What is an MP3 file? It is a compressed sound sample. It is as if the sample was zipped or arj-ed. Only this way compression is even better and the file does not need to be decompressed to be played.

The MP part of MP3 stands for Mpeg. You probably know that name from the compressed movies. Mpeg actually stands for Moving Picture Experts Group. But nowadays this group is also involved in compressing sound samples and multi-media "streams" (both pictures and sound).

MP3 is the standard extension for a file that is encoded with Mpeg 1 layer 3 encoding. There are also layer 1 and layer 2 encoding techniques. The main difference is that layer 3 has a better compression ratio. If you take a CD recording and use layer 3 encoding, you can a compress a file more than ten times without audible quality loss. If you allow loss of quality you can compress a file more than 20 times and be left with an "FM-radio quality" or even 40 times and end up with a "better than shortwave radio" quality.

That is about all I know about the subject. If you want to know more, check these links:

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