What is Max Input/Record?

[Jayordon]

I am looking into Dahua NVR's and from what I can tell, the biggest different between the NVR5000 series and NVR4000 series is a spec that says "Max Input/Record". What does this mean? I tried to read up on it, but there just wasn't much information. From my understanding, it refers to the input bandwidth. So in the 5000 series, they get 320Mbps. The bandwidth appears to be the same regardless of how many channels. So does that mean that a 32 channel NVR could potentially not be able to records 32 cameras? Or do the 8 channels just have way more bandwidth than necessary?

Could I put 16x8MP cameras on an NVR recording @ 30fps? Or is that too much for an NVR to handle? What about 16x4MP cameras?

 

[SouthernYankee]

NO... not even close

looking at the Dahua NVR5832 specs 4 cameras at 8 MP at 30 FPS or 16 cameras at 1080P at 30 FPS.

The current goto settings for ip surveillance, are 4MP cameras at 15 FPS. Even at that level that NVR will not support 16 cameras at normal operations, unless the quality is set vey low.

The Mb/s depends on the quality of the video, the complexity of the picture, the motion, compression, Iframe value, bit rate type.......

Bandwidth calculator | CCTV Calculator

CCTV Calculator is a tool designated for camera system basic parameters determination and testing. It enables easy calculation of an appropriate lens focal length, camera viewing angle, IP camera bandwith, storage capacity for records archiving and of other camera system parameters.

www.cctvcalculator.net

 

[Jayordon]

I thought the 4 cameras at 8MP @30 or 16 1080p @30 was the output rating, not the input. Is that not the case?

The calculator you linked indicates that 16 8MP cameras @30fps using .265 uses less than 300Mbps

 

[SouthernYankee]

That is just a general calculator. You are assuming that all you are doing is recording, absolutely no process. You are also assuming that the H.265 compression is real good, which is normally not the case.

More megapixel is not necessarily better.
Camera Sensor size, bigger is general better. 1/1.8 is bigger than 1/3
Camera lens size, a bigger number give more range but less field of view


Cameras to look at
IPC-T5442TM-AS-LED . Review IPC-T5442TM-AS-LED (Full Color, Starlight+) - 4MP starlight
.................... Dahua IPC-T5442TM-AS-LED review
IPC-T5442TM-AS ..... Review-OEM 4mp AI Cam IPC-T5442TM-AS Starlight+ - 4MP starlight+
IPC-HDW5442t-ZE .... Dahua IPC-HDW5442T-ZE 4MP Varifocal Turret - Night Perfomance testing -- variable focus 2.7 mm-12mm 4 MP Starlight
IPC-B5442E-ZE ...... Review - OEM IPC-B5442E-ZE 4MP AI Varifocal Bullet Camera With Starlight+ -- variable 2.7mm-12mm bullet
IPC-B5442E-Z4E .... bullet 8mm-32mm variable focus zoom 4MP
IPC-HFW7442H-Z ..... Review - Dahua IPC-HFW7442H-Z 4MP Ultra AI Varifocal Bullet Camera -- 4 MP variable focus AI


If this is for a business than go with the NVR. If this is for home use Look at Blue Iris

 

[Jayordon]

That is just a general calculator. You are assuming that all you are doing is recording, absolutely no process. You are also assuming that the H.265 compression is real good, which is normally not the case.

More megapixel is not necessarily better.
Camera Sensor size, bigger is general better. 1/18 is bigger than 1/3
Camera lens size, a bigger number give more range but less field of view


