1.2.5 compression

what does it mean to compress a file?

to make its size smaller

what are the benefits of compression?

files take up less storage space, files can be transferred quicker, files can be read from or written to quicker

what are the two types of compression?

lossy and lossless

how does lossy compression work?

an algorithm is used to analyse and remove data that cannot be heard or seen by humans

what does further lossy compression do?

remove data that humans can see or hear

what does lossy compression do to data?

removes it permanently so the file can never return to its original form

what type of files is lossy compression used for?

images, audio and video to reduce the file size

how does lossless compression work?

reduces the size of a file without permanently removing any data

why would a file compressed with a lossless algorithm be larger than a file compressed with a lossy algorithm?

no data has been permanently removed so the file is returned to its original form when decompressed, meaning no quality is lost

what type of files is lossless compression used for?

files that wouldn’t work if data was removed, such as programs, games or word documents