Pass through everything but note on/note off

[fapplin]

I have a micro-controller that I'm receiving MIDI on via a 5-DIN connector from my keyboard controller. I would like to handle only note on/note off and pass through all other messages to the software synth. Is there an easy way to do this or do I have handle all messages via callbacks? And, if I have to do callbacks can you give me an example of using callbacks in a class?

Thanks.

[franky47]

That would be very easy to with the upcoming filter feature:

// Return `true` to let the message Thru, false to consume it:
bool everythingButNotes(const midi::Message& message)
{
  return message.type != midi::NoteOn && message.type != midi::NoteOff;
}

// The usual callbacks to handle Note messages:
void onNoteOn(byte pitch, byte velocity, byte channel)
{
}

void onNoteOff(byte pitch, byte velocity, byte channel)
{
}

void setup()
{
  MIDI.setThruFilter(everythingButNotes);
  MIDI.setHandleNoteOn(onNoteOn);
  MIDI.setHandleNoteOff(onNoteOff);
  // ...
}

I'm hoping to get it released sometime in September, watch this space!

[fapplin]

Has the setThruFilter() been implemented, yet? If so, can you tell me how to implement the callbacks in a class? I have a class called MyMidi that currently I wrap the sendNoteOn() and sendNoteOff() functions - like this.

void MyMidi::doNoteOn(byte channel, byte pitch, byte velocity) {
MIDI.sendNoteOn(pitch, velocity, channel);
}

How can I change that so I'm using the callbacks like MIDI.setHandleNoteOn(onNoteOn), but via my class?

Thanks,

Frank

[franky47]

It's implemented in the v5.1.0 branch, so you could pull the code out of that and use it.

Regarding interfacing with class methods, it depends on how you use instances of said class. Is it a singleton, or do you have multiple instances to bind to different (or same) callbacks & send methods?

[fapplin]

I'm not sure if showing the code helps answer your question, but here's a couple snippets.

In the main .ino file, it looks like:

myMidi kmidi;

void setup() {
   kmidi.initialize();
   :
   :
}

in my MidiProcessing.cpp file,

#include "MidiProcessing.h"

// USB MIDI object
Adafruit_USBD_MIDI usb_midi;
//
// Create a new instance of the Arduino MIDI Library,
// and attach usb_midi as the transport.
MIDI_CREATE_INSTANCE(Adafruit_USBD_MIDI, usb_midi, MIDI);


myMidi::myMidi()
{

} // end constructor

void myMidi:::initialize()
{
#if defined(ARDUINO_ARCH_MBED) && defined(ARDUINO_ARCH_RP2040)
  // Manual begin() is required on core without built-in support for TinyUSB such as mbed rp2040
  TinyUSB_Device_Init(0);
#endif

  MIDI.begin(MIDI_CHANNEL_OMNI);
  MIDI.turnThruOff();

  Serial1.setRX(17);
  Serial1.setTX(16);
  Serial1.begin(31250);

  while ( !TinyUSBDevice.mounted() ) delay(1);

}

[fapplin]

OK. Looking at my code - I have 2 different things going on with the MIDI. I'm reading in the MIDI via serial, making modifications, and sending it out via USB. So, I think I will separate the 2 out. The MIDI out through the USB - I will use straight C with the callbacks (because I'll only have 3 callbacks to do). The MIDI in through the serial port - I'll handle in the MIDIProcessing class.

So, the my question becomes how do I do the filtering. Back in August you gave this proposed example.

// Return `true` to let the message Thru, false to consume it:
bool everythingButNotes(const midi::Message& message)
{
  return message.type != midi::NoteOn && message.type != midi::NoteOff;
}

// The usual callbacks to handle Note messages:
void onNoteOn(byte pitch, byte velocity, byte channel)
{
}

void onNoteOff(byte pitch, byte velocity, byte channel)
{
}

void setup()
{
  MIDI.setThruFilter(everythingButNotes);
  MIDI.setHandleNoteOn(onNoteOn);
  MIDI.setHandleNoteOff(onNoteOff);
  // ...
}

Is this how to do it now with your new version?

[franky47]

Yes, this should do it.