Analysis of NVR Access, Decoding and Forwarding Ability of Network Hard Disk Video Recorder

1. Detailed description of NVR access capability

One

Single-way maximum pixel

The single maximum pixel means the maximum number of pixels a video camera can access in each path of the VCR.

The maximum pixel of the video recorder can be queried by the parameters of the official website.

For example,

DS-7100N-SN is 2 million,

DS-7800N-K1 is 5 million.

Regularity: The maximum capacity of products with SNSNH suffix is usually 2 million, and that of products with K1K2K4 suffix is usually 5 million.

Common mistakes

Four 3-megapixel cameras were purchased, but a DS-7104N-SN with a single maximum pixel of 2 million was chosen, and only 3 million cameras were lowered to 2 million cameras, losing 3 million effects.

Two

Support brand

Network products must be compatible with the front and back end before they can be used normally, so when matching video recorders and cameras, the products of the same brand are preferred.

If you can't choose the same brand of camera, you usually need to choose the camera that supports the standard ONVIF protocol.

Three

Access bandwidth

Access bandwidth determines how many millions of cameras a VCR can receive, and whether it can access X millions of cameras at full capacity. Generally, we need to calculate:

Give an example:

DS-7808N-K1 official network found access bandwidth of 80 Mbps

It plans to access 8 DS-2CD3T45D-I3.

H.265 camera, 400W resolution, code rate 4.5Mbps.

4.5x8 = 36Mpbs < 80Mbps

Access bandwidth is larger than the sum of bitstream, so DS-7808N-K1 can access 8 DS-2CD3T45D-I3.

Haikang Video Channel Distribution Camera Rate List:

The local "residual bandwidth of network reception" of VCR is the residual access bandwidth. If the residual bandwidth is less than the rate of video camera, it can not be added.

The above is an introduction to access capability. In practical application, attention should also be paid to the type of front-end and back-end products. If you buy the high-end model of the project camera, try to choose the high-end model of the project video recorder. If you choose 71N-SN and other economic products, you will have normal preview and playback, but the high-end intelligent function can not be used.

II. Detailed Explanation of NVR Decoding Capability

Satisfying the conditions of the previous section, the camera can be connected to the VCR, but can you preview it and report the "insufficient resources" error?

Then? Solution?

When using a camera, "access" and "decoding" are two concepts. If the access condition is satisfied, it can be added by VCR and recorded normally, but if the decoding resources are insufficient, the camera added normally will show "insufficient resources" when previewing or playback, and it must be previewed or replayed remotely by computer or mobile phone.

One

What is decoding capability?

Decoding ability is the processing ability of the video when it is output locally. Simply put, when VGA or HDMI monitors are connected to the VCR, how many millions of pictures can be displayed simultaneously on the monitor, including preview and playback scenarios.

Two

VCR Drainage Mechanism

Video recorder decoding capacity is limited by the chip, and the main and sub stream preview display is automatically selected according to the local preview split-screen mode without exceeding the maximum capacity.

Three

Decoding Ability of Different Video Recorders

At present, the decoding capability of mainstream video recorders is divided into three blocks.

Are decoding resources adequate?

Take our K4 equipment for example, decoding resources have 8 channels 1080p, such as 7932N-SN with 32 channels of 4 million cameras, will there be insufficient resources?

Can't.

Single screen: take the main stream, 8 channels 1080p > 4 million

32 Pictures: Substream, 8-way 1080p = 16-way 720p = 32-way 4CIF

The default subcode rate of the camera is 4CIF, and 32 are just enough.

Four

What to do about "insufficient resources"

When multi-screen preview, VCR prompts "insufficient resources", the following steps are usually needed.

1. Upgrade the VCR

Video recorders in the latest version of the streaming mechanism have been optimized, so encountering this problem, it is recommended to upgrade the VCR to the latest version.

2. View stream fetch

When the VCR previews, the left-click screen will appear as the control bar of the picture above, select "channel information". If you see 704X576 (such as the picture above), or 640x480 with smaller resolution, you will get the sub-stream; if you see the high-definition resolution of the camera, such as 1920x1080, you will get the main stream.

According to the video streaming mechanism, 9, 16 and 32 previews should take sub-streams. If the main stream is found here, the sub-streams are not found, thus occupying the decoding resources, resulting in insufficient residual resources and other pictures reporting "insufficient resources".

Upper limit of substream

Factor stream is used for multi-screen preview, or remote preview of network transmission, saving decoding, bandwidth and other resources, so video recorders have upper limit on sub-stream requirements.

For the old equipment, the sub-stream resolution needs to be <4CIF bit rate <1024 for the new equipment, and the sub-stream resolution needs to be <720p bit rate <2048 for the new equipment.

3. Modifying Substream Parameters

If it is found that the video recorder does not pick up the sub-stream of a channel, it is suggested to use IE browser to access the network camera directly and modify the sub-stream parameters. It is suggested that the resolution be changed to 4CIF and the bit rate be adjusted to 512k.

Tips

Why not modify it on the VCR?

When the sub-stream is not fetched, it is very likely that the VCR will not get the sub-stream parameters of the camera, which will result in the situation that the local modification can not be made, or the modification will not take effect.

4. Re-add the camera

After successfully modifying the camera parameters, the camera is re-added to the local interface of the VCR.

Forwarding capability

Forwarding capability is generally used for platforms. When we add devices to the client or platform software, we usually add video recorders directly. Then we can see all the cameras in NVR in the device of platform software, whether you are analog, coaxial or network.

When we preview, playback, or even use decoding equipment to upload the camera image to the TV wall, we use the NVR transfer capability. Generally, it is used with decoding equipment. The most commonly used is when the third-party IPC accesses NVR, the decoding equipment can take the stream directly from NVR. Generally, the NVR forwarding capability is very strong, and usually does not need attention.