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 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 00026 #if !defined(_SPANDSP_SUPER_TONE_RX_H_) 00027 #define _SPANDSP_SUPER_TONE_RX_H_ 00028 00029 /*! \page super_tone_rx_page Supervisory tone detection 00030 00031 \section super_tone_rx_page_sec_1 What does it do? 00032 00033 The supervisory tone detector may be configured to detect most of the world's 00034 telephone supervisory tones - things like ringback, busy, number unobtainable, 00035 and so on. 00036 00037 \section super_tone_rx_page_sec_2 How does it work? 00038 00039 The supervisory tone detector is passed a series of data structures describing 00040 the tone patterns - the frequencies and cadencing - of the tones to be searched 00041 for. It constructs one or more Goertzel filters to monitor the required tones. 00042 If tones are close in frequency a single Goertzel set to the centre of the 00043 frequency range will be used. This optimises the efficiency of the detector. The 00044 Goertzel filters are applied without applying any special window functional 00045 (i.e. they use a rectangular window), so they have a sinc like response. 00046 However, for most tone patterns their rejection qualities are adequate. 00047 00048 The detector aims to meet the need of the standard call progress tones, to 00049 ITU-T E.180/Q.35 (busy, dial, ringback, reorder). Also, the extended tones, 00050 to ITU-T E.180, Supplement 2 and EIA/TIA-464-A (recall dial tone, special 00051 ringback tone, intercept tone, call waiting tone, busy verification tone, 00052 executive override tone, confirmation tone). 00053 */ 00054 00055 /*! Tone detection indication callback routine */ 00056 typedef void (*tone_report_func_t)(void *user_data, int code, int level, int delay); 00057 00058 typedef struct super_tone_rx_segment_s super_tone_rx_segment_t; 00059 00060 typedef struct super_tone_rx_descriptor_s super_tone_rx_descriptor_t; 00061 00062 typedef struct super_tone_rx_state_s super_tone_rx_state_t; 00063 00064 #if defined(__cplusplus) 00065 extern "C" 00066 { 00067 #endif 00068 00069 /*! Create a new supervisory tone detector descriptor. 00070 \param desc The supervisory tone set desciptor. If NULL, the routine will allocate space for a 00071 descriptor. 00072 \return The supervisory tone set descriptor. 00073 */ 00074 SPAN_DECLARE(super_tone_rx_descriptor_t *) super_tone_rx_make_descriptor(super_tone_rx_descriptor_t *desc); 00075 00076 /*! Free a supervisory tone detector descriptor. 00077 \param desc The supervisory tone set desciptor. 00078 \return 0 for OK, -1 for fail. 00079 */ 00080 SPAN_DECLARE(int) super_tone_rx_free_descriptor(super_tone_rx_descriptor_t *desc); 00081 00082 /*! Add a new tone pattern to a supervisory tone detector set. 00083 \param desc The supervisory tone set descriptor. 00084 \return The new tone ID. */ 00085 SPAN_DECLARE(int) super_tone_rx_add_tone(super_tone_rx_descriptor_t *desc); 00086 00087 /*! Add a new tone pattern element to a tone pattern in a supervisory tone detector. 00088 \param desc The supervisory tone set desciptor. 00089 \param tone The tone ID within the descriptor. 00090 \param f1 Frequency 1 (-1 for a silent period). 00091 \param f2 Frequency 2 (-1 for a silent period, or only one frequency). 00092 \param min The minimum duration, in ms. 00093 \param max The maximum duration, in ms. 00094 \return The new number of elements in the tone description. 00095 */ 00096 SPAN_DECLARE(int) super_tone_rx_add_element(super_tone_rx_descriptor_t *desc, 00097 int tone, 00098 int f1, 00099 int f2, 00100 int min, 00101 int max); 00102 00103 /*! Initialise a supervisory tone detector. 00104 \param s The supervisory tone detector context. 00105 \param desc The tone descriptor. 00106 \param callback The callback routine called to report the valid detection or termination of 00107 one of the monitored tones. 00108 \param user_data An opaque pointer passed when calling the callback routine. 00109 \return The supervisory tone detector context. 00110 */ 00111 SPAN_DECLARE(super_tone_rx_state_t *) super_tone_rx_init(super_tone_rx_state_t *s, 00112 super_tone_rx_descriptor_t *desc, 00113 tone_report_func_t callback, 00114 void *user_data); 00115 00116 /*! Release a supervisory tone detector. 00117 \param s The supervisory tone context. 00118 \return 0 for OK, -1 for fail. 00119 */ 00120 SPAN_DECLARE(int) super_tone_rx_release(super_tone_rx_state_t *s); 00121 00122 /*! Free a supervisory tone detector. 00123 \param s The supervisory tone context. 00124 \return 0 for OK, -1 for fail. 00125 */ 00126 SPAN_DECLARE(int) super_tone_rx_free(super_tone_rx_state_t *s); 00127 00128 /*! Define a callback routine to be called each time a tone pattern element is complete. This is 00129 mostly used when analysing a tone. 00130 \param s The supervisory tone context. 00131 \param callback The callback routine. 00132 */ 00133 SPAN_DECLARE(void) super_tone_rx_segment_callback(super_tone_rx_state_t *s, 00134 void (*callback)(void *data, int f1, int f2, int duration)); 00135 00136 /*! Apply supervisory tone detection processing to a block of audio samples. 00137 \brief Apply supervisory tone detection processing to a block of audio samples. 00138 \param super The supervisory tone context. 00139 \param amp The audio sample buffer. 00140 \param samples The number of samples in the buffer. 00141 \return The number of samples processed. 00142 */ 00143 SPAN_DECLARE(int) super_tone_rx(super_tone_rx_state_t *super, const int16_t amp[], int samples); 00144 00145 #if defined(__cplusplus) 00146 } 00147 #endif 00148 00149 #endif 00150 /*- End of file ------------------------------------------------------------*/