218 lines
5.3 KiB
C
218 lines
5.3 KiB
C
/** @file latent_client.c
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*
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* @brief This simple client demonstrates the most basic features of JACK
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* as they would be used by many applications.
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*/
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#include <stdio.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <inttypes.h>
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#include <jack/jack.h>
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jack_port_t *input_port;
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jack_port_t *output_port;
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jack_client_t *client;
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jack_default_audio_sample_t *delay_line;
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jack_nframes_t delay_index;
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jack_nframes_t latency = 1024;
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#ifdef WIN32
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#define jack_sleep(val) Sleep((val))
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#else
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#define jack_sleep(val) usleep((val) * 1000)
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#endif
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/**
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* The process callback for this JACK application is called in a
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* special realtime thread once for each audio cycle.
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*
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* This client does nothing more than copy data from its input
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* port to its output port. It will exit when stopped by
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* the user (e.g. using Ctrl-C on a unix-ish operating system)
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*/
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int
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process (jack_nframes_t nframes, void *arg)
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{
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jack_default_audio_sample_t *in, *out;
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int k;
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in = jack_port_get_buffer (input_port, nframes);
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out = jack_port_get_buffer (output_port, nframes);
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for (k=0; k<nframes; k++) {
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out[k] = delay_line[delay_index];
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delay_line[delay_index] = in[k];
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delay_index = (delay_index + 1) % latency;
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}
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return 0;
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}
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void
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latency_cb (jack_latency_callback_mode_t mode, void *arg)
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{
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jack_latency_range_t range;
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if (mode == JackCaptureLatency) {
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jack_port_get_latency_range (input_port, mode, &range);
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range.min += latency;
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range.max += latency;
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jack_port_set_latency_range (output_port, mode, &range);
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} else {
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jack_port_get_latency_range (output_port, mode, &range);
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range.min += latency;
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range.max += latency;
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jack_port_set_latency_range (input_port, mode, &range);
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}
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}
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/**
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* JACK calls this shutdown_callback if the server ever shuts down or
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* decides to disconnect the client.
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*/
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void
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jack_shutdown (void *arg)
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{
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fprintf(stderr, "JACK shut down, exiting ...\n");
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exit (1);
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}
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int
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main (int argc, char *argv[])
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{
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const char **ports;
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const char *client_name = "latent";
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const char *server_name = NULL;
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jack_options_t options = JackNullOption;
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jack_status_t status;
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if (argc == 2)
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latency = atoi(argv[1]);
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delay_line = malloc( latency * sizeof(jack_default_audio_sample_t));
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if (delay_line == NULL) {
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fprintf (stderr, "no memory");
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exit(1);
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}
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memset (delay_line, 0, latency * sizeof(jack_default_audio_sample_t));
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/* open a client connection to the JACK server */
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client = jack_client_open (client_name, options, &status, server_name);
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if (client == NULL) {
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fprintf (stderr, "jack_client_open() failed, "
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"status = 0x%2.0x\n", status);
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if (status & JackServerFailed) {
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fprintf (stderr, "Unable to connect to JACK server\n");
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}
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exit (1);
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}
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if (status & JackServerStarted) {
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fprintf (stderr, "JACK server started\n");
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}
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if (status & JackNameNotUnique) {
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client_name = jack_get_client_name(client);
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fprintf (stderr, "unique name `%s' assigned\n", client_name);
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}
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/* tell the JACK server to call `process()' whenever
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there is work to be done.
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*/
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jack_set_process_callback (client, process, 0);
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/* tell the JACK server to call `latency()' whenever
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the latency needs to be recalculated.
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*/
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if (jack_set_latency_callback)
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jack_set_latency_callback (client, latency_cb, 0);
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/* tell the JACK server to call `jack_shutdown()' if
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it ever shuts down, either entirely, or if it
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just decides to stop calling us.
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*/
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jack_on_shutdown (client, jack_shutdown, 0);
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/* display the current sample rate.
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*/
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printf ("engine sample rate: %" PRIu32 "\n",
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jack_get_sample_rate (client));
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/* create two ports */
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input_port = jack_port_register (client, "input",
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JACK_DEFAULT_AUDIO_TYPE,
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JackPortIsInput, 0);
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output_port = jack_port_register (client, "output",
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JACK_DEFAULT_AUDIO_TYPE,
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JackPortIsOutput, 0);
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if ((input_port == NULL) || (output_port == NULL)) {
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fprintf(stderr, "no more JACK ports available\n");
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exit (1);
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}
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/* Tell the JACK server that we are ready to roll. Our
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* process() callback will start running now. */
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if (jack_activate (client)) {
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fprintf (stderr, "cannot activate client");
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exit (1);
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}
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/* Connect the ports. You can't do this before the client is
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* activated, because we can't make connections to clients
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* that aren't running. Note the confusing (but necessary)
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* orientation of the driver backend ports: playback ports are
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* "input" to the backend, and capture ports are "output" from
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* it.
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*/
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ports = jack_get_ports (client, NULL, NULL,
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JackPortIsPhysical|JackPortIsOutput);
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if (ports == NULL) {
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fprintf(stderr, "no physical capture ports\n");
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exit (1);
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}
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if (jack_connect (client, ports[0], jack_port_name (input_port))) {
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fprintf (stderr, "cannot connect input ports\n");
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}
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free (ports);
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ports = jack_get_ports (client, NULL, NULL,
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JackPortIsPhysical|JackPortIsInput);
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if (ports == NULL) {
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fprintf(stderr, "no physical playback ports\n");
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exit (1);
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}
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if (jack_connect (client, jack_port_name (output_port), ports[0])) {
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fprintf (stderr, "cannot connect output ports\n");
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}
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free (ports);
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/* keep running until stopped by the user */
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jack_sleep (-1);
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/* this is never reached but if the program
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had some other way to exit besides being killed,
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they would be important to call.
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*/
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jack_client_close (client);
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exit (0);
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}
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