Video recorders came first with the camera and monitor, closely followed by the video cassette recorder (VCR), technology then brought us the multiplexer, which allowed multiple video streams to be recorded on the same tape and separated into streams. discreet and visible. . Today there are different types of video recorders like DVR and NVR. One of the problems that the user must face when choosing a security system is whether or not he wants to record with the NVR or DVR.
In this article we have provided a brief overview of the most important types of video recorders such as DVRs and NVRs.
digital video recorder
DVR is defined as a digital video recorder, a device that records video from analog cameras to one or more hard drives. Videos from IP cameras can be recorded to DVRs, but a codec is needed for each camera to convert the IP video stream back to an analog signal so it can be recorded. Some DVRs connect to the network and can be viewed with the camera.
DVRs have the following internal components:
1- An analog-to-digital converter or encoder, which converts analog video signals into the digital domain.
2- Digital storage, generally hard drives, where the digital representation of analog signals is stored and is ready for use.
3- A database, relating the digital information with the references; time, alarms, and other metadata, allowing you to quickly and easily retrieve and display video information.
4- Digital to analog conversion and playback controls.
5- Typically found more on smaller standalone DVRs and less common on enterprise-grade DVRs.
6- An operating system, which runs the entire DVR.
7- A computer network interface, found on most recent DVRs, to allow the DVR to be interrogated remotely.
DVRs have an input for each connected camera, that is, there is a direct connection, usually by BNC, UTP or fiber between each camera and the DVR.
network video recorder
NVR is defined as a Network Video Recorder, a device for recording digitized IP video streams, originating from analog cameras connected via IP encoders and/or IP cameras where the IP video streams are created within each camera. It includes a computer and special software required not only to record the video, but also to allow many people to view the real-time and recorded video that includes both the computer and special video management software. The computer can use the Windows, UNIX or MAC operating system.
Network Video Server is a computer running a special VMS (Video Management Software) that is used to record video from IP cameras and is very similar to NVR in that both record the video. The NVR comes with VMS already installed, while the video server does not include the VMS software. The video server runs the Windows operating system and is more flexible than NVR because it is easier to expand, but NVR has a fixed limit to the number of cameras it will support.
NVRs have the following internal components:
1- Digital storage, usually hard drives, where digital IP video signals are stored
and they are ready to use.
2- A database, relating the digital information with the references; time, alarms and other metadata, so that required video information can be quickly and easily retrieved and displayed.
3- Digital to analog conversion and playback controls. They are typically more found in smaller standalone NVRs and less common within enterprise-grade NVRs.
4- An operating system, which runs the entire NVR.
5- A computer network interface, which is the main input for IP video transmissions on the NVR and also the main way to connect playback equipment in large systems.
Main differences between DVR and NVR
While DVRs are a great option for home surveillance, they’re not your only option. A network video recorder serves the same intended purpose of recording activity in and around your home, but it does so using a different process. Here we note the main differences between NVR and DVR such as their structures, cost, reliability, flexibility, etc.
NVR is a single common input, a network connection for all IP video inputs. This common connection is also used for playback client PC connection. A network switch connects individual IP cameras, IP encoders, and playback PCs to this single common connection. NVRs are less expensive than DVRs. The internal components inside an NVR are fewer than DVRs. A/D encoding takes place outside of an NVR on the IP camera and IP encoders. The bare minimum needed in an NVR is a single network connection, operating system, database, and storage devices. The operating system and database can be software, so only a minimal amount of hardware is needed, and the necessary A/D conversion circuitry in the DVR is also completely eliminated, saving cost. NVRs are more reliable than DVRs. The more components, the more there is to go wrong and the lower the reliability of the device. NVRs can produce more detail than DVRs. DVRs record analog video signals and the maximum resolution that can be recorded is that produced by the analog cameras themselves. NVRs can record IP video streams and can also record megapixel cameras, but DVRs cannot. NVRs can deliver many more high-definition recordings than DVRs, allowing fine details to be discerned from a surveillance view, even when the image is digitally enlarged. The DVR takes an analog signal, processes it, compresses it, and stores it. The NVR takes the stream directly from the IP camera and archives it, because the cameras are already outputting a JPEG or MPEG, so there is no need for compression on the NVR side. NVRs are more flexible in their application than DVRs. The NVRs can record standard and megapixel resolution IP cameras and analog cameras. DVRs can only record analog cameras. DVRs have BNC connectors for analog cameras, but NVRs use Ethernet cable.