Compression

Question 1

Data Compression

Answer 1

When we make files smaller whilst tying to make compressed file as true to original as possible

Question 2

Uses of compressing data

Answer 2

Smaller files take up less storage space
Streaming & Downloading files from internet quicker as take up less bandwidth
Allow web pages to load more quickly in browsers
Allows you to send the same content with a smaller file size through Email Services allowing you to evade size of attachment restrictions

Question 3

Two Types of Compression

Answer 3

Lossy

Lossless

Question 4

Lossy

Answer 4

permanently removing data from file- limits number of bits the file needs and reduces its size

Question 5

Lossless

Answer 5

makes file smaller temporarily removing data to store file and the restores it to its original state when opened

Question 6

Pros of Lossy

Answer 6

Greatly reduced file size meaning more files can be stored
Lossy Files take up less bandwidth so can be downloaded & streamed more quickly
Commonly used- lots of software can read Lossy files

Question 7

Cons of Lossy

Answer 7

Loses data- File cant be turned back to original
Cant be used on text or software files, these files need to retain all information of original
Lossy files worse quality than original but loss in quality is normally unnoticeable

Question 8

Pros of Lossless

Answer 8

Data removed temporarily so there is no reduction in quality- compressed file should look/sound like original
Lossless files can be decompressed- turned back to the original
Lossless compression can be used on text and software files

Question 9

Cons of Lossless

Answer 9

Only a slight reduction in file size, so lossless file still take up quite a bit of space on your device
ex) A lossless song may have a file size of around 30MB, while the same song with lossy compression maybe 5MB