Loopback magic - Extending the Virtual Console capabilities thanks to Virtual Controllers

[MichelSliepenbeek]

...... what is it that "easy example" is trying to accomplish?

If you go to Operate Mode, you will see that when you Click the < > buttons the Pages of the Multi Page frame will Skip.
If you move the Loopback Slider on the left, you will notice that on every single page it has a different function.

If (in design mode) you click on the different Widgets and follow the External Controls you can learn how to do this.


In the workspace where i created this example from i used a Novation Launchpad as External Control for the Red, Green and Blue buttons.
For the example this is not relevant, i should have removed them. Apologies for the confusion.
I suggest you ignore everything in Universe 2. Just concentrate on Universe 1 where the regular Fixtures are and Universe 3 where the Loopback channels are.


"Catch up with the external controller input value" is an option for a slider.
Here you find further information: https://docs.qlcplus.org/v4/virtual-console/slider

To understand what it does:
- in Design Mode on the page "1 Level By Loopback" click on the Slider in the Multi Page Frame (it says Level) and on the First Tab enable "Catch up with the external controller input value".
- in Operate Mode on page "1 Level By Loopback" set the loopback Slider to 100, now go to page 2 and set the Loopback Slider to 255. Go back to Page 1 and lower the slider. You should notice that from 255 to 100 the Level Slider remains at 100. Only when your Loopback Slider goes below 100 the Level Slider will "Catch Up".


A Speed Dial is a Widget that you can use to control the Speed of your Functions: https://docs.qlcplus.org/v4/virtual-console/speed-dial
In Design Mode on page "2 Time By Loopback" click on the Speed Dial and on the Input Tab you will see that the range is set from 100 mS to 1500mS.
In Operate Mode on page "2 Time By Loopback" if you move the Loopback Slider from 0 to 255, you will notice that the Speed Dial goes from 100 mS to 1500mS.

Why do I need it?

This was meant to be an easy example of what you can do with Loopback.
I just picked some commonly used widgets (Slider in Submaster mode, Speed Dial, XY -Pad, a Crossfader of a Cue List and a Multi page Frame).

[mcasto]

Okay. I've been running stage plays at a community theater using QLC+ to manage both lights and sound. Lights work completely as expected.

Sound, though, is a critter of a completely different breed.

The ideal situation would be a cue list with all light and sound cues. The issue I have encountered in every production is that we need background music to continue playing through a scene while other sounds (usually sound effects) also play.

What I have been doing is to build my cue list with all the cues that don't require simultaneous play (lights & single-shot sfx) then placing buttons outside the cue list to toggle the music that has to play simultaneously with the other sounds.

That's the only way I have, thus far, found to play those music files simultaneously with other sound files.

Well, I experimented with triggering scripts from the cue list, and that worked fine, but it gave me no control over the sound file that was playing externally. It just played all the way through, and it seemed like a *very* clunky solution.

Could loopbacks be set up to handle this scenario?

So, could I place a button on the Virtual Console that toggles the background music (which I do now anyway) but use a loopback in the cue list chaser to toggle that button at the appropriate times?

[GGGss]

I was thinking of suggesting the solution of adding all your music pieces in another chaser and using the VC Cue List with the 'side fader' in 'steps' mode. https://docs.qlcplus.org/v4/virtual-console/cue-list
What this allows is to have an external control (a loopback channel) and give it a value.

Try it if you like.
Create a generic dimmer in a loopback universe.
Create one or two scenes with a '1' and '2' value set for this loopback dimmer.
Create a chaser with the audio files you referred to.
Add this Chaser to a cue list on your VC. Set it with the side fader in steps-mode. Bind the external input to the loopback dimmer.
In your main cue list, add a step and call for one of the above scenes.
I haven't tested it right now, but I've seen it working.
My only uncertainty is what happens when you proceed with the next step in your main cue list.

[thibaultphil]

hello,
I am facing the same need. I build my chaser as follows:
-script to trigger music via VLC (argument: systemcommand:"vlc.exe" arg:--no-video arg:--play-and-exit arg:"C:\JLB\musique\08 interrogation sandrine.mp3" " .
-launch of the light scene.

The VLC app remains in the foreground which allows me to control the volume and its shutdown.

