path: root/src/fdmdv_demod.c

/*---------------------------------------------------------------------------*\

  FILE........: fdmdv_demod.c
  AUTHOR......: David Rowe
  DATE CREATED: April 30 2012

  Given an input raw file (8kHz, 16 bit shorts) of FDMDV modem samples
  outputs a file of bits.  The output file is assumed to be arranged
  as codec frames of 56 bits (7 bytes) which are received as two 28
  bit modem frames.

  Demod states can be optionally logged to an Octave file for display
  using the Octave script fdmdv_demod_c.m.  This is useful for
  checking demod performance.

\*---------------------------------------------------------------------------*/

/*
  Copyright (C) 2012 David Rowe

  All rights reserved.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License version 2.1, as
  published by the Free Software Foundation.  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 for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with this program; if not, see <http://www.gnu.org/licenses/>.
*/

#include <assert.h>
#include <errno.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "codec2_fdmdv.h"
#include "debug_alloc.h"
#include "freedv_api.h"
#include "octave.h"

/* lof of information we want to dump to Octave */

#define MAX_FRAMES 50 * 60 /* 1 minute at 50 symbols/s */

int main(int argc, char *argv[]) {
  FILE *fin, *fout;
  struct FDMDV *fdmdv;
  char *packed_bits;
  int *rx_bits;
  int *codec_bits;
  COMP rx_fdm[FDMDV_MAX_SAMPLES_PER_FRAME];
  short rx_fdm_scaled[FDMDV_MAX_SAMPLES_PER_FRAME];
  int i, bit, byte, c;
  int nin, nin_prev;
  int sync_bit = 0, reliable_sync_bit;
  int sync = 0;
  int f;
  FILE *foct = NULL;
  struct MODEM_STATS stats;
  COMP *rx_fdm_log;
  int rx_fdm_log_col_index;
  COMP *rx_symbols_log;
  int sync_log[MAX_FRAMES];
  float rx_timing_log[MAX_FRAMES];
  float foff_log[MAX_FRAMES];
  int sync_bit_log[MAX_FRAMES];
  int rx_bits_log[FDMDV_BITS_PER_FRAME * MAX_FRAMES];
  float snr_est_log[MAX_FRAMES];
  float *rx_spec_log;
  int max_frames_reached;
  int bits_per_fdmdv_frame;
  int bits_per_codec_frame;
  int bytes_per_codec_frame;
  int Nc;

  if (argc < 2) {
    printf("usage: %s InputModemRawFile OutputBitFile [Nc [OctaveDumpFile]]\n",
           argv[0]);
    printf("e.g    %s hts1a_fdmdv.raw hts1a.c2\n", argv[0]);
    exit(1);
  }

  if (strcmp(argv[1], "-") == 0)
    fin = stdin;
  else if ((fin = fopen(argv[1], "rb")) == NULL) {
    fprintf(stderr, "Error opening input modem sample file: %s: %s.\n", argv[1],
            strerror(errno));
    exit(1);
  }

  if (strcmp(argv[2], "-") == 0)
    fout = stdout;
  else if ((fout = fopen(argv[2], "wb")) == NULL) {
    fprintf(stderr, "Error opening output bit file: %s: %s.\n", argv[2],
            strerror(errno));
    exit(1);
  }

  if (argc >= 4) {
    Nc = atoi(argv[3]);

    if ((Nc < 2) || (Nc > FDMDV_NC_MAX)) {
      fprintf(stderr, "Error number of carriers must be between 2 and %d\n",
              FDMDV_NC_MAX);
      exit(1);
    }
  } else
    Nc = FDMDV_NC;

  fdmdv = fdmdv_create(Nc);
  modem_stats_open(&stats);

  bits_per_fdmdv_frame = fdmdv_bits_per_frame(fdmdv);
  bits_per_codec_frame = 2 * fdmdv_bits_per_frame(fdmdv);
  bytes_per_codec_frame = (bits_per_codec_frame + 7) / 8;

  /* malloc some buffers that are dependent on Nc */

  packed_bits = (char *)MALLOC(bytes_per_codec_frame);
  assert(packed_bits != NULL);
  rx_bits = (int *)MALLOC(sizeof(int) * bits_per_codec_frame);
  assert(rx_bits != NULL);
  codec_bits = (int *)MALLOC(2 * sizeof(int) * bits_per_fdmdv_frame);
  assert(codec_bits != NULL);

