Convert AMR Online

 

AMR - Adaptive Multi-Rate

 

Format introduction:

The Adaptive Multi-Rate (AMR or AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR was adopted as the standard speech codec by 3GPP in October 1999 and is now widely used in GSM and UMTS.

Technical details:

AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200-3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s. Sampling frequency 8 kHz/13-bit (160 samples for 20 ms frames), filtered to 200-3400 Hz.

 

File extension	.amr, .3ga
MIME	audio/amr
Developed by	3GPP
Type of format	Audio compression format
Associated programs	Audacity, FFmpeg, MPlayer, QuickTime, VLC media player
Sample file	sample.amr
Wikipedia	AMR on Wikipedia