Shorten (SHN) is a file format used for compressing audio data. It is a form of data compression of files and is used to losslessly compress CD-quality audio files (44.1 kHz 16-bit stereo PCM). Shorten is no longer developed and other lossless audio codecs such as FLAC, Monkey's Audio(APE), TTA, and WavPack (WV) have become more popular. However, Shorten is still in use by some people because there are legally traded concert recordings in circulation that are encoded as Shorten files. Shorten files use the .shn file extension.
A file with the CDDA file extension is a CD Digital Audio file that stores audio in the AIFF format. CDDA files are normally seen only when audio files have been ripped from an audio CD that uses the CD Digital Audio specification. This is most often done through the Apple iTunes program with the Audio CD burn option.