The resolution of CCTV cameras and recorders is always increasing
The image becomes clearer with more pixels, pixels are the little dots that make up an image
Modern equipment is measured in Megapixels, or Million Pixels.
The amount of megapixels is measured by multiplying the image width with the height.
For example 1920 x 1080, commonly known as 1080P is 2 Megapixel
1920 x 1080 = 2,037,600 pixels
This graphic shows what portion of a 4K (8 Megapixel) screen the different resolutions would give before being resized to fit the screen