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AMR Format. Advanced Multi-Rate Codec.

Adaptive Multi-Rate (AMR or AMR-NB) audio codec is a proprietary audio compression technology optimized for speech coding. AMR codec has been adapted for use in speech applications by 3GPP consortium (3rd Generation Partnership Project) in October 1998 and now widely used in GSM and UMTS. Encoder adapts to the quality of communication and uses the most appropriate bitrate based on current conditions.

Many modern phones allow you to store short audio recording in the AMR format. There are both free and commercial software to convert, but it should be remembered that AMR does not provide a good quality for non-voice content.

Main features

  • AMR codec uses eight basic bit rates 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 kbit/s.
  • AMR utilizes Discontinuous Transmission (DTX) in conjunction with the Voice Activity Detection (VAD) and Comfort Noise Generation (CNG), in order to reduce the use of bandwidth during a quiet sound.
  • AMR is a hybrid voice coder that uses algebraic code-excited linear prediction (ACELP).

With Audio Converter Plus you can:

  • Convert MP3 to AMR
  • Convert WAV to AMR
  • Convert AAC to AMR