MantisBT - Issues

0010285: ghosting midi notes stick around in pianoroll when switching modes

Thu, 16 Apr 2026 13:15:29 +0000

Building ardour from git.

When switching editing modes in the dedicated pianoroll editor, a ghost of the midi note stays around.

0009447: Audio stuttering/crackling and Ardour crash when adjusting system volume

Thu, 16 Apr 2026 13:13:59 +0000

If Ardour is run from command line, there is a lot of "Sending key 'state' to UI failed, out of space" printed out every second. But this is not that annoying...
If you adjust system global volume the audio starts to stutter/crackle unpleasantly. If you're adjusting volume long enough - Ardour crashes.
The more tracks Ardour session has the worse effect you get. If you have one or two tracks, you probably won't notice the problem at all.

Example video: https://youtu.be/l-GYdu2_RpU

Thanks! :*

0010282: recording midi-notes from other tracks in a new midi-track randomly is not in timesync, nightly build 542 and 434

Wed, 15 Apr 2026 16:52:50 +0000

As the summary says it is randomly, but reproducible if i do it a few times in a row.
I tried several things to make it reliably occur, but found no setting to do that ( the recording midi-track set to mute or not, syncopated 16th notes in the recorded track or not, so forth).
In 9.2 it didn't happen yet, but i focused on testing it in nightly builds.

0006040: MIDI mixer faders should be volume and not velocity multiplier

Wed, 15 Apr 2026 16:28:19 +0000

One basic Synthesizers/Samplers, strong velocity is equal to high volume.
It is not the case on SoundBanks Samplers. These have multiple layers of samples so a strong velocity sounds totally different than a low one at matching volume.

Since faders are very automation oriented, I think being velocity multipliers doesn't make sense.
They should be volume CC.

Because of that I simply never use these faders and have Volume CC on every track, which is not handy to manipulate. Since I use a control surface, it's such a pity!

Now, the ideal scenario would be to have faders configurable, something like:
MIDI faders are:
- Velocity Multipliers
- List of all CC ...

This way, anyone could even use faders for pitch e.g. or whatever is the most useful for them.
Individually for each fader would even be better!

0010284: Any "Layers" setting change ("Overlaid" vs "Stacked") should mutate all selected tracks...

Wed, 15 Apr 2026 14:37:11 +0000

Currently, it appears that if you want to enforce/change a certain layering style across multiple tracks, you have to adjust *one at a time*, which can be very tedious...

Therefore, it would be nice if you could select multiple tracks, right-click on one, change the Layers setting, and have it apply to all selected!

Thanks for considering! : )

-J

0010283: The "-L" and "-R" descriptors for regions from a use of Make Mono Regions disappear when splitting the regions...

Wed, 15 Apr 2026 07:27:33 +0000

See the gif below.

The "-L" and "-R" descriptions attached to region names are very convenient in quickly discerning which mono-channel region is Left or Right (etc.).

But right now, as soon as you split one of these regions in two (and perhaps via other edits), that "-L" or "-R" descriptor is lost... : /

For now I will manually change the region names to include "-L" or "-R".
But it would be nice in the future if this information could be preserved during the region re-naming mutation. : )

Thanks!
-J

0010280: Ardour 9 hangs on "Indexing plugins"

Wed, 15 Apr 2026 06:49:39 +0000

Ardour 9 hangs on the "Indexing plugins" stage of the splash screen with 99.9% CPU usage. This is not a crash. There is nothing in the debugger. No weird logs. The process still responds to CTRL+C and shuts down gracefully.

0010261: Crash when expanding a newly created MIDI region to the left

Wed, 15 Apr 2026 06:46:19 +0000

Steps to reproduce
- create a new session
- create a new empty MIDI region
- expand it to the left

0010260: MIDI automation points disappear when hovering the line

Wed, 15 Apr 2026 06:38:01 +0000

All MIDI automation points disappear when hovering the automation line.

0010262: MIDI instruments play the last notes after stop and resume playing

Wed, 15 Apr 2026 05:10:04 +0000

I have several tracks with various MIDI instruments (some with liquidsfz native player, some with yadbridge and VST instruments; I guess that's not really important here).

