Video compression refers to the relationship between the quality of digital video images and the quantity of data space used on DVR hard drives. The less a video is compressed, the higher and more detailed the video quality will be. The opposite is true as well: if a video is highly compressed, the picture quality will be visibly poorer.
So, why would one compress a video? Uncompressed, finely detailed video takes up much more hard drive space than compressed lower-resolution video, meaning you’ll be able to capture significantly more footage without endangering memory use. You have to decide whether to record less video of better quality, or more video of poorer quality; it all depends on your needs. Refer to the comprehensive chart below for an outline of what you can expect from each compression level.