NVR有着怎样的优势去“叫板”DVR?纵观NVR的功能与特色，有几个方面可与“前辈”DVR进行比较。
工作方式
传统嵌入式DVR系统为模拟前端，监控点与中心DVR之间采用模拟方式互联，因受到传输距离以及模拟信号损失的影响，监控点的位置也存在很大的局限性，无法实现远程部署。而NVR作为全网络化架构的视频监控系统，监控点设备与NVR之间可以通过任意IP网络互联，因此，监控点可以位于网络的任意位置，不会受到地域的限制。
对于NVR，不可以独立工作、自成系统，NVR需要与前端的IP摄像机或DVS 配合使用，实现对前端视频的存储和管理。对于DVR，可以直接连接模拟摄像机进行视频获取、编码压缩、存储和管理，完全可以自成系统独立工作。
布线
因DVR采用模拟前端，中心到每个监控点都需要布设视频线、音频线、报警线、控制线等诸多线路，稍不留神，哪条线出了问题还需一条一条进行人工排查，因此布线的工作量相当繁琐，并且，工程规模越大则工作量越大，布线成本也越高。对比NVR，在NVR系统中，中心点与监控点都只需一条网线即可进行连接，免去了上述包括视频线、音频线等在内的所有繁琐线路，成本的降低也就自然而然了。
DVR通常具有丰富的接口，包括视频输入输出、音频输入输出、PTZ 控制接口、报警输入输出接口、存储扩展接口、网络接口等，这些接口对于自成系统的DVR来讲是基本而必须的;而对于NVR ，其功能定位在视频的存储与转发，并且通常作为“中间件”部署在二级机房，那么意味着远离现场，远离各类视频音频输入输出、远离报警接口，远离工作站，因此，为其部署多余的接口意味着成本的增加及故障点的增加。
即插即用
长久以来，包括NVR在内的网络产品，因罩着网络这层神秘面纱——要设IP地址，要操作复杂的管理后台等等，一直让大部分工程商“敬而远之”，但现在，使用NVR已经不必这样了，只需接上网线、打开电源，系统会自动搜索IP前端、自动分配IP地址、自动显示多画面，在安装设置上不说优于DVR，但至少是旗鼓相当了。
DVR 系统中，通常由于其本身具有视频采集、编码压缩、存储、管理等全面的功能，可以自成系统独立工作，因此，较少考虑不同厂商系统间的兼容性，缺乏“团队合作精神”，通常视频编码方式、网络传输协议、视频文件系统等均私有化，不利于集成。但是，基于目前模拟监控超高的市场占有率和应用率，DVR 可以实现真正的“即插即用”，因为模拟监控与DVR的接口是非常标准的复合视频(BNC)及PTZ控制接口(485)，因此，从这个角度讲，DVR具有更好的“开放性”。
录像存储
DVR受到用户欢迎的一个重要因素就是它拥有强大的录像、存储功能，但是这一性能的发挥仍旧受制于其模拟前端，即DVR无法实现前端存储，一旦中心设备或线路出现故障，录像资料就无从获取了;而目前，市面上的NVR产品及系统可以支持中心存储、前端存储以及客户端存储三种存储方式，并能实现中心与前端互为备份，一旦因故导致中心不能录像时，系统会自动转由前端录像并存储;在存储的容量上，NVR也装置了大容量硬盘，并设硬盘接口、网络接口、USB接口，可满足海量的存储需求。
NVR可以采用各种方式进行存储，如DAS 、SAN、NAS等，可以采取各种级别的RAID技术实现数据保护，并且NVR 的集中存储方式更有利于存储设备的集中部署，从而降低存储设备成本、维护成本、机房成本。DVR系统，存储通常是由DVR 内部挂接的多块硬盘或***磁盘阵列完成，不便于集中存储设备的部署。但是，需要注意的是DVR由于存储不依赖于网络的连接，因此，网络的中断对其存储功能没有任何影响，而NVR 的存储要求网络实时畅通，一旦网络中断，视频录像数据将会丢失，或者需要前端的编码器/IP摄像机具有本地视频数据的缓存功能。存储方式同样决定了两个产品的定位，中小型系统及大规模系统。
安全性
网络产品长期以来被认为有安全隐患。的确，在没有安全可靠的机制条件下，网络确实是一个多事之地。然而，在网络监控系统中，一旦通过使用AES码流加密、用户认证和授权等这些手段来确保安全，网络监控产品源于网络的安全隐忧就完全消除了。目前，NVR产品及系统已经可以实现这些保障;而相比之下，DVR模拟前端传输的音频、视频裸信号，没有任何加密机制，很容易被非法截获，而一旦被截获则很轻易就被显示出来。
管理
NVR监控系统的全网管理应当说是其一大亮点，它能实现传输线路、传输网络以及所有IP前端的全程监测和集中管理，包括设备状态的监测和参数的浏览;而DVR同样又是因其中心到前端为模拟传输，从而无法实现传输线路以及前端设备的实时监测和集中管理，前端或线路有故障时，要查实具体原因非常不便。
从以上几点可以看出，NVR占优!另一方面，当前高清视频传感器以CMOS为主，CMOS传感器直接输出数字化的视频信号。在摄像机中通过DSP或ASIC对数字高清视频信号直接进行压缩编码，然后以网络方式传输，要比一般摄像机直接输出高清信号来得经济。基于上述原因，在市场上用于监控的高清摄像机基本上都是网络摄像机，能够接收网络摄像机发来的视音频码流，并能进行本地存储和浏览的设备，就是NVR。因此，从DVR演变成NVR是高清监控的趋势，但是从另一方面来说，NVR由于与网络直接相连，其受网络传输带宽的影响较大。这也是制约NVR发展的一个比较重要的因素。另外，相对于DVR，NVR在实时视频预览方面远远落后于DVR，预览延时现象普遍存在于目前市场上的NVR产品。
纵观视频监控整个市场，NVR前景一片大好，再加上有着较大市场竞争优势的产品功能，大有由其主沉浮的气势。然而，真要做到这个结果却并不容易，单从产品功能来看，与之相比，DVR已经过几载沉淀，受过市场和时间的严苛洗礼，其成熟的市场认知度是当前NVR所无可比拟的。另外，国内DVR市场竞争相当激烈，DVR厂商数量众多，层次良莠不齐，但另一方面，竞争也促使一些高质量的主流厂商不断完善产品性能、推动技术进步，他们并没有无视网络化的大时代潮流。虽说DVS与DVR、NVR定位不同，但至少说明，对NVR来说，欲主江山，除了具备技术优势，还需要有着准确的市场定位、迅速的市场反应等很多不可或缺的条件因素。
What are the advantages of NVR to "wow" DVR? Throughout the functions and features of NVR, several aspects can be compared with the "predecessor" DVR.
