Glitch when starting playlist after "on":false state

[lookasek]

What happened?

When starting the playlist (preset 5: Turn on) while the controller is in the "on": false state, the LEDs glitch for a brief moment. The behavior occurs regardless of whether the playlist is started via the physical button (preset 7: Power), app, or web UI. The flash is visible before the transition into the playlist's first effect begins. The playlist works correctly.

To Reproduce Bug

1. Use WLED version: 15.3.
2. Prepare the following set of presets and playlists:
   Presets JSON:

{"0":{},
"1":{"mainseg":0,"on":true,"bri":false,"transition":25,"tb":0,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep on"},
"2":{"mainseg":0,"on":true,"bri":false,"tb":1600,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep off"},
"3":{"mainseg":0,"on":true,"bri":false,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Solid"},
"4":{"mainseg":0,"on":false,"bri":false,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Off"},
"5":{"playlist":{"ps":[1],"dur":[15],"transition":[0],"repeat":1,"end":3,"r":0},"on":true,"n":"Turn on"},
"6":{"playlist":{"ps":[2],"dur":[14],"transition":[0],"repeat":1,"end":4,"r":0},"on":true,"n":"Turn off"},
"7":{"ps":"5~6~","n":"Power"}}

3. Set the current preset to 4 ("Off", i.e. {"on":false})
4. Start preset 7 ("Power", i.e. playlist 5/6).
5. Observe a brief LED flash just before the playlist "Turn on" starts.

Expected Behavior

When starting a playlist while "on": false, the LEDs should remain off until the smooth transition begins. There should be no flash or sudden burst of light.

Install Method

Binary from WLED.me

What version of WLED?

WLED 0.15.3

Which microcontroller/board are you seeing the problem on?

ESP32

Relevant log/trace output

Anything else?

Tested on Gledopto GL-C-016WL-D with WS2811 FCOB CCT led strip.

I also tested with the following preset set:

{"0":{},
"1":{"mainseg":0,"on":true,"bri":false,"transition":25,"tb":0,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep on"},
"2":{"mainseg":0,"on":true,"bri":false,"tb":1600,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep off"},
"3":{"mainseg":0,"on":true,"bri":false,"transition":15,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Solid"},
"4":{"mainseg":0,"on":false,"bri":false,"n":"Off"},
"5":{"mainseg":0,"on":true,"bri":false,"transition":15,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Solid"},
"6":{"playlist":{"ps":[2],"dur":[14],"transition":[0],"repeat":1,"end":4,"r":0},"on":true,"n":"Turn off"},
"7":{"ps":"5~6~","n":"Power"}}

Transitioning from preset 4 ("Off") to preset 5 works without any glitches.

Code of Conduct

• I agree to follow this project's Code of Conduct

[DedeHai]

some LED strips glitch when the relay is switched on, nothing much can be done about that.

[lookasek]

some LED strips glitch when the relay is switched on, nothing much can be done about that.

@DedeHai at first I also thought it was a matter of switching power on the relay. I also tested with the relay option unused (constant power supply to the LEDs) and this problem also occurs. Why does this error not appear in the second case I described (transition from the "on":false state to the "Solid" preset)?

I have used this model of CCT strip from BTF Lightning in a very large number of WLED projects and have never had any problems with them.

Today I spent half a day testing and from my observations the problem only occurs when we change the "on" state from false to true using the playlist, when we use a regular preset for this purpose the flashing does not occur.

[DedeHai]

if the relay is not used and this still occurs that may be a software glitch indeed. so this only happens on the cct strip (analg?) and not on an addressable one?

[lookasek]

The described case concerns the WS2811 FCOB CCT digital LED strip (information is included in the issue).

[lookasek]

Is there any additional information you need to reproduce the reported error?

[DedeHai]

I tried you presets and it works just fine for me.

try it on a different strip and/or a different controller. another option is to try nightly build 0.16

[lookasek]

I tried you presets and it works just fine for me.

try it on a different strip and/or a different controller. another option is to try nightly build 0.16

I will test tomorrow on a different set (same controller model and LED strip). I'll let you know what the situation is like.

[lookasek]

@DedeHai sorry for the delay, I ran some tests today on another set of the Gledopto controller and CTT LED strip from BTF Lightning. The situation is identical to the first set. Below I am sending some information and recordings (one when starting the LED using a playlist and the other when using a preset).

I conducted the tests using the WLED_0.15.3_ESP32.bin firmware downloaded directly from the releases of wled/WLED repository.

I used this list of presets:
{"0":{}, "1":{"mainseg":0,"on":true,"bri":false,"transition":0,"tb":0,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep on"}, "2":{"mainseg":0,"on":true,"bri":false,"tb":1600,"seg":[{"id":0,"fx":6,"sx":240,"ix":128,"sel":true}],"n":"Sweep off"}, "3":{"mainseg":0,"on":true,"bri":false,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Solid"}, "4":{"mainseg":0,"on":false,"bri":false,"seg":[{"id":0,"fx":0,"sx":128,"ix":128,"sel":true}],"n":"Off"}, "5":{"playlist":{"ps":[1],"dur":[15],"transition":[0],"repeat":1,"end":3,"r":0},"on":true,"n":"Turn on"}, "6":{"playlist":{"ps":[2],"dur":[14],"transition":[0],"repeat":1,"end":4,"r":0},"on":true,"n":"Turn off"}, "7":{"ps":"5~6~","n":"Power"}}

FIRST TEST:
I start the test with Preset with ID 4. Then, when I start the playlist with ID 5 (both directly and using the preset with ID 7), the LEDs flash momentarily. Below is a video recorded in Slow Motion:
https://github.com/user-attachments/assets/ff0dbef8-b960-4483-818d-9f74fa116ffb

SECOND TEST:
I start the test with Preset with ID 4. Then, when I start the preset with ID 1 (this preset is used at the beginning in the playlist with ID 5), the LEDs turn on correctly. Below is a video recorded in Slow Motion:
https://github.com/user-attachments/assets/d7e1ef1e-3aa9-49bf-965b-93888f3bd930

What information do you need to possibly reproduce the described issue?

[DedeHai]

I would need you to test this on a non-gledopto controller and a different LED strip type to make sure it is not simply related to bad hardware design or an inherent property of those strips. And/Or test with 0.16

[lookasek]

Ok, I will try to perform additional tests on another controller (QuinLED) and an addressable RGB strip.

However, don't you think, like me, that it's most likely a software issue, considering that launching the preset itself doesn't cause the flashing, but launching the playlist with that preset does?

[DedeHai]

possible, but it worked when I tested it and GLEDOPTO are known for sub par hardware.

edit:
if you run that test and it works on normal RGB strips, try also setting output type to those CCT ones you have but keep the RGB connected just to test if it may be something in CCT processing code that could cause it.

[blazoncek]

FYI if color selected in off state is not black and you start a preset (or playlist, it really doesn't matter which except for the transition time) and transition is not 0 you may see a brief display of starting color.

To overcome this add "seg":{"col":[[0,0,0],[0,0,0],[0,0,0]]} to your off preset.

[lookasek]

FYI if color selected in off state is not black and you start a preset (or playlist, it really doesn't matter which except for the transition time) and transition is not 0 you may see a brief display of starting color.

@blazoncek can a flash also occur when the transition is set to 0 (in the above described tests I had preset ID 1 with "transition":0)?

To overcome this add "seg":{"col":[[0,0,0],[0,0,0],[0,0,0]]} to your off preset.

If I change the off state color to black, is it possible to turn on the LEDs to the color set by the user before turning it off?