How to render movie clip with transparency or if not how to Join transparent PNGs into a clip?

How can you render say a movie clip containing just characters with all the background being transparent?
Seems only PNGs can have transparency. I'm making a movie in a movie making program and it does not take in image series, so i cannot bring DAZ rendered series of images and form them into a chunck in my program( Filmora). So how do i make the image series into a clip and keep transparency? Is there a utility program for this for Windows 10?.
If i'm correct DAZ for windows renders AVI but AVI does not keep transparency right?
Comments
get the free Hitfilm express by liking/sharing it on Facebook or Twitter, it imports image series with alpha and has lots of chromakeying options and filters.
You might try Moho website & see if it has that capability but I sort of doubt that a finished animation would have transparency.
HI Guys. I think i got it. I installed the Lagarith codec which contains RGBA. So i can render AVI from DAZ and it will retain the transparency!!!!!
Previously i intalled Lagarith codec for the purpose of using to get transparent things out of Unity(Game engine)into video avi. and it works.
So this workstoo. I was surprised because suddenly i got a popup promting me to choose the codec of my DAZ Rendered movie