Compression

Question 1

What are the reasons for compression?

Answer 1

• Reduces size of file: Takes up less space.
• Maximise the amount you can store on a device.
• Smaller files are quicker when transferred (streamed) over the internet.

Question 2

What is lossy compression?

Answer 2

• Some of the data is lost permantley.
• Reduces file size.
• Reduces the quality.
• Suitable for: Images, Videos and Audio.
• Cannot be used on text or executable files.

Question 3

What is loseless compression?

Answer 3

• None of the data is lost. It is encoded differently.
• Can be turned back to it’s original format.
• Used on all types of data.
• Less effective than lossy compression at reducing file size.
• Suitable for documents and executable files.