1.5 Data compression

Question 1

What is compression?

Answer 1

A method that uses an
algorithm to reduce the size of a file.

Question 2

What is lossless compression?

Answer 2

No data is lost — original file can be exactly restored.

Question 3

What is lossy compression?

Answer 3

Some data is removed — smaller file but original can’t be fully restored.

A method that uses an
algorithm to reduce unnecessary and
redundant data in the file. This data is permanently removed from the file. Ex: Images, sound files

Question 4

What is Run-Length Encoding (RLE)?

Answer 4

A type of lossless compression that stores repeated values as counts.
This algorithm will group together repeating pixels
and store how many times they occur.

Question 5

Benefits of compression

Answer 5

• Not as much storage space is needed to store the file.
• It will take less time to transmit the file from one device to another.
• It will be quicker to upload and download the file.
• Not as much bandwidth is needed to transmit the file over the internet.

Question 6

perceptual music
shaping:

Answer 6

a process that is used in lossy compression that removes sounds that are not normally heard by the human ear.