Data Compression: What it is and how it works

Data compression is used everywhere. Mp3, mp4, rar, zip, jpg and png files (along with many others) all use compressed data. Without data compression a 3 minute song would be over 100Mb and a 10 minute video would easily be over 1Gb. Data compression condenses large files into much smaller ones. It does this by getting rid of data that isn’t needed while retaining the information in the file.

Does that mean information is different to data? Yes. Lets take an example: I ask Bob who won the Arsenal game. He then launches into a 30 minute monologue about the match, detailing every pass, throw-in, tackle etc. Right at the end he tells me Arsenal won. I only wanted to know who won, so all the data Bob gave me about the game was useless. He could have compressed the data he sent into two words, ‘Arsenal won’, because that’s all the information I needed. Data compression works on the same principle. Continue reading