Portable MP3 players first started to appear in 1999 some 12 years after research had begun at the Fraunhofer Institut in Germany.
They store music in a computer audio format known (unsurprisingly!) as MP3. MP3 stands for MPEG (Motion Pictures Expert Group) Audio Layer. It is a compression standard that reduces the size of a music file to less than a tenth of its original size with little or no loss of sound quality. It is the result of the development of standards MPEG-1 (a video compression standard with low bandwidth) and MPEG-2 (an audio and video compression standard with high bandwidth, also used with DVD technology) and, confusingly, is part of the MPEG-2 standard.
MP3 players use either flash memory or large capacity but small-sized hard drives to store and play music files. The sound is not quite as good as a CD, but it is still of high quality.
MP3 files can be downloaded from the Internet to a computer using specialist software. They can be transferred to a portable MP3 player or recorded onto a CD. They can also be transferred from a CD or an MP3 player back to a computer, and files can be sent via the Internet to someone else.