Cameras to look at
IPC-T5442TM-AS-LED . Review IPC-T5442TM-AS-LED (Full Color, Starlight+) - 4MP starlight
.................... Dahua IPC-T5442TM-AS-LED review
IPC-T5442TM-AS ..... Review-OEM 4mp AI Cam IPC-T5442TM-AS Starlight+ - 4MP starlight+
IPC-HDW5442t-ZE .... Dahua IPC-HDW5442T-ZE 4MP Varifocal Turret - Night Perfomance testing -- variable focus 2.7 mm-12mm 4 MP Starlight
IPC-B5442E-ZE ...... Review - OEM IPC-B5442E-ZE 4MP AI Varifocal Bullet Camera With Starlight+ -- variable 2.7mm-12mm bullet
IPC-B5442E-Z4E .... bullet 8mm-32mm variable focus zoom 4MP
IPC-HFW7442H-Z ..... Review - Dahua IPC-HFW7442H-Z 4MP Ultra AI Varifocal Bullet Camera -- 4 MP variable focus AI


If this is for a business than go with the NVR. If this is for home use Look at Blue Iris

Lol, I never said more MP is better. I'm just trying to get an idea of the capabilities of these NVR's. I've used Lorex NVR's before and they can support 16 8MP cameras at 30fps so it's just confusing to me. It also seems weird that the bandwidth wouldn't scale up with higher channel NVR's.

 

[SouthernYankee]

Lorax is Dahua. So if that work for you this will work for you.

 

[wittaj]

Lorex will not show 16 8MP cams at 30FPS either...

Here is what there $1,000 dollar NVR and it states:

Live Display Speed (Max) Up to 4ch 4K@30fps

Simultaneous Playback 4ch@4K 30fps

32-channel 4K Ultra HD Network Video Recorder

A 4K (8 megapixel) NVR with Lorex Cloud remote connectivity. Supports 32 cameras.

www.lorextechnology.com

As @SouthernYankee mentions, MP and FPS is only part of the equation. The specs are silent as to what bitrate that is at that is can support 16 8MP cams at 30FPS....

The better NVRs are capable of Network Bit Rate 320Mbps total, and you are correct, that is the same whether it is a 16 or 32 camera NVR.

So one needs to do the math based on their resolutions, FPS, bitrate, compression, etc. and determine if the NVR is capable for it.

My neighbor bought the cheaper end Lorex unit from Costco that capped out at 80Mbps. Even though his cameras are capable of 60FPS and 20,480 bitrate, the NVR would drop it to 30FPS and 4092 bitrate so that it could handle all his cameras. And the picture quality of 8MP cams suffer at 4092 bitrate.

Bitrate is an important factor of picture quality. Do you want an NVR dropping bitrate to push 16 8MP cams at 30FPS?

Movies are shot at 24 FPS, so I doubt you need higher to watch on your mobile device and tablet LOL. Most of us find that 15FPS is more than enough. Actually you can go to about 10FPS before it starts to get noticeable. Shutter speed to get a clean image is more important than FPS. Some of my cams are at 8FPS. Police only care about the ability to get a clean image, not see a smooth video of the perp running.

No police officer ever has said "wow that person really is running smooth in your video". They want the ability to freeze frame and get a clean image. So be it if the video is a little choppy....and at 10-15FPS it won't be appreciable. My other neighbor runs his at 60FPS but on auto shutter, so the person or car goes by looking smooth, but it is a blur when trying to freeze frame it.

Many of us have learned running a camera or NVR at every rated spec can hinder performance and 15 FPS may produce a better image than 30 FPS for the same shutter speed because the camera is operating below capacity. Just like we are concerned about computer CPU getting too high or maxing out, we need to be concerned about the little CPU in these cameras and NVRs.

As always YMMV.

 

[Jayordon]

Lorex will not show 16 8MP cams at 30FPS either...

Here is what there $1,000 dollar NVR and it states:

Live Display Speed (Max) Up to 4ch 4K@30fps

Simultaneous Playback 4ch@4K 30fps

32-channel 4K Ultra HD Network Video Recorder

A 4K (8 megapixel) NVR with Lorex Cloud remote connectivity. Supports 32 cameras.

www.lorextechnology.com

As @SouthernYankee mentions, MP and FPS is only part of the equation. The specs are silent as to what bitrate that is at that is can support 16 8MP cams at 30FPS....

The better NVRs are capable of Network Bit Rate 320Mbps total, and you are correct, that is the same whether it is a 16 or 32 camera NVR.

