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Version 1.0 - Initial commit Changes to be committed: new file: .gitattributes new file: .gitignore new file: APRStt-Implementation-Notes.pdf new file: CHANGES.txt new file: LICENSE-dire-wolf.txt new file: LICENSE-other.txt new file: Makefile.linux new file: Makefile.win new file: Quick-Start-Guide-Windows.pdf new file: Raspberry-Pi-APRS.pdf new file: User-Guide.pdf new file: aclients.c new file: aprs_tt.c new file: aprs_tt.h new file: atest.c new file: audio.c new file: audio.h new file: audio_win.c new file: ax25_pad.c new file: ax25_pad.h new file: beacon.c new file: beacon.h new file: config.c new file: config.h new file: decode_aprs.c new file: decode_aprs.h new file: dedupe.c new file: dedupe.h new file: demod.c new file: demod.h new file: demod_9600.c new file: demod_9600.h new file: demod_afsk.c new file: demod_afsk.h new file: digipeater.c new file: digipeater.h new file: direwolf.c new file: direwolf.conf new file: direwolf.desktop new file: direwolf.h new file: dsp.c new file: dsp.h new file: dtmf.c new file: dtmf.h new file: dw-icon.ico new file: dw-icon.png new file: dw-icon.rc new file: dw-start.sh new file: dwgps.c new file: dwgps.h new file: encode_aprs.c new file: encode_aprs.h new file: fcs_calc.c new file: fcs_calc.h new file: fsk_demod_agc.h new file: fsk_demod_state.h new file: fsk_filters.h new file: fsk_gen_filter.h new file: gen_packets.c new file: gen_tone.c new file: gen_tone.h new file: hdlc_rec.c new file: hdlc_rec.h new file: hdlc_rec2.c new file: hdlc_rec2.h new file: hdlc_send.c new file: hdlc_send.h new file: igate.c new file: igate.h new file: kiss.c new file: kiss.h new file: kiss_frame.c new file: kiss_frame.h new file: kissnet.c new file: kissnet.h new file: latlong.c new file: latlong.h new file: ll2utm.c new file: misc/README-dire-wolf.txt new file: misc/strcasestr.c new file: misc/strsep.c new file: misc/strtok_r.c new file: morse.c new file: multi_modem.c new file: multi_modem.h new file: ptt.c new file: ptt.h new file: pttest.c new file: rdq.c new file: rdq.h new file: redecode.c new file: redecode.h new file: regex/COPYING new file: regex/INSTALL new file: regex/LICENSES new file: regex/NEWS new file: regex/README new file: regex/README-dire-wolf.txt new file: regex/re_comp.h new file: regex/regcomp.c new file: regex/regex.c new file: regex/regex.h new file: regex/regex_internal.c new file: regex/regex_internal.h new file: regex/regexec.c new file: rrbb.c new file: rrbb.h new file: server.c new file: server.h new file: symbols-new.txt new file: symbols.c new file: symbols.h new file: symbolsX.txt new file: textcolor.c new file: textcolor.h new file: tocalls.txt new file: tq.c new file: tq.h new file: tt_text.c new file: tt_text.h new file: tt_user.c new file: tt_user.h new file: tune.h new file: udp_test.c new file: utm/LatLong-UTMconversion.c new file: utm/LatLong-UTMconversion.h new file: utm/README.txt new file: utm/SwissGrid.cpp new file: utm/UTMConversions.cpp new file: utm/constants.h new file: utm2ll.c new file: version.h new file: xmit.c new file: xmit.h
2015-07-27 00:35:07 +00:00
//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2011,2013 John Langner, WB2OSZ
//
// 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, either version 2 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
/*------------------------------------------------------------------
*
* Name: gen_packets.c
*
* Purpose: Test program for generating AFSK AX.25 frames.
*
* Description: Given messages are converted to audio and written
* to a .WAV type audio file.
*
*
* Bugs: Most options not implemented for second audio channel.
