Data Compression

Question 1

Define run-length encoding:

Answer 1

A method of compressing data (often images) by removing repeated data

Question 2

Define dictionary encoding:

Answer 2

A method of compressing data in text files by replacing common strings

Question 3

How does jpeg compression work:

Answer 3

The image is split into 8x8 grids, and removes the data least likely to affect the perception of the image, and then uses run-time encoding

Question 4

How does run-length encoding work:

Answer 4

Identifies sequences of identical data values / colour pixels and represents these as one data value / one pixel colour, together with a count of how many such values are in the sequence