DVR or NVR is a choice you must make before installing a CCTV system. This choice is important because it can affect the time you have to spend installing the equipment, as well as the quality of the video you get as a result. This article will tell you everything you need to know about DVRs and NVRs:

• Main advantages and disadvantages of NVR and DVR

What is the difference between NVR and DVR?

This is an analog video recorder and NVR is a network video recorder. Main function Each of them is video recording, so what's the difference between them?

These two types of DVRs differ in the way they process video. A DVR is an electronic device to which analog surveillance cameras are connected. The video is encoded and processed directly in the DVR.

Unlike DVR, it uses software. The video is first encoded and processed by the network video camera, and then transferred to the NVR for storage or remote viewing.

NVR and DVR are used with different types of security cameras, which reflects the most significant difference between these two types of DVRs. A DVR uses analog CCTV cameras that are connected to it via , while an NVR uses IP CCTV cameras whose video is transmitted via a network cable.

Note. There are also hybrid video surveillance systems (HVR), which combine the functions of both NVR and DVR.

Advantages and Disadvantages of NVR

NVR advantages:

1. Convenient installation

As mentioned earlier, the DVR connects to the network. The device can be placed almost anywhere as long as it is on the same network as the IP surveillance cameras.

2. Easy cable connection

All you need to connect security cameras to an NVR is a wireless router and a PoE switch.

3. More high quality records

You will be able to enjoy higher resolution videos.

4. Connection range

IP surveillance cameras can be placed thousands of miles away from the NVR if they are connected via the Internet. With NVR security systems, you can monitor your CCTV system from anywhere in the world.

Disadvantages of NVR:

1. Unstable signals

Due to its dependence on the Internet, the NVR may suffer from signal loss and the recording quality may be degraded when using other wireless devices at the same time. electronic devices(for example, telephones). In addition, thick walls can block the signal.

2. Possible compatibility issues

Not all IP security cameras will work with every NVR. The devices must support the same video format.

Advantages and Disadvantages of DVR

DVR is an older technology compared to NVR, but it has its advantages.

Advantages of an analog video recorder:

1. Saving money

The price is usually important factor influencing decision-making on the purchase of a video surveillance system. If your main concern is staying within your budget, choosing an analog DVR can save you a lot of money.

2. Don't worry about signal loss

The biggest advantage of an analog security system is that it works on its own. A DVR system can provide you with a continuous stream of video, keeping your property completely safe.

3.Ease of use

Surveillance cameras do not need to be programmed when connected to a DVR.

Note. Some network video recorders can recognize IP video cameras and automatically set their addresses, which greatly simplifies the task.

Disadvantages of DVR:

1. Lots of cable work

Each camera needs to be connected to the DVR with a separate cable, so you can’t do without drilling holes in the walls.

2. Lower quality video

Although new technologies have greatly improved the recording quality of analog cameras (the highest resolution is 1080p), they still cannot catch up with network cameras.

3. Shorter transmission range

Cameras can be placed no more than 300 meters from the DVR.

conclusions

There is no single correct answer to the question of which DVR is better - DVR or NVR. It all depends on the specific situation and your requirements.

Source reolink.com. The article was translatedsite administratorElena Ponomarenko.

Nowadays, since there are DVR, NVR and HVR, some customers feel confused about how to choose the right one. Today we will make it easier for you.

As the names of all these devices imply, they are all designed to record video from security cameras. The main difference between them is what types of cameras they are designed to be enjoyable to play with.

Digital video recorder (DVR)
The DVR is designed to work with standard analog security camera systems like HD TVI cameras and HD CVI cameras. This does not mean that every DVR works with all of these cameras. These DVR categories are simply lines with the previously mentioned types of security cameras. Standard HD AHD cameras are designed to be paired with standard AHD DVRs in the same way that HD-TVI and HD-CVI cameras are designed to be paired with corresponding TVI DVRs and CVI DVRs.

