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comparison spandsp-0.0.3/spandsp-0.0.3/src/spandsp/t31.h @ 5:f762bf195c4b

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import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
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4:26cd8f1ef0b1 5:f762bf195c4b
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * t31.h - A T.31 compatible class 1 FAX modem interface.
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2004 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2, as
14 * published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: t31.h,v 1.37 2006/10/24 13:45:28 steveu Exp $
26 */
27
28 /*! \file */
29
30 #if !defined(_T31_H_)
31 #define _T31_H_
32
33 /*! \page t31_page T.31 Class 1 FAX modem protocol handling
34 \section t31_page_sec_1 What does it do?
35 The T.31 class 1 FAX modem modules implements a class 1 interface to the FAX
36 modems in spandsp.
37
38 \section t31_page_sec_2 How does it work?
39 */
40
41 typedef struct t31_state_s t31_state_t;
42
43 typedef int (t31_modem_control_handler_t)(t31_state_t *s, void *user_data, int op, const char *num);
44
45 #define T31_TX_BUF_LEN (4096*32)
46 #define T31_TX_BUF_HIGH_TIDE (4096*32 - 1024)
47 #define T31_TX_BUF_LOW_TIDE (1024)
48
49 /*!
50 T.31 descriptor. This defines the working state for a single instance of
51 a T.31 FAX modem.
52 */
53 struct t31_state_s
54 {
55 at_state_t at_state;
56 t31_modem_control_handler_t *modem_control_handler;
57 void *modem_control_user_data;
58
59 /*! The current receive signal handler */
60 span_rx_handler_t *rx_handler;
61 void *rx_user_data;
62
63 /*! The current transmit signal handler */
64 span_tx_handler_t *tx_handler;
65 void *tx_user_data;
66 /*! The transmit signal handler to be used when the current one has finished sending. */
67 span_tx_handler_t *next_tx_handler;
68 void *next_tx_user_data;
69
70 /*! If TRUE, transmit silence when there is nothing else to transmit. If FALSE return only
71 the actual generated audio. Note that this only affects untimed silences. Timed silences
72 (e.g. the 75ms silence between V.21 and a high speed modem) will alway be transmitted as
73 silent audio. */
74 int transmit_on_idle;
75
76 uint8_t hdlc_tx_buf[256];
77 int hdlc_tx_len;
78 int hdlc_tx_ptr;
79 /*! TRUE if DLE prefix just used */
80 int dled;
81 uint8_t tx_data[T31_TX_BUF_LEN];
82 /*! \brief The number of bytes stored in transmit buffer. */
83 int tx_in_bytes;
84 /*! \brief The number of bytes sent from the transmit buffer. */
85 int tx_out_bytes;
86 int tx_holding;
87 int tx_data_started;
88 int bit_no;
89 int current_byte;
90
91 /*! \brief The current bit rate for the FAX fast message transfer modem. */
92 int bit_rate;
93 int rx_message_received;
94
95 /*! \brief A tone generator context used to generate supervisory tones during
96 FAX handling. */
97 tone_gen_state_t tone_gen;
98 /*! \brief An HDLC context used when receiving HDLC over V.21 messages. */
99 hdlc_rx_state_t hdlcrx;
100 /*! \brief An HDLC context used when transmitting HDLC over V.21 messages. */
101 hdlc_tx_state_t hdlctx;
102 /*! \brief A V.21 FSK modem context used when transmitting HDLC over V.21
103 messages. */
104 fsk_tx_state_t v21tx;
105 /*! \brief A V.21 FSK modem context used when receiving HDLC over V.21
106 messages. */
107 fsk_rx_state_t v21rx;
108
109 #if defined(ENABLE_V17)
110 /*! \brief A V.17 modem context used when sending FAXes at 7200bps, 9600bps
111 12000bps or 14400bps*/
112 v17_tx_state_t v17tx;
113 /*! \brief A V.29 modem context used when receiving FAXes at 7200bps, 9600bps
114 12000bps or 14400bps*/
115 v17_rx_state_t v17rx;
116 #endif
117
118 /*! \brief A V.29 modem context used when sending FAXes at 7200bps or
119 9600bps */
120 v29_tx_state_t v29tx;
121 /*! \brief A V.29 modem context used when receiving FAXes at 7200bps or
122 9600bps */
123 v29_rx_state_t v29rx;
124
125 /*! \brief A V.27ter modem context used when sending FAXes at 2400bps or
126 4800bps */
