File formats and codecs

Uncompressed

WAV and AIFF

WAV and AIFF are the standard file formats for uncompressed PCM audio. Generally they will be the source material for your lossy encoded files, unless you skip the step of making uncompressed files and go straight from CD to lossy compressed encodings.

The best practice would be to archive your uncompressed files somewhere, and keep them to make new encodings from as technology improves, or for purposes of keeping a backup.

For more information check out the Wikpedia pages on them: WAV and AIFF

Compressed

MP3

MP3 is the compressed format most prevalent on the internet and most universally supported by media players. It uses lossy compression to greatly reduce the amount of data needed to store the audio. For DJing applications, care should be taken not to reduce the amount of data too far, to maintain the audio quality of your files.

AAC

AAC is a more recent technology, intended as the successor to MP3. It is the default encoder in Apple iTunes and is part of the MPEG-4 specification. While AAC has many improvements over MP3, it is less widely adopted at the time of writing.

Ogg Vorbis

Ogg is an open source container format which can contain all sorts of media, Vorbis is the open source lossy audio compression format which uses the Ogg containers.

Check out more information on Ogg Vorbis here:

Ogg
Vorbis