|Coming of age: storage devices have evolved to better record, manage and play back high-quality images|
Storage devices have also evolved to better record, manage, and play back increasingly high-quality images. Digital Video Recorders (DVRs), Network Video Recorders (NVRs) and Video Management Systems (VMS) are specialty recording hardware appliances and software that capture and store images for security, safety (liability claims and lawsuits), positive identification in investigations and business intelligence functions. Because there are so many solutions available, it’s important that companies choose the right devices and installations to fit their security needs.
Let the application be your guide
It is difficult to deny the advantages delivered by today’s most advanced cameras but there is an emerging industry trend toward “value” camera lines that include advanced HD imaging capabilities with fewer of the bells and whistles found in top-of-the-line HD cameras. This trend ensures end users have the flexibility to select the best camera for their needs and budget. After all, recorded images will only be as good as the camera transmitting the feeds, so dealers or integrators play an important role in recommending comprehensive solutions that exploit the cameras high image quality while meeting application and security goals.
So the question remains: What type of recording solution should you deploy? The broad brushstroke answer is to examine the specifics of each type and align those capabilities with the desired level of security and safety at the location or facility.
DVRs, NVRs and VMS software remain the prevailing options today and each has its benefits and challenges. Some technologies offer a hybrid approach, handling both analogue and IP or network cameras. Others feature analytics for intelligent recording or scalability to increase the total number of cameras nearly infinitely with additional servers and storage expansion modules.
|Guided choice: DVRs, NVRs and VMS software remain the prevailing options today & each has its benefits and challenges|
Flexible recording options
In addition to the requirements of the application, other considerations include: ease of use and playback; ability to record multiple streams or selectively record on alarm or ‘exception’; and the potential to upgrade.
Here’s a look at the different solutions:
DVRs—Digital video recorders are the original workhorses of the surveillance industry. These plug-and-play devices are perfect for SMBs in any vertical market and are small, compact and competitively priced, excelling at installations from four to 16 cameras.
DVRs include embedded software and strictly manage analogue signals via integrated encoders. Many incorporate the H.264 compression algorithm to conserve bandwidth and disk space when recording to hard drives. Video motion detection is also a feature of many DVRs, recording selectively on pre-programmed motion within the camera’s field of view. The amount of video storage for a DVR can be expanded with the selection of larger disk capacities for recorded video.
DVRs are well-suited to applications of 16 channels (cameras) and under, but once you go above the designed number of camera ports, users will need to add boxes or migrate to an NVR. These hardware solutions also require a point-to-point connection—cabling from the camera is connected directly to the DVR.
"Video management system software enables video surveillance equipment users to monitor manage and record IP surveillance video from a variety of security cameras".
NVRs— A network video recorder (NVR) records video from a surveillance system in a digital format to a disk drive, USB flash drive, SD memory card or other storage device. An NVR contains no dedicated video capture hardware, and the most sophisticated employ advanced streaming capabilities and features to optimise bandwidth utilisation and management which is increasingly important for large networks employing high-resolution cameras.
Network video recorders are distinct from DVRs as their input is from a network rather than a direct connection to a video capture card. Video on a DVR is converted to a digital format, compressed and processed at the DVR, while video on an NVR is encoded and processed at the camera, then streamed to the NVR for storage or remote viewing. NVRs offer comprehensive control of network recording solutions, simultaneously recording and providing remote access to live views, delivering the same high-quality images with live video and during playback of recorded images.
NVRs offer greater scalability and more storage to support larger, comprehensive surveillance installations of up to 64 cameras or more with a single device. Many also offer intelligent motion detection and powerful search capabilities to quickly and easily find specific incidents and can be expanded seamlessly with on-board and external storage.
NVRs provide greater freedom of deployment because the recorders can be placed virtually anywhere as long as they are on the same LAN network as the IP-based cameras. Unlike a DVR system, with an NVR-based system, a camera that is capable of capturing high resolution images can also record and playback at the desired resolution. The most advanced incorporate distributed processing and H.264 compression algorithms to improve bandwidth utilisation and also accept MPEG-4 and JPEG formats to allow simultaneous, live viewing of multiple cameras. NVRs also support mobile access and control via apps that enable mobile camera monitoring and recorder management via compatible smartphones and tablets.
Due to their advanced features and capabilities NVRs may require a slightly larger initial investment, but offer greater manageability and a lower total cost of ownership over the life of the system due to ease of installation, manageability and future scalability.
VMS—Video management system software enables video surveillance equipment users to monitor manage and record IP surveillance video from a variety of security cameras, hardware and access control systems. Like an NVR, a VMS-based system is well-suited for large, multi-recorder, multi-site installations and is generally only limited in the number of cameras by the server supporting the network system.
"Storage devices are integral parts of an integrated video surveillance specification."
VMS moves integrators more fully into the IT realm, requiring integrators and installers to manage the software and its potential impact on the network. Compared to a hardware-based system like an NVR, VMS systems can include annual licensing fees based on the number of cameras connected to the system.
VMS systems are highly scalable and enable live viewing, recorder control and system management from a single, easy-to-use graphical user interface. VMS solutions may also include software extension modules that enable system configurations supporting up to thousands of cameras and hundreds of recorders and encoders, giving the user additional flexibility to grow their surveillance system and investment at their own pace.
Recorded data can be quickly downloaded and the video file format converted to MP4 for easy PC viewing. VMS systems can also receive live images from a camera/encoder or via a recorder on the network, creating a system that that’s highly manageable and configurable by the end user, which like an NVR, supports mobile access and management capabilities
Video management software fosters the unification of large networked video systems with simplified central operation. It represents an investment in the future scalability of an enterprise surveillance operation. As compared to an embedded DVR or NVR, VMS offers additional system flexibility and a greater ability to scale the system up with additional cameras. DVRs and NVRs vary in their capacity as far as the number of cameras or channels they can support, but many include the ability to connect to existing analogue systems through integrated encoders.
One size does not fit all
Storage devices are integral parts of an integrated video surveillance specification. Each type, DVR, NVR and VMS, offers the systems integrator the ability to specify the technology based on the nature of the protected premises and the overall vision of the end user. For smaller, SMB applications, like retail applications, a DVR may be the perfect solution. For larger systems with a variety of cameras that may need additional controls and capabilities, NVRs may be the product to select. For enterprise locations with hundreds or even thousands of cameras, VMS could be the right implementation, as it offers more manageability overall.
Selecting the most effective recording solution for the job requires a detailed understanding of every aspect of the installation, with an eye toward customer needs, expectations and goals. Beyond upfront costs, important issues like reliability, longevity and total cost of ownership over the life of the system should also be considered to select the best recording solution for the job.