asterisk

History

Kevin P. Fleming 8d5deb312b Merged revisions 157859 via svnmerge from https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r157859 \| kpfleming \| 2008-11-19 15:34:47 -0600 (Wed, 19 Nov 2008) \| 7 lines the gcc optimizer frequently finds broken code (use of uninitalized variables, unreachable code, etc.), which is good. however, developers usually compile with the optimizer turned off, because if they need to debug the resulting code, optimized code makes that process very difficult. this means that we get code changes committed that weren't adequately checked over for these sorts of problems. with this build system change, if (and only if) --enable-dev-mode was used and DONT_OPTIMIZE is turned on, when a source file is compiled it will actually be preprocessed (into a .i or .ii file), then compiled once with optimization (with the result sent to /dev/null) and again without optimization (but only if the first compile succeeded, of course). while making these changes, i did some cleanup work in Makefile.rules to move commonly-used combinations of flag variables into their own variables, to make the file easier to read and maintain ........ git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@157974 65c4cc65-6c06-0410-ace0-fbb531ad65f3		2008-11-20 00:08:12 +00:00
..
inc	Merged revisions 111856 via svnmerge from	2008-03-28 21:46:02 +00:00
src	Merged revisions 82265 via svnmerge from	2007-09-11 21:43:47 +00:00
COPYRIGHT	remove extraneous svn:executable properties	2005-11-29 18:24:39 +00:00
Makefile	Merged revisions 157859 via svnmerge from	2008-11-20 00:08:12 +00:00
README	remove extraneous svn:executable properties	2005-11-29 18:24:39 +00:00
libgsm.vcproj	set proper mime-type and eol-style on all files	2006-02-14 19:14:15 +00:00

README

GSM 06.10 13 kbit/s RPE/LTP speech compression available
--------------------------------------------------------

The Communications and Operating Systems Research Group (KBS) at the
Technische Universitaet Berlin is currently working on a set of
UNIX-based tools for computer-mediated telecooperation that will be
made freely available.

As part of this effort we are publishing 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.

Jutta Degener (jutta@cs.tu-berlin.de)
Carsten Bormann (cabo@cs.tu-berlin.de)

Communications and Operating Systems Research Group, TU Berlin
Fax: +49.30.31425156, Phone: +49.30.31424315

--
Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.