kopia lustrzana https://github.com/f4exb/sdrangel
288 wiersze
8.7 KiB
C++
288 wiersze
8.7 KiB
C++
///////////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2021 Jon Beniston, M7RCE <jon@beniston.com> //
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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 General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// (at your option) any later version. //
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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 General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////////
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#include "DVB2.h"
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//
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// Update working parameters for the next frame
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// This prevents parameters changing during a frame
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//
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void DVB2::base_end_of_frame_actions(void)
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{
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if( m_params_changed )
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{
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m_format[0] = m_format[1];
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ldpc_lookup_generate();
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m_params_changed = 0;
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}
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// reset the pointer
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m_frame_offset_bits = 0;
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}
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//
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// This configures the system and calculates
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// any required intermediate values
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//
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int DVB2::set_configure( DVB2FrameFormat *f )
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{
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int bch_bits = 0;
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int error = 0;
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if( f->broadcasting )
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{
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// Set standard parameters for broadcasting
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f->frame_type = FRAME_NORMAL;
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f->bb_header.ts_gs = TS_GS_TRANSPORT;
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f->bb_header.sis_mis = SIS_MIS_SINGLE;
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f->bb_header.ccm_acm = CCM;
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f->bb_header.issyi = 0;
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f->bb_header.npd = 0;
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f->bb_header.upl = 188*8;
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f->bb_header.sync = 0x47;
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}
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f->bb_header.ro = f->roll_off;
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// Fill in the mode specific values and bit lengths
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if( f->frame_type == FRAME_NORMAL )
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{
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f->nldpc = 64800;
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bch_bits = 192;
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f->bch_code = BCH_CODE_N12;
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// Apply code rate
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switch(f->code_rate )
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{
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case CR_1_4:
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f->q_val = 135;
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f->kbch = 16008;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_1_3:
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f->q_val = 120;
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f->kbch = 21408;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_2_5:
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f->q_val = 108;
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f->kbch = 25728;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_1_2:
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f->q_val = 90;
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f->kbch = 32208;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_3_5:
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f->q_val = 72;
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f->kbch = 38688;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_2_3:
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bch_bits = 160;
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f->q_val = 60;
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f->kbch = 43040;
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f->bch_code = BCH_CODE_N10;
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break;
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case CR_3_4:
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f->q_val = 45;
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f->kbch = 48408;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_4_5:
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f->q_val = 36;
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f->kbch = 51648;
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f->bch_code = BCH_CODE_N12;
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break;
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case CR_5_6:
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bch_bits = 160;
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f->q_val = 30;
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f->kbch = 53840;
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f->bch_code = BCH_CODE_N10;
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break;
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case CR_8_9:
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bch_bits = 128;
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f->q_val = 20;
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f->kbch = 57472;
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f->bch_code = BCH_CODE_N8;
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break;
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case CR_9_10:
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bch_bits = 128;
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f->q_val = 18;
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f->kbch = 58192;
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f->bch_code = BCH_CODE_N8;
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break;
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default:
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// loggerf("Configuration error DVB2\n");
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error = -1;
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break;
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}
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}
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if( f->frame_type == FRAME_SHORT )
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{
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f->nldpc = 16200;
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bch_bits = 168;
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f->bch_code = BCH_CODE_S12;
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// Apply code rate
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switch(f->code_rate )
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{
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case CR_1_4:
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f->q_val = 36;
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f->kbch = 3072;
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break;
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case CR_1_3:
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f->q_val = 30;
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f->kbch = 5232;
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break;
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case CR_2_5:
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f->q_val = 27;
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f->kbch = 6312;
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break;
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case CR_1_2:
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f->q_val = 25;
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f->kbch = 7032;
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break;
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case CR_3_5:
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f->q_val = 18;
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f->kbch = 9552;
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break;
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case CR_2_3:
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f->q_val = 15;
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f->kbch = 10632;
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break;
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case CR_3_4:
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f->q_val = 12;
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f->kbch = 11712;
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break;
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case CR_4_5:
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f->q_val = 10;
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f->kbch = 12432;
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break;
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case CR_5_6:
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f->q_val = 8;
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f->kbch = 13152;
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break;
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case CR_8_9:
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f->q_val = 5;
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f->kbch = 14232;
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break;
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case CR_9_10:
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error = 1;
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f->kbch = 0;
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break;
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default:
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// loggerf("Configuration error DVB2\n");
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error = -1;
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break;
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}
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}
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if( error == 0 )
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{
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// Length of the user packets
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f->bb_header.upl = 188*8;
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// Payload length
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f->bb_header.dfl = f->kbch - 80;
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// Transport packet sync
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f->bb_header.sync = 0x47;
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// Start of LDPC bits
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f->kldpc = f->kbch + bch_bits;
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// Number of padding bits required (not used)
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f->padding_bits = 0;
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// Number of usable data bits (not used)
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f->useable_data_bits = f->kbch - 80;
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// Save the configuration, will be updated on next frame
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m_format[1] = *f;
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// reset various pointers
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m_dnp = 0;// No deleted null packets
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// Signal we need to update on the next frame.
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if( m_params_changed )
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base_end_of_frame_actions();
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else
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m_params_changed = 1;
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}
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return error;
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}
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void DVB2::get_configure( DVB2FrameFormat *f )
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{
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*f = m_format[1];
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}
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// Points to first byte in transport packet
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int DVB2::add_ts_frame_base( u8 *ts )
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{
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if( m_frame_offset_bits == 0 )
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{
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// New frame needs to be sent
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add_bbheader(); // Add the header
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}
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// Add a new transport packet
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unpack_transport_packet_add_crc( ts );
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// Have we reached the end?
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if( m_frame_offset_bits == m_format[0].kbch )
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{
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// Yes so now Scramble the BB frame
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bb_randomise();
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// BCH encode the BB Frame
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bch_encode();
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// LDPC encode the BB frame and BCHFEC bits
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ldpc_encode();
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// Signal to the modulation specific class we have something to send
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base_end_of_frame_actions();
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return 1;
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}
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return 0;
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}
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//
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// Dump NULL packets appends a counter to the end of each UP
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// it is not implemented at the moment.
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//
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int DVB2::next_ts_frame_base( u8 *ts )
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{
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int res = 0;
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// See if we need to dump null packets
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if( m_format[0].null_deletion == 1 )
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{
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if(((ts[0]&0x1F) == 0x1F)&&(ts[1] == 0xFF ))
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{
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// Null packet detected
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if( m_dnp < 0xFF )
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{
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m_dnp++;// Increment the number of null packets
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return 0;
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}
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}
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}
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// Need to send a new transport packet
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res = add_ts_frame_base( ts );
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if( res ) m_dnp = 0;// Clear the DNP counter
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// return whether it is time to transmit a new frame
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return res;
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}
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DVB2::DVB2(void)
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{
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// Clear the transport queue
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m_tp_q.empty();
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init_bb_randomiser();
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bch_poly_build_tables();
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build_crc8_table();
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m_dnp = 0;// No deleted null packets
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m_frame_offset_bits = 0;
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m_params_changed = 1;
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}
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DVB2::~DVB2(void)
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{
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}
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