Way to work
Traditional embedded DVR system for analog front end, and the center point to point using simulation interconnection between DVR, because is affected by the transmission distance and the analog signal loss, the location of the point to point there are a lot of limitations, unable to realize remote deployment. NVR as the network architecture of video monitoring system, equipment and point to point by any IP network interconnection between NVR, therefore, can point to point in the network of arbitrary position, is not subject to geographical restrictions.
For NVR, it is not allowed to work independently and form a system by itself. NVR needs to be used in cooperation with the front-end IP camera or DVS to realize the storage and management of front-end video. For DVR, video acquisition, coding compression, storage and management can be directly connected to the analog camera, which can work independently of the system.
wiring
For DVR using analog front end, the center to each point needs to deploy video line, audio line, alarm line, control line and other lines, a bit not careful, which line out the problems still need a a manual screening, so the wiring workload is quite tedious, and engineering scale, the greater the workload, the greater the wiring cost is also higher. Contrast NVR, in the NVR system, central point and monitoring points are just an Internet connection can be made, from the above, including video line, audio line, etc, all of the red line, cost reduction is naturally.
DVR usually has a rich interface, including video input and output, audio input and output, PTZ control interface, alarm input/output interface, storage extension interface, network interfaces, etc., these interfaces for DVR system of its own is a basic and necessary; As for NVR, its function orientation in the video storage and forwarding, and generally as "middleware" deployment in the secondary room, so means that far away from the scene, from the various video audio input and output, from alarm interface, away from the workstation, therefore, for the deployment of redundant interface means that the cost increase and the increase of the fault point.
Plug and play
For a long time, including NVR, network products, due to cover the network the veil of mystery, to set the IP address, to the management of the complex background and so on, has been that most engineering contractor "away", but for now, use the NVR had not so, just connected to cable, open the power supply, the system will automatically search IP front-end, automatically assign IP addresses, automatic display picture more, on the installation Settings not better than that of the DVR, but at least is on a par.
