Half Rate Speech: ANSI-C Code for GSM Half Rate Speech Codec
The present document contains an electronic copy of the ANSI‑C code for the GSM half rate codec. The ANSI‑C code is necessary for a bit exact implementation of the half rate speech transcoder (GSM 06.20 [2]), Voice Activity Detector (GSM 06.42 [6]), comfort noise (GSM 06.22 [4]), Discontinuous Transmission (GSM 06.41 [5]) and example solutions for substituting and muting of lost frames (GSM 06.21 [3]).