X/Y 16bit cross fade issue

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GRE
Posts: 12
Joined: Thu Jun 08, 2023 11:11 am
Real Name: Greg_

QLC 4.12.7 on latest Windows 10
Fixture: any moving head with 16 bit pan and tilt.
Create solo frame with two buttons linked to:
Scene1: Pan 0,0 Tilt: 0,0
Scene2: Pan 255,255 Tilt:255,255
Set reasonable fade in time (10s or more).
Switch buttons and observe Pan/Tilt MSB and LSB DMX values during cross fade. Moving heads jumps.

Play around with identical start/end values for MSB or LSB. Switch on/off Button1, switch between Scene1 and Scene2. Moving heads goes crazy: jumps or shakes in position, Funny ;)
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GGGss
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I can't confirm your observation.
In my project, it does what it has to do.
Are you sure your fixture definition is ok?
Attachments
MSBLSB-test.qxw
(3.35 KiB) Downloaded 201 times
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MichelSliepenbeek
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There is a similarity with this issue: viewtopic.php?p=68651#p68651

In the Fixture Definition "both the Dimmer and the Dimmer Fine channel were set up as Fine (LSB)".
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GRE
Posts: 12
Joined: Thu Jun 08, 2023 11:11 am
Real Name: Greg_

Tested on a few build-in fixtures (Robe, Varytec).
The same project on my private PC with clean QLC+ installation - no problems.
I will check QLC+ installation/system on the notebook to find the source of problems.
Thank you for help.
GRE
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Real Name: Greg_

QLC+ removed and installed again on notebook - no success.
Any idea what is going on during x/y crossfade?
Attachments
msblsb test2.qxw
Pan/tilt MSB/LSB test file
(3.69 KiB) Downloaded 213 times
GRE
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Real Name: Greg_

Two more examples of position crossfade MSB LSB problems. Tested on different hardware (Win10)
Attachments
msblsb test 255_0_255_0.qxw
Pan from 0,0 255,0 Tilt from 0,0 to 255,0 => 8 bit crossfade
(3.68 KiB) Downloaded 208 times
msblsb test 0_255_255_255.qxw
Pan from 0,0 to 0,255 => Pan LSB goes crazy
(3.68 KiB) Downloaded 182 times
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GGGss
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msblsb test works as intended...
Whatever I do, it just delivers.

Try one thing: DISable your DMX interface and try again. Use the DMX monitor to watch the output.
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GRE
Posts: 12
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Real Name: Greg_

Output to ArtNet or nothing selected for test. Profile: none. Cross fade time: Speed Dial. Simple Desk, fixtures and Magic 3d Easy View to trace DMX.
Project "msblsb test 255_0_255_0.qxw": Crossfade on MSB only. Pan LSB and Tilt LSB stays at 0.
Project "msblsb test 0_255_255_255.qxw": Pan LSB = Tilt LSB value during crossfade (runs from 0 to 255).
Tested clean installation on 3rd PC (Win10 x64) - the same story. Both projects tested. No matter what fixture has been used. Playing with the start/end values (same/different start/end) I get unexpected moving head behavior during cross fade.
With some start/end settings output behavior similar to: https://www.youtube.com/watch?v=ucSjt2FkHMA, starts from 0:36 (different problem, not my case: viewtopic.php?t=15404)
I don't know where else to look for the source of the problems. Software conflict?
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GGGss
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The thing about the EFX... is another problem.

In both projects, now set the LSB to a 1 value.
Run your scenes, and you will notice the LSB also rising.

There was a time where the 16bit values were off and @Massimo had to try and fix it. We (temporarily) agreed that the LSB would be a copy of the MSB.
With a non zero value of the LSB channels, the movement should be a little more fluent. But far from ideal.

Please have a look here: viewtopic.php?p=65405&hilit=16bit+values#p65405
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GGGss
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mcallegari wrote: Tue Jul 26, 2022 9:15 am The sample project was not meant to show 16bit fading on dimmer. If you want to do that as well, set dimmer fine equal to dimmer coarse value.
That's the compromise to have this feature working.
Implementing proper 16bit fading (with arbitrary values) is much more difficult, as it implies to add a sort of "super channels" handling single channels (coarse+fine)
@massimo, Is there an evolution on this matter?
How did you solve it in v5?
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mcallegari
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No update on this, sorry.
v5 shares the same engine of v4 so channel fading is identical.
GRE
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Real Name: Greg_

Smooth transitions are important for larger projects. Theoretically, using scenes you can bypass the lack of custom tracks in EFX.
The original project file already has hundreds of features, but I see I need to rethink it from scratch. There is a high risk of running into a "risky" MSB/LSB set during the live show that causes unexpected noisy moving head movements.
Problems on dimmer channels cause the brightness to change. Problems on the Pan/Tilt cause the moving head drive system to jerk. In one submitted project example, the Pan drive was triggered more than 200 times without justification in one cross fade! Drive systems, especially belts, will not last very long with such problems. Moving heads literally "buzz" during such problematic transitions at certain transition speeds.
I've always been told that incorrect show design wears out moving heads and scanners - unjustified jerky movements of moving heads are not a good idea.
In this case, there is no chance - this is a very big problem.
On the other hand, you can play music using only moving heads. ;)
How do you deal with projects with dozens of scenes, transitions and EFX for moving heads?
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GGGss
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If you are worried about the wear and tear, park the LSB channels through Simple Desk.
The buzzing you are talking about, I never experienced this.
Under show conditions, the movers are only used for say 40% of its pan/tilt range, so that part of the bearings, belts and pulleys are stressed. Even under these conditions, they last a long time. The zoom/focus is another story because they move in a linear way and stress their guide rails. The same goes for rotating gobos. The bearing raceways wear out.

More problematic here are the movers with mechanical shutters. The dimming is very bad when the shutter has to come almost completely closed. I use a dimmer curve for that purpose.
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GRE
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Real Name: Greg_

More test:
msblsb test 255_0_255_255.qxw - 8 bit MSB cross fade on PAN. Pan LSB stays at 0.
msblsb test 127_0_127_127.qxw - Why does the value of Tilt LSB change? start=stop.
msblsb test 127_0_0_127.qxw - Why does Mr. MSB repeatedly change the value to 0 <-> 255? Switching New Scene 1 to Button New Scene 0 causes an 8-bit transition on the Tilt channel.
It is worth performing extended tests for combinations of common values start and end for Pan and Tilt. For example: one/multiple values = 0, 255, 127, individual start and end values equal or different, etc. In version 4.12.7 different behavior can be observed for A>B than B>A. Very often the MSB values are not logically related to the LSB (and vice versa) during the transition.
The current transition algorithm fails most tests.
Attachments
msblsb test 127_0_0_127.qxw
(3.68 KiB) Downloaded 212 times
msblsb test 127_0_127_127.qxw
(3.7 KiB) Downloaded 200 times
msblsb test 255_0_255_255.qxw
(3.68 KiB) Downloaded 213 times
GRE
Posts: 12
Joined: Thu Jun 08, 2023 11:11 am
Real Name: Greg_

In the archive I found a thread describing this problem as well: http://www.qlcplus.org/forum/viewtopic.php?t=9061. Posts from 2015.
Looks like this issue was never properly resolved.
Additionally, I performed tests for 16-bit color channels. Transitions between scenes are also calculated incorrectly - similarly to X/Y.
Are fixes planned for transitions in 16-bit channels?
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