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 Lesser General Public License version 2.1, 00014 * as 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 Lesser General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU Lesser General Public 00022 * License 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 1.21 2008/09/19 16:24:25 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 /*! The per band parameters for both encoding and decoding G.722 */ 00060 typedef struct 00061 { 00062 int16_t nb; 00063 int16_t det; 00064 int16_t s; 00065 int16_t sz; 00066 int16_t r; 00067 int16_t p[2]; 00068 int16_t a[2]; 00069 int16_t b[6]; 00070 int16_t d[7]; 00071 } g722_band_t; 00072 00073 typedef struct 00074 { 00075 /*! TRUE if the operating in the special ITU test mode, with the band split filters 00076 disabled. */ 00077 int itu_test_mode; 00078 /*! TRUE if the G.722 data is packed */ 00079 int packed; 00080 /*! TRUE if encode from 8k samples/second */ 00081 int eight_k; 00082 /*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */ 00083 int bits_per_sample; 00084 00085 /*! Signal history for the QMF */ 00086 int16_t x[12]; 00087 int16_t y[12]; 00088 int ptr; 00089 00090 g722_band_t band[2]; 00091 00092 uint32_t in_buffer; 00093 int in_bits; 00094 uint32_t out_buffer; 00095 int out_bits; 00096 } g722_encode_state_t; 00097 00098 typedef struct 00099 { 00100 /*! TRUE if the operating in the special ITU test mode, with the band split filters 00101 disabled. */ 00102 int itu_test_mode; 00103 /*! TRUE if the G.722 data is packed */ 00104 int packed; 00105 /*! TRUE if decode to 8k samples/second */ 00106 int eight_k; 00107 /*! 6 for 48000kbps, 7 for 56000kbps, or 8 for 64000kbps. */ 00108 int bits_per_sample; 00109 00110 /*! Signal history for the QMF */ 00111 int16_t x[12]; 00112 int16_t y[12]; 00113 int ptr; 00114 00115 g722_band_t band[2]; 00116 00117 uint32_t in_buffer; 00118 int in_bits; 00119 uint32_t out_buffer; 00120 int out_bits; 00121 } g722_decode_state_t; 00122 00123 #if defined(__cplusplus) 00124 extern "C" 00125 { 00126 #endif 00127 00128 /*! Initialise an G.722 encode context. 00129 \param s The G.722 encode context. 00130 \param rate The required bit rate for the G.722 data. 00131 The valid rates are 64000, 56000 and 48000. 00132 \param options 00133 \return A pointer to the G.722 encode context, or NULL for error. */ 00134 g722_encode_state_t *g722_encode_init(g722_encode_state_t *s, int rate, int options); 00135 00136 int g722_encode_release(g722_encode_state_t *s); 00137 00138 /*! Encode a buffer of linear PCM data to G.722 00139 \param s The G.722 context. 00140 \param g722_data The G.722 data produced. 00141 \param amp The audio sample buffer. 00142 \param len The number of samples in the buffer. 00143 \return The number of bytes of G.722 data produced. */ 00144 int g722_encode(g722_encode_state_t *s, uint8_t g722_data[], const int16_t amp[], int len); 00145 00146 /*! Initialise an G.722 decode context. 00147 \param s The G.722 decode context. 00148 \param rate The bit rate of the G.722 data. 00149 The valid rates are 64000, 56000 and 48000. 00150 \param options 00151 \return A pointer to the G.722 decode context, or NULL for error. */ 00152 g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, int rate, int options); 00153 00154 int g722_decode_release(g722_decode_state_t *s); 00155 00156 /*! Decode a buffer of G.722 data to linear PCM. 00157 \param s The G.722 context. 00158 \param amp The audio sample buffer. 00159 \param g722_data 00160 \param len 00161 \return The number of samples returned. */ 00162 int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len); 00163 00164 #if defined(__cplusplus) 00165 } 00166 #endif 00167 00168 #endif