GUI input sluggish in Ardour 6.5 on Ubuntu Studio 20.04

Ardour 6.5
Ubuntu Studio 20.04, which uses XFCE window manager.
Vital 1.0.7 installed from .deb package.

Standalone works just fine.
Vst3 in Carla also.
LV2 freezes Carla and Ardour completely.

The issues:

  • Mouse and keyboard input lag
    Vst3 in Ardour has some strange GUI behavior. When Vital is open in Ardour, both Ardour and Vital are sluggish to react to mouse/key input, and to draw GUI changes.
    Example: If I right-click a control in Vital to select “Enter value”, the menu takes a long time to come up, several seconds. But if I just keep moving the mouse cursor around, it appears quicker. Then when I click on Enter value, and type in the value and press Enter, nothing shows. I move the mouse around, and I see the numbers pop up kinda slowly, and then the edit box disappears, accepting the value.
    Or click an encoder to drag, then release. Nothing happens, until after I move the mouse around during a second or so.
    This behavior applies to everything in Vital, and also somewhat in Ardour when Vital is visible.
    It feels like Vital doesn’t receive any mouse click/key inputs until it receives (many) mouse movement events. No mouse movement, no commands reach Vital.
    Mouse and key inputs are not lost - when I keep moving the mouse around, all previous clicks and key commands trickle in bursts to Vital and it reacts.
  • Intermittent GUI Freezing
    The waveform/filter/etc curves update in realtime when audio is played, apart from intermittent half-second freezing
    The same in Ardour, the playhead stutters and sporadically freezes for a second, when Vital GUI is visible.
    Audio playback is not affected, though.

This might initially be interpreted as sluggish GUI, but it is in fact click/key input detection that is sluggish, and the GUI just responds when it gets inputs.

So for now, I must edit and save my presets in Vital standalone, and then load them in Ardour once I am happy with them.

Ardour 6.6 was released last week which includes many fixes for vst3 ->

1 Like

Ok, that version is not available in the Ubuntu 20.04 Ardour backports repository, so I would have to buy it to get it :slight_smile:
Which I totally would, seems awkward though when I have the 6.5 included.

Thanks, I will look into this.

You could also build it yourself.

Actually, that might be fun, been a while since I built any Linux software. Would give my 12 cores something to do… :slight_smile: