Calculating Bandwidth

[mlapaglia]

I'm using the Bandwidth Calculator tool to see if a custom made setup would use too much bandwidth.

Does the bandwidth the NVR shows is available the max amount it can take from the cameras at once? I added 2 1080p cameras and the reported bandwidth was over 50 Mbps. Does that mean a NVR like http://www.nellyssecurity.com/recorders/nvrs/8-channel/hikvision-7608ni-se2-8p-8-channel-poe-plug-n-play-hi-def-nvr-recorder.html wouldn't work? This doesn't seem right because some of the complete kits use the same NVR with 8 cameras.

 

[bp2008]

Forget about bandwidth calculators. Many are built specifically for one company's equipment and ideas and it won't be clear what is actually going on.

Instead, multiply your number of cameras by the bit rate you will be running them at. You might run a 1080p camera anywhere from 4 to 12 Mbps, maybe as high as 16 Mbps if the camera supports it. 8 Mbps is a decent compromise. So pretend you have 2 cameras at 8 Mbps each, 2 times 8 is 16, so 16 Mbps. It is as simple as that.

If you want to find out something like the hard drive space required for storing video, then go to google and you can multiply a bit rate and a unit of time. search "16 Mbps * 7 days" or "16 Mbps * 1 hour". Or if you want to find out how much video you can store in 2.5 TB of space, you can do a division: "2.5 TB / 16 Mbps".

 

[bp2008]

Does the bandwidth the NVR shows is available the max amount it can take from the cameras at once?

I believe so, yes, but I always use Blue Iris on a PC, where there is no such bandwidth limit. If the NVR says "50 Mbps throughput" then you should make sure your combined bit rates from all connected cameras does not exceed 50 Mbps.

 

[mlapaglia]

If I'm thinking of using 8 of the 2042wd-i then, I would need a better NVR like the EYEsurv ESDV-NVR4K-8, which can do 250Mbps? http://www.nellyssecurity.com/recorders/nvrs/8-channel/eyesurv-esdv-nvr4k-8-8-channel-4k-network-video-recorder.html

I assume I would want to run the cameras at their highest bitrate to get the best picture? I have plenty of 2-4tb hard drives laying around I can throw in it since the storage demands would be higher.

 

[bp2008]

Correct me if I am wrong but the 256 Mbps NVR costs the same as the 50 Mbps NVR. Seems like a much better choice.

If you are going to record using motion detection, you can certainly get away with running the highest bit rate. That is what I recommend. Some people like continuous recording though, and when you record continuously, you fill hard drives FAST. If you put two of your 4 TB drives in, you should have just over 7 TB of usable space. 8 cams at 16 Mbps each (I think that might be the max encoding bit rate for Hik 4MP cams?) is 128 Mbps. 7 TB / 128 Mbps is 5.06 days if you have all 8 cams recording continuously. You could stretch that out over months or years if recording only on motion.

 

[mlapaglia]

Correct, I'm only thinking of recording motion. The cameras are constantly sending video though, so that would requires (16mbps * number of cameras) constantly right?

The only reason I'm asking is because Nelly's offers a package like this http://www.nellyssecurity.com/custom-systems-packages/hi-def-ip-security-camera-systems/8-camera-systems/complete-8-channel-hikvision-4mp-bullet-dome-ip-surveillance-system.html

Do the cameras just not run at their max bitrate? Seems like a waste of a camera if you aren't using all it has to offer?

 

[bp2008]

The NVR does need to be able to handle all the streams at the same time even if doing motion recording, yes. I don't know why they would bundle an NVR with such weak specs with that many 4MP cameras. I guess they must expect you to run them at a lower bit rate. It isn't exactly a waste of a camera to run at less than max bit rate. You might not even be able to tell the difference between 16 Mbps and 8 Mbps even if you compare them side by side. The law of diminishing returns applies here. The higher your bit rates get, the less benefit you get from increasing it further.

 

[nayr]

Ive got 7 cameras right now, mixed 1080p-4MP with high quality everywhere and my NVR is reporting I am using well over 50Mbps... closer to 100Mbps.

so yeah, get a 16ch with 200Mbps throughput, minimum.

 

[mlapaglia]

Which NVR are you using?

Another thing I thought of, is the 50Mbps limit inclusive of everything (network, cpu, and disk)

Does the NVR have no problem streaming 8 feeds at 16Mbps each, but if it were to record all those the disk wouldn't be fast enough, this the 50Mbps "bandwidth"?

 

[nayr]

Dahua 4216-4k

My WD Purples have no problem writing ~160MB/s which is 1280Mbps, so no.. your HDD's are way faster than your camera feeds.

Thats likely a maximum bus speed, so it includes all throughput.. streaming/recording/downloading/etc.

My cameras are all 8-10Mbps, I dont have any cranked up to 16Mbps.. even 4MP

 

[Shengli]

Isn't fps also a factor in the calculation? and what video compression you use, H.264 / H.265

The reason i ask is because I was looking at the 4216 paired with 6 x 2560x1440p @ 25fps cameras. According to Dahua the camera video max bitrate is 11.25

So that would be 6 x 11.25 = around 67Mbps? could this be true?

 

[nayr]

nerp, more fps = higher bitrate.. if you just bump the FPS and keep the bitrate unchanged, you actually loose quality.

for example, my alpr cam is set to 5fps, and the highest bitrate I can set is 5120Kb/s, if I change that to 25fps, now my max bitrate is 16384Kb/s

so for calculating storage space, bitrate's king.. fps means nothing.

your math is solid.

 

[Shengli]

I just thought that 6 x 2k cameras @ 25fps would eat up a lot more bandwidth. Which is why i was initially looking at the 5216-4ks2 (quadcore) 320Mbps model. But with what i learned from you, that would be crazy overkill

And i was even thinking of using H.265 which would decrease the bandwidth even more.

 

[nayr]

h265 does cut bandwidth down even more.. for the same quality.

my 4216-4k supposedly does h265, I dont have any cameras to test it tho.. I hope it works fine when I finally do get some h265 cameras.

 

[Shengli]

I was told by a AliExpress seller that the 4216-4K is mixed codec. Meaning it could only do 8 cams @ H.264 and 8 cams on H.265 and not all cams running H.265. But their replies are rather cryptic to understand, so i could be mistaken.

 

[nayr]

that could very well be true, h265 does require more processing.. I did hear reports that a true 4k camera struggled @ max bitrate but I never got clarification if it was h264 or h265.

Its a lil early in the game to setup an all-h265 system, you'd really be limiting your choices.. I suspect one day the'll be all we can buy but thats still a ways out it seems.

 

[Shengli]

Yeah i discovered that as well. The camera will probably be the DH-IPC-HDW4431C-A But i am still very much undecided with the NVR.

 

[Shengli]

Did you have the P (onboard poe) version of the Nvr? if so how load is it. Since i have heard other people describing them as near vacuum cleaner noise (60-70db+)

 

[nayr]

no, mine is not PoE.. i dont think its very loud, but I have a server room full of louder equipment than this.

 

[Shengli]

Okay thank you. Btw i just noticed that the 4216 and 4216-4k only have 1 lan port. I this the same with yours?