onNoteOn() - Illegal operation in audio thread: String creation (in HISE plugin only!?)

[gorangrooves]

Just when I thought I was done...
I have a script which works perfectly in the HISE standalone, but in the HISE plugin version, I am getting an error.

I have a label DisplayMidiIn which is declared onInit and set to empty text.
Then, onNoteOn I have this:

        const var MidiIn = Message.getNoteNumber();
 	DisplayMidiIn.set("text", "MIDI in: " + MidiIn); 

I get an error about "Illegal operation in audio thread: String creation" for the line that sets the text.

The same kind of error happens onController where I want to set another label to display the controller number. Again, works perfectly in the standalone but not in the plugin.

What is going on here?

[d.healey]

@gorangrooves Don't do audio stuff in your interface script. Defer the interface script and use a separate script for audio stuff.

[gorangrooves]

@d-healey hmmm so what is onNoteOn script portion of the interface script for, if not for this? All I want to do is to display a note being played by setting the text of a label in onNoteOn script. How come it works perfectly in the standalone, but not in the plugin? It makes no sense to me.

[d.healey]

@gorangrooves Why you only get the error in the plugin I don't know.

There are two threads, audio and message. The audio is the fast lane, and you want to keep it clear of slow moving traffic (like GUI stuff) so that you don't get audio dropouts. The message thread is the slow lane, here you can take your time.

You should almost always defer your main interface script - defer means move everything in that script into the slow lane. This prevents the UI stuff from interfering with the audio thread. Use Synth.deferCallbacks(true); in on init.

Anything you want to happen on the audio thread you put in a separate script.

[gorangrooves]

@d-healey Thanks for that explanation. Splitting my main script into several just to display these labels doesn't seem like a practical or even relevant solution. Everything has worked perfectly in the currently compiled plugins the way I have it set up, and the new stuff in the standalone. I don't even really know if there is any "audio" specific function in the Interface script that is not relevant to the GUI.

The main playable functionalities are happening inside the samplers and their scripts anyway. The interface script deals with GUI, meters, sliders, and any action a user wants to take. Surely displaying a note played is relevant to the GUI and not to the audio performance side of a plugin. I would expect this to work in the interface onNoteOn/ onController.

Do you know of another way I can set the labels with played-in notes without reshuffling everything else I have put together to date?

If it works in the standalone, but not in the plugin, could this be a bug, @Christoph-Hart ? (Sorry if I screamed "bug" prematurely again. I'll be known as "that bug guy" ).

[d.healey]

@gorangrooves I don't think you need to split your script because it sounds like you're only using it for GUI purposes. So you just need to defer it.

[gorangrooves]

@d-healey I tried that, but it is not as simple as "just" , as it opens up a can of worms in the form of new errors (Call of setNoteNumber() outside of midi event callback).

So, going back to my original script, if I do something like this:

*onNoteOn
label.set("text", "Static text");

It will work fine.

However, as soon as we try to add this:

label.set("text", "Dynamic text: " + Message.getNoteNumber()):

all hell gets loose: Illegal operation in audio thread: String creation

[d.healey]

@gorangrooves Then perhaps you are doing stuff in the audio thread in your interface script and you'll need to do some re-arranging.

[gorangrooves]

@d-healey Nope. This is definitely a bug. YAY I finally found a real bug :lady_beetle:

How do I know? I created a blank project with nothing more than a label. I set the label with MIDI in number onNoteOn. It works perfectly in the standalone, but not in the plugin HISE.

Further, I compiled one of my plugins that get this error and it works as it should.

I filed a bug report.
It has the snippet, if you want to try it out.

[Christoph Hart]

There is a bug, but the bug is that it doesn't complain in the standalone version. You absolutely must not do this in the audio thread and the error that is reported is correctly.

I'll check why the AudioThreadGuard (yup, that's what it's called) isn't enabled in the standalone HISE version.

[gorangrooves]

@Christoph-Hart Damn it. I was hoping you were not going to say that.

[Christoph Hart]

@gorangrooves But I don't think that this is a big problem. Can't you just defer the Interface script?

[gorangrooves]

@Christoph-Hart I tried that. Now I get:

Call of setNoteNumber() outside of midi event callback

on the following line for my note audition buttons and mapping (onNoteOn):

Message.setNoteNumber(noteSources[arrayPos]);

Full portion of that code:

arrayPos = noteTriggers.indexOf(Message.getNoteNumber());
    if (arrayPos > -1)
    {      
       Message.setNoteNumber(noteSources[arrayPos]);  // yes so play its matching source note
    }else{
       Message.ignoreEvent(true); // no ignore it..
    };

If moving a controller, I get this:

Call of setControllerValue() outside of midi event callback

for that infamous Table line I recently cried bug about:

 if(Message.getControllerNumber() == 4)
    {
	    UnifiedVari = Message.getControllerValue();
		
	    tv = Math.round(127 * (VarHatsControllerTable.getTableValue(UnifiedVari/127.0)));
	    Message.setControllerValue(tv);
	    
	    Console.print("table value: " + tv);
    }

If I could understand exactly what kind of script should go where, I could perhaps split them. It seems that only these two are throwing a fit.

What does this mean and what do I need to do, please?

[Christoph Hart]

You basically have two tasks in one function that cannot coexist:

• you can only change the note number in a synchronous callback
• you can only do UI stuff in a deferred callback

You'll need to untwist that into separate functions. Ideally anything that changes the note number is a separate script and the rest can stay in the main UI script.

[gorangrooves]

@Christoph-Hart Thank you!

So, lets say I create a script file called extra.js.

Inside it, I put the script relevant to the mapping (and anything else which may currently cause an error), including the relevant onNoteOn portion of the script.

I include the script in my project with

include("extra.js");

before the line

Synth.deferCallbacks(true);

And that should do the job?

[d.healey]

@gorangrooves You need to put the audio stuff in a completely separate MIDI processor.

[gorangrooves]

@d-healey So, I create a MIDI script processor for the Main Container (the sampler window) and put all of this there?

[d.healey]

@gorangrooves I can't say without being more familiar with your project.

Anything that is not UI related needs to go into one or more separate MIDI processors.

[gorangrooves]

@d-healey Ok, but are we talking about the same thing? See the image, please.

[d.healey]

@gorangrooves Yes