Troubleshooting Sub stream blink in Black and white at night

X

xebra

Getting the hang of it
Dec 28, 2024
44
44
SW Idaho
I've tried searching for information like this, but nothing comes up. I must be using the wrong search terms.
I have continuous record on this one camera. The recordings are an hour long so I clipped a section to show what's happening.
This affect of blinking (defocusing?) doesn't occur during the day in color, but randomly in Black and white at night, with and without the IR LED on.
I forced a recording for about an hour during the day in color but no blinking on the main stream or anytime during the day.
I'll need to rewatch the camera this evening, directly through the camera web interface to see if the blinking occurs there too. I should have thought of that earlier..:rolleyes:
The last change I made was to the bit rate for the sub stream up to 1280 but haven't had it overnight at that bit rate.
Any advice will be appreciated.
In the video clip, the blink occurs at 6:01:16 and again at 6:01:33. In an hour recording I'll see 5 or more at seemingly random intervals.

The camera is a Dahua

Varifocal Turret IPC-T54IR-ZE-S3

FW :

V3.142.15OG003.0.R,Build Date: 2024-12-21

View attachment Frontblink.20250405_060000.mp4
 

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Last edited:
If you notice, there is a light flash from the light at the far garage just before those times and it appears that is changing the exposure of the camera due to the rapid change in available light.

That is why you don't see it during the day.

Might be a short in that garage light causing it to flicker intermediately.
 
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Thanks for the quick response!
I have a recording from last night and it does the same thing. The owner repaired the lights on the garage across the street yesterday afternoon.
 
Further investigation showed that with a color sub stream recording up until midnight, no blink.
Just after midnight the sub stream changed to B & W and I saw several blinks
I'm nearly certain this is a refurbished camera I got from Empiretech in the past 3 months, so it makes me wonder if it was originally returned for this issue...
 
wittaj said:
If you notice, there is a light flash from the light at the far garage just before those times and it appears that is changing the exposure of the camera due to the rapid change in available light.

That is why you don't see it during the day.

Might be a short in that garage light causing it to flicker intermediately.
Click to expand...
^^^^
This
 
If it is still happening and the neighbors light isn't wonky, then I would look at turning off smart IR if you have it on, and if not backing down the IR hotspot. And make sure WDR isn't on.

Further, you have exceeded many of the limits we suggest for settings. Gain and gamma over 60 can be problematic, along with NR over 50, and a shutter range of 18-33ms is too slow for freeze frame of a perp.

All of those higher numbers can also cause the exposure issue you are seeing.
 
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Thanks again for the replies.
WDR is now off. Smart IR was off.
I'll tinker with the camera settings (gamma, gain, & shutter, NR , etc) tonight.
Here's a portion of a video taken last night, after the garage light across the street had been fixed.
The first blink occurs at about 1:20:05. There is another about 10 minutes later. So in this particular video, the blink rate is reduced.

View attachment Frontblink2.20250407_010000.mp4
 
There is a lot of bright there and with that slow shutter range you gave it I think periodically the exposure is adjusting for that bright light.

Make the shutter fixed at 1/60 or 1/120 and drop those other parameters below 60 and I suspect it will go away.
 
NOW there's a bright lights on the garage across the street. The garage wasn't so bright when their lights were working before they started to die. They do have a motion sensor light (with camera?) in the middle of the garage.
The other source is a yard light on a 6 foot pole with a 17W LED curly off to the left of the image, just barely.
I forgot to add that the IR LED is set to 1. I'll adjust the settings after dark.
Thanks!
 
Walk outside and in pass the front of the camera. Go all the way past the visible view left to right crossing in front of it
Move fast, even run if possible.

It looks like the shutter is adjusting to some input. As crazy as it sounds, it reacts as soon as a bug flys close bottom left of screen
 
well crap... It's pretty dark at the moment and not about to get any darker.
I mentioned earlier that I turned WDR off for night view.
The blinking has stopped, but I'm not 100% sure if it was just the WDR or ?
For me, there is nothing worse than fixing something and then not knowing exactly what you did that fixed it! :(
I re-read the tuning suggestions that wittaj wrote a while ago and made some ( bunch of?) changes.
I have a reasonable image in the Main when recording and the sub is acceptable. There may be some more tweaking, but the image looks a lot better.

Thanks to all that gave suggestions!
 
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