“.amr” is a popular filename extension for AMR. Many cell phones use AMR for speech recording storage. MP3 is a proprietary format, it is a common audio format for consumer audio storage. The Extension of AMR File is “.amr”, this is compressed audio format developed by Ericsson; used by many 3G cell phones for voice recordings such as MMS messages; incorporates the Algebraic Code Excited Linear Prediction (ACELP) algorithm, which is designed to efficiently compress human speech audio. AMR is especially associated with the Global System for Mobile Communications (GSM). Many software like Apple QuickTime Player, RealNetworks RealPlayer and AMR Player can play AMR audio
It is possible to transcibe AMR Audio files using Quicktime for windows and the vPedal Quicktime Assistant ~ or Alternatively you can first convert the AMR to MP3 audio file.
a free converter is available > from amrtomp3converter.com