*
*------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>
#include <assert.h>
#include "audio.h"
#include "ax25_pad.h"
#include "hdlc_send.h"
#include "gen_tone.h"
#include "textcolor.h"
static void usage (char **argv);
static int audio_file_open (char *fname, struct audio_s *pa);
static int audio_file_close (void);
static int g_add_noise = 0;
static float g_noise_level = 0;
int main(int argc, char **argv)
{
int c;
int digit_optind = 0;
int err;
unsigned char fbuf[AX25_MAX_PACKET_LEN+2];
int flen;
int packet_count = 0;
int i;
int chan;
/*
* Set up default values for the modem.
*/
struct audio_s modem;
modem.num_channels = DEFAULT_NUM_CHANNELS; /* -2 stereo */
modem.samples_per_sec = DEFAULT_SAMPLES_PER_SEC; /* -r option */
modem.bits_per_sample = DEFAULT_BITS_PER_SAMPLE; /* -8 for 8 instead of 16 bits */
for (chan = 0; chan < MAX_CHANS; chan++) {
modem.modem_type[chan] = AFSK; /* change with -g */
modem.mark_freq[chan] = DEFAULT_MARK_FREQ; /* -m option */
modem.space_freq[chan] = DEFAULT_SPACE_FREQ; /* -s option */
modem.baud[chan] = DEFAULT_BAUD; /* -b option */
}
/*
* Set up other default values.
*/
int amplitude = 50; /* -a option */
int leading_zeros = 12; /* -z option */
char output_file[256]; /* -o option */
FILE *input_fp = NULL; /* File or NULL for built-in message */
packet_t pp;
strcpy (output_file, "");
while (1) {
int this_option_optind = optind ? optind : 1;
int option_index = 0;
static struct option long_options[] = {
{"future1", 1, 0, 0},
{"future2", 0, 0, 0},
{"future3", 1, 0, 'c'},
{0, 0, 0, 0}
};
/* ':' following option character means arg is required. */
c = getopt_long(argc, argv, "gm:s:a:b:B:r:n:o:z:82",
long_options, &option_index);
if (c == -1)
break;
switch (c) {
case 0: /* possible future use */
text_color_set(DW_COLOR_INFO);
dw_printf("option %s", long_options[option_index].name);
if (optarg) {
dw_printf(" with arg %s", optarg);
}
dw_printf("\n");
break;
case 'b': /* -b for data Bit rate */
modem.baud[0] = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Data rate set to %d bits / second.\n", modem.baud[0]);
if (modem.baud[0] < 100 || modem.baud[0] > 10000) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable bit rate in range of 100 - 10000.\n");
exit (EXIT_FAILURE);
}
break;
case 'B': /* -B for data Bit rate */
/* 300 implies 1600/1800 AFSK. */
/* 1200 implies 1200/2200 AFSK. */
/* 9600 implies scrambled. */
modem.baud[0] = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Data rate set to %d bits / second.\n", modem.baud[0]);
if (modem.baud[0] < 100 || modem.baud[0] > 10000) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable bit rate in range of 100 - 10000.\n");
exit (EXIT_FAILURE);
}
switch (modem.baud[0]) {
case 300:
modem.mark_freq[0] = 1600;
modem.space_freq[0] = 1800;
break;
case 1200:
modem.mark_freq[0] = 1200;
modem.space_freq[0] = 2200;
break;
case 9600:
modem.modem_type[0] = SCRAMBLE;
text_color_set(DW_COLOR_INFO);
dw_printf ("Using scrambled baseband signal rather than AFSK.\n");
break;
}
break;
case 'g': /* -g for g3ruh scrambling */
modem.modem_type[0] = SCRAMBLE;
text_color_set(DW_COLOR_INFO);
dw_printf ("Using scrambled baseband signal rather than AFSK.\n");
break;
case 'm': /* -m for Mark freq */
modem.mark_freq[0] = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Mark frequency set to %d Hz.\n", modem.mark_freq[0]);
if (modem.mark_freq[0] < 300 || modem.mark_freq[0] > 3000) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable value in range of 300 - 3000.\n");
exit (EXIT_FAILURE);
}
break;
case 's': /* -s for Space freq */
modem.space_freq[0] = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Space frequency set to %d Hz.\n", modem.space_freq[0]);
if (modem.space_freq[0] < 300 || modem.space_freq[0] > 3000) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable value in range of 300 - 3000.\n");
