00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * lpc10.h - LPC10 low bit rate speech codec. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2006 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, or 00014 * the Lesser GNU General Public License version 2.1, as published by 00015 * the Free Software Foundation. 00016 * 00017 * This program is distributed in the hope that it will be useful, 00018 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00019 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00020 * GNU General Public License for more details. 00021 * 00022 * You should have received a copy of the GNU General Public License 00023 * along with this program; if not, write to the Free Software 00024 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00025 * 00026 * $Id: lpc10.h,v 1.15 2008/02/09 15:31:36 steveu Exp $ 00027 */ 00028 00029 #if !defined(_SPANDSP_LPC10_H_) 00030 #define _SPANDSP_LPC10_H_ 00031 00032 /*! \page lpc10_page LPC10 encoding and decoding 00033 \section lpc10_page_sec_1 What does it do? 00034 The LPC10 module implements the US Department of Defense LPC10 00035 codec. This codec produces compressed data at 2400bps. At such 00036 a low rate high fidelity cannot be expected. However, the speech 00037 clarity is quite good, and this codec is unencumbered by patent 00038 or other restrictions. 00039 00040 \section lpc10_page_sec_2 How does it work? 00041 ???. 00042 */ 00043 00044 #define LPC10_SAMPLES_PER_FRAME 180 00045 #define LPC10_BITS_IN_COMPRESSED_FRAME 54 00046 00047 /*! 00048 LPC10 codec unpacked frame. 00049 */ 00050 typedef struct 00051 { 00052 int32_t ipitch; 00053 int32_t irms; 00054 int32_t irc[10]; 00055 } lpc10_frame_t; 00056 00057 /*! 00058 LPC10 codec encoder state descriptor. This defines the state of 00059 a single working instance of the LPC10 encoder. 00060 */ 00061 typedef struct 00062 { 00063 int error_correction; 00064 00065 /* State used only by function high_pass_100hz */ 00066 float z11; 00067 float z21; 00068 float z12; 00069 float z22; 00070 00071 /* State used by function lpc10_analyse */ 00072 float inbuf[LPC10_SAMPLES_PER_FRAME*3]; 00073 float pebuf[LPC10_SAMPLES_PER_FRAME*3]; 00074 float lpbuf[696]; 00075 float ivbuf[312]; 00076 float bias; 00077 int32_t osbuf[10]; /* No initial value necessary */ 00078 int32_t osptr; /* Initial value 1 */ 00079 int32_t obound[3]; 00080 int32_t vwin[3][2]; /* Initial value vwin[2][0] = 307; vwin[2][1] = 462; */ 00081 int32_t awin[3][2]; /* Initial value awin[2][0] = 307; awin[2][1] = 462; */ 00082 int32_t voibuf[4][2]; 00083 float rmsbuf[3]; 00084 float rcbuf[3][10]; 00085 float zpre; 00086 00087 /* State used by function onset */ 00088 float n; 00089 float d__; /* Initial value 1.0f */ 00090 float fpc; /* No initial value necessary */ 00091 float l2buf[16]; 00092 float l2sum1; 00093 int32_t l2ptr1; /* Initial value 1 */ 00094 int32_t l2ptr2; /* Initial value 9 */ 00095 int32_t lasti; /* No initial value necessary */ 00096 int hyst; /* Initial value FALSE */ 00097 00098 /* State used by function lpc10_voicing */ 00099 float dither; /* Initial value 20.0f */ 00100 float snr; 00101 float maxmin; 00102 float voice[3][2]; /* Initial value is probably unnecessary */ 00103 int32_t lbve; 00104 int32_t lbue; 00105 int32_t fbve; 00106 int32_t fbue; 00107 int32_t ofbue; 00108 int32_t sfbue; 00109 int32_t olbue; 00110 int32_t slbue; 00111 00112 /* State used by function dynamic_pitch_tracking */ 00113 float s[60]; 00114 int32_t p[2][60]; 00115 int32_t ipoint; 00116 float alphax; 00117 00118 /* State used by function lpc10_pack */ 00119 int32_t isync; 00120 } lpc10_encode_state_t; 00121 00122 /*! 