There are many audio formats, each having its own advantages and drawbacks. Many people prefer to keep their music collections in such popular formats as MP3, WMA, AAC, M4A, OGG etc. Others collect files in FLAC, APE, MPC, WV. These are just the most popular audio formats, with the difference that the first group contains so called "lossy" formats, while the second one represents "lossless" audio formats (of course, WMA and M4A may also contain lossless audio, but for the sake of simplicity we will not go into detail in this article). Depending on the source of your songs, you may get a variety of formats in your audio collection.