exit (EXIT_FAILURE);
}
break;
case 'n': /* -n number of packets with increasing noise. */
packet_count = atoi(optarg);
g_add_noise = 1;
break;
case 'a': /* -a for amplitude */
amplitude = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Amplitude set to %d%%.\n", amplitude);
if (amplitude < 0 || amplitude > 100) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Amplitude must be in range of 0 to 100.\n");
exit (EXIT_FAILURE);
}
break;
case 'r': /* -r for audio sample Rate */
modem.samples_per_sec = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Audio sample rate set to %d samples / second.\n", modem.samples_per_sec);
if (modem.samples_per_sec < MIN_SAMPLES_PER_SEC || modem.samples_per_sec > MAX_SAMPLES_PER_SEC) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable audio sample rate in range of %d - %d.\n",
MIN_SAMPLES_PER_SEC, MAX_SAMPLES_PER_SEC);
exit (EXIT_FAILURE);
}
break;
case 'z': /* -z leading zeros before frame flag */
leading_zeros = atoi(optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Send %d zero bits before frame flag.\n", leading_zeros);
/* The demodulator needs a few for the clock recovery PLL. */
/* We don't want to be here all day either. */
/* We can't translast to time yet because the data bit rate */
/* could be changed later. */
if (leading_zeros < 8 || leading_zeros > 12000) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Use a more reasonable value.\n");
exit (EXIT_FAILURE);
}
break;
case '8': /* -8 for 8 bit samples */
modem.bits_per_sample = 8;
text_color_set(DW_COLOR_INFO);
dw_printf("8 bits per audio sample rather than 16.\n");
break;
case '2': /* -2 for 2 channels of sound */
modem.num_channels = 2;
text_color_set(DW_COLOR_INFO);
dw_printf("2 channels of sound rather than 1.\n");
break;
case 'o': /* -o for Output file */
strcpy (output_file, optarg);
text_color_set(DW_COLOR_INFO);
dw_printf ("Output file set to %s\n", output_file);
break;
case '?':
/* Unknown option message was already printed. */
usage (argv);
break;
default:
/* Should not be here. */
text_color_set(DW_COLOR_ERROR);
dw_printf("?? getopt returned character code 0%o ??\n", c);
usage (argv);
}
}
if (optind < argc) {
char str[400];
// dw_printf("non-option ARGV-elements: ");
// while (optind < argc)
// dw_printf("%s ", argv[optind++]);
//dw_printf("\n");
if (optind < argc - 1) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Warning: File(s) beyond the first are ignored.\n");
}
if (strcmp(argv[optind], "-") == 0) {
text_color_set(DW_COLOR_INFO);
dw_printf ("Reading from stdin ...\n");
input_fp = stdin;
}
else {
input_fp = fopen(argv[optind], "r");
if (input_fp == NULL) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Can't open %s for read.\n", argv[optind]);
exit (EXIT_FAILURE);
}
text_color_set(DW_COLOR_INFO);
dw_printf ("Reading from %s ...\n", argv[optind]);
}
while (fgets (str, sizeof(str), input_fp) != NULL) {
text_color_set(DW_COLOR_REC);
dw_printf ("%s", str);
}
if (input_fp != stdin) {
fclose (input_fp);
}
}
else {
text_color_set(DW_COLOR_INFO);
dw_printf ("built in message...\n");
}
if (strlen(output_file) == 0) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR: The -o ouput file option must be specified.\n");
usage (argv);
exit (1);
}
err = audio_file_open (output_file, &modem);
if (err < 0) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR - Can't open output file.\n");
exit (1);
}
gen_tone_init (&modem, amplitude);
assert (modem.bits_per_sample == 8 || modem.bits_per_sample == 16);
assert (modem.num_channels == 1 || modem.num_channels == 2);
assert (modem.samples_per_sec >= MIN_SAMPLES_PER_SEC && modem.samples_per_sec <= MAX_SAMPLES_PER_SEC);
if (packet_count > 0) {
/*
* Generate packets with increasing noise level.