NVR paired with IP network security camera. There are two different kinds of network video recorder, but don't worry, they are both still used with IP cameras. The first type, and much more common, requires connecting the IP camera to a router or switch. This will mean using the search function on the NVR to "ping" the cameras, and then adding them to the NVRs device list to begin viewing. Although this is not a very difficult step, it may be one you don't want to take.
In this case, the second option is to go with an NVR that is built in network or PoE (power over Ethernet) ports. This will allow you to connect your IP camera directly to the back of your NVR just like you would with a DVR. This will remove the step from having to manually add them to the list of devices, and it will remove all the worry of ensuring that they are properly connected to the network.

The hybrid recorder is rapidly growing in popularity due to its versatility. Hybrid Video Recorders (HVRs) are compatible with standard analog signal and digital signal. Here it is necessary to change the channel types as the needs of users, what we mean is that 8 channel HVR can be 4 channel analog signal and 4 channel digital signal, can supply 4pcs AHD/TVI/Analog/CVI cameras and 4pcs IP cameras.

Now it's not just the fact that you get a lot for what you pay for that makes them so attractive to consumers. Since here HVR it is possible to connect quite acceptable AHD / CVI / TVI / analogue channels as well as IP cameras.

It will only be a matter of replacing cameras instead of DVRs and all the cables. Depending on the size of your system, this could save you thousands of dollars in upgrade costs.

So to sum it up like MVTEAM

It is important to understand the difference between a DVR and an NVR, as both types of DVRs are often lumped together as “digital.” The most obvious difference between a DVR and an NVR is that while a DVR records information from analog sources - television cameras, an NVR records video streams already generated at the camera level, its inputs and outputs contain digital IP data consisting of compressed and encoded video signal.

In the article, Shawn Ciccarelli, Product Manager network products from Reditron, outlines the differences between digital video recorders (DVRs) and network video recorders (NVRs), and what these differences mean for system designers and end users.

First came the television camera and video monitor, soon followed by the video cassette recorder (VCR), which recorded one video stream on a three-hour tape at 25 frames per second. Often it could only be turned on using an external device (for example, a packet switch).
Then technology brought onto the scene the video multiplexer, which made it possible to record several video streams at once on the same film, and to separate them into several separate images for viewing; a video recorder appeared with the ability to record while skipping certain periods of time (time-lapse VCR), which thus made it possible to use three-hour cassettes to record more television cameras, although at the expense of partial loss of information from them.

Digital Video Recorder (DVR)

The rapid development of video compression algorithms (JPEG, M-JPEG, Wavelet, MPEG-4, etc.), the increase in the speed of data processing by computers and the rapid fall in the cost of storing a unit of information gave impetus to the development of digital video recorders. The latter can be imagined as a combination of a functional similarity to a multiplexer with a computer disk for recording instead of a tape, housed in one housing that has several additional ports for connections.
DVR is a convenient, albeit limited, replacement for multiplexer-video recorder pairings and provides non-linear access to recorded material, typically selected by camera ID, time and date. The level of quality of the recorded video signal is generally higher than that achievable in analog tape video recorders, but may be lower: this depends on the compression algorithm and the specific system configuration.
The main advantage of DVR is that for each video stream it is available large quantity programmable parameters (resolution, frame rate, options for turning on additional devices, recording on/off time, etc.), however, the DVR is useful only where it is possible to directly connect all existing analog cameras to it.
Good modern DVRs have built-in UDP (CAT 5) network ports - thus, the device can be assigned an IP address and accessed over an Ethernet network.
However, there are many limitations, not the least of which is that if the device crashes, you will most likely lose all your video recordings (or, for starters, they may not be taken at all). Network video recorders (NVRs) do not have this drawback, since they can be used in “mirror” mode, but I will talk about this a little later.
From a reliability point of view, if you are going to use a DVR, make sure that the model you choose to implement has a hard drive industry standard, and not specially designed by the manufacturer - otherwise failure will befall you much sooner than you think (most DVR failures occur from overloading and overheating of hard drives). Ask the manufacturer what kind of drives they use.

Like most things in this world, a DVR's actual performance, ease of use, and reliability depend on who made it, the features of the specific model, and how much you paid for it.

