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The ITU G.722 codec, Copyright (C) 2005 Steve Underwood, Copyright (c) CMU 1993 Computer Science, Speech Group Chengxiang Lu and Alex Hauptmann
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ld_sugar Add symbol versioning info. Jul 30, 2016
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LICENSE Reorder entries in chronological order. Jul 29, 2016
Makefile Add symbol versioning info. Jul 30, 2016 spelling fixes Jul 29, 2016
g722.h Add libg722, an lighweight G.722 implementation taken out of Jan 13, 2015
g722_decode.c Add the original CMU (c) text, remove reference to SpanDSP Jul 29, 2016
g722_decoder.h GC reference to spandsp. Jul 29, 2016
g722_encoder.h GC reference to spandsp. Jul 29, 2016
g722_private.h GC reference to spandsp. Jul 29, 2016
pcminb.dat Add original test data (16 bit signed, big endian, 16kHz) and Jul 29, 2016
test.c Add support for 16000 kHz sampling rate in the decoded file Jul 29, 2016
test.checksum Also test encoding 8kHz data. Jul 29, 2016
test.g722 Add simple test case and relevant makefile glue. Jan 26, 2016



The G.722 module is a bit exact implementation of the ITU G.722 specification for all three specified bit rates - 64000bps, 56000bps and 48000bps. It passes the ITU tests.

To allow fast and flexible interworking with narrow band telephony, the encoder and decoder support an option for the linear audio to be an 8k samples/second stream. In this mode the codec is considerably faster, and still fully compatible with wideband terminals using G.722.


The code was originally written by Milton Anderson from BELLCORE, and has been modified by the Chengxiang Lu and Alex Hauptmann from the Speech Group, School of Computer Science, Carnegie Mellon University, to be fairly fast and efficient, while retaining high fidelity.

Steve Underwood improved the code a lot later on and contributed it into several popular open source projects.

Librarized by Sippy Software, Inc.


This code is mostly Public Domain. Library test code is under BSD 2-clause license.

See LICENSE for copyright details and each individual file for specifics.

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