ITU-T Recommendations

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.