--- /dev/null
+/*
+ * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
+ * Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
+ * Copyright (C) 2012 by Hoernchen <la@tfc-server.de>
+ * Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com>
+ * Copyright (C) 2013 by Elias Oenal <EliasOenal@gmail.com>
+ * Copyright (C) 2016, 2017 Konsulko Group
+ *
+ * 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/>.
+ */
+
+/*
+ * Note that this version replaces the standalone main() with separate
+ * init/start/stop API calls to allow building into another application.
+ * Other than removing the separate controller thread and adding an output
+ * function callback, other changes have been kept to a minimum to
+ * potentially allow using other rtl_fm features by modifying rtl_fm_init.
+ *
+ * December 2016, Scott Murray <scott.murray@konsulko.com>
+ */
+
+/*
+ * written because people could not do real time
+ * FM demod on Atom hardware with GNU radio
+ * based on rtl_sdr.c and rtl_tcp.c
+ *
+ * lots of locks, but that is okay
+ * (no many-to-many locks)
+ *
+ * todo:
+ * sanity checks
+ * scale squelch to other input parameters
+ * test all the demodulations
+ * pad output on hop
+ * frequency ranges could be stored better
+ * scaled AM demod amplification
+ * auto-hop after time limit
+ * peak detector to tune onto stronger signals
+ * fifo for active hop frequency
+ * clips
+ * noise squelch
+ * merge stereo patch
+ * merge soft agc patch
+ * merge udp patch
+ * testmode to detect overruns
+ * watchdog to reset bad dongle
+ * fix oversampling
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+#include <pthread.h>
+
+#include "rtl-sdr.h"
+#include "rtl_fm.h"
+#include "convenience/convenience.h"
+
+#define DEFAULT_SAMPLE_RATE 24000
+#define DEFAULT_BUF_LENGTH RTL_FM_DEFAULT_BUF_LENGTH
+#define MAXIMUM_OVERSAMPLE RTL_FM_MAXIMUM_OVERSAMPLE
+#define MAXIMUM_BUF_LENGTH RTL_FM_MAXIMUM_BUF_LENGTH
+#define AUTO_GAIN -100
+#define BUFFER_DUMP 4096
+
+#define FREQUENCIES_LIMIT 1000
+
+#define DEFAULT_SQUELCH_LEVEL 140
+#define DEFAULT_CONSEQ_SQUELCH 10
+
+static volatile int do_exit = 0;
+static int lcm_post[17] = {1,1,1,3,1,5,3,7,1,9,5,11,3,13,7,15,1};
+static int ACTUAL_BUF_LENGTH;
+
+static int *atan_lut = NULL;
+static int atan_lut_size = 131072; /* 512 KB */
+static int atan_lut_coef = 8;
+
+struct dongle_state
+{
+ int exit_flag;
+ pthread_t thread;
+ rtlsdr_dev_t *dev;
+ int dev_index;
+ uint32_t freq;
+ uint32_t rate;
+ int gain;
+ uint16_t buf16[MAXIMUM_BUF_LENGTH];
+ uint32_t buf_len;
+ int ppm_error;
+ int offset_tuning;
+ int direct_sampling;
+ int mute;
+ struct demod_state *demod_target;
+};
+
+struct demod_state
+{
+ int exit_flag;
+ pthread_t thread;
+ int16_t lowpassed[MAXIMUM_BUF_LENGTH];
+ int lp_len;
+ int16_t lp_i_hist[10][6];
+ int16_t lp_q_hist[10][6];
+ int16_t result[MAXIMUM_BUF_LENGTH];
+ int16_t droop_i_hist[9];
+ int16_t droop_q_hist[9];
+ int result_len;
+ int rate_in;
+ int rate_out;
+ int rate_out2;
+ int now_r, now_j;
+ int pre_r, pre_j;
+ int prev_index;
+ int downsample; /* min 1, max 256 */
+ int post_downsample;
+ int output_scale;
+ int squelch_level, conseq_squelch, squelch_hits, terminate_on_squelch;
+ int downsample_passes;
+ int comp_fir_size;
+ int custom_atan;
+ int deemph, deemph_a;
+ int now_lpr;
+ int prev_lpr_index;
+ int dc_block, dc_avg;
+ void (*mode_demod)(struct demod_state*);
+ pthread_rwlock_t rw;
+ pthread_cond_t ready;
+ pthread_mutex_t ready_m;
+ struct output_state *output_target;
+};
+
+struct output_state
+{
