You may come across downloaded music files in the .amr format. Windows does not have the capability to open up .amr files. The only option then is to install an audio player like QuickTime player or RealPlayer to play .amr files.
What is AMR
AMR is an audio compression technique optimized for speech coding.
Open .AMR files
.AMR files can be opened with most third-party media players. We would recommend using Real Player or Nokia Multimedia Player. Nokia Multimedia player can also open files in 3GP format.