compression

Question 1

what is data compression

Answer 1

making file sizes smaller:
less storage space taken up
faster streaming and downloading
web pages load quicker
same content with smaller file size

Question 2

what is lossy compression
pros and cons

Answer 2

lossy removes data permanently from the file which reduces number of bits needed
pros
greatly reduces file size
less bandwidth
commonly used

cons
loses data and file cannot go back to original
can’t be used on text
worse quality

e.g MP3. ACC. JPEG

Question 3

lossless compression
pros and cons

Answer 3

lossless makes file sizes smaller less smaller by temporarily removing data and then is restored to original state when opened

pros
no reduction in quality
turn back to original
used on text and software files

cons
only slight reduction in file size less

e,g FLAC . ZIP. PNG

Question 4

explain and understand huffman coding

Answer 4

lossless compression technique
1. gives each data value à unique binary code
2. shorter binary codes appear more frequently
3. replace every character in string with huffman code

1 is on the right
0 is on the left

Question 5

RLE run length encoding

Answer 5

lossless compression
looks for repeating data called à run
stores number of times data repeats and only one copy of that data