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.
PVF is a special low-bandwidth ADPCM-based digital audio format for recording and storing human speech. A .pvf file contains digitally recorded speech in the PVF format. Such .pvf files were mainly used with legacy voice modems and software-based answering machines. Often, to be used with a specific modem, a .pvf file would have to be converted into the device-specific RMD format. Currently, PVF audio files can still be played with several major media players as well as converted into other formats (like WAV) with multi-format converter tools.