This Recommendation describes a low complexity encoder and decoder that may be used for 7 kHz bandwidth audio signals working at 24 kbit/s or 32 kbit/s. Further, this algorithm is recommended for use in hands-free applications such as conferencing where there is a low probability of frame loss. It may be used with speech or music inputs. The bit rate may be changed at any 20 ms frame boundary. New Annex C contains the description of a low-complexity extension mode to G.722.1, which doubles the algorithm to permit 14 kHz audio bandwidth using a 32 kHz audio sample rate, at 24, 32, and 48 kbit/s. This mode is suitable for use in video conferencing, teleconferencing, and Internet streaming applications, and uses the same 20 ms frame length, 40 ms algorithmic delay, and same algorithmic steps as the 7 kHz mode. Less than 5.5 WMOPS are required for encoding and decoding in the baseline 7 kHz mode, and less than 11 WMOPS are required for encoding and decoding in the 14 kHz mode of Annex C.
This Recommendation includes a software package which contains the encoder and decoder source code and a set of test vectors for developers. These vectors are a tool providing an indication of success in implementing this code. The fixed-point code implements both the 7 kHz mode (main body) and the 14 kHz mode (Annex C). The floating point implements only the 7 kHz mode.