  /* malloc some of the larger variables to prevent out of stack problems */

  rx_fdm_log =
      (COMP *)MALLOC(sizeof(COMP) * FDMDV_MAX_SAMPLES_PER_FRAME * MAX_FRAMES);
  assert(rx_fdm_log != NULL);
  rx_spec_log = (float *)MALLOC(sizeof(float) * MODEM_STATS_NSPEC * MAX_FRAMES);
  assert(rx_spec_log != NULL);
  rx_symbols_log = (COMP *)MALLOC(sizeof(COMP) * (Nc + 1) * MAX_FRAMES);
  assert(rx_fdm_log != NULL);

  f = 0;
  nin = FDMDV_NOM_SAMPLES_PER_FRAME;
  rx_fdm_log_col_index = 0;
  max_frames_reached = 0;

  while (fread(rx_fdm_scaled, sizeof(short), nin, fin) == nin) {
    for (i = 0; i < nin; i++) {
      rx_fdm[i].real = (float)rx_fdm_scaled[i] / FDMDV_SCALE;
      rx_fdm[i].imag = 0;
    }
    nin_prev = nin;
    fdmdv_demod(fdmdv, rx_bits, &reliable_sync_bit, rx_fdm, &nin);

    /* log data for optional Octave dump */

    if (f < MAX_FRAMES) {
      fdmdv_get_demod_stats(fdmdv, &stats);

      /* log modem states for later dumping to Octave log file */

      memcpy(&rx_fdm_log[rx_fdm_log_col_index], rx_fdm,
             sizeof(COMP) * nin_prev);
      rx_fdm_log_col_index += nin_prev;

      for (c = 0; c < Nc + 1; c++)
        rx_symbols_log[f * (Nc + 1) + c] = stats.rx_symbols[0][c];
      foff_log[f] = stats.foff;
      rx_timing_log[f] = stats.rx_timing;
      sync_log[f] = stats.sync;
      sync_bit_log[f] = sync_bit;
      memcpy(&rx_bits_log[bits_per_fdmdv_frame * f], rx_bits,
             sizeof(int) * bits_per_fdmdv_frame);
      snr_est_log[f] = stats.snr_est;

      modem_stats_get_rx_spectrum(&stats, &rx_spec_log[f * MODEM_STATS_NSPEC],
                                  rx_fdm, nin_prev);

      f++;
    }

    if ((f == MAX_FRAMES) && !max_frames_reached) {
      fprintf(stderr, "MAX_FRAMES exceed in Octave log, log truncated\n");
      max_frames_reached = 1;
    }

    if (reliable_sync_bit) sync = 1;
    // printf("sync_bit: %d reliable_sync_bit: %d sync: %d\n", sync_bit,
    // reliable_sync_bit, sync);

    if (sync == 0) {
      memcpy(codec_bits, rx_bits, bits_per_fdmdv_frame * sizeof(int));
      sync = 1;
    } else {
      memcpy(&codec_bits[bits_per_fdmdv_frame], rx_bits,
             bits_per_fdmdv_frame * sizeof(int));

      /* pack bits, MSB received first  */

      bit = 7;
      byte = 0;
      memset(packed_bits, 0, bytes_per_codec_frame);
      for (i = 0; i < bits_per_codec_frame; i++) {
        packed_bits[byte] |= (codec_bits[i] << bit);
        bit--;
        if (bit < 0) {
          bit = 7;
          byte++;
        }
      }

      fwrite(packed_bits, sizeof(char), bytes_per_codec_frame, fout);
      sync = 0;
    }

    /* if this is in a pipeline, we probably don't want the usual
       buffering to occur */

    if (fout == stdout) fflush(stdout);
  }

  /* Optional dump to Octave log file */

  if (argc == 5) {
    if ((foct = fopen(argv[4], "wt")) == NULL) {
      fprintf(stderr, "Error opening Octave dump file: %s: %s.\n", argv[4],
              strerror(errno));
      exit(1);
    }
    octave_save_complex(foct, "rx_fdm_log_c", rx_fdm_log, 1,
                        rx_fdm_log_col_index, FDMDV_MAX_SAMPLES_PER_FRAME);
    octave_save_complex(foct, "rx_symbols_log_c", (COMP *)rx_symbols_log,
                        Nc + 1, f, MAX_FRAMES);
    octave_save_float(foct, "foff_log_c", foff_log, 1, f, MAX_FRAMES);
    octave_save_float(foct, "rx_timing_log_c", rx_timing_log, 1, f, MAX_FRAMES);
    octave_save_int(foct, "sync_log_c", sync_log, 1, f);
    octave_save_int(foct, "rx_bits_log_c", rx_bits_log, 1,
                    bits_per_fdmdv_frame * f);
    octave_save_int(foct, "sync_bit_log_c", sync_bit_log, 1, f);
    octave_save_float(foct, "snr_est_log_c", snr_est_log, 1, f, MAX_FRAMES);
    octave_save_float(foct, "rx_spec_log_c", rx_spec_log, f, MODEM_STATS_NSPEC,
                      MODEM_STATS_NSPEC);
    fclose(foct);
  }

  // fdmdv_dump_osc_mags(fdmdv);

  fclose(fin);
  fclose(fout);
  FREE(rx_fdm_log);
  FREE(rx_spec_log);
  fdmdv_destroy(fdmdv);

  if (packed_bits != NULL) FREE(packed_bits);

  return 0;
}