/////////////////////////////////////////////////////////////////////////////////////// // Copyright (C) 2021 Jon Beniston, M7RCE // // // // 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 . // /////////////////////////////////////////////////////////////////////////////////////// #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 parameters 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 usable 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) { init_bb_randomiser(); bch_poly_build_tables(); build_crc8_table(); m_dnp = 0;// No deleted null packets m_frame_offset_bits = 0; m_params_changed = 1; } DVB2::~DVB2(void) { }