How many NVRs can add cameras at the same time?

Due to the special nature of surveillance, cameras will be added to recorders in multiple scenarios. The most typical case is that the same camera is needed by the doorman, the boss, and the computer room, so the camera will be added to three recorders. We have mentioned this before, and today we will summarize this issue again.

1. How many NVRs can add cameras at the same time?

How many NVRs can add IPC at the same time?

Cameras are divided into wired and wireless cameras. Wired cameras can generally be added to three NVRs at the same time, and wireless cameras can generally be added to two recorders at the same time.

Wireless cameras, including outdoor wireless and indoor wireless IPC, can generally support being added by two recorders at the same time.

For example, the maximum number of streams for Hikvision's distribution series IPCs (3 series, 1 series) is 6. When an NVR adds an IPC, it will simultaneously take the main stream and sub-stream of the IPC, that is, each NVR occupies 2 IPC resources, so a distribution IPC can be added by a maximum of 3 NVRs.

The distribution series ball machine has a maximum of 20 channels, which can be added by up to 10 NVRs.

2. What should I pay attention to when cameras are added to multiple NVRs?

1. The number of video recorders is limited

If the number of recorders exceeds the maximum number of streams supplied by the camera, for example, if 5 recorders scan and add cameras at the same time, the camera will have insufficient stream supply and will "compete" for the bitstream. The final phenomenon is that the recorder screen flickers and the recording progress bar is intermittent.

2. Switches need attention

We all know that if the data traffic bandwidth of the switch's uplink interface exceeds 70M, it needs to be equipped with a gigabit port to ensure that data transmission is not congested and to ensure the smoothness of the video.

If a camera is added to multiple recorders, the bitrate provided by each camera will double. For example, for an H.264 200W camera, the default bitrate size is 4M+0.5M. If it is added to two NVRs, the flow rate provided is 9M. If it is added to three NVRs, the flow rate provided is 13.5M. Therefore, the choice of switch is different from the original one, and the bandwidth provided by the port must be considered.

3. Pay attention to management settings

Having two NVRs managing the same camera at the same time is like having one employee having two direct supervisors. Whose instructions should he obey?

On the NVR management IPC, commands are sent down. For example, if NVR1 changes the IPC password, the original password saved on NVR2 will fail to pass the verification on the IPC, and the video stream will be disconnected. At this time, you need to re-add or modify the configuration on NVR2, such as password settings, IP address management, bitstream parameters, image parameters, time management, etc.

Another point that needs to be emphasized is the encoding method of IPC. If multiple NVRs support H.265 encoding, then after adding one NVR, you can change the IPC encoding to H.265 and use it normally. However, if one or more of them do not support H.265, you must configure IPC to H.264, otherwise some recorders will not be able to record or preview.

Therefore, if there are multiple NVRs managing the same camera at the same time, it is necessary to comprehensively consider the capabilities supported by the recorders and the consistency of the parameters. In terms of settings, it is necessary to modify the settings on the first one and then add them to the second one.

3. Example: Hikvision cameras are added to multiple NVRs

1. Introduction to Adaptive Scenarios and Principles

Application scenario: You want to implement the function of previewing the images of several cameras on multiple recorders at the same time. For example, a recorder (A) in the monitoring center needs to record and preview, a recorder (B) at the guardhouse needs to preview, and a recorder (C) in the lobby needs to preview.

Common method: Add the camera to each NVR. Possible problems: "Preview screen is black", "IPC disconnection", "Record playback timeline jumps randomly". Solution: Use "Custom Add" and RTSP stream to add the camera.

RTSP principle: By inputting the RTSP stream address of the camera into the recorder, the main and sub streams of the camera can be accessed, and basic functions such as real-time preview, recording and playback can be performed, but there is no control function (PTZ control, bit rate modification, OSD setting, etc.).

2. Practical Examples

Example environment: As shown in the figure, a DS-2CD3Q10FD-IW needs to be added to three recorders, namely the main recorder, auxiliary recorder A, and auxiliary recorder B.

1. Add cameras to the main recorder normally

On this recorder, just follow the normal steps to add it.

2. Auxiliary recorder B is added using RTSP
2.1 Enter the recorder [Main Menu] - [Channel Management] - [Channel Configuration], click "Custom Add", select Protocol Management, and enter the Protocol Management interface.

2.2 In the [Protocol Management] menu interface, enter the stream address of the camera's main and sub streams in the "Resource Path" column.
Main stream: /ch1/main/av_stream Sub stream: /ch1/sub/av_stream

*Note: This path is the streaming path for Hikvision cameras. For third-party camera paths, please consult the third-party manufacturer.

2.3. Click OK to enter the [Custom Add IP Channel] interface, select the IP of the camera to be added, select the "Custom 1" protocol set in step 2.2, enter the camera's user name and password, and click "Add".

To add multiple cameras, just repeat step 3, use the protocol "Custom1", enter the corresponding IP, user name, and password of the camera to be added.

3. Auxiliary recorder B is added using RTSP

Repeat the steps in 2 on auxiliary recorder B to connect the camera to the third recorder.