[mcasto]

@thibaultphil ... I did that in the last show, but I hated the fact that VLC stayed in the foreground, because the cues triggered that way needed to continue through several other cues, which meant I'd hit that cue, VLC would trigger & keep focus, then I'd have to manually switch back to QLC to continue running my other cues, then go back to VLC to control it if necessary. It technically worked, but it was far from ideal.

@GGGss, running lights while the music plays isn't the issue I'm trying to resolve. Running other sound cues while is the issue. I need to run sound cue A and leave it running while sound cue B also plays. I'll try your suggestion in case I'm missing something when reading it, but I think having the sound cues in their own chaser will result in the same problem of "stop playing cue A when cue B starts," which is not what I need.

[mcasto]

@thibaultphil, yeah. The step slider behaved just like any other method for the sound cues. As soon as the next cue starts, the previous cue stops. Unless I'm completely misunderstanding something, which is quite possible.

[thibaultphil]

Have you tried using a button matrix in VC with music per button. The music can overlap but there is a latency on startup

[GGGss]

Have you tried using a button matrix in VC with music per button. The music can overlap but there is a latency on startup

We (Massimo) are working on this ... the latency gap lowered from a hefty 378ms to an acceptable 29ms. Fun stuff to be coming alive in the next version.

[thibaultphil]

thank you very much for your investment in this great tool

[thierry]

The ideal situation would be a cue list with all light and sound cues. The issue I have encountered in every production is that we need background music to continue playing through a scene while other sounds (usually sound effects) also play.

What I have been doing is to build my cue list with all the cues that don't require simultaneous play (lights & single-shot sfx) then placing buttons outside the cue list to toggle the music that has to play simultaneously with the other sounds.

That's the only way I have, thus far, found to play those music files simultaneously with other sound files.

Could loopbacks be set up to handle this scenario?

So, could I place a button on the Virtual Console that toggles the background music (which I do now anyway) but use a loopback in the cue list chaser to toggle that button at the appropriate times?

@mcasto

Your idea of using loopbacks to control buttons that toggle audio files is valid.

This "loopback magic" enables to create a cue list with multiple concurrent audio cues.
See attached example "Concurrent audio cues.qxw" where you just have to define your own audio files.

This example is based on the following components:
- a generic dimmer fixture with LTP channels on a loopback universe to create control channels,
- audio functions controlled by buttons, themlselves controlled by these control channels,
- a cue list or chaser with scripts using "startfunction" (and implicitely "stopfunction") to create 0-1 transitions on the control channels, in order to toggle the buttons.

[standup]

Hello everyone. I wanted to ask you if you managed to program the color selection from the document from google as posted by thierry in the start of this thread.

I am trying to do so from the document and still can not make it work. I do not understand how to set up the inputs and outputs from and to loopback.

Can you please help me?

Ideally i would like to have 18 colors which i can modulate in live mode and assign them to 4 groups.

Thank you very much in advance

[thierry]

Hello standup

I've published in QLC+ virtual setup on Loopback Universe the workspace ("vSETUP 18 Colors + 4 zones") you are looking for, with the 2 following virtual controllers documented in section "Virtual setup example #1" of the Google doc:
- RGB Color Configurator - with 18 RGB colors
- RGB Color to Zone Distributor - 18 colors assigned to 4 zones

This workspace is based on the following virtual fixtures (to be added in your personal "fixtures" folder):
- vFixture-RGB Color Configurator-Output-3CH.qxf
- vFixture-RGB Color to Zone Distrib-Output-3CH.qxf
- vFixture-RGB Color to Zone Distrib-Internal-18CH.qxf

Note that only "Zone 1" is functional in this workspace. To assign colors to 4 different zones, 4 instances of the frame "ICF - RGB Color to Zone1" are needed, with different outputs (ie scene functions) for the 54 sliders in level mode included in each frame, and different input channels for the 18 submasters included in each frame. This is quite a long and error prone task, even by updating the qxw file with a text editor.

With so many sliders (submasters and sliders in level mode), a kind of patching tool would be helpful to assign the input & output channels of all sliders within a frame.

[MichelSliepenbeek]

Maybe this example will help you a bit in the right direction.

It is a color selector that works for 4 Fixture Groups (you might want to change names "Front Left" to "Zone 1", "Front Right" to "Zone 2", "Rear Left" to "Zone 3" and "Rear Right" to "Zone 4" to make it fit with your situation).
It uses 14 fixed colors (or 12 Fixed colors and White and Black, depending on which definition of "color"you want to use).