127 v27ter_tx_state_t v27ter_tx;
128 /*! \brief A V.27ter modem context used when receiving FAXes at 2400bps or
129 4800bps */
130 v27ter_rx_state_t v27ter_rx;
131
132 /*! \brief Used to insert timed silences. */
133 silence_gen_state_t silence_gen;
134
135 /*! \brief Rx power meter, use to detect silence */
136 power_meter_t rx_power;
137 int16_t last_sample;
138 int32_t silence_threshold_power;
139
140 t38_core_state_t t38;
141
142 /*! \brief Samples of silence heard */
143 int silence_heard;
144 /*! \brief Samples of silence awaited */
145 int silence_awaited;
146 /*! \brief Samples elapsed in the current call */
147 int64_t call_samples;
148 int64_t dte_data_timeout;
149 int modem;
150 int short_train;
151 int hdlc_final;
152 int data_final;
153 queue_t rx_queue;
154
155 uint8_t hdlc_rx_buf[256];
156 int hdlc_rx_len;
157
158 int t38_mode;
159 int timed_step;
160 int current_tx_data;
161 int64_t next_send_samples;
162 int next_tx_indicator;
163
164 int current_rx_type;
165 int current_tx_type;
166
167 /*! \brief TRUE is there has been some T.38 data missed */
168 int missing_data;
169
170 int octets_per_non_ecm_packet;
171
172 /*! \brief Error and flow logging control */
173 logging_state_t logging;
174 };
175
176 #ifdef __cplusplus
177 extern "C" {
178 #endif
179
180 void t31_call_event(t31_state_t *s, int event);
181
182 int t31_at_rx(t31_state_t *s, const char *t, int len);
183
184 /*! Process a block of received T.31 modem audio samples.
185 \brief Process a block of received T.31 modem audio samples.
186 \param s The T.31 modem context.
187 \param amp The audio sample buffer.
188 \param len The number of samples in the buffer.
189 \return The number of samples unprocessed. */
190 int t31_rx(t31_state_t *s, int16_t amp[], int len);
191
192 /*! Generate a block of T.31 modem audio samples.
193 \brief Generate a block of T.31 modem audio samples.
194 \param s The T.31 modem context.
195 \param amp The audio sample buffer.
196 \param max_len The number of samples to be generated.
197 \return The number of samples actually generated.
198 */
199 int t31_tx(t31_state_t *s, int16_t amp[], int max_len);
200
201 int t31_t38_send_timeout(t31_state_t *s, int samples);
202
203 /*! Select whether silent audio will be sent when transmit is idle.
204 \brief Select whether silent audio will be sent when transmit is idle.
205 \param s The T.31 modem context.
206 \param transmit_on_idle TRUE if silent audio should be output when the transmitter is
207 idle. FALSE to transmit zero length audio when the transmitter is idle. The default
208 behaviour is FALSE.
209 */
210 void t31_set_transmit_on_idle(t31_state_t *s, int transmit_on_idle);
211
212 /*! Initialise a T.31 context. This must be called before the first
213 use of the context, to initialise its contents.
214 \brief Initialise a T.31 context.
215 \param s The T.31 context.
216 \param at_tx_handler A callback routine to handle AT interpreter channel output.
217 \param at_tx_user_data An opaque pointer passed in called to at_tx_handler.
218 \param modem_control_handler A callback routine to handle control of the modem (off-hook, etc).
219 \param modem_control_user_data An opaque pointer passed in called to modem_control_handler.
220 \param tx_t38_packet_handler ???
221 \param tx_t38_packet_user_data ???
222 \return A pointer to the T.31 context. */
223 t31_state_t *t31_init(t31_state_t *s,
224 at_tx_handler_t *at_tx_handler,
225 void *at_tx_user_data,
226 t31_modem_control_handler_t *modem_control_handler,
227 void *modem_control_user_data,
228 t38_tx_packet_handler_t *tx_t38_packet_handler,
229 void *tx_t38_packet_user_data);
230
231 /*! Release a T.31 context.
232 \brief Release a T.31 context.
233 \param s The T.31 context.
234 \return 0 for OK */
235 int t31_release(t31_state_t *s);
236
237 #ifdef __cplusplus
238 }
239 #endif
240
241 #endif
242 /*- End of file ------------------------------------------------------------*/

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