Network Video Recorder (NVR)

NVR His arrival heralded the achievement of a new milestone in the development of video recording technology.
It is important to understand the difference between a DVR and an NVR, as both types of DVRs are often lumped together as “digital.” Because the DVR compresses the video signals it receives into digital form and records them on the hard drive, the term “digital” here refers to compression and recording technologies, but not to the transmitted video images. Therefore, the DVR should be located near the cables that carry the analog video signal. NVR, on the other hand, records digital images directly from the IP network.

Thus, the most obvious difference between a DVR and an NVR is that while a DVR records information from analog sources - television cameras, an NVR records video streams already generated at the camera level.

That is, nowhere on the NVR you will find ports for connecting a video signal: its inputs and outputs contain digital IP data consisting of a compressed and encoded video signal. This signal is in most cases in MPEG-4 format. MPEG-4 compression technology has become widespread in the video surveillance industry, mainly in terms of efficiency.
A significant advantage of an NVR-based architecture is that network video recorders can be located anywhere on the network - in a monitoring center near clusters of cameras, distributed at the ends of the network, collected together into a single unit - in fact, anywhere. During use, their location is indifferent to the operator - he or she simply calls the desired video stream and, if he or she has the appropriate viewing rights, receives it on their screens.
Network video recorders record and play back simultaneously, and recordings stored on any one of them can be remotely viewed simultaneously by multiple authorized operators distributed throughout the network, completely independently and without affecting each other.
The importance of independence from physical location, if necessary at a great distance from the cameras, should not be underestimated - it is known with what zeal that system administrators observe load limits on the networks under their control, however, having correctly calculated the distribution of data flows within the network and strategically placed network video recorders , we can minimize the impact of video streams passing through the network on the load of network resources.
In general, the NVR can be placed on a local area network (LAN) in close proximity (in the network sense, that is, not necessarily physically close) to a cluster of cameras - thus the main load falls on local network, which can easily cope with such a load, thereby freeing up the resources of other parts of the network, perhaps more limited in capabilities. The system administrator can designate what share bandwidth it is ready to devote the network to the transmission of video data, and this will become a limit value that cannot be exceeded even in the case of the highest workload on the video components of the system.
Further, if the video recording is required at some other point in the network (usually in the control center, but not necessarily), the required sequence can be easily called up by the operator and exported to his workplace and analyzed, reviewed (which is not the same thing), and appropriate action can be taken in response to the information it contains.
To make it easier to calculate the required video stream intensity and disk storage capacity, spreadsheet-based calculator applications are used. Applications allow you to make calculations for each of the cameras separately using parameters such as: type of observation location (busy street / internal corridor, etc.), functional parameters of the camera (constant panning, operator-controlled zooms or fixed camera for personnel identification, etc.), video resolution and update rate in frames per second, and when using video motion detectors - the frequency of movements in the frame and their nature.

A good NVR should now have features such as:

The "mirroring server" technique is now often used to duplicate the recording of video streams to additional network video recorders located in different parts of the network, allowing high level protection from network failures; if one of the parts fails, the other comes into operation as a backup. You can place as many NVRs in your system as you like; adding another is just a matter of connection and configuration. No additional cables are required.
This technique is especially useful when consolidating multiple independent systems into a single manageable space, or during system rationalization or expansion, because it simplifies the system and reduces the cost of all new cabling.
Also, to reduce the need for disk space (and, therefore, costs), a function is used to set the frame rate depending on the activity in the surveillance area (ACF).
This function is fundamentally based on the processing of the video signal when encoding it with a television camera. When the camera is running, if there are no objects moving in its field of view, the video recorder switches to low frame rate mode (usually 1 frame per second). And when motion is detected, the frame rate automatically increases to a preset value, usually in as little as 100 microseconds (1/10 of a second). This function is most effective in places where there is not a lot of activity, for example, in corridors and fire exits, or inside buildings that are empty at night; this can save up to 50 percent of the disk space that would have been used in the absence of ACF.

So what can we expect in the future?

