when playing dvd's?

[ElQuapo]

Does anyone know what this could be.

When playing back some of my dvd's (noticed it on both the new Star Wars IV dvd and on some of the Indiana Jones dvd's) there is a Purple/Green line at the bottom of my tv screen. It starts out purple at the left of the screen and turns green at the right side. It is only about 1mm thick. This is when playing on my NAD T513 dvd player.

Is it my dvdplayer? it doesn't happen with all dvd's.
Maybe the SCART cable?
Or is it just something wrong with these particular dvd's?

I think the last is correct but I can't figure it out. Has anyone else with the PAL versions of these movies experienced the same?

Thanks for any help in advance.

[thecoalman]

I've seen a green line at the bottom of some videos when playing in MS Media player but it never showed up on the TV. Right at the very bottom and the reason I know it wasn't visible on the TV was because it was widescreen.