Rate–distortion theory

Okay kiddo, do you know what a picture is? Just like the ones you draw or the ones you see on TV? Great! Now, imagine you want to send this picture to your friend who lives far away. But you don't want it to take up too much space, like your toy box filling up with toys! You want to make sure your friend can still see the picture clearly, but you don't want it to take up too much space.

That's where rate-distortion theory comes in. It helps us figure out how much information we can remove from a picture, video, or audio clip before it starts looking or sounding bad. It's like a game - how much can we take out of the picture, video or audio clip without making it too hard for someone to understand what it is?

The rate part of rate-distortion theory means how many bits, or pieces, of information we need to send the picture or video clip to someone. The distortion part of the theory means how much the picture or video changes when we remove some of those bits of information.

So, let's say you have a big picture and you want to send it to your friend using a computer. But your friend doesn't have a lot of storage space, so you need to figure out how much of the picture you can take out without making it look blurry or distorted.

By using rate-distortion theory, you can find out the lowest number of bits you can use to send the picture without making it look bad. It's like a puzzle, you need to figure out which pieces to leave in and which to take out. The fewer the pieces, the smaller the file size, but still good enough quality for your friend to see what the picture is.

That's what rate-distortion theory is all about - making sure we can send pictures, videos, and audio clips with as few bits as possible, but still keep them looking or sounding good.