+ int exit_flag;
+ pthread_t thread;
+ rtl_fm_output_fn_t output_fn;
+ void *output_fn_data;
+ int16_t result[MAXIMUM_BUF_LENGTH];
+ int result_len;
+ int rate;
+ pthread_rwlock_t rw;
+ pthread_cond_t ready;
+ pthread_mutex_t ready_m;
+};
+
+struct controller_state
+{
+ int exit_flag;
+ pthread_t thread;
+ uint32_t freqs[FREQUENCIES_LIMIT];
+ int freq_len;
+ int freq_now;
+ int edge;
+ int wb_mode;
+ pthread_cond_t hop;
+ pthread_mutex_t hop_m;
+
+ void (*freq_callback)(uint32_t, void*);
+ void *freq_callback_data;
+
+ int scanning;
+ int scan_direction;
+ void (*scan_callback)(uint32_t, void*);
+ void *scan_callback_data;
+ uint32_t scan_step;
+ uint32_t scan_min;
+ uint32_t scan_max;
+ int scan_squelch_level;
+ int scan_squelch_count;
+};
+
+// multiple of these, eventually
+struct dongle_state dongle;
+struct demod_state demod;
+struct output_state output;
+struct controller_state controller;
+
+#if 0
+static void sighandler(int signum)
+{
+ fprintf(stderr, "Signal caught, exiting!\n");
+ do_exit = 1;
+ rtlsdr_cancel_async(dongle.dev);
+}
+#endif
+
+/* more cond dumbness */
+#define safe_cond_signal(n, m) pthread_mutex_lock(m); pthread_cond_signal(n); pthread_mutex_unlock(m)
+#define safe_cond_wait(n, m) pthread_mutex_lock(m); pthread_cond_wait(n, m); pthread_mutex_unlock(m)
+
+/* {length, coef, coef, coef} and scaled by 2^15
+ for now, only length 9, optimal way to get +85% bandwidth */
+#define CIC_TABLE_MAX 10
+int cic_9_tables[][10] = {
+ {0,},
+ {9, -156, -97, 2798, -15489, 61019, -15489, 2798, -97, -156},
+ {9, -128, -568, 5593, -24125, 74126, -24125, 5593, -568, -128},
+ {9, -129, -639, 6187, -26281, 77511, -26281, 6187, -639, -129},
+ {9, -122, -612, 6082, -26353, 77818, -26353, 6082, -612, -122},
+ {9, -120, -602, 6015, -26269, 77757, -26269, 6015, -602, -120},
+ {9, -120, -582, 5951, -26128, 77542, -26128, 5951, -582, -120},
+ {9, -119, -580, 5931, -26094, 77505, -26094, 5931, -580, -119},
+ {9, -119, -578, 5921, -26077, 77484, -26077, 5921, -578, -119},
+ {9, -119, -577, 5917, -26067, 77473, -26067, 5917, -577, -119},
+ {9, -199, -362, 5303, -25505, 77489, -25505, 5303, -362, -199},
+};
+
+void rotate_90(unsigned char *buf, uint32_t len)
+/* 90 rotation is 1+0j, 0+1j, -1+0j, 0-1j
+ or [0, 1, -3, 2, -4, -5, 7, -6] */
+{
+ uint32_t i;
+ unsigned char tmp;
+ for (i=0; i<len; i+=8) {
+ /* uint8_t negation = 255 - x */
+ tmp = 255 - buf[i+3];
+ buf[i+3] = buf[i+2];
+ buf[i+2] = tmp;
+
+ buf[i+4] = 255 - buf[i+4];
+ buf[i+5] = 255 - buf[i+5];
+
+ tmp = 255 - buf[i+6];
+ buf[i+6] = buf[i+7];
+ buf[i+7] = tmp;
+ }
+}
+
+void low_pass(struct demod_state *d)
+/* simple square window FIR */
+{
+ int i=0, i2=0;
+ while (i < d->lp_len) {
+ d->now_r += d->lowpassed[i];
+ d->now_j += d->lowpassed[i+1];
+ i += 2;
+ d->prev_index++;
+ if (d->prev_index < d->downsample) {
+ continue;
+ }
+ d->lowpassed[i2] = d->now_r; // * d->output_scale;
+ d->lowpassed[i2+1] = d->now_j; // * d->output_scale;
+ d->prev_index = 0;
+ d->now_r = 0;
+ d->now_j = 0;
+ i2 += 2;
+ }
+ d->lp_len = i2;
+}
+
+int low_pass_simple(int16_t *signal2, int len, int step)
+// no wrap around, length must be multiple of step
+{
+ int i, i2, sum;
+ for(i=0; i < len; i+=step) {
+ sum = 0;
+ for(i2=0; i2<step; i2++) {
+ sum += (int)signal2[i + i2];
+ }
+ //signal2[i/step] = (int16_t)(sum / step);
+ signal2[i/step] = (int16_t)(sum);
+ }
+ signal2[i/step + 1] = signal2[i/step];
+ return len / step;
+}
+
+void low_pass_real(struct demod_state *s)
+/* simple square window FIR */
+// add support for upsampling?
