Fluidsynth not automatically recognized as a virtual midi port

[pissalou]

I start fluidsynth as a server, aconnect commands shows the port is open. When listing the ports using observer.get_output_ports(), fluidsynth port is not listed unless the observer is configured with .track_any=true. I would expect it is not necessary to set .track_any=true in this case as alsa recognize fluidsynth as a virtual port.

Steps to reproduce on ubuntu 23.04:
$ sudo fluidsynth -a alsa -m alsa_seq -o audio.alsa.device=hw:1 -is
$ aconnect -lo
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
client 128: 'FLUID Synth (76540)' [type=user,pid=76540]
0 'Synth input port (76540:0)'
$ ./build/midiout

Would you like to open a virtual output port? [y/N] NN
No output ports available!

[pissalou]

Additional info: ports are listed under PipeWire when running midiprobe.
$ ./midiprobe
Displaying ports for: ALSA (sequencer)
0 MIDI input sources:
0 MIDI output sinks:

Displaying ports for: ALSA (raw)
0 MIDI input sources:
0 MIDI output sinks:

Displaying ports for: JACK
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
0 MIDI input sources:
0 MIDI output sinks:

Displaying ports for: PipeWire
1 MIDI input sources:

• [ client: 0, port: 49, device: Midi Through, portname: Midi Through:(capture_0) Midi Through Port-0, display: Midi Through Port-0]
  2 MIDI output sinks:
• [ client: 0, port: 48, device: Midi Through, portname: Midi Through:(playback_0) Midi Through Port-0, display: Midi Through Port-0]
• [ client: 0, port: 482, device: FLUID Synth (80888), portname: FLUID Synth (80888):(playback_0) Synth input port (80888:0), display: Synth input port (80888:0)]

Displaying ports for: Dummy
0 MIDI input sources:
0 MIDI output sinks:

[jcelerier]

hm, ALSA exposes a SND_SEQ_PORT_TYPE_SOFTWARE property for virtual ports but fluidsynth does not seem to enable it. It enables "SYNTHESIZER" though, I added it to the requirements for being listed as a port. Fixed in 175c8aa and backported to 4.X

[jcelerier]

Can you check if it works for you now ?

[pissalou]

I pulled the latest 4.x and compiled the examples but it was the same behaviour as previously: fluidsynth port does not appear on the list unless I set .track_any=true in the observer. I will learn how to use the debugger in vscode and hopefully will be able to report more useful info.

[jcelerier]

Is track_virtual enabled ? it's off by default: https://github.com/celtera/libremidi/blob/master/include/libremidi/observer_configuration.hpp#L73
It used to be on but people would complain about too many random ports showing up :')

[pissalou]

Ok, my bad: I was not aware track_virtual was default false. With the parameter set to true, it is now listing fluidsynth as expected :-) Another good reason for setting configuration from the commandline instead of prompting when considering issue #114.

[jcelerier]

👍 I'll close this one and add an issue to turn input as command-line arguments