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@J3698
Created February 24, 2019 01:43
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Metronome Example Program
/*
Copyright (C) 2002 Anthony Van Groningen
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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <math.h>
#include <getopt.h>
#include <string.h>
#include <jack/jack.h>
#include <jack/transport.h>
typedef jack_default_audio_sample_t sample_t;
const double PI = 3.14;
jack_client_t *client;
jack_port_t *output_port;
unsigned long sr;
int freq = 880;
int bpm;
jack_nframes_t tone_length, wave_length;
sample_t *wave;
long offset = 0;
int transport_aware = 0;
jack_transport_state_t transport_state;
void
usage ()
{
fprintf (stderr, "\n"
"usage: jack_metro \n"
" [ --frequency OR -f frequency (in Hz) ]\n"
" [ --amplitude OR -A maximum amplitude (between 0 and 1) ]\n"
" [ --duration OR -D duration (in ms) ]\n"
" [ --attack OR -a attack (in percent of duration) ]\n"
" [ --decay OR -d decay (in percent of duration) ]\n"
" [ --name OR -n jack name for metronome client ]\n"
" [ --transport OR -t transport aware ]\n"
" --bpm OR -b beats per minute\n"
);
}
void
process_silence (jack_nframes_t nframes)
{
sample_t *buffer = (sample_t *) jack_port_get_buffer (output_port, nframes);
memset (buffer, 0, sizeof (jack_default_audio_sample_t) * nframes);
}
void
process_audio (jack_nframes_t nframes)
{
sample_t *buffer = (sample_t *) jack_port_get_buffer (output_port, nframes);
jack_nframes_t frames_left = nframes;
while (wave_length - offset < frames_left) {
memcpy (buffer + (nframes - frames_left), wave + offset, sizeof (sample_t) * (wave_length - offset));
frames_left -= wave_length - offset;
offset = 0;
}
if (frames_left > 0) {
memcpy (buffer + (nframes - frames_left), wave + offset, sizeof (sample_t) * frames_left);
offset += frames_left;
}
}
int
process (jack_nframes_t nframes, void *arg)
{
if (transport_aware) {
jack_position_t pos;
if (jack_transport_query (client, &pos)
!= JackTransportRolling) {
process_silence (nframes);
return 0;
}
offset = pos.frame % wave_length;
}
process_audio (nframes);
return 0;
}
int
sample_rate_change () {
printf("Sample rate has changed! Exiting...\n");
exit(-1);
}
int
main (int argc, char *argv[])
{
sample_t scale;
int i, attack_length, decay_length;
double *amp;
double max_amp = 0.5;
int option_index;
int opt;
int got_bpm = 0;
int attack_percent = 1, decay_percent = 10, dur_arg = 100;
char *client_name = 0;
char *bpm_string = "bpm";
int verbose = 0;
jack_status_t status;
const char *options = "f:A:D:a:d:b:n:thv";
struct option long_options[] =
{
{"frequency", 1, 0, 'f'},
{"amplitude", 1, 0, 'A'},
{"duration", 1, 0, 'D'},
{"attack", 1, 0, 'a'},
{"decay", 1, 0, 'd'},
{"bpm", 1, 0, 'b'},
{"name", 1, 0, 'n'},
{"transport", 0, 0, 't'},
{"help", 0, 0, 'h'},
{"verbose", 0, 0, 'v'},
{0, 0, 0, 0}
};
while ((opt = getopt_long (argc, argv, options, long_options, &option_index)) != EOF) {
switch (opt) {
case 'f':
if ((freq = atoi (optarg)) <= 0) {
fprintf (stderr, "invalid frequency\n");
return -1;
}
break;
case 'A':
if (((max_amp = atof (optarg)) <= 0)|| (max_amp > 1)) {
fprintf (stderr, "invalid amplitude\n");
return -1;
}
break;
case 'D':
dur_arg = atoi (optarg);
fprintf (stderr, "durarg = %u\n", dur_arg);
break;
case 'a':
if (((attack_percent = atoi (optarg)) < 0) || (attack_percent > 100)) {
fprintf (stderr, "invalid attack percent\n");
return -1;
}
break;
case 'd':
if (((decay_percent = atoi (optarg)) < 0) || (decay_percent > 100)) {
fprintf (stderr, "invalid decay percent\n");
return -1;
}
break;
case 'b':
got_bpm = 1;
if ((bpm = atoi (optarg)) < 0) {
fprintf (stderr, "invalid bpm\n");
return -1;
}
bpm_string = (char *) malloc ((strlen (optarg) + 4) * sizeof (char));
strcpy (bpm_string, optarg);
strcat (bpm_string, "_bpm");
break;
case 'n':
client_name = (char *) malloc (strlen (optarg) * sizeof (char));
strcpy (client_name, optarg);
break;
case 'v':
verbose = 1;
break;
case 't':
transport_aware = 1;
break;
default:
fprintf (stderr, "unknown option %c\n", opt);
case 'h':
usage ();
return -1;
}
}
if (!got_bpm) {
fprintf (stderr, "bpm not specified\n");
usage ();
return -1;
}
/* Initial Jack setup, get sample rate */
if (!client_name) {
client_name = (char *) malloc (9 * sizeof (char));
strcpy (client_name, "metro");
}
if ((client = jack_client_open (client_name, JackNoStartServer, &status)) == 0) {
fprintf (stderr, "jack server not running?\n");
return 1;
}
jack_set_process_callback (client, process, 0);
output_port = jack_port_register (client, bpm_string, JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0);
sr = jack_get_sample_rate (client);
/* setup wave table parameters */
wave_length = 60 * sr / bpm;
tone_length = sr * dur_arg / 1000;
attack_length = tone_length * attack_percent / 100;
decay_length = tone_length * decay_percent / 100;
scale = 2 * PI * freq / sr;
if (tone_length >= wave_length) {
fprintf (stderr, "invalid duration (tone length = %" PRIu32
", wave length = %" PRIu32 "\n", tone_length,
wave_length);
return -1;
}
if (attack_length + decay_length > (int)tone_length) {
fprintf (stderr, "invalid attack/decay\n");
return -1;
}
/* Build the wave table */
wave = (sample_t *) malloc (wave_length * sizeof(sample_t));
amp = (double *) malloc (tone_length * sizeof(double));
for (i = 0; i < attack_length; i++) {
amp[i] = max_amp * i / ((double) attack_length);
}
for (i = attack_length; i < (int)tone_length - decay_length; i++) {
amp[i] = max_amp;
}
for (i = (int)tone_length - decay_length; i < (int)tone_length; i++) {
amp[i] = - max_amp * (i - (double) tone_length) / ((double) decay_length);
}
for (i = 0; i < (int)tone_length; i++) {
wave[i] = amp[i] * sin (scale * i);
}
for (i = tone_length; i < (int)wave_length; i++) {
wave[i] = 0;
}
if (jack_activate (client)) {
fprintf (stderr, "cannot activate client");
return 1;
}
while (1) {
sleep(1);
};
}
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