+{
+ int i=0, i2=0;
+ int fast = (int)s->rate_out;
+ int slow = s->rate_out2;
+ while (i < s->result_len) {
+ s->now_lpr += s->result[i];
+ i++;
+ s->prev_lpr_index += slow;
+ if (s->prev_lpr_index < fast) {
+ continue;
+ }
+ s->result[i2] = (int16_t)(s->now_lpr / (fast/slow));
+ s->prev_lpr_index -= fast;
+ s->now_lpr = 0;
+ i2 += 1;
+ }
+ s->result_len = i2;
+}
+
+void fifth_order(int16_t *data, int length, int16_t *hist)
+/* for half of interleaved data */
+{
+ int i;
+ int16_t a, b, c, d, e, f;
+ a = hist[1];
+ b = hist[2];
+ c = hist[3];
+ d = hist[4];
+ e = hist[5];
+ f = data[0];
+ /* a downsample should improve resolution, so don't fully shift */
+ data[0] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
+ for (i=4; i<length; i+=4) {
+ a = c;
+ b = d;
+ c = e;
+ d = f;
+ e = data[i-2];
+ f = data[i];
+ data[i/2] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
+ }
+ /* archive */
+ hist[0] = a;
+ hist[1] = b;
+ hist[2] = c;
+ hist[3] = d;
+ hist[4] = e;
+ hist[5] = f;
+}
+
+void generic_fir(int16_t *data, int length, int *fir, int16_t *hist)
+/* Okay, not at all generic. Assumes length 9, fix that eventually. */
+{
+ int d, temp, sum;
+ for (d=0; d<length; d+=2) {
+ temp = data[d];
+ sum = 0;
+ sum += (hist[0] + hist[8]) * fir[1];
+ sum += (hist[1] + hist[7]) * fir[2];
+ sum += (hist[2] + hist[6]) * fir[3];
+ sum += (hist[3] + hist[5]) * fir[4];
+ sum += hist[4] * fir[5];
+ data[d] = sum >> 15 ;
+ hist[0] = hist[1];
+ hist[1] = hist[2];
+ hist[2] = hist[3];
+ hist[3] = hist[4];
+ hist[4] = hist[5];
+ hist[5] = hist[6];
+ hist[6] = hist[7];
+ hist[7] = hist[8];
+ hist[8] = temp;
+ }
+}
+
+/* define our own complex math ops
+ because ARMv5 has no hardware float */
+
+void multiply(int ar, int aj, int br, int bj, int *cr, int *cj)
+{
+ *cr = ar*br - aj*bj;
+ *cj = aj*br + ar*bj;
+}
+
+int polar_discriminant(int ar, int aj, int br, int bj)
+{
+ int cr, cj;
+ double angle;
+ multiply(ar, aj, br, -bj, &cr, &cj);
+ angle = atan2((double)cj, (double)cr);
+ return (int)(angle / 3.14159 * (1<<14));
+}
+
+int fast_atan2(int y, int x)
+/* pre scaled for int16 */
+{
+ int yabs, angle;
+ int pi4=(1<<12), pi34=3*(1<<12); // note pi = 1<<14
+ if (x==0 && y==0) {
+ return 0;
+ }
+ yabs = y;
+ if (yabs < 0) {
+ yabs = -yabs;
+ }
+ if (x >= 0) {
+ angle = pi4 - pi4 * (x-yabs) / (x+yabs);
+ } else {
+ angle = pi34 - pi4 * (x+yabs) / (yabs-x);
+ }
+ if (y < 0) {
+ return -angle;
+ }
+ return angle;
+}
+
+int polar_disc_fast(int ar, int aj, int br, int bj)
+{
+ int cr, cj;
+ multiply(ar, aj, br, -bj, &cr, &cj);
+ return fast_atan2(cj, cr);
+}
+
+int atan_lut_init(void)
+{
+ int i = 0;
+
+ atan_lut = malloc(atan_lut_size * sizeof(int));
+
+ for (i = 0; i < atan_lut_size; i++) {
+ atan_lut[i] = (int) (atan((double) i / (1<<atan_lut_coef)) / 3.14159 * (1<<14));
+ }
+
+ return 0;
+}
+
+int polar_disc_lut(int ar, int aj, int br, int bj)
+{
+ int cr, cj, x, x_abs;
+
+ multiply(ar, aj, br, -bj, &cr, &cj);
+
+ /* special cases */
+ if (cr == 0 || cj == 0) {
+ if (cr == 0 && cj == 0)
+ {return 0;}
+ if (cr == 0 && cj > 0)
+ {return 1 << 13;}
+ if (cr == 0 && cj < 0)
+ {return -(1 << 13);}
+ if (cj == 0 && cr > 0)
+ {return 0;}
+ if (cj == 0 && cr < 0)
+ {return 1 << 14;}
+ }
+
+ /* real range -32768 - 32768 use 64x range -> absolute maximum: 2097152 */
+ x = (cj << atan_lut_coef) / cr;
+ x_abs = abs(x);
+
+ if (x_abs >= atan_lut_size) {
+ /* we can use linear range, but it is not necessary */
+ return (cj > 0) ? 1<<13 : -1<<13;
+ }
+
+ if (x > 0) {
+ return (cj > 0) ? atan_lut[x] : atan_lut[x] - (1<<14);
+ } else {
+ return (cj > 0) ? (1<<14) - atan_lut[-x] : -atan_lut[-x];
+ }
+
+ return 0;
+}
+
+void fm_demod(struct demod_state *fm)
+{
+ int i, pcm;
+ int16_t *lp = fm->lowpassed;
+ pcm = polar_discriminant(lp[0], lp[1],
