00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * g722.h - The ITU G.722 codec. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2005 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU General Public License version 2, as 00014 * published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU General Public License 00022 * along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * Based on a single channel G.722 codec which is: 00026 * 00027 ***** Copyright (c) CMU 1993 ***** 00028 * Computer Science, Speech Group 00029 * Chengxiang Lu and Alex Hauptmann 00030 * 00031 * $Id: g722.h,v 1.16 2007/04/08 08:16:17 steveu Exp $ 00032 */ 00033 00034 00035 /*! \file */ 00036 00037 #if !defined(_SPANDSP_G722_H_) 00038 #define _SPANDSP_G722_H_ 00039 00040 /*! \page g722_page G.722 encoding and decoding 00041 \section g722_page_sec_1 What does it do? 00042 The G.722 module is a bit exact implementation of the ITU G.722 specification for all three 00043 specified bit rates - 64000bps, 56000bps and 48000bps. It passes the ITU tests. 00044 00045 To allow fast and flexible interworking with narrow band telephony, the encoder and decoder 00046 support an option for the linear audio to be an 8k samples/second stream. In this mode the 00047 codec is considerably faster, and still fully compatible with wideband terminals using G.722. 00048 00049 \section g722_page_sec_2 How does it work? 00050 ???. 00051 */ 00052 00053 enum 00054 { 00055 G722_SAMPLE_RATE_8000 = 0x0001, 00056 G722_PACKED = 0x0002 00057 }; 00058 00059 typedef struct 00060 { 00061 /*! TRUE if the operating in the special ITU test mode, with the band split filters 00062 disabled. */ 00063 int itu_test_mode; 00064 /*! TRUE if the G.722 data is packed */ 00065 int packed; 00066 /*! TRUE if encode from 8k samples/second */ 00067 int eight_k; 00068 /*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */ 00069 int bits_per_sample; 00070 00071 /*! Signal history for the QMF */ 00072 int x[24]; 00073 00074 struct 00075 { 00076 int s; 00077 int sp; 00078 int sz; 00079 int r[3]; 00080 int a[3]; 00081 int ap[3]; 00082 int p[3]; 00083 int d[7]; 00084 int b[7]; 00085 int bp[7]; 00086 int sg[7]; 00087 int nb; 00088 int det; 00089 } band[2]; 00090 00091 unsigned int in_buffer; 00092 int in_bits; 00093 unsigned int out_buffer; 00094 int out_bits; 00095 } g722_encode_state_t; 00096 00097 typedef struct 00098 { 00099 /*! TRUE if the operating in the special ITU test mode, with the band split filters 00100 disabled. */ 00101 int itu_test_mode; 00102 /*! TRUE if the G.722 data is packed */ 00103 int packed; 00104 /*! TRUE if decode to 8k samples/second */ 00105 int eight_k; 00106 /*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */ 00107 int bits_per_sample; 00108 00109 /*! Signal history for the QMF */ 00110 int x[24]; 00111 00112 struct 00113 { 00114 int s; 00115 int sp; 00116 int sz; 00117 int r[3]; 00118 int a[3]; 00119 int ap[3]; 00120 int p[3]; 00121 int d[7]; 00122 int b[7]; 00123 int bp[7]; 00124 int sg[7]; 00125 int nb; 00126 int det; 00127 } band[2]; 00128 00129 unsigned int in_buffer; 00130 int in_bits; 00131 unsigned int out_buffer; 00132 int out_bits; 00133 } g722_decode_state_t; 00134 00135 #if defined(__cplusplus) 00136 extern "C" 00137 { 00138 #endif 00139 00140 /*! Initialise an G.722 encode context. 00141 \param s The G.722 encode context. 00142 \param rate The required bit rate for the G.722 data. 00143 The valid rates are 64000, 56000 and 48000. 00144 \param options 00145 \return A pointer to the G.722 encode context, or NULL for error. */ 00146 g722_encode_state_t *g722_encode_init(g722_encode_state_t *s, int rate, int options); 00147 00148 int g722_encode_release(g722_encode_state_t *s); 00149 00150 /*! Encode a buffer of linear PCM data to G.722 00151 \param s The G.722 context. 00152 \param g722_data The G.722 data produced. 00153 \param amp The audio sample buffer. 00154 \param len The number of samples in the buffer. 00155 \return The number of bytes of G.722 data produced. */ 00156 int g722_encode(g722_encode_state_t *s, uint8_t g722_data[], const int16_t amp[], int len); 00157 00158 /*! Initialise an G.722 decode context. 00159 \param s The G.722 decode context. 00160 \param rate The bit rate of the G.722 data. 00161 The valid rates are 64000, 56000 and 48000. 00162 \param options 00163 \return A pointer to the G.722 decode context, or NULL for error. */ 00164 g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, int rate, int options); 00165 00166 int g722_decode_release(g722_decode_state_t *s); 00167 00168 /*! Decode a buffer of G.722 data to linear PCM. 00169 \param s The G.722 context. 00170 \param amp The audio sample buffer. 00171 \param g722_data 00172 \param len 00173 \return The number of samples returned. */ 00174 int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len); 00175 00176 #if defined(__cplusplus) 00177 } 00178 #endif 00179 00180 #endif