spandsp: t38_core.h Source File

spandsp 0.0.6

private/t38_core.h
1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * private/t38_core.h - An implementation of T.38, less the packet exchange part
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2005 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 Lesser General Public License version 2.1,
14 * as 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 Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#if !defined(_SPANDSP_PRIVATE_T38_CORE_H_)
27#define _SPANDSP_PRIVATE_T38_CORE_H_
28
29/*!
30 Core T.38 state, common to all modes of T.38.
31*/
32 struct t38_core_state_s
33{
34 /*! \brief Handler routine to transmit IFP packets generated by the T.38 protocol engine */
35 t38_tx_packet_handler_t *tx_packet_handler;
36 /*! \brief An opaque pointer passed to tx_packet_handler */
37 void *tx_packet_user_data;
38
39 /*! \brief Handler routine to process received indicator packets */
40 t38_rx_indicator_handler_t *rx_indicator_handler;
41 /*! \brief Handler routine to process received data packets */
42 t38_rx_data_handler_t *rx_data_handler;
43 /*! \brief Handler routine to process the missing packet condition */
44 t38_rx_missing_handler_t *rx_missing_handler;
45 /*! \brief An opaque pointer passed to any of the above receive handling routines */
46 void *rx_user_data;
47
48 /*! NOTE - Bandwidth reduction shall only be done on suitable Phase C data, i.e., MH, MR
49 and - in the case of transcoding to JBIG - MMR. MMR and JBIG require reliable data
50 transport such as that provided by TCP. When transcoding is selected, it shall be
51 applied to every suitable page in a call. */
52
53 /*! \brief Method 1: Local generation of TCF (required for use with TCP).
54 Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP).
55 Method 2 is not recommended for use with TCP. */
56 int data_rate_management_method;
57
58 /*! \brief The emitting gateway may indicate a preference for either UDP/UDPTL, or
59 UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device
60 selects the transport protocol. */
61 int data_transport_protocol;
62
63 /*! \brief Indicates the capability to remove and insert fill bits in Phase C, non-ECM
64 data to reduce bandwidth in the packet network. */
65 int fill_bit_removal;
66
67 /*! \brief Indicates the ability to convert to/from MMR from/to the line format to
68 improve the compression of the data, and reduce the bandwidth, in the
69 packet network. */
70 int mmr_transcoding;
71
72 /*! \brief Indicates the ability to convert to/from JBIG to reduce bandwidth. */
73 int jbig_transcoding;
74
75 /*! \brief For UDP (UDPTL or RTP) modes, this option indicates the maximum
76 number of octets that can be stored on the remote device before an
77 overflow condition occurs. It is the responsibility of the transmitting
78 application to limit the transfer rate to prevent an overflow. The
79 negotiated data rate should be used to determine the rate at which
80 data is being removed from the buffer. */
81 int max_buffer_size;
82
83 /*! \brief This option indicates the maximum size of a UDPTL packet or the
84 maximum size of the payload within an RTP packet that can be accepted
85 by the remote device. */
86 int max_datagram_size;
87
88 /*! \brief This is the version number of ITU-T Rec. T.38. New versions shall be
89 compatible with previous versions. */
90 int t38_version;
91
92 /*! \brief Allow time for TEP playout */
93 int allow_for_tep;
94
95 /*! \brief The fastest data rate supported by the T.38 channel. */
96 int fastest_image_data_rate;
97
98 /*! \brief Pace transmission */
99 int pace_transmission;
100
101 /*! \brief TRUE if IFP packet sequence numbers are relevant. For some transports, like TPKT
102 over TCP they are not relevent. */
103 int check_sequence_numbers;
104
105 /*! \brief The number of times each packet type will be sent (low byte). The
106 depth of redundancy (2nd byte). Higher numbers may increase reliability
107 for UDP transmission. Zero is valid for the indicator packet category,
108 to suppress all indicator packets (typicaly for TCP transmission). */
109 int category_control[5];
110
111 /*! \brief The sequence number for the next packet to be transmitted */
112 int tx_seq_no;
113 /*! \brief The sequence number expected in the next received packet */
114 int rx_expected_seq_no;
115
116 /*! \brief The current receive indicator - i.e. the last indicator received */
117 int current_rx_indicator;
118 /*! \brief The current receive data type - i.e. the last data type received */
119 int current_rx_data_type;
120 /*! \brief The current receive field type - i.e. the last field_type received */
121 int current_rx_field_type;
122 /*! \brief The current transmit indicator - i.e. the last indicator transmitted */
123 int current_tx_indicator;
124 /*! \brief The bit rate for V.34 operation */
125 int v34_rate;
126
127 /*! A count of missing receive packets. This count might not be accurate if the
128 received packet numbers jump wildly. */
129 int missing_packets;
130
131 /*! \brief Error and flow logging control */
132 logging_state_t logging;
133};
134
135#endif
136/*- End of file ------------------------------------------------------------*/
logging_state_t
struct logging_state_s logging_state_t
Definition logging.h:75
t38_core_state_s
Definition private/t38_core.h:33
t38_core_state_s::current_tx_indicator
int current_tx_indicator
The current transmit indicator - i.e. the last indicator transmitted.
