Convert avr to pgm

What is the difference between .avr and .pgm?

Description: The AVR (Audio Visual Research) file format is a proprietary audio format developed by Audio Visual Research for use on Macintosh computers. It was primarily used in older Mac operating systems and is less common today. AVR files were designed for storing digitized audio data, often used in conjunction with early audio editing and processing software on the Mac platform. This format allowed for the storage and manipulation of various types of audio information, making it a useful tool for researchers, musicians, and audio engineers during its time of popularity.; A PGM file is a grayscale image file saved in the portable gray map (PGM) format and encoded with one or two bytes (8 or 16 bits) per pixel. It contains header information and a grid of numbers that represent different shades of gray from black (0) to white (up to 65,536). PGM files are typically stored in ASCII text format, but also have a binary representation.