Compression

Simply put, compression is the science of storing large amounts of data in small packages. Without compression, digital video would be impractical for all but the most powerful computer systems. A single uncompressed frame of full-screen video consumes nearly 1 MB of storage. Capturing and playing back 30 uncompressed frames per second is beyond the capability of most hard disks and processors; the data rate (or flow of information) is simply too high.