+ fm->pre_r, fm->pre_j);
+ fm->result[0] = (int16_t)pcm;
+ for (i = 2; i < (fm->lp_len-1); i += 2) {
+ switch (fm->custom_atan) {
+ case 0:
+ pcm = polar_discriminant(lp[i], lp[i+1],
+ lp[i-2], lp[i-1]);
+ break;
+ case 1:
+ pcm = polar_disc_fast(lp[i], lp[i+1],
+ lp[i-2], lp[i-1]);
+ break;
+ case 2:
+ pcm = polar_disc_lut(lp[i], lp[i+1],
+ lp[i-2], lp[i-1]);
+ break;
+ }
+ fm->result[i/2] = (int16_t)pcm;
+ }
+ fm->pre_r = lp[fm->lp_len - 2];
+ fm->pre_j = lp[fm->lp_len - 1];
+ fm->result_len = fm->lp_len/2;
+}
+
+void am_demod(struct demod_state *fm)
+// todo, fix this extreme laziness
+{
+ int i, pcm;
+ int16_t *lp = fm->lowpassed;
+ int16_t *r = fm->result;
+ for (i = 0; i < fm->lp_len; i += 2) {
+ // hypot uses floats but won't overflow
+ //r[i/2] = (int16_t)hypot(lp[i], lp[i+1]);
+ pcm = lp[i] * lp[i];
+ pcm += lp[i+1] * lp[i+1];
+ r[i/2] = (int16_t)sqrt(pcm) * fm->output_scale;
+ }
+ fm->result_len = fm->lp_len/2;
+ // lowpass? (3khz) highpass? (dc)
+}
+
+void usb_demod(struct demod_state *fm)
+{
+ int i, pcm;
+ int16_t *lp = fm->lowpassed;
+ int16_t *r = fm->result;
+ for (i = 0; i < fm->lp_len; i += 2) {
+ pcm = lp[i] + lp[i+1];
+ r[i/2] = (int16_t)pcm * fm->output_scale;
+ }
+ fm->result_len = fm->lp_len/2;
+}
+
+void lsb_demod(struct demod_state *fm)
+{
+ int i, pcm;
+ int16_t *lp = fm->lowpassed;
+ int16_t *r = fm->result;
+ for (i = 0; i < fm->lp_len; i += 2) {
+ pcm = lp[i] - lp[i+1];
+ r[i/2] = (int16_t)pcm * fm->output_scale;
+ }
+ fm->result_len = fm->lp_len/2;
+}
+
+void raw_demod(struct demod_state *fm)
+{
+ int i;
+ for (i = 0; i < fm->lp_len; i++) {
+ fm->result[i] = (int16_t)fm->lowpassed[i];
+ }
+ fm->result_len = fm->lp_len;
+}
+
+void deemph_filter(struct demod_state *fm)
+{
+ static int avg; // cheating...
+ int i, d;
+ // de-emph IIR
+ // avg = avg * (1 - alpha) + sample * alpha;
+ for (i = 0; i < fm->result_len; i++) {
+ d = fm->result[i] - avg;
+ if (d > 0) {
+ avg += (d + fm->deemph_a/2) / fm->deemph_a;
+ } else {
+ avg += (d - fm->deemph_a/2) / fm->deemph_a;
+ }
+ fm->result[i] = (int16_t)avg;
+ }
+}
+
+void dc_block_filter(struct demod_state *fm)
+{
+ int i, avg;
+ int64_t sum = 0;
+ for (i=0; i < fm->result_len; i++) {
+ sum += fm->result[i];
+ }
+ avg = sum / fm->result_len;
+ avg = (avg + fm->dc_avg * 9) / 10;
+ for (i=0; i < fm->result_len; i++) {
+ fm->result[i] -= avg;
+ }
+ fm->dc_avg = avg;
+}
+
+int mad(int16_t *samples, int len, int step)
+/* mean average deviation */
+{
+ int i=0, sum=0, ave=0;
+ if (len == 0)
+ {return 0;}
+ for (i=0; i<len; i+=step) {
+ sum += samples[i];
+ }
+ ave = sum / (len * step);
+ sum = 0;
+ for (i=0; i<len; i+=step) {
+ sum += abs(samples[i] - ave);
+ }
+ return sum / (len / step);
+}
+
+int rms(int16_t *samples, int len, int step)
+/* largely lifted from rtl_power */
+{
+ int i;
+ long p, t, s;
+ double dc, err;
+
+ p = t = 0L;
+ for (i=0; i<len; i+=step) {
+ s = (long)samples[i];
+ t += s;
+ p += s * s;
+ }
+ /* correct for dc offset in squares */
+ dc = (double)(t*step) / (double)len;
+ err = t * 2 * dc - dc * dc * len;
+
+ return (int)sqrt((p-err) / len);
+}
+
+void arbitrary_upsample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* linear interpolation, len1 < len2 */
+{
+ int i = 1;
+ int j = 0;
+ int tick = 0;
+ double frac; // use integers...
+ while (j < len2) {
+ frac = (double)tick / (double)len2;
+ buf2[j] = (int16_t)(buf1[i-1]*(1-frac) + buf1[i]*frac);
+ j++;
+ tick += len1;
+ if (tick > len2) {
+ tick -= len2;
+ i++;
+ }
+ if (i >= len1) {
+ i = len1 - 1;
+ tick = len2;
+ }
+ }
+}
+
+void arbitrary_downsample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* fractional boxcar lowpass, len1 > len2 */
+{
+ int i = 1;
+ int j = 0;
+ int tick = 0;
+ double remainder = 0;
+ double frac; // use integers...
