It’s been a while since I took statistics, but yes, I guess that is a binomial distribution. It does not influence the results in the way you are implying it does, though. The calculator does actually account for it (the Population Proportion input), and the sample size actually decreases the lower/higher your proportion is. My point was that a question like, “Do you watch anime weekly,” is not like a question like, “How many hours of anime do you watch in a week,” where you certainly couldn’t assume a normal distribution for the number of hours watched.
All video codecs are lossy, meaning you will lose some quality. AV1 and H.265 are modern video codecs with the best quality to bitrate ratios, meaning you can get better quality for the same bitrate, or the same quality with a lower bitrate. The downside the these codecs is that they are very complex and computational expensive to do in software. You’ll want to make sure your GPU supports hardware encoding for the codecs you intend to record with. The reason most people will recommend AV1 over H.265 is that AV1 is royalty free. With H.265, companies have to pay a royalty to use H.265. Because of this, most companies (Netflix, YouTube, Facebook, Twitch, etc.) want to use AV1 going forward, meaning in the near future, it will probably be the dominant codec.