Many tools are already available to help the operator identify and display the desired events from the video stream. For example, software that controls a video surveillance system and alarms analyzes the movement in the frame and, at the operator’s command, displays a set of thumbnail images (icons) of scenes containing similar movement of objects. By clicking on the icon, you thereby cause playback of the corresponding video fragment. The system is able to analyze 24 hours of video recording and display a set of icons within just a few seconds. Changing search parameters allows the operator to comb through enormous quantities of recorded material quickly and efficiently.
The analysis program then independently searches for the requested events, allowing the operator to concentrate on more specialized and urgent tasks. And these aren't just user-friendliness features: they also help reduce overall network load.
This is just the tip of the iceberg - new developments include, for example, crowd detection (too many people in a small area), motion detection (a person or vehicle moving, say, from left to right in the frame), abandoned object detection (suitcase , left at the airport terminal), movement against the general flow (a person walking back along the customs corridor), detection of objects based on shape characteristics ( vehicles), tracking objects and detecting thefts (disappearance of an object from view).
It can be expected that the use of analytical programs will cause a significant increase in the performance of systems when searching recorded video images to analyze events that have already occurred. And here you can’t do without a network video recorder.

When and how will NVR replace DVR?

Some say that NVRs will replace DVRs in the near future, others say that DVRs will remain for a considerable period of time

The full name of NVR (Network Video Recorder) is a network video recorder, and its key features reflected in the letter N - network. In NVR system, the advanced devices are IP video cameras or IP video servers. Analog video, audio and other ancillary signals are digitized and then transmitted to the NVR in the form of a network stream. Video storage, management and forwarding are centralized through the NVR, which in turn is not tied to a physical location and can be placed anywhere on the local network. NVR is an intermediate link that is responsible for capturing video and audio streams from the network, storing and redirecting them.

NVR vs. DVR

The first difference between NVR and DVR: NVR cannot work independently, on its own, IP cameras/servers are required. While the DVR can be directly connected to analog cameras to capture, encode, store and manage video, it can operate independently. At the same time, there is an opinion that DVR and NVR are fundamentally different categories of products intended for different tasks. For small projects - DVR by low prices and ease of use, for large distributed projects - NVR is a powerful network solution. Due to the fact that at the moment the share advanced products has increased greatly and recycling rates remain high, DVRs suggest mature stability.

In practice, the NVR can be located flexibly and is not limited by a physical location, only requiring a network connection with a certain bandwidth. But, on the other hand, NVR assumes an already existing local network, otherwise building a new infrastructure will be expensive. The DVR is connected directly to the video camera (microphones and other equipment), so the physical location must be taken into account, in particular the signal transmission distance and the level of signal loss. NVR supports storage various types: DAS, NAS, SAN, etc., as well as various levels of RAID arrays to protect data from loss, but at the same time, network storage is also not tied to a physical location, which reduces the cost of renting premises and Supplies. In DVR, storage is carried out on several internal or external hard drives, without the ability to select the archive location. However, we note that DVR archives do not depend on the network state and network problems do not affect the operation of the storage, and the NVR always works with a live network stream, and in case of interruptions or problems in the network, the video recording will be lost (local recording can be provided on IP cameras/servers ).

System capabilities

NVR systems are truly digital, opening up the possibility of using advanced HD cameras, storing and managing high-definition video. Analog DVR cameras depend on analog technology, channel width, digitization chip and cannot achieve resolution greater than D1. HD is only required in some projects, and in some projects there is no need for high resolution at all, especially in small systems.

NVR uses open architectures and requires pre-installed operating system, software, special network characteristics and storage devices to implement full functionality. NVR has excellent integration capabilities, including various access control systems, etc., NVR systems are more convenient and flexible.

DVR systems use their own compression, storage, and video capture formats and often do not imply compatibility with systems from other manufacturers due to the use of proprietary protocols and formats that are not suitable for integration. However, based on the current market share of analog control devices, DVR can be called a plug-and-play device due to the availability of standard BNC and RS-485 interfaces. And from this side DVR is more open.

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