DVR在高清路上的演进
然而，事实是现在超过90%以上的监控系统都是采用DVR+模拟摄像机的方式组网，NVR+IPC的方式还没有大规模用到视频监控中来，特别是在已部署了DVR、架设好了同轴电缆的应用，用户出于成本和使用习惯的考虑往往只希望在几个最重要的监控点安装高清网络摄像机，原有的D1画质硬盘录像机系统尽可能保留。
在受到前端输入信号源不高清的影响后，DVR厂家开始考虑从两个方面实现高清接入。首先是在保留现有模拟摄像机接入和处理的架构下，将NVR的功能集成到DVR中来，即该类DVR可直接接入一定路数的高清IP摄像机信号，于是混合型硬盘录像机(Hybird DVR)应运而生，混合DVR(HVR)除支持模拟摄像机外还同时支持IP设备如编码器或网络摄像机的接入，一台混合型DVR可同时处理多路模拟视频信号和多路高清IP视频信号。混合型DVR(HVR)组网架构可参见图2。
这样类似DVR+NVR的高清硬盘录像机融合方案使用户的系统可以平稳地向全IP过渡，并且保护了前期模拟摄像机和线路的投资。在客户操作界面上也保持了原先DVR的方式，将需要编***的模拟视频信号和高清IPC视频通过一个界面统一显示和管理，在模拟监控改造项目和集中模拟监控节点多但又有较少监控点比较分散且需求高清的中小型项目中，混合型的DVR即具有较大的市场需求。
The evolution of DVR in hd
However, the fact is now more than more than 90% of the monitoring system are the DVR + simulation network camera, was no large-scale use NVR + IPC way video monitoring, especially in the deployed the DVR set up, the application of coaxial cable, user for reasons of cost and habits often only hope in a few of the most important point to install hd webcam, original D1 quality hard disk video recorder system reserved as much as possible.
Affected by the lack of high definition input signal from the front-end, DVR manufacturers began to consider high definition access from two aspects. First in retaining the existing analog camera access and processing under the architecture of the NVR functions are integrated into the DVR, namely the DVR can direct access to certain because of hd IP camera signal, so the hybrid hard disk video recorder (Hybird DVR) arises at the historic moment, hybrid DVR (HVR) in addition to the support analog cameras at the same time also support access IP devices such as encoders or network camera, a hybrid DVR can handle multiple analog video signals at the same time and multiple hd IP video signal. The network architecture of hybrid DVR(HVR) can be seen in figure 2.
In this way, DVR+NVR hd hard disk video recorder fusion scheme enables users to make a smooth transition to full IP system, and protects the investment of early analog camera and circuit. On the customer interface also maintained the original DVR, will need to make * * * the analog video signal and hd IPC video through a unified interface display and management, in a simulated monitoring renovation project and centralized simulation monitoring nodes but there is another more scattered point to less demand and high definition of small and medium-sized projects, the hybrid DVR has a large market demand.
另外一种方式就是改变传统DVR的输入信号，除IP视频监控市场中主流的ONVIF和PSIA协议联盟之外，现又诞生一个新的基于同轴电缆传输高清的HDcctv联盟，该标准让真正的纯高清DVR成为一种可能。HDcctv系统与广播行业兼容的高清晰度(HDTV)视频信号可以经由传统的CCTV媒介进行数字化传输而不需要打包，并且不会出现人眼可感知的压缩延迟。利用模拟安防系统中从摄像到DVR的传输线路不变，在此基础上为高清视频传输定义了视频分辨率和帧率等信息的握手协议。这样一种模拟的高清视频传输模式(HD-SDI)是HD-CCTV中最为重要的基本核心的技术。HD-CCTV阵营的支持者期望新标准能催生一个更容易布署、成本更低的网际网络协议(IP)系统替代方案。在HDcctv中的串行数字传输链路是从为专业广播市场开发的SDI基本技术派生而来的，由广电行业衍生而来的非编码技术为前端高清视频信号进入DVR提供了技术支撑，目前已在安防行业掀起了讨论的热潮，但是还没有成熟可靠的产品及方案被批量应用。图4是HD-SDI与IP网络传输性能的简单对比。
随着加入HDcctv联盟和认可这种传输技术的客户的增加，HDcctv方案或将成为新应用的标准之一。这种架构的优势主要体现在实时性上，相对IP高清解决方案来说HDcctv是实时监控，类似传统模拟系统中模拟信号不经过DVR的编***和网络传输，直接由光端机传输到监控中心通过矩阵上电视墙，成像效果更好，实时性更高。使用HDcctv方案构建的高清系统的关键因素就是要降低基于HDcctv标准的高清硬盘录像机和前端摄像机的成本，这需要从芯片到生产厂家的共同努力。
除了上述方式外，DVR在高清之路上还有别的可能的选择呢?答案是肯定的。安防市场的发展，一直延续着IT行业一样的技术创新之路，一直在市场需求中不断推出更高性价比、更多功能的产品。无论是DVR，还是HVR或NVR，接入方式和存储方式的变迁，都是为了更大程度地满足和实现用户的需求。随着物联网技术的大力发展，安防行业和IT行业融合的加剧，未来DVR不仅在高清化下需要寻求突破，更在应对高速无线网络和智能化监控需求等方面提出了更高的要求，最终高清的视频数据需要合理的存储模式和网络传输手段，并最终通过人工智能达到视频监控的智能化，增强监控系统的事前预警功能，实现无人值守。就类似通讯行业3G、WiMAX或Wi-Fi的发展，最终还是会走融合之路。
监控系统也将像三网融合一样，将现有的模拟系统、高清系统、智能化系统、报警系统等无缝地融合到一起。譬如，已有这样的硬盘录像机，基于五大管理平台----即嵌入式软件平台、嵌入式硬件平台、核心技术平台、管理系统平台和测试平台，以力图打造性能更优异、功能更强大、图像更高清的DVR。
而且随着高清前端采集和高清存储及传输的发展，视频管理平台和显示也都要考虑高清和标清混合的模式，并在整个系统的输入、传输、输出上都保持同步的高清，才能最终营造高清的整体系统。我们很欣喜地看到，目前无论是DVR+NVR模式的混合型硬盘录像机的输出还是管理平台，都已基本支持1080P的高清视频，具备相应完善的接口，为建立一个全系列互相融合的高清监控环境提供了很好的环境(见图5)。
Another way is to change the traditional DVR input signal, in addition to IP video surveillance market mainstream ONVIF and PSIA alliance agreement, born is now a new hd HDcctv alliance based on the coaxial cable transmission, the standard for the real pure hd DVR become a possibility. HDcctv system compatible with broadcasting industry high definition (HDTV) video signal can be digitized through traditional CCTV media transmission without the need for packaging, and will not delay the compression of the human eye can perceive. The handshake protocol of video resolution and frame rate and other information for hd video transmission is defined based on the invariable transmission line from camera to DVR in the analog security system. Such a simulated HD video transmission mode (hd-sdi) is the most important basic core technology in hd-cctv. Supporters of the hd-cctv camp hope the new standards will lead to an easier and cheaper alternative to the Internet protocol (IP) system. In the HDcctv serial digital transmission link from the basic technology for professional broadcast market development of SDI is derived, by the coding technology of radio, film and television industry for the front-end hd video signals into the DVR provides the technical support, has raised a hot wave of discussion in the security industry, but has not yet been mature and reliable products and solutions by batch applications. Figure 4 shows a simple comparison of hd-sdi and IP network transmission performance.
