Listing port names, sending MIDI messages to specific ports

[intonarumori]

I've been working on an app that will be available on Android, iOS, macOS and Windows.

I've noticed that my iConnectivity MIO10 MIDI interface shows up differently on different platforms:

• On iOS I get a list of 10 MIDI devices each with it's own name (MIO DIN1, MIO DIN2, etc.)
• On Android it shows up as one device with 10 different ports

Correct me if I'm wrong but it looks like I can send MIDI messages to different devices, but cannot target individual ports.
I've looked at the Android source code at it seems the library only uses the first output port when sending messages.

FlutterMidiCommand/android/src/main/kotlin/com/invisiblewrench/fluttermidicommand/ConnectedDevice.kt

Lines 44 to 46 in d9928a6

	Log.d("FlutterMIDICommand", "Open output port")
	this.outputPort = this.midiDevice.openOutputPort(0)
	this.outputPort?.connect(this.receiver)

As a side note, port names are also not available right now, I think MidiPort should be extended with a name field and we should probably use getName() to populate it, even though this might still return an empty string on certain devices.

Let me know what you think, I did some experiments with updating MidiPort but since 3-4 repositories need to be updated, it would be great to agree on an implementation before I open PRs.

Many thanks.

Please find a screenshot of the Example app connected to the MIO10.

[intonarumori]

To add some details, here's the ESI MIDIMate connected to the Example app. This one has two MIDI cables and both can be used for both input and output.

The default implementation of connecting to port 0 input and port 0 output unfortunately can only utilize one of the available MIDI cables.

[intonarumori]

I've been thinking how to solve this with the current APIs and couldn't come up with a clean solution.

• We either take each connected MIDI device and "unroll" the ports so for FlutterMidiCommand this device would appear as multiple devices, each with an associated port under the hood, this would basically resemble the same device list as on macOS
• Or we extends the APIs and include the port number when connecting to a device and also include the port when sending MIDI messages.

Do you have preference and ideas on how to approach this?

[mortenboye]

Thank you for diving into this.
Of the two proposed solution, I lean more towards the former, "unrolling" devices/ports into separate devices. This keeps the API, the structures and the "addressing" of messages the same, but will still support all ports of a device.