G.722 is an ITU-T standard codec that uses sub-band adaptive differential pulse code modulation (SB-ADPCM) within a bit rate of 64 kbit/s. The system is referred to as 64 Kbps (7 kHz) audio coding. SB-ADPCM splits the frequency band into two sub-bands (higher and lower) and the signals in each sub-band are encoded using ADPCM. Extensions to the G.722 standard include the following;

• G.722.1 - Is the ITU-T standard for low-complexity coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss.
• G.722.2 -  Is the ITU-T standard for coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss.

See G.7xx for more information on how these standards are used in telephony networks.

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ITU Recommendation G.722
7 kHz audio-coding within 64 kbit/s

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Using low bandwidth CODECs helps reduce bandwidth requirements however due to the overhead of IP, UDP and RTP protocols, such reduction is limited.

The International Telecommunication Union
The International Telecommunication Union is an international organization within which governments and the private sector coordinate global telecom networks and services. This home page offers numerous links to highlights and current topics, standardization, radiocommunication, telecommunication, and general secretariat sectors.

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