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#include <alsa/asoundlib.h>
#include <alsa/seq.h>
#include <jack/jack.h>
#include <sys/time.h>
static jack_nframes_t sample_frames = 0;
void normalize(struct timeval *tv)
{
if (tv->tv_sec == 0) {
while (tv->tv_usec <= -1000000) { tv->tv_usec += 1000000; --tv->tv_sec; }
while (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
} else if (tv->tv_sec < 0) {
while (tv->tv_usec <= -1000000) { tv->tv_usec += 1000000; --tv->tv_sec; }
while (tv->tv_usec > 0) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
} else {
while (tv->tv_usec >= 1000000) { tv->tv_usec -= 1000000; ++tv->tv_sec; }
while (tv->tv_usec < 0) { tv->tv_usec += 1000000; --tv->tv_sec; }
}
}
int
jack_process(jack_nframes_t nframes, void *arg)
{
sample_frames += nframes;
}
jack_nframes_t
rt_to_frame(struct timeval tv, jack_nframes_t sample_rate)
{
if (tv.tv_sec < 0) tv.tv_sec = -tv.tv_sec;
if (tv.tv_usec < 0) tv.tv_usec = -tv.tv_usec;
return
tv.tv_sec * sample_rate +
((tv.tv_usec / 1000) * sample_rate) / 1000 +
((tv.tv_usec - 1000 * (tv.tv_usec / 1000)) * sample_rate) / 1000000;
}
int
main(int argc, char **argv)
{
snd_seq_t *handle;
int portid;
int npfd;
struct pollfd *pfd;
int queue;
int i;
int rval;
struct timeval starttv;
int countdown = -1;
snd_seq_queue_timer_t *timer;
snd_timer_id_t *timerid;
jack_client_t *jclient;
jack_nframes_t sample_rate;
if ((jclient = jack_client_new("queue-timer-jack")) == 0) {
fprintf(stderr, "failed to connect to JACK server\n");
return 1;
}
jack_set_process_callback(jclient, jack_process, 0);
sample_rate = jack_get_sample_rate(jclient);
if (snd_seq_open(&handle, "hw", SND_SETQ_OPEN_DUPLEX, 0) < 0) {
fprintf(stderr, "failed to open ALSA sequencer interface\n");
return 1;
}
snd_seq_set_client_name(handle, "generator");
if ((portid = snd_seq_create_simple_port
(handle, "generator",
SND_SETQ_PORT_CAP_READ | SND_SETQ_PORT_CAP_SUBS_READ, 0)) < 0) {
fprintf(stderr, "failed to create ALSA sequencer port\n");
return 1;
}
if ((queue = snd_seq_alloc_queue(handle)) < 0) {
fprintf(stderr, "failed to create ALSA sequencer queue\n");
return 1;
}
snd_seq_queue_timer_alloca(&timer);
snd_seq_get_queue_timer(handle, queue, timer);
snd_timer_id_alloca(&timerid);
/* To test a PCM timer: */
/*
snd_timer_id_set_class(timerid, SND_TIMER_CLASS_PCM);
snd_timer_id_set_sclass(timerid, SND_TIMER_SCLASS_NONE);
snd_timer_id_set_card(timerid, 0);
snd_timer_id_set_device(timerid, 0);
snd_timer_id_set_subdevice(timerid, 0);
*/
/* To test the system timer: */
snd_timer_id_set_class(timerid, SND_TIMER_CLASS_GLOBAL);
snd_timer_id_set_sclass(timerid, SND_TIMER_SCLASS_NONE);
snd_timer_id_set_device(timerid, SND_TIMER_GLOBAL_SYSTEM);
snd_seq_queue_timer_set_id(timer, timerid);
snd_seq_set_queue_timer(handle, queue, timer);
if (jack_activate(jclient)) {
fprintf (stderr, "cannot activate jack client");
exit(1);
}
snd_seq_start_queue(handle, queue, 0);
snd_seq_drain_output(handle);
gettimeofday(&starttv, 0);
while (countdown != 0) {
snd_seq_queue_status_t *status;
const snd_seq_real_time_t *rtime;
struct timeval tv, qtv, jtv, diff, jdiff;
jack_nframes_t frames_now;
snd_seq_queue_status_alloca(&status);
snd_seq_get_queue_status(handle, queue, status);
rtime = snd_seq_queue_status_get_real_time(status);
gettimeofday(&tv, 0);
frames_now = sample_frames;
fprintf(stderr, " frames: %ld\n", frames_now);
qtv.tv_sec = rtime->tv_sec;
qtv.tv_usec = rtime->tv_nsec / 1000;
tv.tv_sec -= starttv.tv_sec;
tv.tv_usec -= starttv.tv_usec;
normalize(&tv);
jtv.tv_sec = frames_now / sample_rate;
frames_now -= jtv.tv_sec * sample_rate;
jtv.tv_usec = (int)(((float)frames_now * 1000000) / sample_rate);
diff.tv_sec = tv.tv_sec - qtv.tv_sec;
diff.tv_usec = tv.tv_usec - qtv.tv_usec;
normalize(&diff);
jdiff.tv_sec = jtv.tv_sec - qtv.tv_sec;
jdiff.tv_usec = jtv.tv_usec - qtv.tv_usec;
normalize(&jdiff);
fprintf(stderr, " real time: %12ld sec %8ld usec /%12ld frames\nqueue time: %12ld sec %8ld usec /%12ld frames\n jack time: %12ld sec %8ld usec /%12ld frames\n rq diff: %12ld sec %8ld usec /%12ld frames\n jq diff: %12ld sec %8ld usec /%12ld frames\n",
tv.tv_sec, tv.tv_usec, rt_to_frame(tv, sample_rate),
qtv.tv_sec, qtv.tv_usec, rt_to_frame(qtv, sample_rate),
jtv.tv_sec, jtv.tv_usec, rt_to_frame(jtv, sample_rate),
diff.tv_sec, diff.tv_usec, rt_to_frame(diff, sample_rate),
jdiff.tv_sec, jdiff.tv_usec, rt_to_frame(jdiff, sample_rate));
fprintf(stderr, "\n");
struct timespec ts;
ts.tv_sec = 1;
ts.tv_nsec = 0;
nanosleep(&ts, 0);
}
}
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