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private/t38_core.h
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/*
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* SpanDSP - a series of DSP components for telephony
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*
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* private/t38_core.h - An implementation of T.38, less the packet exchange part
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2005 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#if !defined(_SPANDSP_PRIVATE_T38_CORE_H_)
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#define _SPANDSP_PRIVATE_T38_CORE_H_
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/*!
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Core T.38 state, common to all modes of T.38.
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*/
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struct
t38_core_state_s
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{
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/*! \brief Handler routine to transmit IFP packets generated by the T.38 protocol engine */
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t38_tx_packet_handler_t *
tx_packet_handler
;
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/*! \brief An opaque pointer passed to tx_packet_handler */
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void
*
tx_packet_user_data
;
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/*! \brief Handler routine to process received indicator packets */
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t38_rx_indicator_handler_t *
rx_indicator_handler
;
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/*! \brief Handler routine to process received data packets */
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t38_rx_data_handler_t *
rx_data_handler
;
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/*! \brief Handler routine to process the missing packet condition */
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t38_rx_missing_handler_t *
rx_missing_handler
;
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/*! \brief An opaque pointer passed to any of the above receive handling routines */
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void
*
rx_user_data
;
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/*! NOTE - Bandwidth reduction shall only be done on suitable Phase C data, i.e., MH, MR
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and - in the case of transcoding to JBIG - MMR. MMR and JBIG require reliable data
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transport such as that provided by TCP. When transcoding is selected, it shall be
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applied to every suitable page in a call. */
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/*! \brief Method 1: Local generation of TCF (required for use with TCP).
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Method 2: Transfer of TCF is required for use with UDP (UDPTL or RTP).
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Method 2 is not recommended for use with TCP. */
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int
data_rate_management_method
;
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/*! \brief The emitting gateway may indicate a preference for either UDP/UDPTL, or
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UDP/RTP, or TCP for transport of T.38 IFP Packets. The receiving device
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selects the transport protocol. */
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int
data_transport_protocol
;
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/*! \brief Indicates the capability to remove and insert fill bits in Phase C, non-ECM
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data to reduce bandwidth in the packet network. */
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int
fill_bit_removal
;
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/*! \brief Indicates the ability to convert to/from MMR from/to the line format to
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improve the compression of the data, and reduce the bandwidth, in the
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packet network. */
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int
mmr_transcoding
;
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/*! \brief Indicates the ability to convert to/from JBIG to reduce bandwidth. */
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int
jbig_transcoding
;
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/*! \brief For UDP (UDPTL or RTP) modes, this option indicates the maximum
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number of octets that can be stored on the remote device before an
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overflow condition occurs. It is the responsibility of the transmitting
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application to limit the transfer rate to prevent an overflow. The
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negotiated data rate should be used to determine the rate at which
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data is being removed from the buffer. */
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int
max_buffer_size
;
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/*! \brief This option indicates the maximum size of a UDPTL packet or the
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maximum size of the payload within an RTP packet that can be accepted
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by the remote device. */
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int
max_datagram_size
;
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/*! \brief This is the version number of ITU-T Rec. T.38. New versions shall be
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compatible with previous versions. */
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int
t38_version
;
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/*! \brief Allow time for TEP playout */
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int
allow_for_tep
;
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/*! \brief The fastest data rate supported by the T.38 channel. */
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int
fastest_image_data_rate
;
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/*! \brief The number of times each packet type will be sent (low byte). The
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depth of redundancy (2nd byte). Higher numbers may increase reliability
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for UDP transmission. Zero is valid for the indicator packet category,
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to suppress all indicator packets (typicaly for TCP transmission). */
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int
category_control
[5];
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/*! \brief TRUE if IFP packet sequence numbers are relevant. For some transports, like TPKT
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over TCP they are not relevent. */
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int
check_sequence_numbers
;
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/*! \brief The sequence number for the next packet to be transmitted */
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int
tx_seq_no
;
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/*! \brief The sequence number expected in the next received packet */
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int
rx_expected_seq_no
;
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/*! \brief The current receive indicator - i.e. the last indicator received */
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int
current_rx_indicator
;
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/*! \brief The current receive data type - i.e. the last data type received */
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int
current_rx_data_type
;
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/*! \brief The current receive field type - i.e. the last field_type received */
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int
current_rx_field_type
;
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/*! \brief The current transmit indicator - i.e. the last indicator transmitted */
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int
current_tx_indicator
;
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/*! \brief The bit rate for V.34 operation */
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int
v34_rate
;
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/*! A count of missing receive packets. This count might not be accurate if the
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received packet numbers jump wildly. */
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int
missing_packets
;
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/*! \brief Error and flow logging control */
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logging_state_t
logging
;
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};
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#endif
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/*- End of file ------------------------------------------------------------*/
src
spandsp
private
t38_core.h
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