00123 LPC10 codec decoder state descriptor. This defines the state of 00124 a single working instance of the LPC10 decoder. 00125 */ 00126 typedef struct 00127 { 00128 int error_correction; 00129 00130 /* State used by function decode */ 00131 int32_t iptold; /* Initial value 60 */ 00132 int first; /* Initial value TRUE */ 00133 int32_t ivp2h; 00134 int32_t iovoic; 00135 int32_t iavgp; /* Initial value 60 */ 00136 int32_t erate; 00137 int32_t drc[10][3]; 00138 int32_t dpit[3]; 00139 int32_t drms[3]; 00140 00141 /* State used by function synths */ 00142 float buf[LPC10_SAMPLES_PER_FRAME*2]; 00143 int32_t buflen; /* Initial value LPC10_SAMPLES_PER_FRAME */ 00144 00145 /* State used by function pitsyn */ 00146 int32_t ivoico; /* No initial value necessary as long as first_pitsyn is initially TRUE_ */ 00147 int32_t ipito; /* No initial value necessary as long as first_pitsyn is initially TRUE_ */ 00148 float rmso; /* Initial value 1.0f */ 00149 float rco[10]; /* No initial value necessary as long as first_pitsyn is initially TRUE_ */ 00150 int32_t jsamp; /* Nno initial value necessary as long as first_pitsyn is initially TRUE_ */ 00151 int first_pitsyn; /* Initial value TRUE */ 00152 00153 /* State used by function bsynz */ 00154 int32_t ipo; 00155 float exc[166]; 00156 float exc2[166]; 00157 float lpi[3]; 00158 float hpi[3]; 00159 float rmso_bsynz; 00160 00161 /* State used by function random */ 00162 int32_t j; 00163 int32_t k; 00164 int16_t y[5]; 00165 00166 /* State used by function deemp */ 00167 float dei[2]; 00168 float deo[3]; 00169 } lpc10_decode_state_t; 00170 00171 #if defined(__cplusplus) 00172 extern "C" 00173 { 00174 #endif 00175 00176 /*! Initialise an LPC10e encode context. 00177 \param s The LPC10e context 00178 \param error_correction ??? 00179 \return A pointer to the LPC10e context, or NULL for error. */ 00180 lpc10_encode_state_t *lpc10_encode_init(lpc10_encode_state_t *s, int error_correction); 00181 00182 int lpc10_encode_release(lpc10_encode_state_t *s); 00183 00184 /*! Encode a buffer of linear PCM data to LPC10e. 00185 \param s The LPC10e context. 00186 \param ima_data The LPC10e data produced. 00187 \param amp The audio sample buffer. 00188 \param len The number of samples in the buffer. This must be a multiple of 180, as 00189 this is the number of samples on a frame. 00190 \return The number of bytes of LPC10e data produced. */ 00191 int lpc10_encode(lpc10_encode_state_t *s, uint8_t code[], const int16_t amp[], int len); 00192 00193 /*! Initialise an LPC10e decode context. 00194 \param s The LPC10e context 00195 \param error_correction ??? 00196 \return A pointer to the LPC10e context, or NULL for error. */ 00197 lpc10_decode_state_t *lpc10_decode_init(lpc10_decode_state_t *st, int error_correction); 00198 00199 int lpc10_decode_release(lpc10_decode_state_t *s); 00200 00201 /*! Decode a buffer of LPC10e data to linear PCM. 00202 \param s The LPC10e context. 00203 \param amp The audio sample buffer. 00204 \param code The LPC10e data. 00205 \param len The number of bytes of LPC10e data to be decoded. This must be a multiple of 7, 00206 as each frame is packed into 7 bytes. 00207 \return The number of samples returned. */ 00208 int lpc10_decode(lpc10_decode_state_t *s, int16_t amp[], const uint8_t code[], int len); 00209 00210 00211 #if defined(__cplusplus) 00212 } 00213 #endif 00214 00215 #endif 00216 /*- End of include ---------------------------------------------------------*/