00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * super_tone_rx.h - Flexible telephony supervisory tone detection. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2003 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 as published by 00014 * the Free Software Foundation; either version 2 of the License, or 00015 * (at your option) any later version. 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: super_tone_rx.h,v 1.4 2005/11/25 14:52:00 steveu Exp $ 00027 */ 00028 00029 #if !defined(_SUPER_TONE_RX_H_) 00030 #define _SUPER_TONE_RX_H_ 00031 00032 /*! \page super_tone_rx_page Supervisory tone detection 00033 00034 \section super_tone_rx_page_sec_1 What does it do? 00035 00036 The supervisory tone detector may be configured to detect most of the world's 00037 telephone supervisory tones - things like ringback, busy, number unobtainable, 00038 and so on. 00039 00040 \section super_tone_rx_page_sec_2 How does it work? 00041 00042 The supervisory tone detector is passed a series of data structures describing 00043 the tone patterns - the frequencies and cadencing - of the tones to be searched 00044 for. It constructs one or more Goertzel filters to monitor the required tones. 00045 If tones are close in frequency a single Goertzel set to the centre of the 00046 frequency range will be used. This optimises the efficiency of the detector. The 00047 Goertzel filters are applied without applying any special window functional 00048 (i.e. they use a rectangular window), so they have a sinc like response. 00049 However, for most tone patterns their rejection qualities are adequate. 00050 00051 The detector aims to meet the need of the standard call progress tones, to 00052 ITU-T E.180/Q.35 (busy, dial, ringback, reorder). Also, the extended tones, 00053 to ITU-T E.180, Supplement 2 and EIA/TIA-464-A (recall dial tone, special 00054 ringback tone, intercept tone, call waiting tone, busy verification tone, 00055 executive override tone, confirmation tone). 00056 */ 00057 00058 #define BINS 128 00059 00060 typedef struct 00061 { 00062 int f1; 00063 int f2; 00064 int recognition_duration; 00065 int min_duration; 00066 int max_duration; 00067 } super_tone_rx_segment_t; 00068 00069 typedef struct 00070 { 00071 int used_frequencies; 00072 int monitored_frequencies; 00073 int pitches[BINS/2][2]; 00074 int tones; 00075 super_tone_rx_segment_t **tone_list; 00076 int *tone_segs; 00077 goertzel_descriptor_t *desc; 00078 } super_tone_rx_descriptor_t; 00079 00080 typedef struct 00081 { 00082 super_tone_rx_descriptor_t *desc; 00083 float energy; 00084 float total_energy; 00085 int detected_tone; 00086 int rotation; 00087 void (*tone_callback)(void *data, int code); 00088 void (*segment_callback)(void *data, int f1, int f2, int duration); 00089 void *callback_data; 00090 super_tone_rx_segment_t segments[11]; 00091 goertzel_state_t state[0]; 00092 uint8_t filler[80]; 00093 } super_tone_rx_state_t; 00094 00095 /*! Create Add a new tone pattern to a supervisory tone detector. 00096 \param desc The supervisory tone set desciptor. If NULL, the routine will allocate space for a 00097 descriptor. 00098 \return The supervisory tone set descriptor. */ 00099 super_tone_rx_descriptor_t *super_tone_rx_make_descriptor(super_tone_rx_descriptor_t *desc); 00100 00101 /*! Add a new tone pattern to a supervisory tone detector set. 00102 \param desc The supervisory tone set descriptor. 00103 \return The new tone ID. */ 00104 int super_tone_rx_add_tone(super_tone_rx_descriptor_t *desc); 00105 00106 /*! Add a new tone pattern element to a tone pattern in a supervisory tone detector. 00107 \param desc The supervisory tone set desciptor. 00108 \param tone The tone ID within the descriptor. 00109 \param f1 Frequency 1 (-1 for a silent period). 00110 \param f2 Frequency 2 (-1 for a silent period, or only one frequency). 00111 \param min The minimum duration, in ms. 00112 \param max The maximum duration, in ms. 00113 \return The new number of elements in the tone description. */ 00114 int super_tone_rx_add_element(super_tone_rx_descriptor_t *desc, 00115 int tone, 00116 int f1, 00117 int f2, 00118 int min, 00119 int max); 00120 00121 /*! Initialise a supervisory tone detector. 00122 \param s The supervisory tone detector context. 00123 \param desc The tone descriptor. 00124 \param callback The callback routine called to report the valid detection or termination of 00125 one of the monitored tones. 00126 \param data An opaque pointer passed when calling the callback routine. 00127 \return The supervisory tone detector context. */ 00128 super_tone_rx_state_t *super_tone_rx_init(super_tone_rx_state_t *s, 00129 super_tone_rx_descriptor_t *desc, 00130 void (*callback)(void *data, int code), 00131 void *data); 00132 00133 /*! Release a supervisory tone detector. 00134 \param s The supervisory tone context. 00135 \return 0 for OK, -1 for fail. */ 00136 int super_tone_rx_free(super_tone_rx_state_t *s); 00137 00138 /*! Define a callback routine to be called each time a tone pattern element is complete. This is 00139 mostly used when analysing a tone. 00140 \param s The supervisory tone context. 00141 \param callback The callback routine. */ 00142 void super_tone_rx_segment_callback(super_tone_rx_state_t *s, 00143 void (*callback)(void *data, int f1, int f2, int duration)); 00144 00145 /*! Apply supervisory tone detection processing to a block of audio samples. 00146 \brief Apply supervisory tone detection processing to a block of audio samples. 00147 \param super The supervisory tone context. 00148 \param amp The audio sample buffer. 00149 \param samples The number of samples in the buffer. 00150 \return The number of samples processed. 00151 */ 00152 int super_tone_rx(super_tone_rx_state_t *super, const int16_t *amp, int samples); 00153 00154 #endif 00155 /*- End of file ------------------------------------------------------------*/