GSM 06.10 Lossy Speech Compressor Library and Utilities

Contains libraries and binaries for a GSM speech compressor. libgsm
contains a standard implementation of 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,
i.e. a frame rate of 50 Hz) into 260 bits; for compatibility with
typical UNIX applications, our implementation turns frames of 160
16-bit linear samples into 33-byte frames (1650 Bytes/s). The quality
of the algorithm is good enough for reliable speaker recognition; even
music often survives transcoding in recognizable form (given the
bandwidth limitations of 8 kHz sampling rate).

The interfaces offered are a front end modelled after compress(1), and
a library API.	Compression and decompression run faster than realtime
on most SPARCstations.	The implementation has been verified against
the ETSI standard test patterns.