* Would probably be better to record real noise from a radio but
* for now just use a random number generator.
*/
for (i = 1; i <= packet_count; i++) {
char stemp[80];
if (modem.modem_type[0] == SCRAMBLE) {
g_noise_level = 0.33 * (amplitude / 100.0) * ((float)i / packet_count);
}
else {
g_noise_level = (amplitude / 100.0) * ((float)i / packet_count);
}
sprintf (stemp, "WB2OSZ-1>APRS,W1AB-9,W1ABC-10,WB1ABC-15:,Hello, world! %04d", i);
pp = ax25_from_text (stemp, 1);
flen = ax25_pack (pp, fbuf);
for (c=0; c<modem.num_channels; c++)
{
hdlc_send_flags (c, 8, 0);
hdlc_send_frame (c, fbuf, flen);
hdlc_send_flags (c, 2, 1);
}
ax25_delete (pp);
}
}
else {
/*
* Builtin default 4 packets.
*/
pp = ax25_from_text ("WB2OSZ-1>APRS,W1AB-9,W1ABC-10,WB1ABC-15:,Hello, world!", 1);
flen = ax25_pack (pp, fbuf);
for (c=0; c<modem.num_channels; c++)
{
hdlc_send_flags (c, 8, 0);
hdlc_send_frame (c, fbuf, flen);
hdlc_send_flags (c, 2, 1);
}
ax25_delete (pp);
hdlc_send_flags (c, 8, 0);
pp = ax25_from_text ("WB2OSZ-1>APRS,W1AB-9*,W1ABC-10,WB1ABC-15:,Hello, world!", 1);
flen = ax25_pack (pp, fbuf);
for (c=0; c<modem.num_channels; c++)
{
hdlc_send_frame (c, fbuf, flen);
}
ax25_delete (pp);
pp = ax25_from_text ("WB2OSZ-1>APRS,W1AB-9,W1ABC-10*,WB1ABC-15:,Hello, world!", 1);
flen = ax25_pack (pp, fbuf);
for (c=0; c<modem.num_channels; c++)
{
hdlc_send_frame (c, fbuf, flen);
}
ax25_delete (pp);
pp = ax25_from_text ("WB2OSZ-1>APRS,W1AB-9,W1ABC-10,WB1ABC-15*:,Hello, world!", 1);
flen = ax25_pack (pp, fbuf);
for (c=0; c<modem.num_channels; c++)
{
hdlc_send_frame (c, fbuf, flen);
}
ax25_delete (pp);
hdlc_send_flags (c, 2, 1);
}
audio_file_close();
return EXIT_SUCCESS;
}
static void usage (char **argv)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("\n");
dw_printf ("Usage: xxx [options] [file]\n");
dw_printf ("Options:\n");
dw_printf (" -a <number> Signal amplitude in range of 0 - 100%%. Default 50.\n");
dw_printf (" -b <number> Bits / second for data. Default is %d.\n", DEFAULT_BAUD);
dw_printf (" -B <number> Bits / second for data. Proper modem selected for 300, 1200, 9600.\n");
dw_printf (" -g Scrambled baseband rather than AFSK.\n");
dw_printf (" -m <number> Mark frequency. Default is %d.\n", DEFAULT_MARK_FREQ);
dw_printf (" -s <number> Space frequency. Default is %d.\n", DEFAULT_SPACE_FREQ);
dw_printf (" -r <number> Audio sample Rate. Default is %d.\n", DEFAULT_SAMPLES_PER_SEC);
dw_printf (" -n <number> Generate specified number of frames with increasing noise.\n");
dw_printf (" -o <file> Send output to .wav file.\n");
dw_printf (" -8 8 bit audio rather than 16.\n");
dw_printf (" -2 2 channels of audio rather than 1.\n");
dw_printf (" -z <number> Number of leading zero bits before frame.\n");
