1.3.1 Compression

Question 1

What is compression?

Answer 1

the process of reducing the storage size required by a file.

Question 2

how does lossy compression work?

Answer 2

lossy compression reduce the size file by removing info.
this could result in a pixelated image or unclear audio recording.
removed info cannot be recovered.

Question 3

How does lossless compression work?

Answer 3

• Lossless compression reduce the size of file without removing data.
• original file can be recovered from the compressed version.

Question 4

What are the 2 methods of lossless compression?

Answer 4

• run length encoding.
• dictionary encoding.

Question 5

What is run length encoding?

Answer 5

RLE is a method of lossless compression. Where repeated values are removed and replaced with one occurrence of the data followed by the number of repetition.

Question 6

What is dictionary encoding?

Answer 6

Dictionary encoding is a method of lossless compression where occurring data is replaced with an index and compressed data are stored in dictionary which matches the occurring data in the index.