I am trying to overlay two video clips. I found the answers in this thread to be really useful:
http://nch.invisionzone.com/topic/25627-using-mask/
However the example there with the flying saucer is using a mostly dark coloured image on a fairly dark background. My video clips are taken outside and are quite light in colour, especially the sky area, and I find that I am seeing dark lines around my cut-out area. If I use feathering that actually makes it worse and I get thicker lines.
I intitally thought the problem might be due to the lighting being very slightly different in the two clips, but I was able to reproduce the problem just using a solid white image overlaid on two tracks.Using the default reactangular mask I don't see the lines, but if you alter the mask shape they appear.
Any ideas how I can remove or reduce these lines?
Thanks
Phil.