Dahua IPC-HFW2831T-ZS image degradation (Synology surveillance station)

Hi,
I am having an issue with a IPC-HFW2831T-ZS which has me stumped.
The camera was purchased two weeks ago but only installed it today. I have two others of the same model that were bought at the same time but those do not present with the same problem.


The problem is that the image degrades (weird colouring, pixelation, timestamp 10-20 seconds behind the rest of the cameras) over a couple of minutes. It gets to be unwatchable and then suddenly it comes back to what it is supposed to be like. The cycle repeats itself all through the day. It doesn't seem to do it when it switches to BW. The problem is not just in live view, the degraded image is present in the recordings created by SurveillanceStation.


I have tried the following without success:
- Deleting the camera from Surveillance Station and configuring from scratch.
- Changing resolution to 1080p
- Changing FPS (tried all values from 5 to 25)
- Using different bitrate values.
- Using different iframe values.
- Enabling/disabling smartcodec
- Using different H264 profiles.
- Changing the cable.
- Factory resetting the camera
- Downgrading to a previous firmware (from Jan-19 to Oct-18)

If I use the browser to view the camera's image or if I use SmartPSS there is no problem. It seems to only happen with SurveillanceStation. I have another two cameras of the same model and have no problem with those (also setup on SurveillanceStation).

The only thing that I have found that is different is that the "bad' camera is always transmitting at 12,000+ bps regardless of what the bitratesettings say on the camera's setup page. It sometimes shoots up to 200,000+ but stays around 20,000 most of the time. The other two cameras do not exceed the limits set on their web pages.

I'm starting to think this might be a dud camera but would like to hear some opinions/suggestions before I try to return it.

Here are some screen captures. The image on the left is from SurveillanceStation and then on the right is form the browser (Firefox) or SmartPSS.

The image starts to look a bit grainy on Surveillance Station (left)


After a minute or two it is heavily artifacted and unwatchable

Then it snaps back to normal


You can see that the camera is not sticking to the max bitrate set in the config page. Even if CBR is selected the bitrate is always variable and over 12,000 kbps

Update:

I got in contact with the supplier who passed it onto Dahua. They asked a few questions but I haven't heard back from them in about two weeks.In the mean time I found the April'19 firmware (I had used the Jan 19 before) and installed it. It seems to have fixed the problem although the image skips a second or so every now and then. I haven't had time to review any of the videos but watching the live feed for 1-3 minutes at a time (what I can spare) shows no image degradation.

IF you are not using the substream turn it off. Also I would not use the water mark.

I would use a frame rate and Iframe value between 10 and 15. You are not shooting a Hollywood move.

SouthernYankee said:

IF you are not using the substream turn it off. Also I would not use the water mark.

I would use a frame rate and Iframe value between 10 and 15. You are not shooting a Hollywood move.

Click to expand...

I assume both suggestions in your first section is to save CPU cycles in the camera, but surely it must be able to handle that unless the firmware is broken?

Same with the frame rate, though it could very well remedy the problem if it’s the Synology hardware that can’t keep up with the image processing. That happened to me btw, basically because I was running Surveillance Station on too low end hardware. SS lost the camera connection as soon as I pushed the frame rate too high, but it could handle 20 FPS with a bunch of other things running on the Synology at the same time.

Sounds to me suspiciously like a bandwidth problem between camera and SS. Also, SY is right: Unless you're trying to capture flying wildlife in the yard, 26 FPS is way overkill. I keep mine set to 10 so recordings of events when I'm mobile don't take forever and a day. I'd use 15 if I could, just to smooth motion out a bit.

Dramus said:

Sounds to me suspiciously like a bandwidth problem between camera and SS. Also, SY is right: Unless you're trying to capture flying wildlife in the yard, 26 FPS is way overkill. I keep mine set to 10 so recordings of events when I'm mobile don't take forever and a day. I'd use 15 if I could, just to smooth motion out a bit.

Click to expand...

Why is it overkill? For bandwidth and storage reasons?

Though I don’t have suspicious people running about in my yard very often and thus haven’t tested in real life, I would assume that it would be easier to get
a good face/body id from a higher resolution, higher FPS stream than the lower quality equivalent (given proper light conditions etc). No?

wrong.

It is the amount of light per pixel the size of a pixel on the sensor that determines resolutions. Note the number of pixels. That Is why the 8MP cameras are very poor at night. And the 2 MP cameras with larger sensors work better at night. The Higher frame rate is just wasting space and band width, CPU time, electricity, heat... Bigger is not better, faster is not better, it is the balance of all functions.

SouthernYankee said:

wrong.

It is the amount of light per pixel the size of a pixel on the sensor that determines resolutions. Note the number of pixels. That Is why the 8MP cameras are very poor at night. And the 2 MP cameras with larger sensors work better at night. The Higher frame rate is just wasting space and band width, CPU time, electricity, heat... Bigger is not better, faster is not better, it is the balance of all functions.

Click to expand...

Right, that part I’ve understood, though I haven’t found my own optimal configuration yet. But even with a 2MP camera with larger sensors, why would more frames per seconds make matters worse? If the camera start dropping frames or degrades the image quality due to too high frame rate/resolution, then I would agree it’s a problem.

It doesn’t necessarily make things worse, but it also doesn’t usually make things any better.

If your camera is taking a crappy pic because the shutter speed is too slow or the camera is out of focus, whether you get 10 crappy pics a second (ie 10 FPS) or 26 crappy pics a second (ie 26 FPS), who cares? Every picture will be crappy. The issue is with the cameras exposure settings or focus.. taking more crappy pics a second (ie a faster FPS) isn’t going to fix that.

Same with good pics. Say the exposure and focus are spot on. At 10 FPS, you get 10 great pictures every second. At 26 FPS, you get 26 great pictures every second. A faster FPS doesn’t hurt, but taking more pics a second doesn’t make the picture quality any better.

Usually where a faster FPS helps is when recording fast moving things. If you have a camera recording a fast moving road, at 10 FPS a fast moving car many only be in just a few frames. Increasing the FPS would get more frames that had the car in it. But for surveillance around houses, most folks here find 10-15 FPS is more than enough.

When you start to add more cameras, the amount of extra work the additional FPS put on the recording device (NVR, Surveillance Station, Blue Iris, etc) can add up and impact the devices performance.

Thanks @aristobrat, I get it. Need to tweak those image settings of mine. Any day now, I’ve been saying for the past 9 months..