The Color Selector (large Frame on the Left) gives you the flexibility to use separate Colors and Levels for the 4 Fixture Groups, but you can also use it to easy set one color and one level for all the Fixtures. It tries to create a "Best of Both Worlds" situation: if you want you can use separate values for each Fixture Group, but if you don't want to you are not obliged to select Four Colors and set Four Levels.
If you use the Color Bar on Top, you can set one color for all four Fixture Groups at once.
If you use the Buttons (0, 64, 128, 192 and 255) in the Middle, you can set the level for all four Fixture Groups at once.

It works for me, but it is not perfect. If you use the Top Bar to set all Groups to Red, change one Group to Yellow and then use the Top Bar to change All Groups to Yellow, you will notice that it will do so for the three groups you did not change, but it will turn Off the group that you changed to Yellow before.
This will only happen with colors that are already in use. So in the given example where you selected Red on the Top Bar and Selected Yellow for one Group: if you first select Orange on the Top Bar and then select Red (on the Top bar), it will work Fine.
If you get lost, you can always use the "Stop Button" (which just will turn Off all selections that were made) and then start again.


If you do not want to be restricted to the use of only 12 colors, the frame in the middle ("Add/Subtract") can be used to make some color adjustments.
If you start with Red for all Fixtures, you can select "+ Green" and by moving the Slider Up you can gradually change your color over Orange (slider half way) to Yellow (slider up).
In the same way If you start with Yellow for all Fixtures, you can select "- Red" and by moving the Slider Up you can gradually change your color over Orange (slider half way) to Red (slider up).

Again it works for me, but it is not perfect. As it uses RGB Matrices with Pattern = Plain Color and Blend Mode = Add or Subtract, you first need to select a color in the Color Selector to get it working and the moment you change the color in the Color Selector it will stop working.

In this example i only used colors Red, Green and Blue. You can expand your possibilities by adding colors Cyan, Yellow and Magenta (and even Black and White) as well.
In the same way you can also use a RGB Matrix with Pattern = Plain Color, Blend Mode = Subtract and Blend Color = R(000) G (078) B(145) to gradually change your White from Neutral to Warm White (or Blend Color = R(053) G (037) B(000) to gradually change your White from Neutral to Cold White).


Remarks:
This example uses Loopback to:
- set the colors. The buttons in the Color Selector on top start "Run once Sequences" that (after being Looped Back) act as External Control for the Buttons in the Color Selectors for the four Fixture Groups,
- set the levels. The (0 .. 255) buttons in the middle start "Run once Sequences" that (after being Looped Back) act as External Control for the Sliders for the four Fixture Groups.

Be aware that (in QLC 4) you can only use one External Control for a Button or a Slider. So if you are already using a Midi Controller (like an AKAI APC mini to select colors and set levels) this will not go together .

You should also notice that all my RGB channels are set up as LTP (Latest Takes Precedence). Might be that with HTP you get different results.

I prefer not to use the term "Loopback Magic". Once you understand how to use it, it is only "Loopback Logic".
in the same way i have a problem with "Virtual". If it does not exist, you cannot use it.

[MichelSliepenbeek]

Another example of how you can use Loopback is a Button Control for an XY pad.


This example uses 4 Loopback Channels (they are in Universe 2, your Fixtures should be in Universe 1).
Two channels are used to control Pan: one is in Absolute Mode the other is in Relative Mode.
Check the attached Input Profile: that is where you make the selection between Absolute and Relative (https://docs.qlcplus.org/v4/input-outpu ... properties).
The other two channels do the same for Tilt.

The Absolute Channels are set up as External Control for the XY Pad.
The Relative Channels are set up as External Control for the Absolute Channels (and make them move Up/Down or Left/Right).
Note that all four channels are set to LTP.

On the work space you will find Buttons that are in Flash Mode: they run Scenes that control the Relative Sliders (which in turn control the Absolute Sliders).
The values used in those scenes are relative to 127 (which is the neutral value for a Channel in Relative Mode): a value close to 127 makes the relative slider move slowly, a larger value will make it move faster.
Feel free to change the values used in those scenes to adapt the "Speed" to your lickings (as an alternative you can also use Sensitivity in your Input Profile).

