Help with syntax - overlaying a segment of VideoB onto VideoA

[trapp]

Could anyone help with the syntax for the following? I have VideoA and VideoB, both avi files, in 320x240. I’d like to lay a horizontal segment from the bottom of VideoB (pixel 186 to240, or 54 pixels) over the bottom of VideoA in the same position.

I’d like to be able to specify the frame in both videos at which the overlay should start: i.e. “begin with frame 24,000 in VideoB and overlay that beginning at frame 35,000 in VideoA.”

Just to gild the lily, since these videos may get out of sync, would it be possible to periodically “realign the overlay” by specifying multiple sets of frame numbers to align from VideoB onto VideoA? That is, say I start with the above figures of frame 24,000 from VideoB to start at frame 35,000 in VideoA, but then, due to edits, frame 100,000 in VideoB should start at frame 150,000 in VideoA, and so on at various specified points throughout the file?

Thanks for any help you can give,

Trapp

[Gavino]

Assuming A is the 'master' and is what is shown when there is no overlap, eg at start ...
a = AviSource(...) # video A
b = AviSource(...) # video B
top = a.Crop(0, 0, 186, 0)
bottom = b.Crop(0, 186, 0, 0)

part1 = a.Trim(0, 34999)
part2 = StackVertical(top.Trim(35000, 110999), bottom.Trim(24000, 99999))
part3 = a.Trim(111000, 149999)
part4 = StackVertical(top.Trim(150000, ...), bottom.Trim(100000, ...))
...
part1 ++ part2 ++ part3 ++ part4 ++ ...

You could probably parameterise it more by introducing a function, but you've got the basic scheme there.

[trapp]

Gavino, thanks for the help. Since I'm quite a beginner, this will real be a good challenge -- thanks so much!

Trapp