SHN files belong to the Shorten file format, which is used for compressing audio data. This file format supports lossless compression of CD-quality music. By the term 'lossless compression', we mean that the original quality of audio content is not lost. The compression is brought about without subtracting any frequencies from the audio files. Tony Robinson of SoftSound, dealing in audio processing applications, wrote the audio compression scheme for .shn files.
The Shorten file format is commonly used for concert recordings that are encoded as .shn files. As they facilitate a lossless compression of audio files, they can be transcoded with different forms of audio codecs without hampering audio quality.
There are a few media players which support the decompression of .shn files. Hence, a decompression program is often required to convert shn files to other file formats. Md5sum applies the .MD5 checksum file accompanying Shorten files to ensure that large .shn files are not corrupted. Shorten is a command-line tool to convert between .shn and .wav file formats. Some media players like Winamp allow .shn files to be converted to the MP3 format, which is one of the most popularly used audio formats.
Shn files can be played in Winamp using the ShnAmp plugin. One needs to open this plugin in WinRAR, locate the in_shn.dll file, and add it in the Winamp Plugins folder. As the last step, Winamp needs to be restarted before shn files can be played in it.
Since the development of newer audio codecs like FLAC, MPEG-4 ALS, and WavPack, the Shorten file format is not being developed any more. The newer codecs have become more popular than SHN.