D-Link Forums

The Graveyard - Products No Longer Supported => IP Cameras => DCS-932L => Topic started by: wjburl on April 10, 2015, 08:02:58 AM

Title: Video "glitch" Causes False Positives on Motion Detection
Post by: wjburl on April 10, 2015, 08:02:58 AM
I have five D-Link cameras.  Three are DCS-932L, one is DCS-932LB1 and one is a DCS-930L.  I’m have a problem with one DCS-932L and the DCS-932LB1.  During the night I’m getting false positives on motion detection.  When I look at a recording, I see a “glitch” in the video.  Yesterday, I installed the latest version of the firmware, but the problem occurred again last night. I isolated a frame and have a link to both the frame and video on  Flikr.  The links are views from the camera located in a detached garage. It is connected to my  LAN via a D-Link Powerline AV adapter.  I only have a problem during the night.   The DCS-932LB1 is connected directly via an Ethernet cable. I have no problem with the other cameras.

http://bit.ly/1MTnXE3
http://bit.ly/1MTpkTf
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: JavaLawyer on April 22, 2015, 06:40:57 AM
If I had to guess I would say the camera is picking up environmental interference. The best way to rule out the camera as the cause is to swap the position of the DCS-932L that's working with one that's experiencing the issue.  If the cause is environmental, the problematic DCS-932L should work perfectly well in the location of the working camera, and the working camera should have issues in the location of the problematic camera.
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: kyis on February 19, 2016, 06:59:40 AM
I'm having the same issue but I believe it's caused by the MJPEG stream being malformed as it looks more like data corruption on one frame periodically than interferences. It occurs on 2 of my DCS-932L(B) not on my rev A, all at the latest fw. It's worth mentioning that image quality remains flawless apart from those bad frames.

I'm wondering if it has to do with a memory problem, I use 20fps at 640*480 with best image quality.
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: FurryNutz on February 19, 2016, 07:08:13 AM
Link>Welcome! (http://forums.dlink.com/index.php?topic=48135.0)


What Mfr and model is the main host router?
What wireless modes are you using?
What is the distance between the Camera and the main host router?
Try using a lower video quality as a test to see if the problem still happens?

I'm having the same issue but I believe it's caused by the MJPEG stream being malformed as it looks more like data corruption on one frame periodically than interferences. It occurs on 2 of my DCS-932L(B) not on my rev A, all at the latest fw. It's worth mentioning that image quality remains flawless apart from those bad frames.

I'm wondering if it has to do with a memory problem, I use 20fps at 640*480 with best image quality.
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: RYAT3 on February 19, 2016, 09:31:02 AM
I saw this once for sure on my dcs2132l rev a that's been in service for a few years.
It was an ftp video clips, 13 seconds, 15fps,640x480. It might have happened previously but nothing as bad as what you're experiencing.  Must be something bad internally or defect in the model.
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: kyis on February 19, 2016, 11:55:28 AM
Thanks for your help.
I'm located in Europe (I hope that's not a problem, this forum was the only one containing the same problem I was experiencing)

The relevant part of the network :
(http://gdurl.com/AHoU)

Camera 1 :
   HW rev B1
   FW version 2.12.01 (2015-10-01)
   In line of sight of wireless AP
Camera 2 :
   HW rev B1
   FW version 2.12.01 (2015-10-01)
   In line of sight of wireless router
Camera 3 :
   HW rev A (A2 I believe, I'll edit when I get a chance to look at the sticker)
   FW version 1.12.02 (2015-10-06)
   A wall away from wifi extender
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: FurryNutz on February 19, 2016, 12:37:14 PM
I'd try this, to help narrow it down, Turn off ALL cameras and additional wireless APs.
Test 1 camera and connect the 1 camera directly to the main host router.
Test with  Max and Minimum quality settings first. See if you notice the same issue. I would do this for each camera one at a time.

You have some additional wireless in your building and need to figure out if this is being caused by interferences or actual FW issue.
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: kyis on February 19, 2016, 05:33:31 PM
Thanks for your help.
I agree and to narrow it down even more I wired one directly to the switch nearest the server.

Some examples of bad frames (Cam1_3.jpg is a normal frame for comparison):
https://goo.gl/hyk9uk (https://goo.gl/hyk9uk)

On Camera 2 I noticed that the problem occurs only in night mode and then I noticed it going away after a while, when we turn off the light string. The light string doesn't have a switching power supply and it doesn't blink so I doubt it's generating too much noise.
On the images the glitch always occurs over the length of the lights, maybe those bright white dots are making a bug surface somewhere...
That's the one I wired to the switch before noticing the weird places the glitch was occurring.

On Camera 1 the glitch occurs both in day and night mode but at different places depending on lighting conditions, still on bright well defined spots.
I lowered the angle of this camera slightly, if the glitch moves with the content of the image, external interference can be ruled out entirely.

You'll notice that on the OP's images the glitch also occurs on a bright blob, I think that narrows it down a notch. ^^

Time to wait and see ^^

Edit1:
I added 2 images "Cam2_moved_x.jpg" showing the glitch tracking the same spot it did before, now I'm lowering the quality to see if it changes anything.
Edit2:
After setting quality from very high to medium for an afternoon, no false positive.
I'm now trying very high quality but lowering the fps from 20 to 15.
Edit3:
15 fps still glitching, lowering to 7.

Final Edit:
After much testing on both cameras, here are my results:
-It's corruption and it occurs around bright parts of the image. (Changing the angle of the camera and maintaining lighting condition makes the error move with the part of the image causing it.)
-It occurs at any framerate, and any quality except medium.

-I tested:
-All day/night modes
-All framerates including auto
-All quality settings
-Wireless
-Wired
-On 2 cameras
Title: Re: Video "glitch" Causes False Positives on Motion Detection
Post by: wrecche on June 04, 2019, 04:13:56 AM
Sad that no one did help.. I'm getting the exact same issue..

And there is no other place to look for any help.

dcs-4701e, 3 years later.