midi_monitor.c

Example of using the Workbench library to monitor MIDI messages.This dead simple rudimentary example demonstrates how to use the Workbench library to initialize the MIDI system and monitor incoming MIDI messages. It is a simplified version of the MIDI monitor example provided in the PortMidi library (https://github.com/PortMidi/portmidi/blob/master/pm_test/mm.c). The example configures the system to use a custom MIDI callback function that processes and prints various types of MIDI messages such as Note On, Note Off, Control Change, Program Change, and System Exclusive messages.

The example includes:

• Initialization of the configuration and MIDI system.
• A custom MIDI callback function (midi_cb) to handle and print MIDI messages.
• A main loop that keeps the application running to continuously monitor MIDI messages.

The main function initializes the configuration with the custom MIDI callback and enters an infinite loop to keep the application running. This setup allows the application to continuously monitor and print incoming MIDI messages.

 
#include "workbench.h"
#include <stdio.h>
 
Config *cfg;
 
static bool in_sysex = false; 
static char *ptos[] = {"C",  "C#", "D",  "D#", "E",  "F",
                       "F#", "G",  "G#", "A",  "A#", "B"};
 
static void print_pitch(int p) { printf("%s%d", ptos[p % 12], (p / 12) - 1); }
 
static void print_velocity(int p, int v) {
  printf(" %sVel: %d\n", strlen(ptos[p % 12]) == 1 ? " " : "", v);
}
 
static int midi_cb(const void *in, void *out, unsigned long length,
                   void *user_data) {
  const PmEvent *in_buffer = (const PmEvent *)in;
 
  for (unsigned long i = 0; i < length; ++i) {
    PmEvent event = in_buffer[i];
    PmMessage message = event.message;
    int status = Pm_MessageStatus(message);
    int data1 = Pm_MessageData1(message);
    int data2 = Pm_MessageData2(message);
 
    int command = status & MIDI_CODE_MASK;
    int chan = status & MIDI_CHN_MASK;
 
    printf("%x\t", message);
 
    if (in_sysex || status == MIDI_SYSEX) {
      int i;
      PmMessage data_copy = Pm_Message(status, data1, data2);
      in_sysex = true;
      for (i = 0; (i < 4) && ((data_copy & 0xFF) != MIDI_EOX); i++)
        data_copy >>= 8;
      if (i < 4) {
        in_sysex = false;
        i++;
      }
      printf("System Exclusive\n");
    } else if (command == MIDI_ON_NOTE && data2 != 0) {
      printf("NoteOn  Chan %2d Key %3d ", chan, data1);
      print_pitch(data1);
      print_velocity(data1, data2);
    } else if ((command == MIDI_ON_NOTE || command == MIDI_OFF_NOTE)) {
      printf("NoteOff Chan %2d Key %3d ", chan, data1);
      print_pitch(data1);
      print_velocity(data1, data2);
    } else if (command == MIDI_CH_PROGRAM) {
      printf("ProgChg Chan %2d Prog %2d\n", chan, data1 + 1);
    } else if (command == MIDI_CTRL) {
      /* controls 121 (MIDI_RESET_CONTROLLER) to 127 are channel
       * mode messages. */
      if (data1 < MIDI_ALL_SOUND_OFF) {
        printf("CtrlChg Chan %2d Ctrl %2d Val %2d\n", chan, data1, data2);
      } else {
        switch (data1) {
        case MIDI_ALL_SOUND_OFF:
          printf("All Sound Off, Chan %2d\n", chan);
          break;
        case MIDI_RESET_CONTROLLERS:
          printf("Reset All Controllers, Chan %2d\n", chan);
          break;
        case MIDI_LOCAL:
          printf("LocCtrl Chan %2d %s\n", chan, data2 ? "On" : "Off");
          break;
        case MIDI_ALL_OFF:
          printf("All Off Chan %2d\n", chan);
          break;
        case MIDI_OMNI_OFF:
          printf("OmniOff Chan %2d\n", chan);
          break;
        case MIDI_OMNI_ON:
          printf("Omni On Chan %2d\n", chan);
          break;
        case MIDI_MONO_ON:
          printf("Mono On Chan %2d", chan);
          if (data2) {
            printf(" to %d received channels\n", data2);
          } else {
            printf(" to all received channels\n");
          }
          break;
        case MIDI_POLY_ON:
          printf("Poly On Chan %2d\n", chan);
          break;
        }
      }
    } else if (command == MIDI_POLY_TOUCH) {
      printf("P.Touch Chan %2d Key %2d ", chan, data1);
      print_pitch(data1);
      printf("\n");
    } else if (command == MIDI_TOUCH) {
      printf("A.Touch Chan %2d Val %2d\n", chan, data1);
    } else if (command == MIDI_BEND) {
      printf("P.Bend  Chan %2d Val %2d\n", chan, (data1 + (data2 << 7)));
    } else if (status == MIDI_SONG_POINTER) {
      printf("    Song Position %d\n", (data1 + (data2 << 7)));
    } else if (status == MIDI_SONG_SELECT) {
      printf("    Song Select %d\n", data1);
    } else if (status == MIDI_TUNE_REQ) {
      printf("    Tune Request\n");
    } else if (status == MIDI_Q_FRAME) {
      printf("    Time Code Quarter Frame Type %d Values %d\n",
             (data1 & 0x70) >> 4, data1 & 0xf);
    } else if (status == MIDI_START) {
      printf("    Start\n");
    } else if (status == MIDI_CONTINUE) {
      printf("    Continue\n");
    } else if (status == MIDI_STOP) {
      printf("    Stop\n");
    } else if (status == MIDI_SYS_RESET) {
      printf("    System Reset\n");
    } else if (status == MIDI_TIME_CLOCK) {
      printf("    Clock\n");
    } else if (status == MIDI_ACTIVE_SENSING) {
      printf("    Active Sensing\n");
    }
  }
  return 0;
}
 
int main(int argc, char **argv) {
  cfg = config_init(argc, argv, NULL, &midi_cb, NULL);
  while (true) {
    Pa_Sleep(1000);
  }
  config_deinit();
  return 0;
}