Transparent video for Air Desktop App

I am developing an Air Desktop app to run on a PC.

The client has supplied me with several video files in mov format that I can see have some sort of transparent background. Basically the video is of a person dancing and the rest of the screen is totally blacked out.

I tested exporting it as a series of PNG files (PNG Sequence with Alpha) with Media Encoder CC and i can import the PNG files into Animate and it makes the black area transparent.

However each PNG file is 1920 x 1080 and there are 1800 PNG files for just one of the videos.

So I want to know if there is a better way to display this video animation within Animate with the transparency?

If not, would there be any implications of having so many PNG files?

Thanks in advance