MIDI does not work correctly with Ardour 8.1 (7.5 does)

Hi, new Ardour user here

I am clueless how to debug my MIDI problems with Ardour 8.1, switching to JACK instead of PipeWire does not solve the problem.

What works: Linux Mint 21.2 with PipeWire 1.0 (0.3.84 worked, too) and Ardour 7.5 (Backports PPA) and a MIDI loop with my workstation, which is also the USB audio interface. Recording up to 8 MIDI arpeggiated channels simultaneously works. Bouncing 4 MIDI channels into stereo audio tracks at once is no problem. Mackie control works, MIDI clock sync too. I was amazed and switched to the payed version 8.1.

What does not work using 8.1: same setup as above with 8.1 does not work. MIDI sounds are missing, the timing is incorrect. Pre-listening to MIDI files in the import dialog is distorted beginning with the second MIDI file. Parts of the first MIDI file are still played back, too. To be sure I installed Debian 12 on a laptop with JACK but MIDI does not work correctly, too. The whole MIDI stack seems to be messed up.

What I tried: Switching to ALSA (Linux Mint), starting “a2jmidid -e” and a lot of settings , I did not try everything with the Debian laptop because as soon as I switch back to 7.5 my Linux Mint setup works.

Where should I start debugging, which settings should I check at least for the Debian/JACK system?

Same here, I had to switch back to 7 (7.2).

Is there one session with this problem or many? Are there tempo changes?

Only one session for me, but I only need one session for midi so I don’t have any other to try on…

There is no tempo changes on mine, in fact I don’t even use the timeline at all (no midi regions), I just send external midi inputs into midi tracks and get the output on the speakers.

Thanks for confirming my issue, here’s how I reproduce the problem:

  • Connect an external device which sends on more than one MIDI channel
  • Create two MIDI tracks
  • Set channel selector to channel 1 for first channel and 2 for the second (recording and playback)

As long as I send only on channel 1 everything is fine. As soon as I send on channel 2 there are stuck “endless” notes, missing sounds and so on. Recording is not necessary, even the pre-listening is ‘corrupt’. There are no plugins involved, I set both MIDI input and output to my keyboard/workstation. Clock sync makes no difference.
Switching between JACK2 or ALSA or PipeWire’s JACK makes no difference. Last version I tried was Ardour 8.2, 7.5 worked.

How can I help to debug this?

Your description of how to reliably reproduce this issue, was sufficient. Thanks.

Fixed in 8.2-5-gc3b55240b1


I just installed the nightly build and recording several MIDI tracks simultaneously works here:

Thanks a lot for the fix, great project.


@x42 Thank you for the quick fix :slight_smile:
@fraslo Thanks for taking the time to investigate this.

I’m having MIDI issues as well. Using Ardour 8.1 from arch linux repository, and pipewire-jack.

The issues I have noticed for now are:

  • Dropped midi events when playing with a midi controller, especially when using aftertouch/modulation/expression pedal actively. Especially noticable is dropped note off events which causes a note to hang.
  • MIDI event latency when routing to hardware synth. If I increase the audio latency buffer size, the MIDI latency increases as well. Is this normal? Shouldn’t be necessary to buffer midi events, they should be sent immediately to the destination port.

Thinking about it, the dropped events and buffered midi events could be related. If I use a lot of expression there will be a lot of midi events. If the events are buffered, we could potentially fill up the buffer, and events are dropped when the buffer is full.

Midi recording with PipeWire’s JACK still has problems on my system, too. So I switched to the supported JACK2. PipeWire plays nice with JACK2, just install it and jackdbus, works fine here.

I rebuilt Ardour from git master (0e88df426eee2c0219c02b3e70c8d8337b4a14e1 of 2024-02-17) and I confirm the issue is fixed. Thanks a lot!

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