Have you ever seen a picture or a video that has some strange lines or patterns around the edges of an object? Those lines or patterns are called ringing artifacts.
You know how sometimes you hear a loud noise and your ears start to "ring"? That's sort of what's happening with ringing artifacts. They are caused by a process called image processing, which is when a computer or camera tries to make an image look clearer or sharper.
When a computer or camera tries to process an image, sometimes it makes mistakes. These mistakes can cause some parts of the image to look like they are vibrating or ringing. It's kind of like when you try to color inside the lines but accidentally color outside of them.
The mistakes happen because the image processing tries to make the edges of objects more defined by adding a kind of halo or border around them. This halo can end up going too far and creates the strange lines or patterns we see.
So next time you see those lines or patterns in a picture or video, remember that they are called ringing artifacts and they happen because of image processing trying to make things look sharper.