How can I fix the video playback issues on my MacBook Air?

I bought a used Macbook Air, running Monterey and am finding what seems to be a system problem with video playback. It first appeared when trying to play a video stored on a USB using Quicktime Player. I thought it was the file or player that were the problem, but then I've found the same problem online--for example, with Facebook Reels. The audio works fine, but the video is jerky (frame by frame). However, videos work find on sites like Youtube and Disney Plus. I'm guessing it's because of the type of file or software used to play the videos, but my troubleshooting so far hasn't helped. I tried running First Aid, updating video codecs, and checking to see if a program was running in the background. No dice.

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