dw_printf (" Default is 12 which is .01 seconds at 1200 bits/sec.\n");
dw_printf ("\n");
dw_printf ("An optional file may be specified to provide messages other than\n");
dw_printf ("the default built-n message. The format should correspond to ...\n");
dw_printf ("blah blah blah. For example,\n");
dw_printf (" WB2OSZ-1>APDW10,WIDE2-2:!4237.14NS07120.83W#\n");
dw_printf ("\n");
dw_printf ("Example: %s\n", argv[0]);
dw_printf ("\n");
dw_printf (" With all defaults, a built-in test message is generated\n");
dw_printf (" with standard Bell 202 tones used for packet radio on ordinary\n");
dw_printf (" VHF FM transceivers.\n");
dw_printf ("\n");
dw_printf ("Example: %s -g -b 9600\n", argv[0]);
dw_printf ("Shortcut: %s -B 9600\n", argv[0]);
dw_printf ("\n");
dw_printf (" 9600 baud mode.\n");
dw_printf ("\n");
dw_printf ("Example: %s -m 1600 -s 1800 -b 300\n", argv[0]);
dw_printf ("Shortcut: %s -B 300\n", argv[0]);
dw_printf ("\n");
dw_printf (" 200 Hz shift, 300 baud, suitable for HF SSB transceiver.\n");
dw_printf ("\n");
dw_printf ("Example: echo -n \"WB2OSZ>WORLD:Hello, world!\" | %s -a 25 -o x.wav -\n", argv[0]);
dw_printf ("\n");
dw_printf (" Read message from stdin and put quarter volume sound into the file x.wav.\n");
exit (EXIT_FAILURE);
}
/*------------------------------------------------------------------
*
* Name: audio_file_open
*
* Purpose: Open a .WAV format file for output.
*
* Inputs: fname - Name of .WAV file to create.
*
* pa - Address of structure of type audio_s.
*
* The fields that we care about are:
* num_channels
* samples_per_sec
* bits_per_sample
* If zero, reasonable defaults will be provided.
*
* Returns: 0 for success, -1 for failure.
*
*----------------------------------------------------------------*/
struct wav_header { /* .WAV file header. */
char riff[4]; /* "RIFF" */
int filesize; /* file length - 8 */
char wave[4]; /* "WAVE" */
char fmt[4]; /* "fmt " */
int fmtsize; /* 16. */
short wformattag; /* 1 for PCM. */
short nchannels; /* 1 for mono, 2 for stereo. */
int nsamplespersec; /* sampling freq, Hz. */
int navgbytespersec; /* = nblockalign * nsamplespersec. */
short nblockalign; /* = wbitspersample / 8 * nchannels. */
short wbitspersample; /* 16 or 8. */
char data[4]; /* "data" */
int datasize; /* number of bytes following. */
} ;
/* 8 bit samples are unsigned bytes */
/* in range of 0 .. 255. */
/* 16 bit samples are signed short */
/* in range of -32768 .. +32767. */
static FILE *out_fp = NULL;
static struct wav_header header;
static int byte_count; /* Number of data bytes written to file. */
/* Will be written to header when file is closed. */
static int audio_file_open (char *fname, struct audio_s *pa)
{
int n;
/*
* Fill in defaults for any missing values.