The HDcctv scheme could become one of the standards for new applications as more customers join the HDcctv alliance and endorse the technology. The advantage of this architecture is mainly reflected in real time, relative IP hd solution HDcctv is real-time monitoring, similar to the traditional analog system analog signal without DVR in * * * and network transmission, direct transmission by the optical transceiver to the monitoring center through the matrix to TV wall, imaging effect is better, higher real-time performance. Use HDcctv scheme to build the key factor of the hd system is to reduce based on HDcctv standard high-definition hard disk video recorder and front camera cost, it needs from the chip to the joint efforts of the manufacturer.
Besides the above methods, what are the other possible options for DVR on the road to gaoqing? The answer is yes. The development of security market has been continuing the same path of technological innovation as IT industry, and has been continuously introducing more cost-effective and multi-functional products in the market demand. Whether it is DVR, HVR or NVR, the change of access mode and storage mode is to meet and realize users' demands to a greater extent. With the developing of Internet technology, integration, security industry and IT industry in the future DVR under Gao Qinghua need to seek breakthrough, not only in dealing with the more high-speed wireless network and intelligent monitoring requirements put forward higher request, eventually hd video data needs to be reasonable storage model and network transmission method, and finally achieve the intelligent video monitoring through artificial intelligence, strengthen the function of monitoring and control system of advance warning, realize unattended. Like the development of 3G, WiMAX or wi-fi in the communications industry, convergence will eventually follow.
The monitoring system will also integrate the existing simulation system, hd system, intelligent system and alarm system seamlessly, just like the integration of the three networks. Has this hard disk video recorder, for example, based on the five management platform - the embedded software platform, the embedded hardware platform, the core technology platform, platform management system and the test platform, to try to create a more excellent performance, more powerful, DVR image more clear.
And as hd the development of the front-end acquisition and hd storage and transmission, video management platform and display are also want to consider Gao Qinghe sd mixed mode, and on the input, transfer and output of the whole system are synchronized hd, to ultimately create a high-definition system as a whole. We are delighted to see that the current whether DVR + NVR mode of the output of the hybrid hard disk video recorder or management platform, have basic support 1080 p hd video, have perfect interface, in order to establish a whole series of merging high-definition monitor environment provides a good environment (see figure 5).
结语
创新、专业是产品取得成功的关键因素，互融、共赢是持续赢得客户信赖的秘诀。视频监控行业的企业只有积淀其自身的核心竞争力，满足市场需求、创造客户价值才能走得更加长远。DVR的高清化只是视频监控中很小的一个插曲，通过硬盘录像机高清化的梳理，可以看到国内关于整个监控的相关产业标准亟待规范，技术演进策略还是缺乏系统性标准。期待未来有一天，无论是DVR还是NVR，无论是模拟摄像机还是IP摄像机，无论是高端行业客户还是民用家庭市场，无论是安防监控系统需求还是基于视频的整体管理解决方案，在行业主管部门和相关标准的规范下，安防产业可以取得有序健康高速的发展。
conclusion
Innovation and professionalism are the key factors for the success of products. Mutual accommodation and win-win cooperation are the secret to win the trust of customers. Video monitoring industry enterprises can only go further if they accumulate their own core competitiveness, meet market demand and create customer value. DVR Gao Qinghua is just the little episode in a video monitoring, through the hard disk video recorder Gao Qinghua comb, you can see the domestic related industry standard specification, for the entire monitoring technology evolution strategy or a lack of systematic standard. Looking forward to the future one day, both in DVR and NVR, both analog camera and IP camera, both high-end clients and civilian family market, whether demand or security monitoring system based on video overall management solutions, in the departments of industry and relevant standard specifications, can achieve orderly high-speed and healthy development of security industry.
