With the rapid development of video surveillance technology, the requirements of customers for video surveillance products are also constantly improving, the functional requirements are more complete and stable, and the performance requirements are more clear and accurate. High-definition surveillance has emerged at this time.
The development of video storage
The development of video surveillance technology is divided into analog video surveillance, digital video surveillance and network video surveillance. The storage device in the era of analog video surveillance is a video tape recorder (VCR); the representative product in the era of digital video surveillance is a digital video recorder (DVR), built-in or The external hard disk is the main storage device. In the era of network video surveillance, network cameras and encoders are responsible for encoding and transmission of video. The storage mainly uses network video recorders (NVRs). NVRs have multiple storage methods, such as DAS and SAN. In the period of networked video surveillance, data has exploded, storage methods have become diversified, and different storage structures have been applied. DAS, NAS, FCSAN, and IPSAN storage systems are used in conjunction with digital network video surveillance systems to implement video data. Massive, high-speed, real-time, stable storage and retrieval.
During the digital video surveillance period, DVRs are used as digital storage devices. Usually, DVRs use a large-capacity built-in hard disk to implement storage expansion or an external disk array through an expansion interface, which can be understood as DAS storage. The DAS architecture is stored in the early single-point and small-scale DVR systems. Because it is easy to deploy and the cost is low, it can be widely used. This method is characterized by a single server (DVR) exclusive storage space.
Monitoring storage development
The development of video surveillance is closely linked to the development of video surveillance itself. Video surveillance has gone through three stages: analog, digital, and network. The applications stored in the video surveillance area have also gone through three phases: analog, digital, and network.
Analog video surveillance originated in the 1980s. Image acquisition, transmission, and display are all based on analog devices. Image storage is also based on analog devices, namely video tape recorders (VCRs). Due to the use of a video tape, on the one hand, the storage capacity is greatly limited. On the other hand, image retrieval is very cumbersome, and remote calls cannot be realized. In addition, there are obvious defects in the preservation time and system maintenance. In the late 1990s, digital video surveillance based on digital signal processing (DSP) gradually began to gain popularity. Various types of codec technologies were widely used in image processing, and processed images could also be transmitted as digital code streams. The storage also began to enter the digital era. The most typical application is a Digital Video Recorder (DVR), which uses an internal hard disk for image storage. This storage approach has fundamentally changed in terms of save time, image retrieval, system maintenance, and remote calls. However, since the digital video surveillance systems at this stage mostly have obvious localization features and the scale is relatively small, the storage also shows obvious front-end and stand-alone features.
In recent years, with the rapid development of information network technologies, networked video surveillance systems, which are centrally managed and controlled through a central service platform and are network video servers and IP Cameras, have begun to be widely deployed. Due to reasonable architecture, flexible expansion, and clear hierarchy, network video surveillance can bring new security application experience to users, and thus quickly become the main form of building a new generation of video surveillance systems. The distributed front-end and platform architecture, centralized management and control, and flexible and convenient user access make the storage part of the network video surveillance system begin to move toward networking. Networked storage brings a whole new storage architecture to video surveillance. On the one hand, users are more flexible in storage deployment and easier to access. On the other hand, it is also more convenient to build a video surveillance system that requires large-capacity storage.
Technical characteristics of video storage
Video storage is a very important part of network video surveillance system applications. Massive video data usually needs to be stored for a long time, and provides services for future video video data retrieval and playback. The user can retrieve, playback, or export the monitoring video of a certain path or a certain time period through the application search interface provided by the system. From tape to hard disk, from IDE to SAS interface, from single disk, JBOD to various RAID technologies, from DAS to NAS, SAN architecture, every technological change in the storage field has driven the corresponding development in the field of video storage.
The storage in the video surveillance field is different from the storage application in the civil domain (such as a video site). The storage of video in the civilian field mainly refers to broadcast television, network video, etc. It stores video files on a server, and then the network users pass through to the video server. The access to the video stream is therefore primarily a live or on-demand video, the process of “reading†and playing the video from the storage device. The video storage in the surveillance field is mainly a “write†process. It is a process of writing video data on the network to a disk array for saving or backing up. Of course, a certain percentage of “reading†operations are also concurrently performed in the writing process. , That is, the network user requests the video recording playback.
The storage device used in the video surveillance system has different characteristics from other types of systems in terms of data reading and writing. Video surveillance systems generally have many monitoring points (more cameras), large video data streams, long storage time, and continuous 24-hour operation. Video surveillance applications mainly write video streams. The specific features are as follows:
Video data is written to or read back from the storage device in streaming media, which is different from traditional file reading and writing.
Multi-channel video writes to the same storage device for a long time, requiring the storage system to work stably for a long time.
Real-time multi-channel video writing requires the storage system to have high bandwidth and constant.
The huge capacity requirements and high storage expansion performance require online replacement of faulty devices or capacity expansion.
Multiple concurrent reads and writes require very high performance for storage devices.
Monitor the future of storage applications
When it comes to storage, it cannot help but talk about cloud storage. This is a highly tempting storage technology. Cloud storage can realize full virtualization of storage, greatly simplifies the application process, save customers' construction costs, and provide stronger storage and sharing. Features. All devices in cloud storage are completely transparent to users. Any authorized user anywhere can connect to cloud storage through an access line for spatial and data access. Users do not need to care about the storage device model, quantity, network structure, storage protocol, application interface, etc., and the application is simple and transparent.
Monitor the emergence of cloud storage, break through the performance and capacity bottlenecks of traditional storage methods, enable cloud storage providers to connect a large number of different types of storage devices in the network to form exceptionally strong storage capacity, and achieve linear expansion of performance and capacity. The storage of data has become possible, allowing companies to have the storage capacity equivalent to a whole piece of cloud and successfully solve the storage problem.
With the help of the cloud storage services provided by the cloud conference manufacturers, enterprises are expected to get rid of the huge investment in hardware storage devices, reduce the manpower expenditure on system maintenance, and quickly reduce financial pressure and enhance the competitiveness of enterprises. By then, users can pay for a small amount of storage costs, can put large-capacity data in the cloud, and set the relevant permissions as needed, anytime, anywhere to share with the need to share personnel, while reducing the time of data transmission, with the help of manufacturers Excellent encryption technology to avoid the occurrence of accidents such as packet loss and leakage caused by the transmission process, and fully guarantee the security of data.
With the trend of the combination of security monitoring technology and user needs becoming more obvious, in the integrated implementation of security monitoring products, storage technology must continue to adapt to the security monitoring application characteristics, and constantly improve themselves, the integration of storage products and security monitoring technology is already The general trend. Monitoring cloud storage systems is the integration of storage and monitoring products also confirmed this trend.
The future of video surveillance systems
In the future video surveillance system, the realization of these functions is fully technically guaranteed. With the development and maturation of wireless communication technology, another important application area is mobile monitoring, that is, the front-end monitoring point is a mobile device, which requires that the entire monitoring system must be an all-digital, intelligent system.
The constant updating of video surveillance technology also puts higher requirements on storage technology. Networking and intelligence are very important directions for video surveillance systems and require the provision of intelligent network-based storage, retrieval, and playback. Therefore, to build the next generation video surveillance system, the storage part will no longer be a simple storage unit, but it should be an integrated system that links the front-end intelligent processing and back-end intelligent retrieval.