He's losing words. Anyone with a parent or loved one suffering from dementia will recognize this pattern. Wen he says "moving cameras," it's because he can't recall the word "videos" and so he's stating the component parts as best he can. E.g., a "camera" is involved and the images are "moving"
Aaron RuparTrump: "We have photographs or tapes -- like moving cameras, right? -- where people are on the side cutting it with a box knife."