I recorded a short video of the Cuisinart ICE-50 churning a batch of vanilla ice cream. The ICE-50 is a now discontinued and no longer supported with spare parts self-chilling ice cream machine. You just pour in the base, turn it on, and it makes a batch of ice cream in about 45 minutes.
The lumps you see are more frozen pieces of ice cream. It freezes on the wall of the tub and is scraped off by the paddle creating a slurry of more and less frozen ice cream. Once it's put into a container and frozen it's nice and smooth.
I would highly recommend the ICE-50 to anyone who is interested in ice cream making. They have not been made or supported for years but our two are tanks and just keep going. I can't offer an opinion on the newer machines other than to say if you buy one but spare parts for everything you can. A motor arm, two stem and paddle assemblies or two of each if you buy them individually, a bucket, and at least four covers. That will keep you going for 20 or 30 years as long as the machine keeps running.