Compression

Question 1

why is compression needed

Answer 1

-To reduce the storage size of a file

Question 2

what is lossy compression

Answer 2

-With lossy, the decompressed file is not identical to the original
-because some data has been permanently removed
-the difference is unlikely to be noticed

Question 3

advantages of Lossy

Answer 3

• Achieves higher compression ratio / smaller file size

Question 4

disadvantages of Lossy

Answer 4

The file is lower quality once it has been
decompressed because some data was permanently removed.

Question 5

what is lossy compression suitable for

Answer 5

Images, sound, video because the difference is
unlikely to be noticed by humans

Question 6

what is Lossless compression

Answer 6

• With Lossless, the decompressed file is identical to the original

Question 7

Advantages of lossless compression

Answer 7

• No data is lost – after decompression the file is identical

Question 8

disadvantages of Lossless compression

Answer 8

Lower compression ratio so the file size won’t be as small

Question 9

what is Lossless compression suitable for

Answer 9

• Text or very high quality images, because if data was removed
  from text files it would not be readable