DS-2CD2686G2-IZS - 8MP varifocal - Bad 'Ghosting' video artefact

[wittaj]

Hi @dimammx
My experience and opinion of Dahua cams is not flattering - i have two that are gathering dust simply because they are not worth using..

What model numbers - every manufacturer makes cameras that they probably shouldn't sell...

 

[Mike A.]

How do you change it from 8MP to 5MP?
The pixel frame extents can be changed but that does not change the fact that it is a 8MP sensor.
Why would one even want to do that? - buy a ferrari and run it at 20mph
As weird of an idea it may be i have already tried that - set the frame size to 1920x1080 to see if it helps - unfortunately makes no difference (@wittaj also posted that it would not change anything)

You can't change the performance of the sensor itself but you can change the resolution/data rate that the camera is pushing out to VLC/OBS and whatever else you're using to view/record. wittaj's comment was related to the ghosting and overall low-light performance of the sensor, not the freezing. No, lowering the resolution won't improve that. But if you've already tried 1080 then you've done that. Did you still see the pausing/freezing?

The buffer size on OBS has been adjusted the same and far higher than the cam max bitrate. All connections to cam are Gigabit adapters and fiber so there is no expectation of a network lag issue.
The freezing can be seen directly on the cam web interface live view or VLC rtsp stream view without any interaction with OBS

That's more what I was trying to get to. As asked above, what are you using to view/record the stream? Have you tried some other? I have several older computers that will gag and skip/pause on a 4K stream in a similar way depending on whatever else is running. Along those same lines, I noticed that the pausing/freezing at about :16 in your last video seems to coincide with the display of "bush baby" at top right and at several other points when it pauses slightly. What are you running to do the ID? Maybe try disabling that as a test to see if you still get the freezing.

Could very well be the camera itself. Some just don't really perform up to spec when you start pushing them. The freezing you probably can solve in some way. The ghosting/blur will be harder given that you have some other image requirements as far as WDR and NR that affect that. For night, maybe try taking exposure up a step and WDR and NR down some and pushing gain up a little and see if that helps any.

 

[ABCcam]

You can't change the performance of the sensor itself but you can change the resolution/data rate that the camera is pushing out to VLC/OBS and whatever else you're using to view/record. wittaj's comment was related to the ghosting and overall low-light performance of the sensor, not the freezing. No, lowering the resolution won't improve that. But if you've already tried 1080 then you've done that. Did you still see the pausing/freezing?

Yes it was also present with 1080

That's more what I was trying to get to. As asked above, what are you using to view/record the stream? Have you tried some other? I have several older computers that will gag and skip/pause on a 4K stream in a similar way depending on whatever else is running. Along those same lines, I noticed that the pausing/freezing at about :16 in your last video seems to coincide with the display of "bush baby" at top right and at several other points when it pauses slightly. What are you running to do the ID? Maybe try disabling that as a test to see if you still get the freezing.

Dedicated AMD Ryzen server user for streaming. Tensor flow AI used for Bird & animal ID's. If this was affecting the image then it would freeze continuously in the day as the bird activity and consequent AI ID activity is very high.
The freezing can be seen from any other PC connected. It seems to be related to image consistency - more prevalent with low light / fast exposure.

Could very well be the camera itself. Some just don't really perform up to spec when you start pushing them. The freezing you probably can solve in some way. The ghosting/blur will be harder given that you have some other image requirements as far as WDR and NR that affect that. For night, maybe try taking exposure up a step and WDR and NR down some and pushing gain up a little and see if that helps any.

The freezing is though easy to remove - use 1/25 or lower exposure = 60 gain, no backlight, DNR 40 to remove flicker & grainy noise.
The challenge is the 'Ghosting swim'.

 

[ABCcam]

Thank you all for inputs.

Thanks to suggested settings and tweaking which works with what, we are now happy with the cam settings.

There still is a slight bit of 'ghosting'/ 'object image fluid swim', but it is not too bad - acceptable
This is definitely something which HIKvision needs to investigate.
It surely cannot be a cam processor limitation as it is not noticeable during the day on current settings and there is a lot more movement in the day.
Clearly visible at night on any objects that move.

The final trick was to use 2688x1520 instead of 3840x2160 on the cam. (thank you @tech_junkie )


Warning - unapologetic plug
- you are welcome to view our live stream on YouTube and tell us what you think

 

[tech_junkie]

Its the best you are going to do on 50Hz powered or PAL Video configured NVR system is 25 FPS.
The best the camera can do is 30fps, but the NVR must be set up for NTSC video out for 60Hz 30FPS.
If you use the computer monitor ports instead of the RCA video out, it doesn't make a difference what video system is set. So putting it into NTSC will let you go into a higher frame rate.
Iframe rate is still a little low, I would try 100. The number represents how many duplicate video frames it receives before discarding video frames till the video frame data changes.
When the clock time doesn't display smoothly in seconds, I first look at this setting. Especially when its looking at something that doesn't change very often.