G722
ITU recommendation G.722 describes coding according to Adaptive Delta Pulse CodeModulation( ADPCM) with a subband. The bandwidth of the subband is 7 kHz with a sampling rate of 16 kHz. The transmission rate is 64 kbit/s, and the voice quality is quite high with a MOS value of 4.5. This method is called HD Voice (High Definition Voice).
The optimized version of the G.722.1 voice codec operates at 24 kbit/s or 32 kbit/s with comparable voice quality.
The G.722.2 version has an adequate bandwidth of 7 kHz, voice pause detection( VAD) and noise generation( CNG), and nine selectable bit rates between 6.6 kbit/s and 23.85 kbit/s. G.722.2 was selected by the Third Generation Partnership Project( 3GPP) for voice compression in mobile networks, and is supported by all mobile radio systems. It can also be used in IP networks for VoIP or web conferencing. The voice quality is very high and has a Mean Opinion Score (MOS) >4.5. The voice compression used, Adaptive Multirate Wideband( AMR- WB), is standardized according to the International Telecommunication Union (ITU) G.722.2. The voice transmission based on this is HD Voice, a high-quality voice communication.