1 2 GSM 06.10 13 kbit/s RPE/LTP speech compression available 3 -------------------------------------------------------- 4 5 The Communications and Operating Systems Research Group (KBS) at the 6 Technische Universitaet Berlin is currently working on a set of 7 UNIX-based tools for computer-mediated telecooperation that will be 8 made freely available. 9 10 As part of this effort we are publishing an implementation of the 11 European GSM 06.10 provisional standard for full-rate speech 12 transcoding, prI-ETS 300 036, which uses RPE/LTP (residual pulse 13 excitation/long term prediction) coding at 13 kbit/s. 14 15 GSM 06.10 compresses frames of 160 13-bit samples (8 kHz sampling 16 rate, i.e. a frame rate of 50 Hz) into 260 bits; for compatibility 17 with typical UNIX applications, our implementation turns frames of 160 18 16-bit linear samples into 33-byte frames (1650 Bytes/s). 19 The quality of the algorithm is good enough for reliable speaker 20 recognition; even music often survives transcoding in recognizable 21 form (given the bandwidth limitations of 8 kHz sampling rate). 22 23 The interfaces offered are a front end modelled after compress(1), and 24 a library API. Compression and decompression run faster than realtime 25 on most SPARCstations. The implementation has been verified against the 26 ETSI standard test patterns. 27 28 Jutta Degener (jutta (a] cs.tu-berlin.de) 29 Carsten Bormann (cabo (a] cs.tu-berlin.de) 30 31 Communications and Operating Systems Research Group, TU Berlin 32 Fax: +49.30.31425156, Phone: +49.30.31424315 33 34 -- 35 Copyright 1992 by Jutta Degener and Carsten Bormann, Technische 36 Universitaet Berlin. See the accompanying file "COPYRIGHT" for 37 details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. 38
