What are video compression artifacts? how do they manifest?

Compression artifacts are noticeable video artifacts caused by lossy compression.
Artifacts are rectangular fields of the same color, which can be quite large in monochrome areas of the image. They also reduce legibility.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.