Which is better, NVR or DVR?

NVR is ( Network Video Recorder the Network hard disk Video Recorder)Abbreviation. The main function of NVR is to receive IPC (Network Camera) The digital video code stream transmitted by the device is stored and managed to realize the distributed architecture advantage brought by networking. In short, through Nvr, multiple network cameras can be viewed, browsed, played back, managed and stored at the same time. Get rid of the shackles of computer hardware, no longer have to face the cumbersome installation of software. If all cameras are networked, then the only way is to have a centralized management core. Dvr, all called Digital Video Recorder (Hard disk video recorder) , That is, digital video recorder, compared with the traditional analog video recorder, uses hard disk recording, so it is often called hard disk recorder, also known as DVR. It is a set of computer system for image calculation, storage and processing, and has the functions of long-term video recording, audio recording, remote monitoring and control of images/voice and dynamic frames, etc, DVR integrates five functions of video recorder, picture splitter, pan-tilt lens control, alarm control, network transmission, etc. One device can replace the functions of a large number of devices in the analog monitoring system, moreover, it gradually has an advantage and popularity in price. 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 digitizes, encodes, compresses and stores analog video on the hard disk. Its 'D' letter mainly involves coding and storage technology, which has little to do with network transmission, therefore, DVR is usually installed nearby in the computer room near the analog camera. However, NVR obtains encoded and compressed video streams from the network and then stores and forwards them. The letter 'N' involves network transmission, so we generally cannot see the direct connection of video signals on NVR devices, its input and output are IP data encoded and added with network protocols. 1. INDEPENDENCE. For NVR, the first difference from DVR is that NVR cannot work independently and form its own system. NVR needs to be used together with IP camera or DVS at the front end, storage and Management of front-end video. For DVR, it can be directly connected to an analog camera for video acquisition, storage and management, and can work independently of its own system. 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 locations of cameras, encoders and control centers, however, only network connectivity is required, and the reasonable allocation and deployment of network video stream broadband need to be considered. Because DVR is directly linked to analog cameras, its physical location is subject to the layout of field devices, and it usually requires nearby cameras, audio devices and auxiliary input and output devices, considering the transmission distance and signal transmission loss, it has certain limitations. 3. High-definition NVR system is a truly digital, networked and open system. It can realize real high-definition storage and video forwarding with front-end high-definition cameras. To achieve true HD, HD support is required for all aspects of video collection, encoding and compression, storage, and display. The current implementation mode of high definition is mainly the way of 'high definition IP camera NVR' at the front end. High definition IP camera can produce millions of pixel-level images, then directly carry out network transmission, storage, display or playback. The DVR system is limited by the technology of the analog camera itself, the channel transmission broadband limit and the chip processing limit, and cannot realize the real high-definition video, and supports D1 resolution at most. 4. Open NVR adopts an open IP architecture and needs to be used together with encoders, management platforms, operating systems, network transmission and storage devices to realize complete functions. Therefore, NVR has good integration capability, which is more convenient and flexible in terms of video interconnection and integration with alarm, entrance guard and other systems. In addition, NVR can run based on common servers and operating systems. Therefore, IT gradually breaks the pattern of proprietary and closed equipment in the field of security monitoring, gradually integrates with IT, and is beneficial to users' purchase and maintenance. DVR system, usually because of its own video capture, coding compression, storage, management and other comprehensive functions, can work independently of its own system, therefore, less consideration is given to the compatibility between systems of different manufacturers and lack of 'Team Spirit'. Usually, video coding methods, network transmission protocols, video file systems, etc. are all privatized, not conducive to integration 5. Interface DVR usually has rich interfaces, including video input and output, audio input and output, PTZ control interface, alarm input and output interface, storage expansion interface, network interface, etc, these interfaces are basic and necessary for DVR with its own system; For NVR, its function is located in the storage and forwarding of video, and is usually deployed in the secondary computer room as a 'middleware', which means far away from the scene, keep away from all kinds of video and audio input and output, alarm interfaces and workstations, so deploying redundant interfaces for them means increasing costs. Hint: the above discussion on DVR and NVR is only to increase readers' understanding of the mentality of the two products, rather than to argue which is better or worse. In fact, the two have different application advantages under different projects and different needs, and will coexist for a long time. Therefore, the key lies in reasonable selection. Which is better, NVR or DVR? DVR is called a hard disk video recorder in Chinese. A hard disk can be placed inside, and an analog camera connected to DVR can be stored. Note: DVR is connected to an analog camera. NVR is called network hard disk video recorder in Chinese, which is more similar to a disk array and provides network storage space for IPC or DVS, that is to say, it stores code streams after coding and network transmission. NVR is connected to a network camera, analog camera (Camera): Analog camera (Camera) It is a front-end equipment for acquiring and monitoring on-site images. It takes CCD image sensor as the core component, plus synchronous signal generation circuit, video signal processing circuit, power supply, etc. In recent years, new low-cost CMOS image sensors have developed rapidly. Cameras based on CMOS image sensors have been applied to videophone or conference television systems with low image quality requirements. Since the resolution and low illumination of CMOS image sensor are not as good as CCD image sensor for the time being, the camera used in TV monitoring system is still CCD camera. Analog Camera (Camera) The output signal is a video signal, which can only transmit one-way video signals. It is necessary to connect a monitor or a hard disk video recorder for monitoring and recording. Network Camera (IP Camera): Network camera (IP Camera)Is in an analog camera (Camera) On the basis of the integrated video compression and network transmission processing module (DVS) , With the technical characteristics of analog cameras and video servers. The network camera can operate independently as long as it is placed in any location with IP network interface. In addition to all the image capture functions of traditional cameras, the network camera also has a built-in digital compression controller and a WEB-based operating system ( Including Web server, FTP server, etc) , So that the video data is compressed and encrypted, through the network ( Lan, Internet, or wireless) Sent to the end user, and the remote user can use the standard web browser or client software on his PC to access the network camera, and monitor the situation of the target site in real time, it can also store image data in real time, and can also control the pan-tilt and lens of the camera through the network for all-round monitoring. Some network cameras also have other functions, such as voice intercom, alarm input, relay output, motion detection, analog video output and SD card local storage of video data.