You've probably noticed, when it snows or when there confetti in a compressed digital video (YouTube, TNT, ...), quality becomes poorest. The youtuber Tom Scott explains why. Everything is a compression history and bit-rate. A video is compressed with a certain bit-rate, which indicates the amount of information that it sends per second. More high is the bit-rate, more the quality is high and the image is sharp and detailed. The modern algorithms allow to use a low bit-rate while maintaining acceptable video quality. How? By sending the pixels of the image only when they are changing. When Scott in front of a plain background, while the bit-rate is used to send just the image of Scott (without the background). He appears in good quality. But once you add snow or confetti, the algorithm has more data to manage with the same bit-rate. It must make sacrifices. If it wants to see all the little confetti that move, it must make Scott less detailed.