"Stop playback" stops the playback as expected.

Then resuming playback (simply "Play from playhead") not only play the next MIDI notes, but also repeats the last notes where we stopped.

This happens also when the playhead is moved completely to an empty area without any content at the end of the session. It apparently plays the last MIDI notes where we stopped.

Tried "MIDI Panic", but it has not influence.

Video recording possible if needed.

Thank you,

user (monthly paying supporter)

0010047: Editing Midi notes in bottom pane does not snap correctly

Wed, 15 Apr 2026 03:52:45 +0000

When i select multiple notes and want to make them shorter/longer the snap indormation says the right thing (i.e. 1bar) but the notes get different lengths.

0010266: Midi note length not snapping to bar properly when dragging via cursor in Piano Roll

Wed, 15 Apr 2026 03:52:18 +0000

Greetings. I am having an issue with the note length not snapping to the grid bar properly in the Piano Roll window.

0010249: Segfault with a specific session

Tue, 14 Apr 2026 15:35:06 +0000

Hi, small session with few stuff. From dmesg ouput:
[ 9409.644878] [ T16310] traps: ArdourGUI[16310] general protection fault ip:7fcf598dff43 sp:7ffd5ca770e8 error:0 in libstdc++.so.6.0.35[dff43,7fcf598ab000+147000]
[ 9559.892790] [ T16615] traps: AudioEngine 1[16615] general protection fault ip:7f993eac6244 sp:7f99057f9540 error:0 in libstdc++.so.6.0.35[c6244,7f993eaab000+147000]

All plugins in this sessions are plugins that I normally use with no problems.
This happens with Ardour-9.2 (both suse and official). gdb output from 9.2.203.

0010278: ui hangs when selecting automation points from outside of the automation track

Tue, 14 Apr 2026 12:02:00 +0000

When selecting an automation track, and the selection starts *outside* of the track rectangle, sometimes the UI hangs for a while.

This also happens with latest Ardour nightly.

0010248: Memory corruption due to faulty PBD::Cond::wait mutex handling

Tue, 14 Apr 2026 11:59:58 +0000

I've been using Ardour 9.2 lately and experiencing many seemingly random crashes. After investigating a little, and with LLM help, I've managed to pinpoint the issue to a faulty implementation of `PBD::Cond::wait` and `PBD::Cond::wait_for` that, if my understanding is correct, boils down to a simple lack of a mutex release. I'm not submitting a patch here, since that would go against the project terms, but it should be a pretty straight-forward fix. Below I attach a summary from my LLM session that hopefully sheds more light on the issue and a possible resolution without giving away any tainted code.

---

Observed crash signatures from multiple coredumps:
- `SIGSEGV` in `ArdourWaveView::WaveViewThreads::_dequeue_draw_request()`
- `SIGABRT` in `WaveViewThreads::_dequeue_draw_request()` on `assert (!_queue_mutex.trylock())`
- `SIGSEGV` in canvas/render code such as `ArdourCanvas::DumbLookupTable::get()`, `Item::visible()`, and `bounding_box()`
- occasional heap-corruption-style crashes in `g_malloc`, `operator new`, and `Cairo::Context::create()`

After checking a series of coredumps the common pattern was always WaveView worker-thread activity. That led to `libs/pbd/pbd/mutex.h`, where `PBD::Cond::wait()` and `wait_for()` create a `std::unique_lock` with `std::adopt_lock`, call `wait()`, and then return without releasing ownership of the temporary lock.

That means the `unique_lock` destructor unlocks the mutex before returning to the caller, even though callers assume they still hold the mutex after `Cond::wait()` returns.

This breaks code such as `WaveViewThreads::_thread_proc()` / `_dequeue_draw_request()`:
- the thread enters `Cond::wait()` with `_queue_mutex` locked
- it wakes up and returns with `_queue_mutex` unintentionally unlocked
- it then continues accessing `_queue` as if it still owns the lock

That explains both the direct assertion failure in `_dequeue_draw_request()` and the other crash variants: once the WaveView request queue is raced/corrupted, the resulting memory corruption later shows up in unrelated render/canvas/heap code.

