CPE 210 CCTV live feed issues
We have a CPE210 P2P bridge from a remote location with 5 Hikvision cameras, via a switcher to the TPLink P2P bridge, back to the Base station (150m away clear LoS) , which is then plugged in to the LAN network with the NVR on the LAN network.
When the cameras are set to High Res (2048 x 1536) the live feed 'stutters' whenever there is movement within the viewing area. As the movement increases there is a loss in feed, so we can lose 10secs of feed then it resumes, freezes again, jumps to 10 sec or so further on etc. This is reflected in the recording as well - so it is to do with the feed to the NVR.
According to the TPLink data summary the amount of data being sent is never more that 20Mbps - the CPE 210 advertises 300Mbps.
We have been playing with resolutions, turning off Motion detection etc, but ultimately I think that the CPE 210 setup should be more than capable ofdealing with the live feed from these cameras.
Can some one help me with this increasingly frustrating problem - TPLink support via email has not been very satisfactory
TIA
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Robotsystems wrote
According to the TPLink data summary the amount of data being sent is never more that 20Mbps - the CPE 210 advertises 300Mbps.
300 Mbps is the WiFi rate over a shared medium in half-duplex mode. Ethernet throughput will be lower due to the overhead in the WiFi protocol (~30% in 802.11n-only mode).
What's more, Ethernet is full-duplex, so don't expect a better goodput than ~90 Mbps full-duplex over a 210 Mbps half-duplex WiFi link under ideal conditions. In most populated areas you won't find such ideal conditions. If the 2.4 GHz band is overcrowded, throughput will decrease significantly.
For example, where I live we reach 95 Mbps goodput on 5 GHz over a distance of 538m, but only 3-5 Mbps if using the 2.4 GHz band on the very same link. There are just too many foreign APs eating up too much AirTime, so the CPE can only acquire a very small amount of AirTime to send data even over a 300 Mbps wireless link.
Note also that 300 Mbps WiFi rate requires a channel width of 40 MHz. 40 MHz means that your CPE needs to acquire 8 channels simultaneously out of the 11 (US) or 13 (rest of the world) channels available in the 2.4 GHz band.
But even if you live in a rural area, a CPE210 can not offer the bandwidth needed by 5 cams with 2048 x 1536 pixels resolution in High Quality with high motion activity - this would require ~108 Mbps Ethernet goodput for all 5 cams.
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Thanks for taking the time to reply
I think I understood the main gist of your advice - but I am definitely no expert!
So, the CPE P2P bridge is only being used for the 5 CCTV cameras. It obviously links to the Home LAN and there are other users on the LAN (domestic internet use) The router he has is a Netgear DGN2200 300M
The client has 5 cameras at the moment - he has seen the quality of the high res and, understandably, wants that, but also having the motion detection capability is also very desirable. He has already indicated that he will probably expand the system to the full NVR capability of 8 cameras.
Can you give me an idea of what I need to look for in a P2P so that we can give the client what he is after - given the situation where we are having to use the P2P to connect the remote cameras with the home where the NVR is.
Appreciate your time, thank you
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I would give CPE710 a try. This is a brand-new AC867 device which means it has a WiFi bandwidth of 867 Mbps at 5 GHz, that's nearly 3x the throughput of a CPE210/510 (which are N300 devices).
Two remarks:
- The CPE710 might not (yet) be available in every country.
- Antenna alignment is more difficult compared to CPE210/510, but needs to be done properly to reach max. WiFi throughput.
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@R1D2 Thanks for the info about the CPE710 - my client has a Netgear DGN2200 N300 router - which seems to only support 2.4GHz. Presumably the CPE710 would not be compatible and would not be supported on the Home LAN?
I understand from the Hikvision technical department that the each camera on the network requires:
2048x1536 at 20fps, on H.264 and bitrate at 4608 will give 4.5mbps
1920x1080 at 20fps, on H.264 and bitrate at 3072 will give 3.0mbps
There are 5 cameras so even at 2048 x 1536 resolution at 20fps the bandwidth requirement would only be 22.5Mbps - so I don't uynderstand your suggestion that they would need 109Mbps - what am I missing?
When we have been tryin to trouble shoot the issue we reduced the fps to 10 and the bitrate to 512kps at the 2048 x 1536 res - but we were still getting the 'stuttering'/freeze framing.
We do have a vertical difference of about 25m between the stations - no account was taken of this at original setup - the units gave 5 bar LED signal connection (out of 5) so we presumed that alignment was ok.
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as I wrote, throughput in the 2.4 GHz band can be significantly reduced if the area is overcrowded or if there are any other interferences.
Why don't you just check the throughput between CPEs with the built-in speed test? Then you would see what throughput you can achieve at your place. The LED bars of a CPE just shows the signal quality, but a good signal quality does say nothing about the actual WiFi rate.
Robotsystems wrote
I understand from the Hikvision technical department that the each camera on the network requires:
2048x1536 at 20fps, on H.264 and bitrate at 4608 will give 4.5mbps
1920x1080 at 20fps, on H.264 and bitrate at 3072 will give 3.0mbps
There are 5 cameras so even at 2048 x 1536 resolution at 20fps the bandwidth requirement would only be 22.5Mbps - so I don't uynderstand your suggestion that they would need 109Mbps - what am I missing?
According to the H.264 bandwidth calculator 2048x1536 requires much more bandwidth per camera depending on complexity, amount of motion and quality settings. See https://www.arxys.com/bandwidth-storage-calculator/
I'm out of the streaming business since long, so I don't know actual video codecs and bandwidth reuqirements, but why don't you just measure the actual required bandwidth per cam at a certain setting to get exact figures?
It seems that Hikvision uses H.264+, an optimized H.264.
Did you read their note »For static scenes with few moving objects, H.264+ can provide up to 75 percent savings.«?
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@R1D2 Thanks for the reply. I did ask the Hikvision support about the bandwidth requirements and that is what they told me.
I hope to do some speed tests on the system next week, I am no expert by any means and I just want to know more about what is going on and why, hence my questions.
Have a good weekend
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just disconnect the cams and start a speed test from the CPE's Tool menu. You can also check the actual WiFi rate of the link on the Status page, perform a frequency analysis and align the antennas if necessary. That's what the tools in the Tools menu are all about.
Have a nice weekend, too!
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