VIOFO A119 V3

probably could be resolved, as you say though it's likely something that they would never give any consideration, just something we need to live with, for now at least, unless there's some other change in technology

I know that PWM is one the methods for adjusting brightness in LED emitter output so I imagine they choose a frequency that optimizes efficiency. On the other hand, as far as I know they can adjust the frequency to avoid the problems we see with flicker in our videos. LED lighting has become popular for professional photography and video so there must be a way to deal with it.
 
I know that PWM is one the methods for adjusting brightness in LED emitter output so I imagine they choose a frequency that optimizes efficiency. On the other hand, as far as I know they can adjust the frequency to avoid the problems we see with flicker in our videos. LED lighting has become popular for photography and video so there must be a way to deal with it.
yeah I've seen those LED based lights that people use for shooting video so there must be some solution, how that would translate to what would be needed for headlights though I have no idea, the harder part would be getting vehicle manufactures to think that it was needed, perhaps when it impacts their own camera systems it might be come a consideration, at the moment that's primarily safety systems like ADAS so maybe that's no issue for that function, might not happen until they start adding recording systems to vehicles as a regular thing, still a way off before that happens I would think, even if they do it won't fix the problem for everything that has already been made
 
yeah I've seen those LED based lights that people use for shooting video so there must be some solution, how that would translate to what would be needed for headlights though I have no idea, the harder part would be getting vehicle manufactures to think that it was needed, perhaps when it impacts their own camera systems it might be come a consideration, at the moment that's primarily safety systems like ADAS so maybe that's no issue for that function, might not happen until they start adding recording systems to vehicles as a regular thing, still a way off before that happens I would think, even if they do it won't fix the problem for everything that has already been made
Photography lights don't use PWM, their LEDs are on full time, normally efficiency and heating are not the primary concern.

The vehicle manufacturers own camera systems can be synchronised with their LED frequency to avoid problems.
 
Photography lights don't use PWM, their LEDs are on full time, normally efficiency and heating are not the primary concern.
That's not quite true. Photographic lighting LEDs may appear to be on full time but they often use very high PWM frequencies between 15khz and 25khz. As I understand things they also can use other types of voltage regulation techniques other than PWM that minimize but does not completely eliminate flickering. And heating in photographic lighting is definitely a concern. Efficiency is also a concern for mobile applications.
 
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That's not quite true. Photographic lighting LEDs may appear to be on full time but they often use very high PWM frequencies between 15khz and 25khz. As I understand things they also can use other types of voltage regulation techniques other than PWM that minimize but does not completely eliminate flickering. And heating in photographic lighting is definitely a concern. Efficiency is also a concern for mobile applications.
2160 (vertical resolution) * 60 (fps) = 129600 (lines per second on the rolling shutter) / 15khz = 8.64 = rolling banding!

I could understand the switching power supply operating at that speed and then smoothed by capacitor to control voltage, but not PWM to switch the LEDs to control illumination.

Might not be noticable for for a still photo, but not good for a video lamp.
 
2160 (vertical resolution) * 60 (fps) = 129600 (lines per second on the rolling shutter) / 15khz = 8.64 = rolling banding!

I could understand the switching power supply operating at that speed and then smoothed by capacitor to control voltage, but not PWM to switch the LEDs to control illumination.

Might not be noticable for for a still photo, but not good for a video lamp.

It's after 2:45 AM your time Nigel and you've been logged on and posting to DCT posting repeatedly all day since this morning, as you do most everyday. Try to get a grip, and get some rest now. It's time to go to bed. Tomorrow's another day.
 
Many years ago I had a chance meeting and discussion with an Osram LED technician who matched customer's needs with their products and designed the installs. He told me they were beginning to use lo-hi switching instead of on-off switching which helped with both LED service life and the visible PWM issues, a rather new concept at the time. Perhaps those photography lights use that as well as high-frequency switching? Anyway I think it would be good for some standards to be set regards PWM frequencies used in general public applications. I'm not terribly sensitive to that but the older Cadillac cars taillights hurt my eyes to be driving behind them due to low-frequency PWM rates and they were also known to set off seizures in some people with epilepsy o_O I'm glad they soon went to faster rates, the newer cars don't bother me but I still encounter an old one now and then and my eyes feel like someone is standing on them until I put a hundred meters or more between us :eek:

As to PWM and cams, it could be an issue when both PWM frequency and FPS 'shutter speed' coincide in a way as to cause a regular pattern to develop, but that would be more luck than anything as neither of these have precise speeds or frequencies, and many PWM frequencies are used so it would be only with that one cam and that one type of light, and maybe not every example of them since they all vary slightly. How this would cause banding (or if it could cause banding) is beyond me, I just understand that there could be an adverse relationship going on here. Something similar could happen with EMI in a specific car with a specific cam which could be determined by using the cam in another different car to see if results varied.

