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sdrangel/plugins/channeltx/moddatv/dvb-s2/DVB2.cpp
2024-04-11 23:31:34 +02:00

288 lines
8.7 KiB
C++

///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com> //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////////
#include "DVB2.h"
//
// Update working parameters for the next frame
// This prevents parameters changing during a frame
//
void DVB2::base_end_of_frame_actions(void)
{
if( m_params_changed )
{
m_format[0] = m_format[1];
ldpc_lookup_generate();
m_params_changed = 0;
}
// reset the pointer
m_frame_offset_bits = 0;
}
//
// This configures the system and calculates
// any required intermediate values
//
int DVB2::set_configure( DVB2FrameFormat *f )
{
int bch_bits = 0;
int error = 0;
if( f->broadcasting )
{
// Set standard parametrs for broadcasting
f->frame_type = FRAME_NORMAL;
f->bb_header.ts_gs = TS_GS_TRANSPORT;
f->bb_header.sis_mis = SIS_MIS_SINGLE;
f->bb_header.ccm_acm = CCM;
f->bb_header.issyi = 0;
f->bb_header.npd = 0;
f->bb_header.upl = 188*8;
f->bb_header.sync = 0x47;
}
f->bb_header.ro = f->roll_off;
// Fill in the mode specific values and bit lengths
if( f->frame_type == FRAME_NORMAL )
{
f->nldpc = 64800;
bch_bits = 192;
f->bch_code = BCH_CODE_N12;
// Apply code rate
switch(f->code_rate )
{
case CR_1_4:
f->q_val = 135;
f->kbch = 16008;
f->bch_code = BCH_CODE_N12;
break;
case CR_1_3:
f->q_val = 120;
f->kbch = 21408;
f->bch_code = BCH_CODE_N12;
break;
case CR_2_5:
f->q_val = 108;
f->kbch = 25728;
f->bch_code = BCH_CODE_N12;
break;
case CR_1_2:
f->q_val = 90;
f->kbch = 32208;
f->bch_code = BCH_CODE_N12;
break;
case CR_3_5:
f->q_val = 72;
f->kbch = 38688;
f->bch_code = BCH_CODE_N12;
break;
case CR_2_3:
bch_bits = 160;
f->q_val = 60;
f->kbch = 43040;
f->bch_code = BCH_CODE_N10;
break;
case CR_3_4:
f->q_val = 45;
f->kbch = 48408;
f->bch_code = BCH_CODE_N12;
break;
case CR_4_5:
f->q_val = 36;
f->kbch = 51648;
f->bch_code = BCH_CODE_N12;
break;
case CR_5_6:
bch_bits = 160;
f->q_val = 30;
f->kbch = 53840;
f->bch_code = BCH_CODE_N10;
break;
case CR_8_9:
bch_bits = 128;
f->q_val = 20;
f->kbch = 57472;
f->bch_code = BCH_CODE_N8;
break;
case CR_9_10:
bch_bits = 128;
f->q_val = 18;
f->kbch = 58192;
f->bch_code = BCH_CODE_N8;
break;
default:
// loggerf("Configuration error DVB2\n");
error = -1;
break;
}
}
if( f->frame_type == FRAME_SHORT )
{
f->nldpc = 16200;
bch_bits = 168;
f->bch_code = BCH_CODE_S12;
// Apply code rate
switch(f->code_rate )
{
case CR_1_4:
f->q_val = 36;
f->kbch = 3072;
break;
case CR_1_3:
f->q_val = 30;
f->kbch = 5232;
break;
case CR_2_5:
f->q_val = 27;
f->kbch = 6312;
break;
case CR_1_2:
f->q_val = 25;
f->kbch = 7032;
break;
case CR_3_5:
f->q_val = 18;
f->kbch = 9552;
break;
case CR_2_3:
f->q_val = 15;
f->kbch = 10632;
break;
case CR_3_4:
f->q_val = 12;
f->kbch = 11712;
break;
case CR_4_5:
f->q_val = 10;
f->kbch = 12432;
break;
case CR_5_6:
f->q_val = 8;
f->kbch = 13152;
break;
case CR_8_9:
f->q_val = 5;
f->kbch = 14232;
break;
case CR_9_10:
error = 1;
f->kbch = 0;
break;
default:
// loggerf("Configuration error DVB2\n");
error = -1;
break;
}
}
if( error == 0 )
{
// Length of the user packets
f->bb_header.upl = 188*8;
// Payload length
f->bb_header.dfl = f->kbch - 80;
// Transport packet sync
f->bb_header.sync = 0x47;
// Start of LDPC bits
f->kldpc = f->kbch + bch_bits;
// Number of padding bits required (not used)
f->padding_bits = 0;
// Number of useable data bits (not used)
f->useable_data_bits = f->kbch - 80;
// Save the configuration, will be updated on next frame
m_format[1] = *f;
// reset various pointers
m_dnp = 0;// No deleted null packets
// Signal we need to update on the next frame.
if( m_params_changed )
base_end_of_frame_actions();
else
m_params_changed = 1;
}
return error;
}
void DVB2::get_configure( DVB2FrameFormat *f )
{
*f = m_format[1];
}
// Points to first byte in transport packet
int DVB2::add_ts_frame_base( u8 *ts )
{
if( m_frame_offset_bits == 0 )
{
// New frame needs to be sent
add_bbheader(); // Add the header
}
// Add a new transport packet
unpack_transport_packet_add_crc( ts );
// Have we reached the end?
if( m_frame_offset_bits == m_format[0].kbch )
{
// Yes so now Scramble the BB frame
bb_randomise();
// BCH encode the BB Frame
bch_encode();
// LDPC encode the BB frame and BCHFEC bits
ldpc_encode();
// Signal to the modulation specific class we have something to send
base_end_of_frame_actions();
return 1;
}
return 0;
}
//
// Dump NULL packets appends a counter to the end of each UP
// it is not implemented at the moment.
//
int DVB2::next_ts_frame_base( u8 *ts )
{
int res = 0;
// See if we need to dump null packets
if( m_format[0].null_deletion == 1 )
{
if(((ts[0]&0x1F) == 0x1F)&&(ts[1] == 0xFF ))
{
// Null packet detected
if( m_dnp < 0xFF )
{
m_dnp++;// Increment the number of null packets
return 0;
}
}
}
// Need to send a new transport packet
res = add_ts_frame_base( ts );
if( res ) m_dnp = 0;// Clear the DNP counter
// return whether it is time to transmit a new frame
return res;
}
DVB2::DVB2(void)
{
// Clear the transport queue
m_tp_q.empty();
init_bb_randomiser();
bch_poly_build_tables();
build_crc8_table();
m_dnp = 0;// No delted null packets
m_frame_offset_bits = 0;
m_params_changed = 1;
}
DVB2::~DVB2(void)
{
}