animation over a video?

[rich2005]

Quote:.... However I already put an alpha channel as the background in my cad package..

Easy to check in Gimp. Open one of your png images. Use Layer -> Transparency and if Add alpha channel is greyed out then the image already has an alpha channel. There is also an indication in the layer menu layer name. No alpha is bold and with alpha not bold. Have a look at this one again https://i.imgur.com/TEYnDrp.jpg