Compression, Lossy, Lossless Keywords Compression, Lossy, Lossless Data Representation Compression

Compression Why does this happen? And how can we prevent it? Objectives BEGINNER: Understand the need for compression. ADVANCED: Know the difference between lossy and lossless. EXPERT: Analyse when lossy and lossless would be used. Starter activity Why does this happen? And how can we prevent it?

What is Compression? Objectives BEGINNER: Understand the need for compression. ADVANCED: Know the difference between lossy and lossless. EXPERT: Analyse when lossy and lossless would be used. Data compression is the process of encoding data so that is needs fewer bits/bytes to represent it. Compression is useful because it helps reduce the consumption of expensive resources, such as hard disk space or transmission bandwidth over the internet. On the downside, compressed data must be decompressed to be used, and this extra processing may be detrimental to some applications. Starter activity

Lossless and Lossy Objectives BEGINNER: Understand the need for compression. ADVANCED: Know the difference between lossy and lossless. EXPERT: Analyse when lossy and lossless would be used. Lossless compression can compress data files without losing any of the information. Lossless compression schemes are reversible so that the original data can be reconstructed. However not all data files can be compressed using Lossless compression. Lossy compression compresses data files but does lose some of the information. It is acceptable if some loss of accuracy is acceptable e.g. video, audio. ADVANTAGE: Can produce smaller data files. DISADVANTAGE: It’s not good if 100% accuracy required e.g. text files Starter activity