DVR system, usually because of its itself has video collection, compression coding, storage, management, and other comprehensive functions, can work independently, its own system, therefore, less consider the compatibility between different vendor system, the lack of "team spirit", usually video encoding, network transmission protocol, video file system such as privatization, is not conducive to the integration. However, based on the simulation monitoring ultra high market share and utility ratio, DVR can realize the real "plug and play", because the interface simulation monitoring and DVR is very standard composite video (BNC) and PTZ control interface (485), as a result, from this perspective, DVR has better "openness".
The video store
DVR are welcomed by the users of an important factor is that it has a powerful video, storage function, but the play is still subject to the performance of the analog front end, namely DVR cannot achieve front storage, once the center of equipment malfunction or line, cannot get the video data; And at present, the NVR products available in the market and the system can support center storage, storage of front end and the client three storage mode, and can realize the center and the front end as backup, once the reason lead to center can't video, the system will automatically turn by the front-end video and storage; In terms of storage capacity, NVR is also equipped with a large-capacity hard disk, and equipped with a hard disk interface, network interface and USB interface, which can meet a large number of storage requirements.
NVR can be used in a variety of ways for storage, such as DAS, SAN and NAS, can take various levels of RAID technology to realize data protection, and NVR centralized storage concentrated deployment of more conducive to a storage device, so as to reduce the storage cost, maintenance cost, machine room costs. In a DVR system, storage is usually done by multiple disks or *** disk arrays mounted within the DVR, making it difficult to deploy centralized storage devices. It is important to note, however, DVR due to storage is not dependent on the network connection, therefore, the network interruption of its storage function has no effect, and the storage requirements of NVR network real-time open, once the network interruption, video video data will be lost, or you need to the front of the encoder/IP camera with functions of local video data cache. Storage also determines the positioning of two products, small - and medium-sized systems and large - scale systems.
security
Network products have long been considered a safety hazard. Indeed, in the absence of a secure and reliable mechanism, the Internet is a place of real trouble. In network monitoring systems, however, once the code flow by using AES encryption, the means such as user authentication and authorization to ensure security, network monitoring products is the result of network safety concerns was completely eliminated. At present, NVR products and systems can achieve these guarantees. By contrast, DVR simulates the audio and video naked signals transmitted from the front end. Without any encryption mechanism, it is easy to be illegally intercepted. Once intercepted, it is easy to be displayed.
management
NVR monitoring and control system of the entire network management should be one big bright spot, it can realize IP transmission lines, transmission network, and all the front-end monitoring and centralized management in the whole process, including equipment state monitoring and parameters of browsing; The DVR also is due to its center to the front for analog transmission, to realize the transmission lines as well as the real-time monitoring and centralized management of the front-end equipment, front or line failure, to verify the specific reason is very inconvenient.
As can be seen from the above points, NVR is dominant! On the other hand, the current hd video sensor is mainly CMOS, which directly outputs digital video signals. In the camera, digital hd video signal is directly compressed and encoded by DSP or ASIC, and then transmitted by network mode, which is more economical than normal camera output hd signal directly. Based on the above reasons, in the market for monitoring of high-definition cameras are basically network cameras, can receive audio stream network cameras, and can perform a local storage and browsing device, is the NVR. Therefore, the evolution from DVR to NVR is the trend of hd monitoring, but on the other hand, NVR is greatly affected by network transmission bandwidth due to its direct connection to the network. This is also a relatively important factor restricting the development of NVR. In addition, compared with DVR, NVR lags far behind DVR in real-time video preview, and preview delay is common in NVR products in the current market.
Throughout video monitoring the whole market, NVR has a promising future. In addition, with the product function with a large competitive advantage in the market, it has a great momentum of ups and downs. Really want to do this the results, however, is not easy, single from the point of product function, in contrast, DVR has precipitation after several years, with the market and the demanding the baptism of time, the mature market awareness is the NVR is incomparable. In addition, the domestic DVR market competition is fierce, DVR manufacturers are numerous, the good and bad are intermingled, but on the other hand, the competition has prompted some mainstream manufacturers of high quality constantly improve product performance, promoting technical progress, they are not ignoring the networked trend of The Times. Though DVS and DVR, NVR orientation is different, but at least, for NVR, for the Lord, in addition to have technical advantages, also need to have accurate market positioning, and the indispensable condition for the rapid market response and so on many factors.
