Support for VST3 as LXVST

I’m involved with a beta test for a Win developer who is building his VST for linux for the first time. It appears the SDK no longer has support for VST2. It’s hard enough to get plugin developers to support linux in the first place; now you get a guy willing to make the effort and his LXVST is limited by the SDK to VST3 format. It gets blacklisted by Ardour but runs fine in Carla.

I’ve searched the forum and the bug tracker, and can’t seem to find a consolidated answer in one place.

Why doesn’t Ardour support VST3? Even as a LXVST? What are the issues?

Thanks in advance for the info

I’ve seen a lot of VST3 stuff in the git commits lately so I wouldn’t be surprised to see Ardour supporting it in a future release.


Try the nightly build,it supports vst3 :wink:

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That’s worth a try. Last one I tried had some issues, you really have to just keep trying til you get one that works.

I currently test linux VST3 plugin builds using reaper for linux. (you can also load linux vst3s into Bitwig though debugging might be more awkward as it uses some form of plugin sandboxing). If your vst3s work in either of those hosts, it would be reasonable to expect them to work in ardour when vst3 support arrives (or else file a bug report with the ardour devs… :slight_smile: )
(Ardour devs - let me know if you need linux VST3 plug-ins for testing)

Yep, the developer is using Reaper for linux. It works for him on that.

Just tried the latest Ardour nightly. It only sees 2 audio output ports (out of 32), and the plugin response is lagged by about 15 seconds. Then it crashes.

Guess I’ll be using Carla for awhile.

You’ve likely created a track with strict i/o, in which case ardour does not allow a plugin to add outputs. A stereo track remains stereo.

You can override this using pin connections or disable strict-i/o for the track.

A backtrace would be helpful. Although it’s more likely an issue with the plugin.

We’ve extensively tested VST3 support (although mainly on Windows and MacOS) with a wide-variety of plugins.

That’d be great. the more the merrier.

On GNU/Linux we’ve tested all u-he plugins, AuburnSounds/Dplug, Surge, Dexed, sfizz, as well as the Steinberg VST host tester and MDA that come with the VST3-SDK. So far only on 64bit Intel and 32bit ARM (RPi) systems

On aarch64 and i386 only the plugins from the VST3 SDK were tested.

Ok - send me an email and I’ll provide a link and some NFRs if required

Cool I wonder what kind of plugins they will be. I do have a vst for roughrider but it doesn’t open in ardour, it’s probably a vst 3 plugin or something

Nope, the channel has all 32 ports.

After Ardour scans the plugin it only shows 2 audio output ports in Plugin Manager. But when I add track based on the plugin MIDI instrument it creates the correct number of ports.

In the log after plugin scan I get 14 lines of “VST3: Ignored extra bus”.

Carla finds all 32 audio output ports, and it seems fine in Carla32 patchbay.

Ah, OK. For the time being Ardour ignores optional output busses (except the first, if and only if the first optional bus has an index of 1).

There is currently no infrastructure in Ardour’s GUI that allows a user to select optional busses. So it’d be an all or nothing approach and Ardour/git prefers main-out only.

Is this plugin already publicly available? It’d be great to have one of these to test while working adding support for multi-out instruments. One question related to that is if adding port is always incremental 1-2, 1-4, …, 1-12, … 1-32, or if a user should be able to select individual ones 1+2, 7+8, 15+16 etc. for AudioUnits we use the former approach (and a user can manually ignore outputs that are not needed).

That is actually a more worrying issue. A shot in the dark: maybe the plugin is not using ?

The Win/Mac versions are publicly available as a paid product. The beta is not, and this is his first crack at LXVST. I wouldn’t want to give anything away without permission. Let me talk to him about it, the easiest way to do it may just be to sign you up on the beta.

VST3 spec may call these “optional” buses but it’s always a fixed number. It’s a multi-out drum plug with it’s own internal mixer and switchable routing to 16 stereo output buses.

Doing a backtrace requires a crash, which I haven’t tried to dupilcate. The first time I just patched ports 1-2 to the Master for monitoring purposes because they were the only ports available. For all I know it may have freaked out because 15 of the internal buses had no output ports created on the plugin instance.

Is there a demo available? got a Link?

Sorry, there’s no downloadable demo or crippleware. But I reached out to him to talk about getting you a test copy.

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