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Strobe gets stuck

Posted: Fri Jan 20, 2023 8:31 pm
by ShakyMUC
Hi Guys,
today I tried to realize a stroboscope with QLC+. In another thread here
viewtopic.php?t=14465
I read about 50ms ON and 50ms OFF. However, there is no answer as to whether it worked with these timings.

I don't come close to these values myself. 1 cycle (ON/OFF) must have at least 250-300ms for me to run properly.
This is not due to the DMX output, USB port, etc. but to QLC+ itself.
If I run the DMX-Out monitor, it can be seen clearly. I have also tested my interface & the device itself with other software at higher speeds/shorter cycles without any problems.

My hardware is a WIN11 - I7-7700 - 32GB - Nvidia GPU - USB3.0 port PC. That shouldn't be the reason (... or?)

Does anyone know if there are any tricks to speed this up?

Re: Strobe gets stuck

Posted: Sat Jan 21, 2023 4:19 pm
by kenact
What fixtures are you using? It's very hard to get a strobe effect with incandescent fixtures, because of the amount of time needed for the light to come on and go off. Many LED fixtures have a built in strobe effect.

Re: Strobe gets stuck

Posted: Fri Jan 27, 2023 9:54 pm
by ShakyMUC
Sorry for my late answer. But I was sick for a few days.

As I told above, it´s not a matter of the fixture (a video light that has no strobe built in) or the interface and so on.
(If I trigger the fixture by an ESP32 generating DMX-Out it works perfect down to 15ms flash time of this fixture and any pause/off time >=15ms)
And I tried it with other fixtures (simple PAR 36) to confirm this for myself. 100% the same behavior and the same minimal timings by QLC.

It´s clearly the problem, that QLC is not running fast enough on my PC. QLC stucks with faster output as I mentioned above. And no, that doesn´t happen in a combined situation while controlling othe/many fixtures
- that already happens while controlling that fixture standalone.

I would be very thankful if someone could test and/or confirm (or not) this fact with another PC. Or give me some hints what I could try else.

Re: Strobe gets stuck

Posted: Sat Jan 28, 2023 4:42 am
by Yestalgia
I'd like to know what interface you're using as well.

Re: Strobe gets stuck

Posted: Sat Jan 28, 2023 10:44 am
by edogawa
I don't know about Win11 but this small test workspace works well enough here on Linux:
The Strobe effect is built using a single generic dimmer, and two chasers - one single-shot that flashes a scene with the channel on, for 15 ms., and a second, looping thie first one,
In VC I made a button to start the "Strobe" chaser, and a speed dial controlling its step speed.
After activating operate mode and clicking the button, the dimmer shows bright in 2d monitor (as the speed dial is set to less than the 15 ms flash time)

I run this test workspace on my oldish i5 laptop, without real DMX interface/output. I perfectly can control Strobe speed with the speed dial now, when exceeding ca. 20 ms, I start to see a flicker in the monitor, and it slows down while I increase sent values.

So, in Linux QLC+ seems very responsive and capable of emulating a strobe effect, though mouse movements and other activity will disturb it to some extent.

but as kenact says, incandescent lights won't give a good strobe effect because they take time to heat up and cool down. With any LED light source it should work fairly well. I've used similar setups in theater, with LED strips, in the past with good enough results... it's not as smooth and regularly pulsing as builtin strobes at higher speed, but basically works.

Re: Strobe gets stuck

Posted: Thu Feb 02, 2023 8:49 pm
by kenact
I have created lightening effects using LEDs, ENTTEC OpenDMX, QLC+ 4.12.6 on a Windows 10, Dual Core 2.4Ghz laptop.

Re: Strobe gets stuck

Posted: Sun Feb 05, 2023 12:59 pm
by Yestalgia
So the thing with the OpenDMX is that it uses the system CPU to generate DMX.

You might be better off using a USB Pro which does the processing onboard. They can be picked up second hand pretty cheap.

That's only if you can't find any other problems in your setup.

Re: Strobe gets stuck

Posted: Tue Feb 07, 2023 3:28 pm
by kenact
Yestalgia wrote: Sun Feb 05, 2023 12:59 pm So the thing with the OpenDMX is that it uses the system CPU to generate DMX.

You might be better off using a USB Pro which does the processing onboard. They can be picked up second hand pretty cheap.

That's only if you can't find any other problems in your setup.
Thanks, but I'm not the one with the problem. As old and slow as my system is, I have no problem creating lightening effects. That was my point.

Re: Strobe gets stuck

Posted: Wed Feb 08, 2023 8:13 am
by Yestalgia
kenact wrote: Tue Feb 07, 2023 3:28 pm Thanks, but I'm not the one with the problem. As old and slow as my system is, I have no problem creating lightening effects. That was my point.
I thought it was OP (my bad). Point stands though if you want precision. I think it might be important if you're trying to do a "Strobeoscope" https://www.google.com/search?tbm=isch&q=stroboscope like op mentions.