If you want to use a Pedal, Joy Stick or two Decoders of a MIDI controller, you can attach those as External Control to the two Relative Sliders.
To make the behaviour "less nervous" i used a Channel Modifier on those Relative Channels (https://docs.qlcplus.org/v4/fixture-man ... properties).
It will act as a 5 way switch: as the Neutral position is extended from 127 to 102..153 it will not kick in immediatelly, then for values 051..102 and 153..204 it will move at a slow speed and for values 000..051 and 204..255 it will move at a higher speed.
Again feel free to change the values to your likings (keep in mind that those Channel Modifiers also affect the values that you use in your Scenes. If you change the values in your Scenes and nothing happens: now you understand why ).


It is important to understand that the Relative Sliders will not return to their natural position by itself.
Therefor you should either use a Joy Stick (which will automatically return to its neutral position) or control the XY pad by only using the buttons (do not use the sliders).
If you might get in a situation where the movement will not stop anymore, just move the two relative sliders back to 127.


Make sure to put the Input Profile in the "InputProfiles" folder of your User Library and to put he Channel Modifier in the "ModifierTemplates" folder of your User Library (and then restart QLC+ to make them become active ).

[MichelSliepenbeek]

I noticed that someone downloaded the .QXW and .QXMT files, but not the .QXI file.

As you can only set a slider to operate in Relative mode in the Input profile, this example will not work properly without the Input Profile.

[MichelSliepenbeek]

Another example of what you can do with Loopback (in combination with Channel Modifiers):

A Flash Button for Functions that are not a Scene.

If you check the on line Manual for Button (https://docs.qlcplus.org/v4/virtual-console/button), you will find:

On button press...
Flash Function: You can "flash" the attached Scene when you keep the button pressed. If another type of Function is attached to the button, nothing happens when you click it.

So if you want to run for instance a RGB Matrix with pattern = Strobe only for as long as you press the Button (you want it to start when you Press the Button and want it to Stop when you Release the Button) it will not work.
With Loopback you can create yourself a workaround.


Explanation:
This example uses 2 LoopBack channels (in Universe 3), that act as a Trigger.
One uses channel modifier "255 On" (which produces value 000 for values 000 - 250 and value 255 for 250 - 255) and the other uses channel modifier "255 Off"(which does the opposite).
Both channels are set to LTP and need to be initialised by Scene "Init Triggers" (with LTP, if you turn a Function Off the channel will go back to the previous value, this Scene just ensures that that previous value is available).
"At rest" Trigger 1 will be Zero and Trigger 2 will be Full. If you push the Flash Button (that launches Scene) "Activate Strobe", the triggers will "Flip" (Trigger 1 wiil become Full, Trigger 2 will become Zero). When you release the Flash Button the triggers wiil go back to their original state.
In the Solo Frame you will find two Buttons. The White Button launches a RGB Matrix, the Black Button launches a Dummy scene. The Black Button has no other function than to (make the Solo Frame) turn off the function "under the White Button".
The White Button uses Trigger 1 as External Control, the Black Button uses Trigger 2 as External Control.

[MichelSliepenbeek]

Another example of what you can do with Loopback:

Jump to a specific step in a Cue List.

I was cleaning up my Computer and came across this example (i made it for this post https://www.qlcplus.org/forum/viewtopic ... 891#p69891, but for some reason did not post it).
Basically it is a variation on the CrossFader option (on Page 4) in the First LoopBack Easy Example in this thread.


If you control a Chaser using a Cue List Widget there is (on the Final Tab of the Cue List Properties) the option to use a Side Fader in Step Mode (https://docs.qlcplus.org/v4/virtual-con ... figuration).
If you connect a Loopback Channel as External Control to that Side Fader, you can use it to make it jump to a specific Step of the Chaser.

In order to make that work you need to do some math (based on the number of steps in your Chaser):
- If your Chaser has 4 steps, create 4 Scenes setting this loopback dimmer to 32 (= 255 / 4 / 2), 100 (= 32 + (255 / 4), 164 and 228.
- If your Chaser has 5 steps, create 5 Scenes setting this loopback dimmer to 26 (= 255 / 5 / 2), 77 (= 26 + (255 / 5), 128, 179 and 230.
- If your Chaser has 6 steps, create 6 Scenes setting this loopback dimmer to 21 (= 255 / 6 / 2), 64 (= 21 + (255 / 6), 107, 149, 191 and 233).
- If your Chaser has 7 steps, create 7 Scenes setting this loopback dimmer to 18 (= 255 / 7 / 2), 54 (= 18 + (255 / 7), 90, 127, 163, 200 and 236).
and so on.