Because all observed crash signatures stem from the same broken mutex-ownership contract and the resulting queue corruption, fixing `PBD::Cond::wait()` should fix the whole crash family, not just the assertion case.

---

I hope this can be helpful. Thanks for going through this bug report and for your amazing work on Ardour!

0010232: Segfault when zooming

Tue, 14 Apr 2026 11:58:42 +0000

Playing long enough and intensively with the zoom eventually results in a segfault (see attached backtrace). It also occured during normal usage although rarely.

0010281: selecting a midi track in edit view with a heavy plugin on is laggy

Tue, 14 Apr 2026 10:47:03 +0000

When I create a midi track, and add the Surge XT plugin to it. When i try to select it, it takes a few seconds for the selection to take effect. I'm guessing this is because the plugin has some kind of overhead. It makes it very difficult to get into a fluid workflow with any midi tracks that uses a "heavy" plugin.

0010223: Looping hiccups when muting tracks

Mon, 13 Apr 2026 21:34:05 +0000

I'm hearing looping audio snippets when muting tracks sent to aux buses.

0010182: Audio Looping Glitch during Soloing whilst Playing

Mon, 13 Apr 2026 21:30:39 +0000

Ardour will loop a tiny portion of audio indefinitely if you attempt to solo a track or bus whilst the playhead is rolling.

See the 2min video I made to demonstrate this:
https://odysee.com/@icterine:a/Ardour-9---Audio-Looping-Glitch-during-Soloing-whilst-Playing:a

And please note that this little loop of audio is sometimes very loud.
I think it depends on *when* you hit the solo button, which determines the fragment of audio looped.

~Just FYI.
Thanks,
-J

0009981: automation disappears when zooming in/out

Mon, 13 Apr 2026 17:01:58 +0000

trying to edit automation has been a headache for me. im trying to edit some modwheel automation and for some reason, when adding points to the edge. and then zooming in and out, my automation goes away?

i just wanna work on music but ive been dealing with these little issues the whole time. im not sure why the automation lane here needs to be under a midi clip. when im automating an effect from the mixer strip, it lets me edit the full lane just fine. it would be nice if i could do that for synth parameters as well. ( maybe im missing something here? )

0010228: Ardour freezes when loading session with addt'l windows open on workspace and must be forcefully closed

Mon, 13 Apr 2026 15:34:02 +0000

When a window is already open on a given workspace in Sway, if I try to open Ardour, it starts to load the session but it never fully completes and ends up freezing with the session open and the loading screen still present but the session window is unresponsive no matter how long it's left open. It does a similar thing when the session is already loaded and another window is opened beside it as well.

0010108: MIDI Tracks - Shift and Mouse Scroll Wheel no longer performs verticals scroll in Draw Mode

Mon, 13 Apr 2026 14:36:26 +0000

When in MIDI track that contains a MIDI region, if you make that region active in `Draw Mode` where you can draw notes into piano roll, SHIFT+MSW no longer performs a vertical scroll.
It instead adjusts note velocity.

Hope this helps

0010279: new_midi_track() does not work via lua script

Mon, 13 Apr 2026 03:15:52 +0000

Testing some combinations of parameters never creates a new track, the scripting window always returns an error.

I was not able to map all the attempted parameter combinations. But I realized that even when entering the required types listed in the Binding Class Reference, there is always a type error in #6, #7, etc. And in some cases, while trying to figure out whether there is an error in the order of the parameters, Ardour simply crashes and closes.

Ardour 9.2 official build.

0010275: Some MIDI regions have bugged playback when importing some session from Ardour8 to Ardour9

Sun, 12 Apr 2026 09:58:40 +0000

Tested on Ardour9 and master.

When importing a session from Ardour8 to Ardour9, I noticed a bug on a few regions of a track that have bugged playback. Here's the issue:

Expected: https://streamable.com/bjbzgf

Issue: https://streamable.com/ummge2

0010269: Stretch Mode trims the decimal part of the stretch factor.

Sat, 11 Apr 2026 22:24:06 +0000

Only integer part of the stretch factor is used to calculate the new length of the region. So it's impossible to work in Strech Mode when you need the entire fractional part to precisely change the length of the region.