Convert pvf to nist

What is the difference between .pvf and .nist?

Description: The Portable Voice Format (PVF) is a digital audio file format primarily used for storing voice recordings. PVF files are designed to encapsulate voice data at various bit rates, making them suitable for applications where voice clarity and file size are critical, such as voicemail systems, interactive voice response systems, and other telephony applications. Unlike more common audio formats that aim for high fidelity and music playback, PVF focuses on the efficient encoding of speech, optimizing for intelligibility and compact file size.; 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.