Lua: get a plugin's current preset

johndev · May 22, 2021, 7:13am

In Lua, is it possible to retrieve information about the preset currently loaded in a given Plugin object?

I need a PresetRecord, for passing to a Plugin:load_preset() call, but that PresetRecord could be looked up via the preset name/label or URI so either of the latter would suffice I think. I’m not finding anything in the class reference documentation that would give me any of those things.

johndev · May 27, 2021, 11:01am

I’ll take the lack of response to mean it’s not possible. Fair enough. I have two more Lua questions which I’ll add here because I’m not sure which is the worse behaviour: creating/spamming multiple topics or adding questions to an existing topic that are not related to its title.

The question in the first post.
It is possible to get/set plugin parameter values via the get/set_plugin_insert_param() functions, and the set of those parameters seems to be the same set shown by the “Edit with generic controls” action in the mixer, all of which are numerical.

Is it possible, and if so: how, to get/set the ones not in that “edit” list. E.g. The currently selected “bank” (name?) of a Dragonfly Reverb, such as “Large Dark Hall”.

Is it possible to select a track/route via Lua? Documentation suggests that it is but I’m getting a Fatal Error when I do this…

local r = Session:route_by_name(“Audio 1”) - - the route to select
local rtav = Editort:rtav_from_route(r) - - get its RouteTimeAxisView
local sl = ArdourUI.SelectionList()
sl:push_back(rtav)
Editor:set_selection(sl, ArdourUI.SelectionOp.Set)

Result is a Fatal Error saying “programming error: unknown selectable type passed to Selection:add()”. According to the manual’s Lua class reference, RouteTimeAxisView is a RouteUI which is a Selectable which is what set_selection() requires. So this error was unexpected. Am I doing something wrong?

This is in Mixbus32c, if that’s relevant.

P.S. Thank you devs for the Lua interface. I’m very much enjoying this ability to script behaviour. Thumbs up. And thanks again for Ardour/Mixbus while I’m at it.

x42 · May 27, 2021, 3:06pm

I’ve just added bindings for the first two (available since 6.7-27, will be in the next update of Harrison Mixbus).

As for (2), you can query a list of scale-points (‘name’ → value pairs eg. “Large Hall” : 5).

github.com

Ardour/ardour/blob/master/share/scripts/s_pluginutils.lua#L41-L57

    
      
          	-- query preset
          	local lp = plugin:last_preset ()
          	print ("valid?", lp.valid, "Preset ID:", lp.uri, "Preset Name:", lp.label, "User Preset (not factory):", lp.user)
          
          
	-- list preset of given plugin
          	if not psets:empty() then
          		for pset in psets:iter() do
          			print (" - ", pset.label, pset.uri)
          		end
          	end
          
          
	-- print scale-points of a given plugin-parameter
          	local _, pd = plugin:get_parameter_descriptor (3, ARDOUR.ParameterDescriptor())
          	local sp = ARDOUR.LuaAPI.desc_scale_points (pd[2]);
          	for k, v in pairs(sp) do
          		print (k, v)
          	end

There is currently no direct API to lookup values for given name, or directly get a list from a processor (without first querying the parameter-descriptor), but we can add some convenience wrappers if needed.

–

I do not know about (3). The code you have posted looks fine…

johndev · May 29, 2021, 6:32am

Thank you very much Robin. I’ll revisit this when the Mixbus update comes. And I’ll raise 3 as a bug in case it truly is.

x42 · May 29, 2021, 1:26pm

I just realized that Editor:set_selection is exclusively for items that are only visible on the editor-timeline.

Track/Bus selection is synced with the Mixer and control-surfaces.

It is not currently possible to select track from Lua scripts, and there are some technical issues with exposing that API.

johndev · May 30, 2021, 4:12am

Okay, thanks for the update.

johndev · August 8, 2021, 11:24am

Those bindings are now present in Mixbus v7.1, thanks Robin.

However, I now see that the answer to question 2 isn’t quite what I was after. To use that Dragonfly example, the problem is that its “Bank” setting isn’t a parameter as such. I.e. It does not show up as a parameter when doing an Edit With Generic Controls, and neither does it show up in Lua when iterating through the plugin’s parameters/descriptors. So the question is, is there any way to get access to such settings in Lua, so its current value can be retrieved and set?

system · November 7, 2021, 5:25pm

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