Accessing multiple USB MIDI ports

[GModal]

I'm working with an ESP32-S3 board, and my project successfully connects to a BLE MIDI peripheral, and sends MIDI data to a USB-OTG MIDI port, plugged into my PC (Ubuntu / Pipewire & JACK). It works very well, currently (thanks everyone!).

And Creating multiple USB MIDI ports in the sketch seems straight-forward:

Adafruit_USBD_MIDI usb_midi(2);

// Create a new instance of the Arduino MIDI Library,
MIDI_CREATE_INSTANCE(Adafruit_USBD_MIDI, usb_midi, MIDI);

void setup() {
    usb_midi.setCableName(1, "BLE-1");
    usb_midi.setCableName(2, "BLE-2");
    MIDI.begin();
    Serial.begin(115200);

    .... snip .....
}

// send MIDI from BLE input buffer:
void sendMIDI() {
    MIDI.send(midi::MidiType (bbuf[2] & 0xF0), bbuf[3], bbuf[4], (bbuf[2] & 0x0F) + 1);
}

The two USB MIDI ports appear on my PC, but I'm having difficulty sending MIDI data to the second port. I'm clearly misunderstanding how to access the second stream defined in usb_midi .

[rppicomidi]

@GModal As it is currently implemented, this library does not support what you want to do. I do not do a lot of Arduino development, but I took a quick look at the Arduino MIDI Library source and I think that the Adafruit TinyUSB Arduino does not quite implement support for multiple virtual USB MIDI cables properly. If I understand the Arduino MIDI Library correctly, each virtual cable needs to have its own interface. The code

MIDI_CREATE_INSTANCE(Adafruit_USBD_MIDI, usb_midi, MIDI);

creates a single MIDI Interface object. Since a USB MIDI device can support up to 16 virtual cables, you need code that sits above the interface level to manage an interface object for each of the up to 16 virtual cables. What I did on the host side in my EZ_USB_MIDI_HOST project is create a EZ_USB_MIDI_HOST_Device class that manages each interface for each virtual cable.

The library contains code that will create the correct USB descriptor, but it needs to be refactored to allocate a new transport for each virtual cable on creation. This post is over a year old, but I will have a go at implementing something. Would that be of interest to you?

[rppicomidi]

I created a library that should give what this discussion post asks. I hope this helps @GModal and others.

[GModal]

I created a library that should give what this discussion post asks. I hope this helps @GModal and others.

Hey rppicomidi -- thanks! I'll give that a look. It would definitely be useful, and honestly seems like an omission.

[rppicomidi]

@GModal When you try it, please let me know if it works on ESP32. I tried to use device agnostic APIs, but I have only tested on Raspberry Pi Pico.