+ buf2[0] = 0;
+ while (j < len2) {
+ frac = 1.0;
+ if ((tick + len2) > len1) {
+ frac = (double)(len1 - tick) / (double)len2;}
+ buf2[j] += (int16_t)((double)buf1[i] * frac + remainder);
+ remainder = (double)buf1[i] * (1.0-frac);
+ tick += len2;
+ i++;
+ if (tick > len1) {
+ j++;
+ buf2[j] = 0;
+ tick -= len1;
+ }
+ if (i >= len1) {
+ i = len1 - 1;
+ tick = len1;
+ }
+ }
+ for (j=0; j<len2; j++) {
+ buf2[j] = buf2[j] * len2 / len1;}
+}
+
+void arbitrary_resample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* up to you to calculate lengths and make sure it does not go OOB
+ * okay for buffers to overlap, if you are downsampling */
+{
+ if (len1 < len2) {
+ arbitrary_upsample(buf1, buf2, len1, len2);
+ } else {
+ arbitrary_downsample(buf1, buf2, len1, len2);
+ }
+}
+
+void full_demod(struct demod_state *d)
+{
+ int i, ds_p;
+ int sr = 0;
+ ds_p = d->downsample_passes;
+ if (ds_p) {
+ for (i=0; i < ds_p; i++) {
+ fifth_order(d->lowpassed, (d->lp_len >> i), d->lp_i_hist[i]);
+ fifth_order(d->lowpassed+1, (d->lp_len >> i) - 1, d->lp_q_hist[i]);
+ }
+ d->lp_len = d->lp_len >> ds_p;
+ /* droop compensation */
+ if (d->comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) {
+ generic_fir(d->lowpassed, d->lp_len,
+ cic_9_tables[ds_p], d->droop_i_hist);
+ generic_fir(d->lowpassed+1, d->lp_len-1,
+ cic_9_tables[ds_p], d->droop_q_hist);
+ }
+ } else {
+ low_pass(d);
+ }
+ /* power squelch */
+ if (d->squelch_level) {
+ sr = rms(d->lowpassed, d->lp_len, 1);
+ if (sr < d->squelch_level) {
+ d->squelch_hits++;
+ for (i=0; i< d->lp_len; i++) {
+ d->lowpassed[i] = 0;
+ }
+ } else {
+ d->squelch_hits = 0;
+ }
+ }
+ d->mode_demod(d); /* lowpassed -> result */
+ if (d->mode_demod == &raw_demod) {
+ return;
+ }
+ /* todo, fm noise squelch */
+ // use nicer filter here too?
+ if (d->post_downsample > 1) {
+ d->result_len = low_pass_simple(d->result, d->result_len, d->post_downsample);}
+ if (d->deemph) {
+ deemph_filter(d);}
+ if (d->dc_block) {
+ dc_block_filter(d);}
+ if (d->rate_out2 > 0) {
+ low_pass_real(d);
+ //arbitrary_resample(d->result, d->result, d->result_len, d->result_len * d->rate_out2 / d->rate_out);
+ }
+}
+
+static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
+{
+ int i;
+ struct dongle_state *s = ctx;
+ struct demod_state *d = s->demod_target;
+
+ if (do_exit) {
+ return;}
+ if (!ctx) {
+ return;}
+ if (s->mute) {
+ for (i=0; i<s->mute; i++) {
+ buf[i] = 127;}
+ s->mute = 0;
+ }
+ if (!s->offset_tuning) {
+ rotate_90(buf, len);}
+ for (i=0; i<(int)len; i++) {
+ s->buf16[i] = (int16_t)buf[i] - 127;}
+ pthread_rwlock_wrlock(&d->rw);
+ memcpy(d->lowpassed, s->buf16, 2*len);
+ d->lp_len = len;
+ pthread_rwlock_unlock(&d->rw);
+ safe_cond_signal(&d->ready, &d->ready_m);
+}
+
+static void *dongle_thread_fn(void *arg)
+{
+ struct dongle_state *s = arg;
+ fprintf(stderr, "dongle_thread_fn running\n");
+ rtlsdr_read_async(s->dev, rtlsdr_callback, s, 0, s->buf_len);
+ fprintf(stderr, "dongle_thread_fn exited!\n");
+ return 0;
+}
+
+static void rtl_fm_scan_callback(void)
+{
+ struct controller_state *s = &controller;
+ uint32_t frequency = rtl_fm_get_freq();
+
+ if(!s->scanning)
+ return;
+
+ if(!s->scan_direction) {
+ frequency += s->scan_step;
+ if(frequency > s->scan_max)
+ frequency = s->scan_min;
+ } else {
+ frequency -= s->scan_step;
+ if(frequency < s->scan_min)
+ frequency = s->scan_max;
+ }
+
+ rtl_fm_set_freq(frequency);
+}
+
+static void rtl_fm_scan_end_callback(void)
+{
+ struct controller_state *s = &controller;
+
+ if(!s->scanning)
+ return;
+
+ rtl_fm_scan_stop();
+
+ if(s->scan_callback)
+ s->scan_callback(rtl_fm_get_freq(), s->scan_callback_data);
+}
+
+static void *demod_thread_fn(void *arg)
+{
+ struct demod_state *d = arg;
