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149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* g722.h - The ITU G.722 codec.
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2005 Steve Underwood
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*
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* Despite my general liking of the GPL, I place my own contributions
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* to this code in the public domain for the benefit of all mankind -
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* even the slimy ones who might try to proprietize my work and use it
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* to my detriment.
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*
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* Based on a single channel G.722 codec which is:
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*
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***** Copyright (c) CMU 1993 *****
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* Computer Science, Speech Group
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* Chengxiang Lu and Alex Hauptmann
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*
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* $Id$
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*/
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/*! \file */
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#if !defined(_G722_H_)
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#define _G722_H_
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/*! \page g722_page G.722 encoding and decoding
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\section g722_page_sec_1 What does it do?
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The G.722 module is a bit exact implementation of the ITU G.722 specification for all three
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specified bit rates - 64000bps, 56000bps and 48000bps. It passes the ITU tests.
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To allow fast and flexible interworking with narrow band telephony, the encoder and decoder
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support an option for the linear audio to be an 8k samples/second stream. In this mode the
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codec is considerably faster, and still fully compatible with wideband terminals using G.722.
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\section g722_page_sec_2 How does it work?
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???.
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*/
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enum
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{
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G722_SAMPLE_RATE_8000 = 0x0001,
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G722_PACKED = 0x0002
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};
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#ifndef INT16_MAX
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#define INT16_MAX 32767
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#endif
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#ifndef INT16_MIN
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#define INT16_MIN (-32768)
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#endif
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typedef struct
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{
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/*! TRUE if the operating in the special ITU test mode, with the band split filters
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disabled. */
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int itu_test_mode;
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/*! TRUE if the G.722 data is packed */
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int packed;
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/*! TRUE if encode from 8k samples/second */
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int eight_k;
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/*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */
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int bits_per_sample;
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/*! Signal history for the QMF */
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int x[24];
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struct
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{
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int s;
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int sp;
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int sz;
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int r[3];
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int a[3];
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int ap[3];
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int p[3];
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int d[7];
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int b[7];
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int bp[7];
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int sg[7];
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int nb;
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int det;
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} band[2];
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unsigned int in_buffer;
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int in_bits;
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unsigned int out_buffer;
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int out_bits;
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} g722_encode_state_t;
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typedef struct
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{
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/*! TRUE if the operating in the special ITU test mode, with the band split filters
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disabled. */
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int itu_test_mode;
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/*! TRUE if the G.722 data is packed */
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int packed;
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/*! TRUE if decode to 8k samples/second */
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int eight_k;
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/*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */
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int bits_per_sample;
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/*! Signal history for the QMF */
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int x[24];
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struct
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{
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int s;
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int sp;
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int sz;
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int r[3];
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int a[3];
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int ap[3];
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int p[3];
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int d[7];
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int b[7];
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int bp[7];
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int sg[7];
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int nb;
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int det;
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} band[2];
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unsigned int in_buffer;
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int in_bits;
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unsigned int out_buffer;
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int out_bits;
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} g722_decode_state_t;
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#ifdef __cplusplus
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extern "C" {
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#endif
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g722_encode_state_t *g722_encode_init(g722_encode_state_t *s, int rate, int options);
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int g722_encode_release(g722_encode_state_t *s);
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int g722_encode(g722_encode_state_t *s, uint8_t g722_data[], const int16_t amp[], int len);
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g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, int rate, int options);
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int g722_decode_release(g722_decode_state_t *s);
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int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len);
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#ifdef __cplusplus
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}
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#endif
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#endif
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