Loopback - Easy Example 8.qxw

(13.49 KiB) Downloaded 21 times

Loopback-EasyExample8.qxi

(583 Bytes) Downloaded 15 times

By the way: there is a reason why i started with a Chaser with 4 steps.
If you have 1 or 2 steps you do not need a Chaser, for a Chaser with 3 steps you can withstand with 000, 127 and 255 (i.o.w. use the "First" and "Last" Scenes in this example and add a "Mid" Scene to that).

[MichelSliepenbeek]

Another example of what you can do with Loopback (in combination with a Channel Modifier):

X-Y Pad acts as a 2D dimmer.


This example uses four spots on the four corners of the stage.
With the X-Y pad you can accent the part of the stage where the action is.

If the actor/singer/speaker is in the Left Front of the stage, move the cursor of the X-Y pad to the Left Front. The Spot in the Left Front will be Full, the others will be Dimmed.
If the actor/singer/speaker then walks to the Right Rear, follow the movement by sliding the cursor of the X-Y pad to the Right Rear. The Spots will act accordingly: The Spot in the Left Front will Dim, the Spot at the Right Rear will come up.
So basically it is a "poor man's follow spot". (Just try it, in this case the Fixture Monitor in 2D View shows it much better than words can describe )


Explanation:

A X-Y pad is designed to control Moving Heads. So as it expects a Fixture with Pan and Tilt Channels, the first step is to create a Fixture Definition with a Pan and a Tilt channel.
This is used to add four "Dummy Pan Tilt" Fixtures to the Loopback Universe.


As the Fixtures are in the four corners (and the X-Y Pad produces 000 - 000 for the Left Rear corner and 255 - 255 for the Right Front corner), the four Dummy Moving Heads need to be set up in the X-Y pad as:
- for the Fixtures on the Left (Fixtures 1=LF and 3=LR), the X-Axis need to be set as Reversed.
- for the Fixtures on the Rear (Fixtures 3=LR and 4=RR), the Y-Axis need to be set as Reversed.


Next step is to define two Sliders in a Standard Frame for each Fixture.
One Slider is in Level Mode and uses the matching Pan Loopback Channel as External Control, The other Slider is in SubMaster Mode and uses the matching Tilt Loopback Channel as External Control.
So if we take the Front Left Fixture as example:
- if the cursor of the X-Y Pad is at the Left Front position, both the Level Slider and the Submaster Slider are Full.
- if the cursor of the X-Y Pad is at the Left Rear position, the Level Slider is Full but the Submaster Slider is Zero.
- if the cursor of the X-Y Pad is at the Right Front position, the Level Slider is Zero but the Submaster is Full.
- if the cursor of the X-Y Pad is at the Right Rear position, both the Level Slider and the Submaster Slider are Zero.

As you do not want to see all those Sliders when running a show it is best to keep the "Faders Frame" minimised.


Finally a Channel Modifier is used to Boost the Center position (or prevent a Dip in the Center position).
So this modifier is "steep in the first part, close to Max in the Middle and Shallow in the last Part".


Save the Fixture Definition to the Fixtures Folder of your User Library and the Channel Modifier to the Modifiers Templates Folder of your User Library, before you (re) start QLC+.

[MichelSliepenbeek]

In this example two more spots were added at Centre Front and another two at the sides (in the Middle between Front and Rear).
They require different Channel Modifiers (next to the one that is attached to the previous post).

QLC+ (again) proves to be very flexible as It is also possible to run EFX's (like Circle and Square) on those "Dummy Moving Heads".
Furthermore some RGB matrices and a Speed Fader were added.


Feel free to change this example to your likings and (maybe) post your result overhere.
As i have exposed most of my tricks by now, it would be nice if another "Loopback Magician" will enter the stage and keep this thread alive.

[GGGss]

Michel,
What you have revealed is a pervasive (even complex) usage of the Loopback feature.
I want to add one or two things, but these are so dependent on the specific usage cases that I don't see the urge to contribute.
Let's rephrase this: I'm willing to assist when Loopback approaches are needed... If only QLC+ would allow for some logic build blocks, life would become much more manageable... (OR AND XOR ... if then else, switch, ...). It seems that the v5 scripting will allow for this. (Making things even more complex for the novice).