Definitely odd that it began at a FW change- has this been the pattern for all the other V3 cams with similar banding reported? If so then something in that FW change which hasn't changed since would have to be the culprit; a change-log might help understand what that might be and whether it could be altered to fix the issue.

Phil
 
So reading the latest posts aimed at LED car lights........

Can anyone with the flickering problem go out and test, in darkness or a suitable dimly lit area, LED's on and off to prove that the cam is indeed reacting to LED car lights.

My car has normal halogen so just maybe that's why I don't have the issue ?
 
Can anyone with the flickering problem go out and test, in darkness or a suitable dimly lit area, LED's on and off to prove that the cam is indeed reacting to LED car lights.
it's a possibility not a certainty, quick test would work out if it's part of the problem or not
 
So reading the latest posts aimed at LED car lights........

Can anyone with the flickering problem go out and test, in darkness or a suitable dimly lit area, LED's on and off to prove that the cam is indeed reacting to LED car lights.

My car has normal halogen so just maybe that's why I don't have the issue ?

It is very common to see flickering LED taillights, brake lights, stops lights and road signage in our dash cam videos. Haven't you noticed this now and again?
 
3DNR can also had some adverse effects on low light footage i read.
 
It is very common to see flickering LED taillights, brake lights, stops lights and road signage in our dash cam videos. Haven't you noticed this now and again?
I'm not referring to flickering LED tail lights but the flashing banding that I thought was the latest theme was being posted about ?
 
I'm not referring to flickering LED tail lights but the flashing banding that I thought was the latest theme was being posted about ?
when you see flickering tail lights or similar they have little effect on the video and just the light themselves flicker, when the LED headlights of the vehicle are the dominant light source in the scene though there's the possibility that it may have a different effect on the scene overall, something worth checking at least
 
I'm not referring to flickering LED tail lights but the flashing banding that I thought was the latest theme was being posted about ?

Sorry, I misunderstood your post. Perhaps it was because we've previously discussed LEDs and PWM as the possible culprit for the banding issue some eight months ago. In fact, I'm the one who first proposed the "LED theory" in this thread back in July in THIS post.

Eventually, my theory proved wrong and soon I too discovered that I was experiencing low light banding even though there was no LED lighting anywhere in the vicinity. I don't recall if we discussed LED headlights at that time but I don't believe they have anything to do with the problem. There is some other issue causing this.

Personally, I've found that setting the camera to 30 fps rather than 60 fps and not using the HDR setting improved the banding issue dramatically but didn't eliminate it completely. The most recent firmware update made no difference.
 
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It would be funny if OP could drive to a place at night where he have the issue, then stop and turn his headlights off and see if the issue are still there.

IMO from what i saw in the pictures not much to worry about.
 
Don't want to start a new topic while I do not expect much interest, but if there are any Mapillary / Openstreetcam enthusiasts out here, you may be interested in checking out this thread.
If you are interested in a simple gpsloc data extraction from A119 V3 - check this post
 
From what I notice the problem appears only at 60 fps, a setting at least strange for low light conditions. I don't have the slightest problem at 30 fps.
 
IMO from what i saw in the pictures not much to worry about.
Are you beta tester, too? Probably, yes. Otherwise I don't understand what does this zeal mean, why you want to minimize and deny a real phenomenon. If you don't see him or don't have him, that doesn't mean he doesn't exist.

I too discovered that I was experiencing low light banding even though there was no LED lighting anywhere in the vicinity. I don't recall if we discussed LED headlights at that time but I don't believe they have anything to do with the problem. There is some other issue causing this.

Personally, I've found that setting the camera to 30 fps rather than 60 fps and not using the HDR setting improved the banding issue dramatically but didn't eliminate it completely. The most recent firmware update made no difference.

Finally an intelligent post.
Indeed, you've right, 30fps atenuate the phenomenon, but doesn't eliminate it.
 
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Finally an intelligent post.
Indeed, you've right, 30fps atenuate the phenomenon, but doesn't eliminate it.

Only because he agrees with you.

My A119 V3, running at 60fps, has never seen any banding so there must be some common denominator and not a blanket issue that you keep posting.

Please accept that it's not all A119 V3 setups that have this issue.
 
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