IGCSE Computer Science 0478: Data compression, lossy and lossless
Students learn why files are compressed and how lossy compression and lossless compression (including run-length encoding) reduce file size, and when to use each.
One content description from the full IGCSE Computer Science 0478 — 1.3 Data Storage and Compression journey. All 19 modules below are in that journey too, with the same content — add just these to a class, or the whole strand.
Modules (19)
1
Compression - losing quality or saving space?
2
Why compression is needed: less storage space
3
Why compression is needed: less bandwidth
4
Why compression is needed: shorter transmission time
5
Lossy compression
6
Lossy compression permanently removes data
7
Effect of resolution and colour depth on image quality and file size
8
Effect of sample rate and resolution on accuracy and file size
9
Lossy compression of an image by reducing resolution or colour depth
10
Lossy compression of a sound by reducing sample rate or sample resolution
11
Redundancy: repeated data that can be shortened
12
Lossless compression
13
Run-length encoding: encoding text
14
Run-length encoding: decoding
15
Run-length encoding of a row of coloured pixels
16
Decoding run-length encoded image data
17
When run-length encoding makes data bigger
18
Comparing lossy and lossless compression
19
Choosing a compression format for a task
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