Is a standard ACELP vocoder adapted by the 3rd Generation Partnership Project (3GPP). It is an Adaptive Multi Rate-Narrow Band (AMR-NB) speech codec. This vocoder is used mainly in 3rd generation mobile telephony devices to compress toll-quality speech at 8000 samples/second. GSM-AMR codec has eight basic bit rates, 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 Kbit. The main features are:
Performance, measured on real hardware:
Encoder+Decoder, 4.75, no VAD - 39MIPS on ARM9E and 25 MIPS on ARM11
Encoder+Decoder, 12.2, DTX1 - 32MIPS on ARM9E and 18 MIPS on ARM11
GSM AMR-NB is delivered with fully automated IntegrIT Testing Environment (ITE) for target platform based on reference ITU-T vectors set along with extended IntegrIT proprietary vectors and methods.
It is specifically optimized under ARM v5TE, ARMv6 and ARMv7 effectively utilizing processors resources and caching capabilities. IntegrIT GSM AMR-NB vocoder is perfectly integrated with IntegrIT CrystalSpeech VoIP Engine to provide superior performance and exceptional perceptual quality on IP channels.
Very careful memory layout design, minimal system stack usage and true fixed point implementation make IntegrIT GSM AMR-NB vocoder ideal for running in OS kernel context
GSM AMR-NB demonstration is available now for Marvell Kirkwood (ARMv5TE), Marvell Armada (ARMv6/v7) evaluation boards, Android 2.2, iPhone4, iPad