The .AMR file extension type is used in association with the Adaptive Multi-Rate ACELP Codec for speech encoding and compression in cell phone systems. .AMR files are found in cell phones and their networks. In 3G cell phone networks, information compressing software is used to enable large amounts of information to travel on limited band width.
Function
The .AMR ACELP coder lowers the rate of speech compression as interference on the network increases, insuring a clear signal. ACELP is an algorithm that stands for Algebraic Code Excited Linear Prediction.
Benefits
Standards among different cellular systems codecs are kept coordinated through the the .AMR ACELP coders. They are also used to compress speech files for conversion to .MP3.
Other Sources
Adaptive Multi-Rate Codecs are found in MMS files, or message with sound, picture and text, in cell phones.
Manufacturer
Sony Erickson is credited with first developing the .AMR speech compression format.
Systems
Apple's Quicktime and RealNetworks RealPlayer make media players that will convert .MP3 files to .AMR for downloading onto cellphones. Miksoft also makes a converter for switching .MP3 and .wav sound files to .AMR files and back.
Tags: Adaptive Multi-Rate, cell phone, cell phones, speech compression