About the Amr file format
- Name
- Adaptive Multi-Rate Codec File
- Extension
- .amr
- Format
- Binary
- Category
- Audio
- Developer
- Nokia
- Description
- An AMR file is an audio file saved in a compressed audio format developed by Ericsson. It is used by many 3G cell phones for voice recordings such as MMS messages. AMR files incorporate the Algebraic Code Excited Linear Prediction (ACELP) algorithm, which is designed to efficiently compress human speech audio.
- MIME Type
- audio/amr
- Sample
- sample.amr
- Wikipedia
- .amr on Wikipedia
Adaptive Multi-Rate Codec File (AMR) is an audio format file that is compressed and used on 3G cell phones. It was developed by Ericsson and is used for phone recordings like Multimedia Messaging Services (MMS).
The Algebraic Code Excited Linear Prediction (ACELP) codec incorporated enables it to compress human speech data better than AAC, MP3, or WMA. AMR is made up of AMR-NB and AMR-WB that are used to encode signals at varying bit rates. The NB (narrowband) is used with low bitrates while the WB (wideband) is used with higher bitrates.
The file format became fully operational in the year 1999, and since then, it is used in GSM and UMTS popularly known as 2G and 3G networks, respectively. It is prevalent with VoIP applications. The file uses the .amr file extension.
Discontinuous transmission (DTX) and Voice activity detection (VAD) applications are used by the AMR to reduce the bandwidth periods during silence periods. The file is also referred to as a hybrid speech coder, due to its ability to transform speech parameter to waveform signals.
Nokia, Ericsson, and Nippon Telegraph and Telephone ( NTT) have incorporated AMR codecs in their operations. Also, the Apple QuickTime Player and RealNetworks RealPlayer can play AMR files.