+ struct output_state *o = d->output_target;
+ fprintf(stderr, "demod_thread_fn running\n");
+ while (!do_exit) {
+ safe_cond_wait(&d->ready, &d->ready_m);
+ pthread_rwlock_wrlock(&d->rw);
+ full_demod(d);
+ pthread_rwlock_unlock(&d->rw);
+ if (d->exit_flag) {
+ do_exit = 1;
+ }
+ if (d->squelch_level) {
+ if(d->squelch_hits > d->conseq_squelch) {
+ d->squelch_hits = d->conseq_squelch + 1; /* hair trigger */
+ //safe_cond_signal(&controller.hop, &controller.hop_m);
+ rtl_fm_scan_callback();
+ continue;
+ } else if(!d->squelch_hits) {
+ rtl_fm_scan_end_callback();
+ }
+ }
+ pthread_rwlock_wrlock(&o->rw);
+ memcpy(o->result, d->result, 2*d->result_len);
+ o->result_len = d->result_len;
+ pthread_rwlock_unlock(&o->rw);
+ safe_cond_signal(&o->ready, &o->ready_m);
+ }
+ fprintf(stderr, "demod_thread_fn exited!\n");
+ return 0;
+}
+
+static void *output_thread_fn(void *arg)
+{
+ struct output_state *s = arg;
+ fprintf(stderr, "output_thread_fn running\n");
+ while (!do_exit) {
+ // use timedwait and pad out under runs
+ safe_cond_wait(&s->ready, &s->ready_m);
+ pthread_rwlock_rdlock(&s->rw);
+ if(s->output_fn) {
+ s->output_fn(s->result, s->result_len, s->output_fn_data);
+ }
+ pthread_rwlock_unlock(&s->rw);
+ }
+ fprintf(stderr, "output_thread_fn exited!\n");
+ return 0;
+}
+
+static void optimal_settings(int freq, int rate)
+{
+ // giant ball of hacks
+ // seems unable to do a single pass, 2:1
+ int capture_freq, capture_rate;
+ struct dongle_state *d = &dongle;
+ struct demod_state *dm = &demod;
+ struct controller_state *cs = &controller;
+ dm->downsample = (1000000 / dm->rate_in) + 1;
+ if (dm->downsample_passes) {
+ dm->downsample_passes = (int)log2(dm->downsample) + 1;
+ dm->downsample = 1 << dm->downsample_passes;
+ }
+ capture_freq = freq;
+ capture_rate = dm->downsample * dm->rate_in;
+ if (!d->offset_tuning) {
+ capture_freq = freq + capture_rate/4;}
+ capture_freq += cs->edge * dm->rate_in / 2;
+ dm->output_scale = (1<<15) / (128 * dm->downsample);
+ if (dm->output_scale < 1) {
+ dm->output_scale = 1;}
+ if (dm->mode_demod == &fm_demod) {
+ dm->output_scale = 1;}
+ d->freq = (uint32_t)capture_freq;
+ d->rate = (uint32_t)capture_rate;
+}
+
+
+void frequency_range(struct controller_state *s, char *arg)
+{
+ char *start, *stop, *step;
+ int i;
+ start = arg;
+ stop = strchr(start, ':') + 1;
+ stop[-1] = '\0';
+ step = strchr(stop, ':') + 1;
+ step[-1] = '\0';
+ for(i=(int)atofs(start); i<=(int)atofs(stop); i+=(int)atofs(step))
+ {
+ s->freqs[s->freq_len] = (uint32_t)i;
+ s->freq_len++;
+ if (s->freq_len >= FREQUENCIES_LIMIT) {
+ break;}
+ }
+ stop[-1] = ':';
+ step[-1] = ':';
+}
+
+void dongle_init(struct dongle_state *s)
+{
+ s->rate = DEFAULT_SAMPLE_RATE;
+ s->gain = AUTO_GAIN; // tenths of a dB
+ s->mute = 0;
+ s->direct_sampling = 0;
+ s->offset_tuning = 0;
+ s->demod_target = &demod;
+}
+
+void demod_init(struct demod_state *s)
+{
+ s->rate_in = DEFAULT_SAMPLE_RATE;
+ s->rate_out = DEFAULT_SAMPLE_RATE;
+ s->squelch_level = 0;
+ s->conseq_squelch = DEFAULT_CONSEQ_SQUELCH;
+ s->terminate_on_squelch = 0;
+ s->squelch_hits = DEFAULT_CONSEQ_SQUELCH + 1;
+ s->downsample_passes = 0;
+ s->comp_fir_size = 0;
+ s->prev_index = 0;
+ s->post_downsample = 1; // once this works, default = 4
+ s->custom_atan = 0;
+ s->deemph = 0;
+ s->rate_out2 = -1; // flag for disabled
+ s->mode_demod = &fm_demod;
+ s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
+ s->prev_lpr_index = 0;
+ s->deemph_a = 0;
+ s->now_lpr = 0;
+ s->dc_block = 0;
+ s->dc_avg = 0;
+ pthread_rwlock_init(&s->rw, NULL);
+ pthread_cond_init(&s->ready, NULL);
+ pthread_mutex_init(&s->ready_m, NULL);
+ s->output_target = &output;
+}
+
+void demod_cleanup(struct demod_state *s)
+{
+ pthread_rwlock_destroy(&s->rw);
