Lossy coding

The lossy coding, as its name suggests, loses some part of data during encoding. For these methods, mathematicians that invent the compression algorithms use human hearing and vision's psychological and physical features, such as not noticing certain types of signal - so, such signals are cut out as unnecessary. The majority of available codecs are like that, and they include the most popular ones like: MPEG1, MPEG2, DivX, XviD, MPEG4, MP3, and a multitude of not so well known ones.