*/
if (pa -> num_channels == 0)
pa -> num_channels = DEFAULT_NUM_CHANNELS;
if (pa -> samples_per_sec == 0)
pa -> samples_per_sec = DEFAULT_SAMPLES_PER_SEC;
if (pa -> bits_per_sample == 0)
pa -> bits_per_sample = DEFAULT_BITS_PER_SAMPLE;
/*
* Write the file header. Don't know length yet.
*/
out_fp = fopen (fname, "wb");
if (out_fp == NULL) {
text_color_set(DW_COLOR_ERROR); dw_printf ("Couldn't open file for write: %s\n", fname);
perror ("");
return (-1);
}
memset (&header, 0, sizeof(header));
memcpy (header.riff, "RIFF", (size_t)4);
header.filesize = 0;
memcpy (header.wave, "WAVE", (size_t)4);
memcpy (header.fmt, "fmt ", (size_t)4);
header.fmtsize = 16; // Always 16.
header.wformattag = 1; // 1 for PCM.
header.nchannels = pa -> num_channels;
header.nsamplespersec = pa -> samples_per_sec;
header.wbitspersample = pa -> bits_per_sample;
header.nblockalign = header.wbitspersample / 8 * header.nchannels;
header.navgbytespersec = header.nblockalign * header.nsamplespersec;
memcpy (header.data, "data", (size_t)4);
header.datasize = 0;
assert (header.nchannels == 1 || header.nchannels == 2);
n = fwrite (&header, sizeof(header), (size_t)1, out_fp);
if (n != 1) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Couldn't write header to: %s\n", fname);
perror ("");
fclose (out_fp);
out_fp = NULL;
return (-1);
}
/*
* Number of bytes written will be filled in later.
*/
byte_count = 0;
return (0);
} /* end audio_open */
/*------------------------------------------------------------------
*
* Name: audio_put
*
* Purpose: Send one byte to the audio output file.
*
* Inputs: c - One byte in range of 0 - 255.
*
* Returns: Normally non-negative.
* -1 for any type of error.
*
* Description: The caller must deal with the details of mono/stereo
* and number of bytes per sample.
*
*----------------------------------------------------------------*/
int audio_put (int c)
{
static short sample16;
int s;
if (g_add_noise) {
if ((byte_count & 1) == 0) {
sample16 = c & 0xff; /* save lower byte. */
byte_count++;
return c;
}
else {
float r;
sample16 |= (c << 8) & 0xff00; /* insert upper byte. */
byte_count++;
s = sample16; // sign extend.
/* Add random noise to the signal. */
/* r should be in range of -1 .. +1. */
r = (rand() - RAND_MAX/2.0) / (RAND_MAX/2.0);
s += 5 * r * g_noise_level * 32767;
if (s > 32767) s = 32767;
if (s < -32767) s = -32767;
putc(s & 0xff, out_fp);
return (putc((s >> 8) & 0xff, out_fp));
}
}
else {
byte_count++;
return (putc(c, out_fp));
}
} /* end audio_put */
int audio_flush ()
{
return 0;
}
/*------------------------------------------------------------------
*
* Name: audio_file_close
*
* Purpose: Close the audio output file.
*
* Returns: Normally non-negative.
* -1 for any type of error.
*
*
* Description: Must go back to beginning of file and fill in the
* size of the data.
*
*----------------------------------------------------------------*/
static int audio_file_close (void)
{
int n;
text_color_set(DW_COLOR_DEBUG);
dw_printf ("audio_close()\n");
/*
* Go back and fix up lengths in header.
*/
header.filesize = byte_count + sizeof(header) - 8;
header.datasize = byte_count;
if (out_fp == NULL) {
return (-1);
}
fflush (out_fp);
fseek (out_fp, 0L, SEEK_SET);
n = fwrite (&header, sizeof(header), (size_t)1, out_fp);
if (n != 1) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Couldn't write header to audio file.\n");
perror (""); // TODO: remove perror.
fclose (out_fp);
out_fp = NULL;
return (-1);
}
fclose (out_fp);
out_fp = NULL;
return (0);
} /* end audio_close */