Internal Program Version: GSM  1.0.22

Contains the library for a GSM speech compressor.

libgsm implements the European GSM 06.10 provisional standard for
full-rate speech transcoding, prI-ETS 300 036, which uses RPE/LTP
(residual pulse excitation/long term prediction) coding at 13 kbit/s.
GSM 06.10 compresses frames of 160 13-bit samples (8 kHz sampling
rate) into 260 bits.

http://www.quut.com/gsm