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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 <gnuradio/io_signature.h>
#include "atsc_viterbi_decoder_impl.h"
#include "atsc_types.h"
#include "atsc_viterbi_mux.h"
namespace gr {
namespace dtv {
atsc_viterbi_decoder::sptr
atsc_viterbi_decoder::make()
{
return gnuradio::get_initial_sptr
(new atsc_viterbi_decoder_impl());
}
atsc_viterbi_decoder_impl::atsc_viterbi_decoder_impl()
: sync_block("dtv_atsc_viterbi_decoder",
io_signature::make(1, 1, sizeof(atsc_soft_data_segment)),
io_signature::make(1, 1, sizeof(atsc_mpeg_packet_rs_encoded)))
{
set_output_multiple(NCODERS);
/*
* These fifo's handle the alignment problem caused by the
* inherent decoding delay of the individual viterbi decoders.
* The net result is that this entire block has a pipeline latency
* of 12 complete segments.
*
* If anybody cares, it is possible to do it with less delay, but
* this approach is at least somewhat understandable...
*/
// the -4 is for the 4 sync symbols
int fifo_size = ATSC_DATA_SEGMENT_LENGTH - 4 - viterbi[0].delay();
for (int i = 0; i < NCODERS; i++)
fifo[i] = new fifo_t(fifo_size);
reset();
}
atsc_viterbi_decoder_impl::~atsc_viterbi_decoder_impl()
{
for (int i = 0; i < NCODERS; i++)
delete fifo[i];
}
void
atsc_viterbi_decoder_impl::reset()
{
for (int i = 0; i < NCODERS; i++)
fifo[i]->reset();
}
std::vector<float>
atsc_viterbi_decoder_impl::decoder_metrics() const
{
std::vector<float> metrics(NCODERS);
for (int i = 0; i < NCODERS; i++)
metrics[i] = viterbi[i].best_state_metric();
return metrics;
}
int
atsc_viterbi_decoder_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const atsc_soft_data_segment *in = (const atsc_soft_data_segment *) input_items[0];
atsc_mpeg_packet_rs_encoded *out = (atsc_mpeg_packet_rs_encoded *) output_items[0];
// The way the fs_checker works ensures we start getting packets
// starting with a field sync, and out input multiple is set to
// 12, so we should always get a mod 12 numbered first packet
assert(noutput_items % NCODERS == 0);
int dbwhere;
int dbindex;
int shift;
float symbols[NCODERS][enco_which_max];
unsigned char dibits[NCODERS][enco_which_max];
unsigned char out_copy[OUTPUT_SIZE];
for (int i = 0; i < noutput_items; i += NCODERS) {
/* Build a continuous symbol buffer for each encoder */
for (unsigned int encoder = 0; encoder < NCODERS; encoder++)
for (unsigned int k = 0; k < enco_which_max; k++)
symbols[encoder][k] = in[i + (enco_which_syms[encoder][k]/832)].data[enco_which_syms[encoder][k] % 832];
/* Now run each of the 12 Viterbi decoders over their subset of
the input symbols */
for (unsigned int encoder = 0; encoder < NCODERS; encoder++)
for (unsigned int k = 0; k < enco_which_max; k++)
dibits[encoder][k] = viterbi[encoder].decode(symbols[encoder][k]);
/* Move dibits into their location in the output buffer */
for (unsigned int encoder = 0; encoder < NCODERS; encoder++) {
for (unsigned int k = 0; k < enco_which_max; k++) {
/* Store the dibit into the output data segment */
dbwhere = enco_which_dibits[encoder][k];
dbindex = dbwhere >> 3;
shift = dbwhere & 0x7;
out_copy[dbindex] = (out_copy[dbindex] & ~(0x03 << shift)) | (fifo[encoder]->stuff(dibits[encoder][k]) << shift);
} /* Symbols fed into one encoder */
} /* Encoders */
// copy output from contiguous temp buffer into final output
for (int j = 0; j < NCODERS; j++) {
memcpy (&out[i + j].data[0],
&out_copy[j * OUTPUT_SIZE/NCODERS],
ATSC_MPEG_RS_ENCODED_LENGTH * sizeof(out_copy[0]));
// adjust pipeline info to reflect 12 segment delay
plinfo::delay(out[i + j].pli, in[i + j].pli, NCODERS);
}
}
return noutput_items;
}
void
atsc_viterbi_decoder_impl::setup_rpc()
{
#ifdef GR_CTRLPORT
add_rpc_variable(
rpcbasic_sptr(new rpcbasic_register_get<atsc_viterbi_decoder, std::vector<float> >(
alias(), "decoder_metrics",
&atsc_viterbi_decoder::decoder_metrics,
pmt::make_f32vector(1,0),
pmt::make_f32vector(1,100000),
pmt::make_f32vector(1,0),
"", "Viterbi decoder metrics", RPC_PRIVLVL_MIN,
DISPTIME)));
#endif /* GR_CTRLPORT */
}
} /* namespace dtv */
} /* namespace gr */
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