How should a host be notified about parameter list changes from a plugin (eg parameters deleted, added or reordered)

SDK for VST 3 audio plug-in and host development.
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nickallen
Posts: 4
Joined: Mon Feb 04, 2019 11:08 am

How should a host be notified about parameter list changes from a plugin (eg parameters deleted, added or reordered)

Post by nickallen » Mon Feb 04, 2019 1:31 pm

Hi,

In the IComponentHandler::restartComponent() method there are some flags passed in. Which of the flags is the correct one to determine if the list of parameters changes (e.g by inserting new parameters, deleting old ones or reordering the pramater list)?

Is it kParamTitlesChanged or kReloadComponent? The name kParamTitlesChanged to me just implies the name of a parameter changed but not insertion or removal.

The documentation for kReloadComponent just says "The Component should be reloaded" but what does this actually mean?

Kind regards,

Nicholas Allen

Arne Scheffler
Posts: 302
Joined: Mon Jun 20, 2016 7:53 am

Re: How should a host be notified about parameter list changes from a plugin (eg parameters deleted, added or reordered)

Post by Arne Scheffler » Mon Feb 04, 2019 5:09 pm

Hi,
in this case you would use kReloadComponent. This triggers that all information should be revalidated by the host. There's no single flag for what you want.
But please be aware that deleting parameters may have side-effects like deleted automation.

I hope this helps,
Arne

nickallen
Posts: 4
Joined: Mon Feb 04, 2019 11:08 am

Re: How should a host be notified about parameter list changes from a plugin (eg parameters deleted, added or reordered)

Post by nickallen » Tue Feb 05, 2019 8:01 am

Arne Scheffler wrote:Hi,
in this case you would use kReloadComponent. This triggers that all information should be revalidated by the host. There's no single flag for what you want.
But please be aware that deleting parameters may have side-effects like deleted automation.

I hope this helps,
Arne
Thank you for your response! So I am right that kParamTitlesChanged means the count and order of parameters changed but just the names of the parameters changed right?

I'm actually asking as a host developer (Bitwig Studio) not a plugin developer. We now also take care of parameter deletions that could even be automated.

Nick

Arne Scheffler
Posts: 302
Joined: Mon Jun 20, 2016 7:53 am

Re: How should a host be notified about parameter list changes from a plugin (eg parameters deleted, added or reordered)

Post by Arne Scheffler » Tue Feb 05, 2019 8:06 am

Yes, kParamTitlesChanged means that only the titles, default values or flags changed, not the count, order or the actual values.

Cheers,
Arne

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