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IP cameras dropping signal strength


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9 replies to this topic

#1 TsVk!

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Posted 12 July 2015 - 11:34 PM

Hi,

I have several DCS3716 located around. Some of these are used for a live view of mechanical processes.

I am connecting these cameras on a Debian host running VLC on an RTP protocol. The local switch is a HP J9562A.

There are frequent and recurring drop outs from the cameras that are causing freeze screens or black screens on the output client. VLC is set to reconnect a dropped connection and performs fine in test situations, but not in the real world. Having frequent complaints about having to restart VLC to resume the feed.

Here's a network monitor graph of what's happening

over 2 days
fbc30p.jpg

and you can see more clearly over 2 hours an individual incident
1625hj4.jpg

As you can see the network isn't dropping completely (which would actually be preferable), but just enough to ruin the connection with the viewer.

I have 4 cameras all behaving the same as this

Any suggestions on the cause of this please?



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#2 Chris Cosgrove

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Posted 13 July 2015 - 06:33 PM

Just a thought, but what struck me, particularly about the first graph,is the almost fixed regularity with which these drop-outs are happening. It seems to be almost every two hours on the dot. Have you some process running that is causing a voltage drop or spike at this sort of interval ?

 

I am thinking of some heavy power using equipment switching on or off at two hour intervals, possibly on the same power circuit as the switch you are using.

 

Chris Cosgrove



#3 TsVk!

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Posted 13 July 2015 - 06:49 PM

I thought that initially too. But the power is POE coming from the switch. There are 4 cameras with this happening regularly but all at different times, all connected to the same switch.

 

I would also expect a power outage/fluctuation to crash the cameras rather than just the monitoring application



#4 Chris Cosgrove

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Posted 14 July 2015 - 06:41 PM

As I said, it was just a thought. I too suffer internet disconnects but they are fairly random. I might go two or three days without a problem then get two or three drop outs in one day.

 

Obviously you have a much better grip on what is happening in your work place than I do, but it is that very regular fault pattern that catches the eye. I still think you should look for something happening every two hours. I can't think of anything more concrete.

 

Chris Cosgrove



#5 TsVk!

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Posted 14 July 2015 - 06:49 PM

I just realised this morning that part of my code on the startup script that I wrote was not put into the associated /.kde/Autostart file.

 

There was no restart & loop playback on signal drop-out implemented. :whistle:

 

I still think the problem is VLC or DLink firmware related, but as long as the workaround fixes it I'm not too fussed if the image drops out for a second every now and then.



#6 TsVk!

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Posted 14 July 2015 - 07:23 PM

Just for reference... (it's good to post the solutions too)

 

To make 3 cameras go to 3 different VLC instances on KDE login, each instance to fullscreen on a specific monitor...  and restart on network loss.

#!/bin/bash
vlc rtsp://admin:@blrcam3:554/live1.sdp --loop -R -f --qt-fullscreen-screennumber=0 &
vlc rtsp://admin:@blrcam1:554/live1.sdp --loop -R -f --qt-fullscreen-screennumber=1 &
vlc rtsp://admin:@blrcam2:554/live1.sdp --loop -R -f --qt-fullscreen-screennumber=2 &

simple, but does the job.



#7 Chris Cosgrove

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Posted 15 July 2015 - 06:24 PM

You speak 'Terminalese' much better than I do - I'm still trying to find the time to fumble my way into Linux - but as you say, at least you have a functioning work-around. If you ever do find a reason for the startling regularity of the drop outs I would love to know.

 

Chris Cosgrove



#8 TsVk!

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Posted 15 July 2015 - 06:31 PM

Sure, I will do.

 

If you happen to come across it somewhere please let me know too.

 

TsVk!



#9 YeahBleeping

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Posted 16 July 2015 - 11:01 AM

 - If all cameras are dropping at RANDOM 2 hr time intervals (each one 2 hrs) then its not vLc or the server or the router its the camera.  If it was the software or hardware then they would all drop at the same time (right?)

 

So I did see that there were firmware updates for this camera on DLinks site are they updated?

 

The below I found in the manual: I wonder if you change the filesize of the volume video file does this change the time of the dropout interval?  ie: Losing sync while the camera is waiting for read write? 

 

Just some thoughts- Since it appears  you have nailed down when these happen can you prepare to watch the back of the camera and see if your net LED connection drops from the camera? - or switch.

 

cycling
.
recording
 source of the stream.
Scheduling the recording entry.
Configuring the setting for the recording.
Select the folder where the recording file will be stored.
Please input a HDD volume between 1MB and 200GB for recording space. The recording data will replace the oldest record
when the total recording size exceeds this value. For example, if each recording file is 6MB, and the total cyclic recording
size is 600MB, then the camera will record 100 files in the specified location (folder) and then will delete the oldest file and
create new file for cyclic recording.
Please note that if the free HDD space is not enough, the recording will stop. Before you set up this option please make sure
your HDD has enough space, and it is better to not save other files in the same folder as recording files.
File size for each recording file. You may input the value in the range of 200-5000.

Edited by YeahBleeping, 16 July 2015 - 11:05 AM.


#10 TsVk!

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Posted 16 July 2015 - 04:14 PM

 - If all cameras are dropping at RANDOM 2 hr time intervals (each one 2 hrs) then its not vLc or the server or the router its the camera.  If it was the software or hardware then they would all drop at the same time (right?)

Not necessarily. It could be the age of the process that effects the signal. It could be a bug in the script of the codec that decodes the protocol... it could be VLC itself. There's no reason to assume it's the cameras or the switch as each camera runs on its own instance of VLC. If they were all running on the same instance of VLC this would be a logical deduction.

 

 

So I did see that there were firmware updates for this camera on DLinks site are they updated?

Yes

 

The below I found in the manual: I wonder if you change the filesize of the volume video file does this change the time of the dropout interval?  ie: Losing sync while the camera is waiting for read write? 

 RTSP protocol, no data is saved or written.

 

 

Just some thoughts- Since it appears  you have nailed down when these happen can you prepare to watch the back of the camera and see if your net LED connection drops from the camera? - or switch.

I can monitor the switch and also the nic in the host the same way as I monitor the camera. I don't think watching lights is a good way to diagnose networking issues.

 

Thanks for lending your mind to this issue anyway.






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