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/*
* rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
* Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
*
* 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/>.
*/
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <unistd.h>
#include "rtl-sdr.h"
#define DEFAULT_SAMPLE_RATE 2048000
#define DEFAULT_ASYNC_BUF_NUMBER 32
#define DEFAULT_BUF_LENGTH (16 * 16384)
#define MINIMAL_BUF_LENGTH 512
#define MAXIMAL_BUF_LENGTH (256 * 16384)
static int do_exit = 0;
static rtlsdr_dev_t *dev = NULL;
void usage(void)
{
fprintf(stderr,
"rtl-sdr, an I/Q recorder for RTL2832 based DVB-T receivers\n\n"
"Usage:\t -f frequency_to_tune_to [Hz]\n"
"\t[-s samplerate (default: 2048000 Hz)]\n"
"\t[-d device_index (default: 0)]\n"
"\t[-g tuner_gain (default: 0 dB)]\n"
"\t[-b output_block_size (default: 16 * 16384)]\n"
"\t[-S force sync output (default: async)]\n"
"\toutput_filename (a '-' dumps samples to stdout)\n\n");
exit(1);
}
static void sighandler(int signum)
{
do_exit = 1;
rtlsdr_cancel_async(dev);
}
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
if (ctx) {
if (fwrite(buf, 1, len, (FILE*)ctx) != len) {
fprintf(stderr, "Short write, samples lost, exiting!\n");
rtlsdr_cancel_async(dev);
}
}
}
int main(int argc, char **argv)
{
struct sigaction sigact;
char *filename = NULL;
int n_read;
int r, opt;
int i, gain = 0;
int sync_mode = 0;
FILE *file;
uint8_t *buffer;
uint32_t dev_index = 0;
uint32_t frequency = 0;
uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
uint32_t out_block_size = DEFAULT_BUF_LENGTH;
while ((opt = getopt(argc, argv, "d:f:g:s:b:S::")) != -1) {
switch (opt) {
case 'd':
dev_index = atoi(optarg);
break;
case 'f':
frequency = (uint32_t)atof(optarg);
break;
case 'g':
gain = atoi(optarg);
break;
case 's':
samp_rate = (int)atof(optarg);
break;
case 'b':
out_block_size = (uint32_t)atof(optarg);
break;
case 'S':
sync_mode = 1;
break;
default:
usage();
break;
}
}
if (argc <= optind) {
usage();
} else {
filename = argv[optind];
}
if(out_block_size < MINIMAL_BUF_LENGTH ||
out_block_size > MAXIMAL_BUF_LENGTH ){
fprintf(stderr,
"Output block size wrong value, falling back to default\n");
fprintf(stderr,
"Minimal length: %u\n", MINIMAL_BUF_LENGTH);
fprintf(stderr,
"Maximal length: %u\n", MAXIMAL_BUF_LENGTH);
out_block_size = DEFAULT_BUF_LENGTH;
}
buffer = malloc(out_block_size * sizeof(uint8_t));
int device_count = rtlsdr_get_device_count();
if (!device_count) {
fprintf(stderr, "No supported devices found.\n");
exit(1);
}
fprintf(stderr, "Found %d device(s):\n", device_count);
for (i = 0; i < device_count; i++)
fprintf(stderr, " %d: %s\n", i, rtlsdr_get_device_name(i));
fprintf(stderr, "\n");
fprintf(stderr, "Using device %d: %s\n",
dev_index,
rtlsdr_get_device_name(dev_index));
r = rtlsdr_open(&dev, dev_index);
if (r < 0) {
fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dev_index);
exit(1);
}
sigact.sa_handler = sighandler;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
sigaction(SIGTERM, &sigact, NULL);
sigaction(SIGQUIT, &sigact, NULL);
sigaction(SIGPIPE, &sigact, NULL);
/* Set the sample rate */
r = rtlsdr_set_sample_rate(dev, samp_rate);
if (r < 0)
fprintf(stderr, "WARNING: Failed to set sample rate.\n");
/* Set the frequency */
r = rtlsdr_set_center_freq(dev, frequency);
if (r < 0)
fprintf(stderr, "WARNING: Failed to set center freq.\n");
else
fprintf(stderr, "Tuned to %u Hz.\n", frequency);
/* Set the tuner gain */
r = rtlsdr_set_tuner_gain(dev, gain);
if (r < 0)
fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
else
fprintf(stderr, "Tuner gain set to %i dB.\n", gain);
if(strcmp(filename, "-") == 0) { /* Write samples to stdout */
file = stdout;
} else {
file = fopen(filename, "wb");
if (!file) {
fprintf(stderr, "Failed to open %s\n", filename);
goto out;
}
}
/* Reset endpoint before we start reading from it (mandatory) */
r = rtlsdr_reset_buffer(dev);
if (r < 0)
fprintf(stderr, "WARNING: Failed to reset buffers.\n");
if (sync_mode) {
fprintf(stderr, "Reading samples in sync mode...\n");
while (!do_exit) {
r = rtlsdr_read_sync(dev, buffer, out_block_size, &n_read);
if (r < 0) {
fprintf(stderr, "WARNING: sync read failed.\n");
break;
}
if (fwrite(buffer, 1, n_read, file) != n_read) {
fprintf(stderr, "Short write, samples lost, exiting!\n");
break;
}
if (n_read < out_block_size) {
fprintf(stderr, "Short read, samples lost, exiting!\n");
break;
}
}
} else {
fprintf(stderr, "Reading samples in async mode...\n");
r = rtlsdr_read_async(dev, rtlsdr_callback, (void *)file,
DEFAULT_ASYNC_BUF_NUMBER, out_block_size);
}
if (do_exit)
fprintf(stderr, "\nUser cancel, exiting...\n");
else
fprintf(stderr, "\nLibrary error %d, exiting...\n", r);
if (file != stdout)
fclose(file);
rtlsdr_close(dev);
free (buffer);
out:
return r >= 0 ? r : -r;
}
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