README
1The "libmgsm" directory contains a subset of the modules contained in the
2GSM distribution from the Technische Universitaet Berlin.
3
4Below is the README available in the gsm-1.0-pl7 distribution. The original
5one can be found at ftp://ftp.cs.tu-berlin.de/pub/local/kbs/tubmik/gsm/.
6
7--
8Paul
9
10
11GSM 06.10 13 kbit/s RPE/LTP speech compression available
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13
14The Communications and Operating Systems Research Group (KBS) at the
15Technische Universitaet Berlin is currently working on a set of
16UNIX-based tools for computer-mediated telecooperation that will be
17made freely available.
18
19As part of this effort we are publishing an implementation of the
20European GSM 06.10 provisional standard for full-rate speech
21transcoding, prI-ETS 300 036, which uses RPE/LTP (residual pulse
22excitation/long term prediction) coding at 13 kbit/s.
23
24GSM 06.10 compresses frames of 160 13-bit samples (8 kHz sampling
25rate, i.e. a frame rate of 50 Hz) into 260 bits; for compatibility
26with typical UNIX applications, our implementation turns frames of 160
2716-bit linear samples into 33-byte frames (1650 Bytes/s).
28The quality of the algorithm is good enough for reliable speaker
29recognition; even music often survives transcoding in recognizable
30form (given the bandwidth limitations of 8 kHz sampling rate).
31
32The interfaces offered are a front end modelled after compress(1), and
33a library API. Compression and decompression run faster than realtime
34on most SPARCstations. The implementation has been verified against the
35ETSI standard test patterns.
36
37Jutta Degener (jutta@cs.tu-berlin.de)
38Carsten Bormann (cabo@cs.tu-berlin.de)
39
40Communications and Operating Systems Research Group, TU Berlin
41Fax: +49.30.31425156, Phone: +49.30.31424315
42
43--
44Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
45Universitaet Berlin. See the accompanying file "COPYRIGHT" for
46details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
47