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1. Introduction

Compression means to reduce the size of a data file whilst still retaining most, or even all, of the original information.

Commonly used file types that can be compressed are documents, music files, video and image files.

Data streaming services compress their files to ensure a lower bits-per-second transfer rate. If they were to deliver uncompressed files the service would be too slow to be of use.

Why do we compress files? The main reasons are:

  • Less storage space required for files
  • Faster download and uploads
  • Smaller file attachments for email
  • Coping with slow links when streaming

We will look at compression in more detail over the next few pages.