+ pthread_cond_destroy(&s->ready);
+ pthread_mutex_destroy(&s->ready_m);
+}
+
+void output_init(struct output_state *s)
+{
+ s->rate = DEFAULT_SAMPLE_RATE;
+ s->output_fn = NULL;
+ s->output_fn_data = NULL;
+ pthread_rwlock_init(&s->rw, NULL);
+ pthread_cond_init(&s->ready, NULL);
+ pthread_mutex_init(&s->ready_m, NULL);
+}
+
+void output_cleanup(struct output_state *s)
+{
+ pthread_rwlock_destroy(&s->rw);
+ pthread_cond_destroy(&s->ready);
+ pthread_mutex_destroy(&s->ready_m);
+}
+
+void controller_init(struct controller_state *s)
+{
+ s->freqs[0] = 100000000;
+ s->freq_len = 0;
+ s->edge = 0;
+ s->wb_mode = 0;
+ pthread_cond_init(&s->hop, NULL);
+ pthread_mutex_init(&s->hop_m, NULL);
+}
+
+void controller_cleanup(struct controller_state *s)
+{
+ pthread_cond_destroy(&s->hop);
+ pthread_mutex_destroy(&s->hop_m);
+}
+
+void sanity_checks(void)
+{
+ if (controller.freq_len == 0) {
+ fprintf(stderr, "Please specify a frequency.\n");
+ exit(1);
+ }
+
+ if (controller.freq_len >= FREQUENCIES_LIMIT) {
+ fprintf(stderr, "Too many channels, maximum %i.\n", FREQUENCIES_LIMIT);
+ exit(1);
+ }
+
+ if (controller.freq_len > 1 && demod.squelch_level == 0) {
+ fprintf(stderr, "Please specify a squelch level. Required for scanning multiple frequencies.\n");
+ exit(1);
+ }
+
+}
+
+int rtl_fm_init(uint32_t freq,
+ uint32_t sample_rate,
+ uint32_t resample_rate,
+ rtl_fm_output_fn_t output_fn,
+ void *output_fn_data)
+{
+ int r = 0;
+
+ dongle_init(&dongle);
+ demod_init(&demod);
+ output_init(&output);
+ controller_init(&controller);
+
+ /*
+ * Simulate the effects of command line arguments:
+ *
+ * -W wbfm -s <sample rate> -r <resample rate>
+ */
+
+ /* Set initial frequency */
+ controller.freqs[0] = freq;
+ controller.freq_len++;
+
+ /* Set mode to wbfm */
+ controller.wb_mode = 1;
+ demod.mode_demod = &fm_demod;
+ demod.rate_in = 170000;
+ demod.rate_out = 170000;
+ demod.rate_out2 = 32000;
+ demod.custom_atan = 1;
+ //demod.post_downsample = 4;
+ demod.deemph = 1;
+ controller.scan_squelch_count = DEFAULT_CONSEQ_SQUELCH;
+ controller.scan_squelch_level = DEFAULT_SQUELCH_LEVEL;
+ demod.squelch_level = 0;
+
+ /* Adjust frequency for wb mode */
+ controller.freqs[0] += 16000;
+
+ /* Set sample rate */
+ demod.rate_in = sample_rate;
+ demod.rate_out = sample_rate;
+
+ /* Set resample rate */
+ output.rate = (int) resample_rate;
+ demod.rate_out2 = (int) resample_rate;
+
+ /* Set output function pointer */
+ if(output_fn) {
+ output.output_fn = output_fn;
+ output.output_fn_data = output_fn_data;
+ }
+
+ /* quadruple sample_rate to limit to Δθ to ±π/2 */
+ demod.rate_in *= demod.post_downsample;
+
+ if (!output.rate) {
+ output.rate = demod.rate_out;
+ }
+
+ sanity_checks();
+
+ if (controller.freq_len > 1) {
+ demod.terminate_on_squelch = 0;
+ }
+
+ ACTUAL_BUF_LENGTH = lcm_post[demod.post_downsample] * DEFAULT_BUF_LENGTH;
+
+ dongle.dev_index = verbose_device_search("0");
+ if (dongle.dev_index < 0) {
+ return -1;
+ }
+
+ r = rtlsdr_open(&dongle.dev, (uint32_t)dongle.dev_index);
+ if (r < 0) {
+ fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dongle.dev_index);
+ return r;
+ }
+
+ if (demod.deemph) {
+ demod.deemph_a = (int)round(1.0/((1.0-exp(-1.0/(demod.rate_out * 75e-6)))));
+ }
+
+ /* Set the tuner gain */
+ if (dongle.gain == AUTO_GAIN) {
+ verbose_auto_gain(dongle.dev);
+ } else {
+ dongle.gain = nearest_gain(dongle.dev, dongle.gain);
+ verbose_gain_set(dongle.dev, dongle.gain);
+ }
+
+ verbose_ppm_set(dongle.dev, dongle.ppm_error);
+
+ //r = rtlsdr_set_testmode(dongle.dev, 1);
+
+ return r;
+}
+
+void rtl_fm_start(void)
+{
+ struct controller_state *s = &controller;
+
+ /*
+ * A bunch of the following is pulled from the controller_thread_fn,
+ * which has been removed.