So one needs to do the math based on their resolutions, FPS, bitrate, compression, etc. and determine if the NVR is capable for it.

My neighbor bought the cheaper end Lorex unit from Costco that capped out at 80Mbps. Even though his cameras are capable of 60FPS and 20,480 bitrate, the NVR would drop it to 30FPS and 4092 bitrate so that it could handle all his cameras. And the picture quality of 8MP cams suffer at 4092 bitrate.

Bitrate is an important factor of picture quality. Do you want an NVR dropping bitrate to push 16 8MP cams at 30FPS?

Movies are shot at 24 FPS, so I doubt you need higher to watch on your mobile device and tablet LOL. Most of us find that 15FPS is more than enough. Actually you can go to about 10FPS before it starts to get noticeable. Shutter speed to get a clean image is more important than FPS. Some of my cams are at 8FPS. Police only care about the ability to get a clean image, not see a smooth video of the perp running.

No police officer ever has said "wow that person really is running smooth in your video". They want the ability to freeze frame and get a clean image. So be it if the video is a little choppy....and at 10-15FPS it won't be appreciable. My other neighbor runs his at 60FPS but on auto shutter, so the person or car goes by looking smooth, but it is a blur when trying to freeze frame it.

Many of us have learned running a camera or NVR at every rated spec can hinder performance and 15 FPS may produce a better image than 30 FPS for the same shutter speed because the camera is operating below capacity. Just like we are concerned about computer CPU getting too high or maxing out, we need to be concerned about the little CPU in these cameras and NVRs.

As always YMMV.

So what is the maximum capability of a 320Mbps NVR? How many 4MP cameras at 20fps can it handle? I'm just looking to get an idea of what I need. What about a 160Mbps NVR?

 

[wittaj]

Assuming one 4MP camera at 8192 bitrate at H264 at 20FPS, that is roughly 8Mbps without any other processing.

Total bandwidth is data coming in and out, so for a 320Mbps, that would be somewhere between 20 to 40 cameras under IDEAL conditions with no other real processing going on and no streaming to a viewer, etc.

If 5 people are live viewing or watching playback, that is part of this total 320Mbps.

Most here do not have an issue with the 320Mbps NVR, but we wanted to make you aware of your statement "Could I put 16x8MP cameras on an NVR recording @ 30fps" onto an NVR doesn't mean that you can watch all cameras at the resolution and FPS at the same time, or that the NVR would even be capable of actually keeping up with that many cameras at that resolution.

Keep in mind the CPUs in these cameras and NVRs are small and usually underpowered. So running them at close to the rated bandwidth capacity means something is suffering in the unit - it is missing motion, or alerts are delayed, or choppy video, etc.

Keep in mind that these type of cameras and NVRs, although are spec'd and capable of these various parameters, real world testing by many of us shows if you try to run these units at higher fps and higher bitrates than needed that you will max out the CPU in the unit and then it bugs out just long enough that you miss something or video is choppy. My car is rated for 6,000RPM redline, but I am not gonna run it in 3rd gear on the highway at 6,000RPM...same with these types of units - gotta keep them under rated capacity. Some may do better than others, but trying to use the rated "spec" of every option available is usually not going to work well, either with a car or a camera or NVR.

I have a cheapo camera I use for overview purposes, but one of the cool things that camera has though in the gui is it shows the CPU usage. If I max out the FPS, bitrate, use it's motion detection and set it to middle sensitivity, the CPU maxes out 100% quite often. If I run it at 15 FPS with an appropriate bitrate and motion detection at a reasonable level, the CPU sits around 40%. I suspect even the more expensive cameras function close to this.

With that said, it sounds like you will be pushing the envelope, so you would want to get the higher end. A 160Mbps or 80Mbps unit will not cut it at all.

 

[Jayordon]

Okay, that makes sense. I'm not actually trying to put 16 8MP cameras on an NVR, I just wanted to be able to gauge what kind of bandwidth something like that would take. Thanks for the explanation