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/* -*- c++ -*- */
/*
* Copyright 2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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; either version 3, or (at your option)
* any later version.
*
* GNU Radio 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "atsc_rs_decoder_impl.h"
#include "gnuradio/dtv/atsc_consts.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace dtv {
static const int rs_init_symsize = 8;
static const int rs_init_gfpoly = 0x11d;
static const int rs_init_fcr = 0; // first consecutive root
static const int rs_init_prim = 1; // primitive is 1 (alpha)
static const int rs_init_nroots = 20;
static const int N = (1 << rs_init_symsize) - 1; // 255
static const int K = N - rs_init_nroots; // 235
static const int amount_of_pad = N - ATSC_MPEG_RS_ENCODED_LENGTH; // 48
atsc_rs_decoder::sptr
atsc_rs_decoder::make()
{
return gnuradio::get_initial_sptr
(new atsc_rs_decoder_impl());
}
atsc_rs_decoder_impl::atsc_rs_decoder_impl()
: gr::sync_block("dtv_atsc_rs_decoder",
io_signature::make(1, 1, sizeof(atsc_mpeg_packet_rs_encoded)),
io_signature::make(1, 1, sizeof(atsc_mpeg_packet_no_sync)))
{
d_rs = init_rs_char(rs_init_symsize, rs_init_gfpoly, rs_init_fcr, rs_init_prim, rs_init_nroots);
assert (d_rs != 0);
nerrors_corrrected_count = 0;
bad_packet_count = 0;
total_packets = 0;
}
int atsc_rs_decoder_impl::decode (atsc_mpeg_packet_no_sync &out, const atsc_mpeg_packet_rs_encoded &in)
{
unsigned char tmp[N];
int ncorrections;
assert((int)(amount_of_pad + sizeof(in.data)) == N);
// add missing prefix zero padding to message
memset(tmp, 0, amount_of_pad);
memcpy(&tmp[amount_of_pad], in.data, sizeof(in.data));
// correct message...
ncorrections = decode_rs_char(d_rs, tmp, 0, 0);
// copy corrected message to output, skipping prefix zero padding
memcpy (out.data, &tmp[amount_of_pad], sizeof (out.data));
return ncorrections;
}
atsc_rs_decoder_impl::~atsc_rs_decoder_impl()
{
if (d_rs)
free_rs_char (d_rs);
d_rs = 0;
}
int
atsc_rs_decoder_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const atsc_mpeg_packet_rs_encoded *in = (const atsc_mpeg_packet_rs_encoded *)input_items[0];
atsc_mpeg_packet_no_sync *out = (atsc_mpeg_packet_no_sync *)output_items[0];
for (int i = 0; i < noutput_items; i++) {
assert(in[i].pli.regular_seg_p());
out[i].pli = in[i].pli; // copy pipeline info...
int nerrors_corrrected = decode(out[i], in[i]);
out[i].pli.set_transport_error(nerrors_corrrected == -1);
if (nerrors_corrrected == -1)
bad_packet_count++;
else
nerrors_corrrected_count += nerrors_corrrected;
total_packets++;
if (total_packets > 1000) {
// FIXME: convert to logger
std::cout << "Error rate: "
<< (float)nerrors_corrrected_count/total_packets
<< "\tPacket error rate: "
<< (float)bad_packet_count/total_packets
<< std::endl;
nerrors_corrrected_count = 0;
bad_packet_count = 0;
total_packets = 0;
}
}
return noutput_items;
}
} /* namespace dtv */
} /* namespace gr */
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