What is an AMR file?
AMR (Adaptive Multi-Rate audio codec) is an audio compression format, which is mostly used for speech encoding. It is an open format that follows lossy encoding and was initially released in 1999. Apart from AMR, it is also depicted by the 3GA extension and can be played on VLC, Real Player, and Windows Media Player.
What is an M4A file?
M4A, which stands for MPEG-4, is one of the most popular lossy audio container formats. It follows the Advanced Audio Coding (AAC) codec scheme while compressing audio files. Mostly, the M4A format is followed for storing and saving audio files from the iTunes Store.