Convert nist to gsm

What is the difference between .nist and .gsm?

Developer: National Institute of Standards and Technology; European Telecommunications Standards Institute (ETSI)

Description: SPHERE (SPeech HEader Resources) is a file format defined by NIST (National Institute of Standards and Technology) and is used with speech audio. SoX can read these files when they contain μ-law and PCM data. It will ignore any header information that says the data is compressed using shorten compression and will treat the data as either μ-law or PCM. This will allow SoX and the command line shorten program to be run together using pipes to encompasses the data and then pass the result to SoX for processing.; A lossy file format used to compress speech in Global Standard for Mobile (GSM) telecommunications. It is very effective for reducing audio file size. However, encoding and decoding audio signals severally is discouraged as the final product will have a lot of noise. Popular with some voice mail software but it is CPU intensive.