Definition private/t38_core.h:123
t38_core_state_s::current_rx_field_type
int current_rx_field_type
The current receive field type - i.e. the last field_type received.
Definition private/t38_core.h:121
t38_core_state_s::missing_packets
int missing_packets
Definition private/t38_core.h:129
t38_core_state_s::tx_seq_no
int tx_seq_no
The sequence number for the next packet to be transmitted.
Definition private/t38_core.h:112
t38_core_state_s::max_buffer_size
int max_buffer_size
For UDP (UDPTL or RTP) modes, this option indicates the maximum number of octets that can be stored o...
Definition private/t38_core.h:81
t38_core_state_s::fastest_image_data_rate
int fastest_image_data_rate
The fastest data rate supported by the T.38 channel.
Definition private/t38_core.h:96
t38_core_state_s::fill_bit_removal
int fill_bit_removal
Indicates the capability to remove and insert fill bits in Phase C, non-ECM data to reduce bandwidth ...
Definition private/t38_core.h:65
t38_core_state_s::rx_missing_handler
t38_rx_missing_handler_t * rx_missing_handler
Handler routine to process the missing packet condition.
Definition private/t38_core.h:44
t38_core_state_s::data_transport_protocol
int data_transport_protocol
The emitting gateway may indicate a preference for either UDP/UDPTL, or UDP/RTP, or TCP for transport...
Definition private/t38_core.h:61
t38_core_state_s::max_datagram_size
int max_datagram_size
This option indicates the maximum size of a UDPTL packet or the maximum size of the payload within an...
Definition private/t38_core.h:86
t38_core_state_s::rx_user_data
void * rx_user_data
An opaque pointer passed to any of the above receive handling routines.
Definition private/t38_core.h:46
t38_core_state_s::rx_expected_seq_no
int rx_expected_seq_no
The sequence number expected in the next received packet.
Definition private/t38_core.h:114
t38_core_state_s::pace_transmission
int pace_transmission
Pace transmission.
Definition private/t38_core.h:99
t38_core_state_s::jbig_transcoding
int jbig_transcoding
Indicates the ability to convert to/from JBIG to reduce bandwidth.
Definition private/t38_core.h:73
t38_core_state_s::rx_indicator_handler
t38_rx_indicator_handler_t * rx_indicator_handler
Handler routine to process received indicator packets.
Definition private/t38_core.h:40
t38_core_state_s::tx_packet_handler
t38_tx_packet_handler_t * tx_packet_handler
Handler routine to transmit IFP packets generated by the T.38 protocol engine.
Definition private/t38_core.h:35
t38_core_state_s::v34_rate
int v34_rate
The bit rate for V.34 operation.
Definition private/t38_core.h:125
t38_core_state_s::rx_data_handler
t38_rx_data_handler_t * rx_data_handler
Handler routine to process received data packets.
Definition private/t38_core.h:42
t38_core_state_s::tx_packet_user_data
void * tx_packet_user_data
An opaque pointer passed to tx_packet_handler.
Definition private/t38_core.h:37
t38_core_state_s::t38_version
int t38_version
This is the version number of ITU-T Rec. T.38. New versions shall be compatible with previous version...
Definition private/t38_core.h:90
t38_core_state_s::current_rx_data_type
int current_rx_data_type
The current receive data type - i.e. the last data type received.
Definition private/t38_core.h:119
t38_core_state_s::current_rx_indicator
int current_rx_indicator
The current receive indicator - i.e. the last indicator received.
Definition private/t38_core.h:117
t38_core_state_s::logging
logging_state_t logging
Error and flow logging control.
Definition private/t38_core.h:132
t38_core_state_s::category_control
int category_control[5]
The number of times each packet type will be sent (low byte). The depth of redundancy (2nd byte)....
Definition private/t38_core.h:109
t38_core_state_s::mmr_transcoding
int mmr_transcoding
Indicates the ability to convert to/from MMR from/to the line format to improve the compression of th...
Definition private/t38_core.h:70
t38_core_state_s::data_rate_management_method
int data_rate_management_method
Method 1: Local generation of TCF (required for use with TCP). Method 2: Transfer of TCF is required ...
Definition private/t38_core.h:56
t38_core_state_s::check_sequence_numbers
int check_sequence_numbers
TRUE if IFP packet sequence numbers are relevant. For some transports, like TPKT over TCP they are no...
Definition private/t38_core.h:103
t38_core_state_s::allow_for_tep
int allow_for_tep
Allow time for TEP playout.
Definition private/t38_core.h:93