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I don't use a Mac or work with video or graphics, but maybe this can help someone.
Apparently this program lets you mask out the background of a video. And the usual price is meant to be $200, down to AU$15.99 for a limited time. It doesn't say for how long.
Details from a 3rd party site:
When we initially came across Flixel Photos’ Cinemagraph Pro ($200*) we though it looked neat enough, but the price tag was nuts. Now it’s marked down almost 93% to $15 for a limited time, and at that price level, it certainly demands some attention. The app does something we’ve never seen executed so easily before: it allows you to create “living photos,” pictures with moving parts.
Using a movie file as the initial input, you can select a specific region of the video to mask—preserving all of the detail and motion within the masked area—while leaving the rest of the image completely static. The resulting file can be outputted as a GIF or otherwise animated, looping video for embedding on a web site, radically reducing the file size relative to a full movie clip while giving a flat web site some slight, eye-catching motion. Resolution support is included for 4K videos and displays, as well as lower-res files.
Thanks OP but it looks like the offer has finished as it's back to normal price now.