spandsp: g722.h Source File

spandsp 0.0.6

g722.h
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1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * g722.h - The ITU G.722 codec.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2005 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * Based on a single channel G.722 codec which is:
26 *
27 ***** Copyright (c) CMU 1993 *****
28 * Computer Science, Speech Group
29 * Chengxiang Lu and Alex Hauptmann
30 */
31
32
33/*! \file */
34
35#if !defined(_SPANDSP_G722_H_)
36#define _SPANDSP_G722_H_
37
38/*! \page g722_page G.722 encoding and decoding
39\section g722_page_sec_1 What does it do?
40The G.722 module is a bit exact implementation of the ITU G.722 specification for all three
41specified bit rates - 64000bps, 56000bps and 48000bps. It passes the ITU tests.
42
43To allow fast and flexible interworking with narrow band telephony, the encoder and decoder
44support an option for the linear audio to be an 8k samples/second stream. In this mode the
45codec is considerably faster, and still fully compatible with wideband terminals using G.722.
46
47\section g722_page_sec_2 How does it work?
48???.
49*/
50
51enum
52{
53 G722_SAMPLE_RATE_8000 = 0x0001,
54 G722_PACKED = 0x0002
55};
56
57/*!
58 G.722 encode state
59 */
60 typedef struct g722_encode_state_s g722_encode_state_t;
61
62/*!
63 G.722 decode state
64 */
65 typedef struct g722_decode_state_s g722_decode_state_t;
66
67#if defined(__cplusplus)
68extern "C"
69{
70#endif
71
72/*! Initialise an G.722 encode context.
73 \param s The G.722 encode context.
74 \param rate The required bit rate for the G.722 data.
75 The valid rates are 64000, 56000 and 48000.
76 \param options
77 \return A pointer to the G.722 encode context, or NULL for error. */
78SPAN_DECLARE(g722_encode_state_t *) g722_encode_init(g722_encode_state_t *s, int rate, int options);
79
80/*! Release a G.722 encode context.
81 \param s The G.722 encode context.
82 \return 0 for OK. */
83SPAN_DECLARE(int) g722_encode_release(g722_encode_state_t *s);
84
85/*! Free a G.722 encode context.
86 \param s The G.722 encode context.
87 \return 0 for OK. */
88SPAN_DECLARE(int) g722_encode_free(g722_encode_state_t *s);
89
90/*! Encode a buffer of linear PCM data to G.722
91 \param s The G.722 context.
92 \param g722_data The G.722 data produced.
93 \param amp The audio sample buffer.
94 \param len The number of samples in the buffer.
95 \return The number of bytes of G.722 data produced. */
96SPAN_DECLARE(int) g722_encode(g722_encode_state_t *s, uint8_t g722_data[], const int16_t amp[], int len);
97
98/*! Initialise an G.722 decode context.
99 \param s The G.722 decode context.
100 \param rate The bit rate of the G.722 data.
101 The valid rates are 64000, 56000 and 48000.
102 \param options
103 \return A pointer to the G.722 decode context, or NULL for error. */
104SPAN_DECLARE(g722_decode_state_t *) g722_decode_init(g722_decode_state_t *s, int rate, int options);
105
106/*! Release a G.722 decode context.
107 \param s The G.722 decode context.
108 \return 0 for OK. */
109SPAN_DECLARE(int) g722_decode_release(g722_decode_state_t *s);
110
111/*! Free a G.722 decode context.
112 \param s The G.722 decode context.
113 \return 0 for OK. */
114SPAN_DECLARE(int) g722_decode_free(g722_decode_state_t *s);
115
116/*! Decode a buffer of G.722 data to linear PCM.
117 \param s The G.722 context.
118 \param amp The audio sample buffer.
119 \param g722_data
120 \param len
121 \return The number of samples returned. */
122SPAN_DECLARE(int) g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len);
123
124#if defined(__cplusplus)
125}
126#endif
127
128#endif
g722_encode_release
int g722_encode_release(g722_encode_state_t *s)
Definition g722.c:463
g722_encode_state_t
struct g722_encode_state_s g722_encode_state_t
Definition g722.h:60
g722_encode
int g722_encode(g722_encode_state_t *s, uint8_t g722_data[], const int16_t amp[], int len)
Definition g722.c:476
g722_encode_init
g722_encode_state_t * g722_encode_init(g722_encode_state_t *s, int rate, int options)
Definition g722.c:437
g722_decode_free
int g722_decode_free(g722_decode_state_t *s)
Definition g722.c:288
g722_decode
int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len)
Definition g722.c:295
g722_decode_release
int g722_decode_release(g722_decode_state_t *s)
Definition g722.c:282
g722_encode_free
int g722_encode_free(g722_encode_state_t *s)
Definition g722.c:469
g722_decode_init
g722_decode_state_t * g722_decode_init(g722_decode_state_t *s, int rate, int options)
Definition g722.c:256
g722_decode_state_t
struct g722_decode_state_s g722_decode_state_t
Definition g722.h:65
g722_decode_state_s
Definition private/g722.h:84
g722_encode_state_s
Definition private/g722.h:56