Material Copyright © 2023 ESPICO Ltd

Specialists in Speech and Audio Software Development


The ETSI standard AMR (Adaptive Multi-Rate) narrow band speech codec belongs to the ACELP family of speech coders. Narrow band AMR operates at eight different bit rates from 4.75kbps to 12.2kbps and incorporates the second-generation vocoder standards EFR-GSM (12.2kbps mode) and IS-641-A (7.4kbps mode). Discontinuous transmission (DTX) functionality is also part of the standard with a choice of two different Voice Activity Detection (VAD) algorithms, VAD1 and VAD2. The ESPICO software includes both algorithms. The codec operates on speech frames of 20ms (160 samples) with a 5ms look-ahead.

The ESPICO implementations are highly optimised, realising low memory and MHz requirements. Contact ESPICO for specific resource requirements.



ESPICO’s optimised solution can be ported to any platform. Available solutions include: