NVR is Network Video Recorder
NVR is an acronym for Network Video Recorder, or network hard disk recorder. The main function of NVR is to receive digital video stream transmitted by IPC (network camera) device through the network, and to store and manage it, so as to realize the distributed architecture advantage brought about by networking. Simply put, Nvr allows you to view, browse, play back, manage, and store multiple webcams at the same time. Get rid of the computer hardware, no longer have to face the installation of software cumbersome. If all cameras are networked, then the only way is to have a centralized management core.
DVR is Digital Video Recorder
That is, digital video recorders, compared to traditional analog video recorders, the use of hard disk recording, so often referred to as hard disk recorders, also known as DVR. It is a set of image computing storage processing computer system, with image / voice and dynamic frames for a long time recording, recording, remote monitoring and control functions, DVR collection of video recorders, screen splitters, head lens control, alarm control, network transmission and other five functions in one, with a single device can replace the analog monitoring system a lot of equipment functions, and gradually in terms of price advantage and popularity.
The difference between NVR and DVR
The difference between DVR and NVR is one letter, but it determines the great essential difference between them. DVR digitally encodes analog video and compresses it and stores it on a hard disk, and its "D" letters are mainly related to coding and storage technology, which has little to do with network transmission, so DVR is usually installed close to the computer room near the analog camera. NVR gets the encoded compressed video stream from the network and then stores and forwards it, and its letter "N" involves the network transmission, so we generally do not see the direct connection of the video signal on the NVR device, its input and output are as well as encoded and added the network protocol IP data.
1, independence
For NVR, the first difference with DVR is that NVR can not work independently, self-contained system, NVR needs to work with the front-end IP camera or DVS, to achieve front-end video storage and management. For DVRs, analog cameras can be connected directly for video acquisition, storage and management, and can work independently of their own systems.
2, physical location
In practical applications, the deployment of NVR is flexible and not limited by physical location, that is, NVR is not limited by the physical location of cameras, encoders and control centers, but only requires network connectivity, the main need to consider the network video stream broadband allocation and deployment. Because DVRs are directly linked to analog cameras, physical location is subject to the layout of field equipment, often requiring proximity to cameras, audio devices, and auxiliary input and output devices, taking into account transmission distances and signal transmission losses.
3, HD
NVR system is a truly digital, networked, open system, with front-end HD cameras can achieve real high-definition storage and video forwarding. If true HD is required, HD support is required for everything from video capture, encoding compression, storage to display. The current approach to HD is primarily the front-end "HD IP Cameras and NVR", which can produce megapixel images and then transmit, store, display or play them back directly over the network. DVR system is subject to analog camera technology, channel transmission broadband limitations and chip processing restrictions, can not achieve true HD video, support up to D1 resolution.
4, openness
NVR adopts an open IP architecture, which needs to be used with encoders, management platforms, operating systems, network transmissions and storage devices to achieve complete functionality. Therefore, NVR has a good integration capability, whether in the connectivity of video, or with the alarm, access control and other systems, are more convenient and flexible. In addition, NVR can be based on the common server and operating system, therefore, gradually broke the security monitoring field of equipment proprietary, closed pattern, and gradually integrate with IT, to facilitate user purchase maintenance. DVR system in general, usually because of its own video acquisition, coding compression, storage, management and other comprehensive functions, can work independently of the system, therefore, less consideration of compatibility between different manufacturers of the system, lack of "team spirit", usually video coding, network transmission protocol, video file system, etc. are privatized, not conducive to integration
5, interface
DVRs usually have a wealth of interfaces, including video input and output, audio input and output, PTZ control interface, alarm input and output interface, storage expansion interface, network interface, etc., which are basic and necessary for self-contained DVRs, while for NVR, its functions are located in the storage and forwarding of video, and usually deployed as "middleware" in the secondary room, which means staying away from the field, away from all kinds of video audio inputs and outputs, away from alarm interfaces, away from workstations, and therefore, Deploying extra interfaces for them means increased costs.
NVR and DVR which is Better
DVR is a hard disk recorder, can be placed inside the hard disk, can store the analog camera connected to the DVR, note: DVR is connected to the analog camera.
NVR is a network hard disk recorder, more similar to a disk array, to provide network storage space for IPC or DVS, that is, storage is code streamed after encoding, network transmission. NVR is a connected network camera
Analog Camera:
Analog Camera is a front-end device for capturing surveillance field images, with CCD image sensors as the core components, plus synchronous signal generation circuits, video signal processing circuits and power supplies. In recent years, the new low-cost CMOS image sensor has developed rapidly, and the camera based on CMOS image sensor has been applied to the video telephone or conference TV system with low image quality requirements. Because the resolution and low illumination of cmOS image sensors are not comparable to CCD image sensors until the main indicators are temporarily comparable, the camera used in the TV surveillance system is still a CCD camera. The signal output from the analog camera (Camera) is a video signal that transmits only one-way video signals and requires a monitor or hard disk recorder to monitor and record.
Network Camera (IP Camera) is an integrated video compression and network transmission processing module (DVS) based on analog cameras (Cameras), which combines the technical features of analog cameras and video servers. Webcams can operate independently in any location with an IP network interface. In addition to all the image capture functions of conventional cameras, the network camera also has built-in digital compression controller and WEB-based operating system (including Web server, FTP server, etc.), so that video data is compressed and encrypted, sent to the end user through the network (LAN, Internet or wireless network), while remote users can use standard web browser or client software on their PC to access the network camera, real-time monitoring of the target site, And can be real-time storage of image data, in addition to the network to control the camera's head and lens, all-round monitoring. Some webcams also have other features, such as voice intercom, alarm input, relay output, motion detection, analog video output, and SD card local storage of recording data.
