example-clients/showtime.c

   1 #include <stdio.h>
   2 #include <errno.h>
   3 #include <unistd.h>
   4 #include <signal.h>
   5 #include <stdlib.h>
   6
   7 #include <jack/jack.h>
   8 #include <jack/transport.h>
   9
  10 jack_client_t *client;
  11
  12
  13 void
  14 showtime ()
  15 {
  16         jack_position_t current;
  17         jack_transport_state_t transport_state;
  18         jack_nframes_t frame_time;
  19
  20         transport_state = jack_transport_query (client, &current);
  21         frame_time = jack_frame_time (client);
  22
  23         printf ("frame: %7" PRIu32 " @ %" PRIu32 "\t", current.frame, frame_time);
  24
  25         switch (transport_state) {
  26         case JackTransportStopped:
  27                 printf ("state: Stopped");
  28                 break;
  29         case JackTransportRolling:
  30                 printf ("state: Rolling");
  31                 break;
  32         case JackTransportStarting:
  33                 printf ("state: Starting");
  34                 break;
  35         default:
  36                 printf ("state: [unknown]");
  37         }
  38
  39         if (current.valid & JackPositionBBT)
  40                 printf ("\tBBT: %3" PRIi32 "|%" PRIi32 "|%04"
  41                         PRIi32, current.bar, current.beat, current.tick);
  42
  43         if (current.valid & JackPositionTimecode)
  44                 printf ("\tTC: (%.6f, %.6f)",
  45                         current.frame_time, current.next_time);
  46
  47         if (current.valid & JackBBTFrameOffset)
  48                 printf ("\tBBT offset: (%" PRIi32 ")",
  49                         current.bbt_offset);
  50
  51         if (current.valid & JackAudioVideoRatio)
  52                 printf ("\taudio/video: (%f)",
  53                         current.audio_frames_per_video_frame);
  54
  55         if (current.valid & JackVideoFrameOffset) {
  56                 if (current.video_offset) {
  57                         printf ("\t video@: (%" PRIi32 ")", current.video_offset);
  58                 } else {
  59                         printf ("\t no video");
  60                 }
  61         }
  62
  63         printf ("\n");
  64 }
  65
  66 void
  67 jack_shutdown (void *arg)
  68 {
  69         exit (1);
  70 }
  71
  72 void
  73 signal_handler (int sig)
  74 {
  75         jack_client_close (client);
  76         fprintf (stderr, "signal received, exiting ...\n");
  77         exit (0);
  78 }
  79
  80 int
  81 main (int argc, char *argv[])
  82
  83 {
  84         /* try to become a client of the JACK server */
  85
  86         if ((client = jack_client_new ("showtime")) == 0) {
  87                 fprintf (stderr, "jack server not running?\n");
  88                 return 1;
  89         }
  90
  91         signal (SIGQUIT, signal_handler);
  92         signal (SIGTERM, signal_handler);
  93         signal (SIGHUP, signal_handler);
  94         signal (SIGINT, signal_handler);
  95
  96         /* tell the JACK server to call `jack_shutdown()' if
  97            it ever shuts down, either entirely, or if it
  98            just decides to stop calling us.
  99         */
 100
 101         jack_on_shutdown (client, jack_shutdown, 0);
 102
 103         /* tell the JACK server that we are ready to roll */
 104
 105         if (jack_activate (client)) {
 106                 fprintf (stderr, "cannot activate client");
 107                 return 1;
 108         }
 109
 110         while (1) {
 111                 usleep (20);
 112                 showtime ();
 113         }
 114
 115         jack_client_close (client);
 116         exit (0);
 117 }