+ */
+
+ /* Reset endpoint before we start reading from it (mandatory) */
+ verbose_reset_buffer(dongle.dev);
+
+ /* set up primary channel */
+ optimal_settings(s->freqs[0], demod.rate_in);
+ if (dongle.direct_sampling) {
+ verbose_direct_sampling(dongle.dev, 1);}
+ if (dongle.offset_tuning) {
+ verbose_offset_tuning(dongle.dev);}
+
+ /* Set the frequency */
+ verbose_set_frequency(dongle.dev, dongle.freq);
+ fprintf(stderr, "Oversampling input by: %ix.\n", demod.downsample);
+ fprintf(stderr, "Oversampling output by: %ix.\n", demod.post_downsample);
+ fprintf(stderr, "Buffer size: %0.2fms\n",
+ 1000 * 0.5 * (float)ACTUAL_BUF_LENGTH / (float)dongle.rate);
+
+ /* Set the sample rate */
+ verbose_set_sample_rate(dongle.dev, dongle.rate);
+ fprintf(stderr, "Output at %u Hz.\n", demod.rate_in/demod.post_downsample);
+ usleep(100000);
+
+ rtl_fm_scan_stop();
+
+ do_exit = 0;
+ pthread_create(&output.thread, NULL, output_thread_fn, (void *)(&output));
+ pthread_create(&demod.thread, NULL, demod_thread_fn, (void *)(&demod));
+ pthread_create(&dongle.thread, NULL, dongle_thread_fn, (void *)(&dongle));
+}
+
+void rtl_fm_set_freq(uint32_t freq)
+{
+ struct controller_state *s = &controller;
+
+ if(s->freqs[0] == freq)
+ return;
+
+ s->freqs[0] = freq;
+ s->freq_len = 1;
+
+ if (s->wb_mode) {
+ s->freqs[0] += 16000;
+ }
+
+ optimal_settings(s->freqs[0], demod.rate_in);
+ if (dongle.offset_tuning) {
+ verbose_offset_tuning(dongle.dev);
+ }
+ rtlsdr_set_center_freq(dongle.dev, dongle.freq);
+
+ // It does not look like refreshing the sample rate is desirable
+ // (e.g. the scanning code in the removed controller thread function
+ // did not do it), and behavior seemed a bit less robust with it
+ // present. However, I am leaving this here as a reminder to revisit
+ // via some more testing.
+ //rtlsdr_set_sample_rate(dongle.dev, dongle.rate);
+
+ // This triggers a mute during the frequency change
+ dongle.mute = BUFFER_DUMP;
+
+ if(s->freq_callback)
+ s->freq_callback(freq, s->freq_callback_data);
+}
+
+void rtl_fm_set_freq_callback(void (*callback)(uint32_t, void *),
+ void *data)
+{
+ struct controller_state *s = &controller;
+
+ s->freq_callback = callback;
+ s->freq_callback_data = data;
+}
+
+uint32_t rtl_fm_get_freq(void)
+{
+ struct controller_state *s = &controller;
+ uint32_t frequency = s->freqs[0];
+
+ if (s->wb_mode)
+ frequency -= 16000;
+
+ return frequency;
+}
+
+void rtl_fm_stop(void)
+{
+ rtl_fm_scan_stop();
+
+ rtlsdr_cancel_async(dongle.dev);
+ do_exit = 1;
+ pthread_join(dongle.thread, NULL);
+ safe_cond_signal(&demod.ready, &demod.ready_m);
+ pthread_join(demod.thread, NULL);
+ safe_cond_signal(&output.ready, &output.ready_m);
+ pthread_join(output.thread, NULL);
+}
+
+void rtl_fm_scan_start(int direction,
+ void (*callback)(uint32_t, void *),
+ void *data,
+ uint32_t step,
+ uint32_t min,
+ uint32_t max)
+{
+ struct controller_state *s = &controller;
+ struct demod_state *dm = &demod;
+ uint32_t frequency = rtl_fm_get_freq();
+
+ if(s->scanning && s->scan_direction == direction)
+ return;
+
+ s->scanning = 1;
+ s->scan_direction = direction;
+ s->scan_callback = callback;
+ s->scan_callback_data = data;
+ s->scan_step = step;
+ s->scan_min = min;
+ s->scan_max = max;
+
+ /* Start scan by stepping in the desired direction */
+ if(!direction) {
+ frequency += s->scan_step;
+ if(frequency > s->scan_max)
+ frequency = s->scan_min;
+ } else {
+ frequency -= s->scan_step;
+ if(frequency < s->scan_min)
+ frequency = s->scan_max;
+ }
+
+ rtl_fm_set_freq(frequency);
+
+ dm->conseq_squelch = s->scan_squelch_count;
+ dm->squelch_hits = s->scan_squelch_count + 1;
+ dm->squelch_level = s->scan_squelch_level;
+}
+
+void rtl_fm_scan_stop(void)
+{
+ struct controller_state *s = &controller;
+ struct demod_state *dm = &demod;
+
+ s->scanning = 0;
+
+ dm->squelch_hits = s->scan_squelch_count + 1;
+ dm->squelch_level = 0;
+}
+
+void rtl_fm_scan_set_squelch_level(int level)
+{
+ struct controller_state *s = &controller;
+
+ s->scan_squelch_level = level;
+}
+
+void rtl_fm_scan_set_squelch_limit(int count)
+{
+ struct controller_state *s = &controller;
+
+ s->scan_squelch_count = count;
+}
+
+void rtl_fm_cleanup(void)
+{
+ //dongle_cleanup(&dongle);
+ demod_cleanup(&demod);
+ output_cleanup(&output);
+ controller_cleanup(&controller);
+
+ rtlsdr_close(dongle.dev);
+}
+
+// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab
Code Review / staging / soundmanager.git / blobdiff