This package contains debug symbols for libgsm, an 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.