The emergence of HD-SDI cameras has created new opportunities and challenges in the field of video storage devices. HD-SDI DVRs have emerged under such high-definition storage requirements. The monitoring system with SDI-DVR as the management device has outstanding advantages. Firstly, it has good compatibility with other devices on the platform. Secondly, the picture quality is better than that of the DVR. The development of new things always needs to undergo some improvement. So, in the future development, what aspects of HD-SDI cameras need to be upgraded?
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H.264 shows up again
As we all know, the amount of digital signals output by SDI cameras is very large. If there is no coding compression, the storage of the back end is almost impossible. From the a&s "Safety Automation" test SDI DVR, manufacturers have adopted the current and advanced H.264 compression format. H.264 can maintain high quality and smoothness while maintaining high compression ratio. Video images are currently the main compression algorithms used in the surveillance field. From the test situation, the code stream of the video is effectively controlled. Under the standard of 1080P@30fps, the code stream detected by the SDI-DVR monitor is generally 4-6 mbps. This encoding compression process also makes SDI The high storage requirement of the video stream data of the camera is no longer a problem for its promotion and application.
After solving the data storage problem, what is the loss of SDI video signal after decompression? This is also the key performance of SDI-DVR. From the test results, different brands of different manufacturers can be seen. The image quality loss of SDI-DVR is also very different. The same HD-SDI camera is selected as the video signal input source. Compared with the test, in terms of definition, some SDI-DVR can still reach the level of 1000 lines after decompression. There is also a significant attenuation in some of the sharpness. In terms of color reproduction, the same is true. Different DVR hardware adoptions, as well as internal design techniques and other details, make different SDI-DVR performance differences.
Compared with the image output by the 1080P@30fps IP camera with the same parameter settings, most of the SDI-DVR compression and decoding results are still much better than the other. In addition, in terms of delay performance, although HD-SDI is decompressed and converted. The transmission of data has produced a certain delay, but after testing, the delay time is generally much smaller than the delay time of the IP camera itself, which is the greatest advantage of the SDI monitoring system.
Streaming media technology coordination bandwidth
In the design of the video playback function, this test can also see that many manufacturers pay attention to the transmission bandwidth control. After the SDI-DVR compresses the SDI digital signal, when the user logs in to the client through the remote IE for monitoring operation, the network bandwidth problem also occurs. Streaming media technology is designed to alleviate this problem. Streaming media technology can also be called streaming media technology. The principle of this technology is to compress the image and sound information and store it on the server. Users can watch while downloading, instead of waiting for the entire compressed file to be downloaded to their own computer. Network transmission technology that can be viewed.
In general, in a networked monitoring system, streaming media technology is often needed to implement distributed network monitoring applications to avoid network bottlenecks caused by concurrent traffic. However, in the actual test, you can see that when you click to view the playback video, the size of the code stream is also detected. Under the influence of the streaming media technology, the video file is automatically downloaded to the local while playing, resulting in the playback stream being compared to the recorded stream. The code stream is much larger. If the video is also being monitored in real time, the bandwidth will still have a certain impact. The manufacturer should provide setting options, such as setting different download rates according to the bandwidth environment of different users, to ensure that the bandwidth occupied during playback is viewed, and the monitoring video or real-time monitoring of other roads is not affected.
Stability is still the main appeal
This SDI-DVR uses Linux as the operating system. In fact, Linux has always been the mainstream operating system used by DVR. SDI-DVR is also applied on this system architecture. The stability advantage of embedded SDI-DVR comes not only from The low failure rate of hardware depends on the high stability of the operating system and application software used in the embedded DVR, and the software platform chosen plays a vital role. In this test, SDI-DVR can be internally connected to 2-8 hard disks or above, and has e-SATA interface to expand capacity at any time.
In terms of exterior structure design, in addition to being beautiful and solid, there is another requirement that heat dissipation must be good. The more video compression boards of SDI-DVR, the higher the power consumption and the more heat dissipation. Coupled with the large heat source of the hard disk, too much heat accumulates in the chassis, which will cause system instability. For the products tested this time, 1-3 small fans will be designed inside the chassis to enhance the heat dissipation inside the chassis and increase the air convection.
In terms of the resolution of video output, SDI-DVR's biggest advantage can be said to support HDMI high-definition output, because the security industry as a whole is moving towards high-definition, and the high-definition output of SDI-DVR can compete with NVR, even In terms of latency, SDI-DVR is still superior. The SDI-DVR of this test has at least one HDMI output interface, and most manufacturers' products can simultaneously output TV, VGA format video, and also have analog-digital mixed design DVR. The video output format selection is more flexible and diverse. .
future development
It is foreseeable that due to the advantages of HD-SDI camera image and the real-time transmission of video data, it will become a product sought after by manufacturers and engineering companies in the next few years, and the equipments that accompany it will be valued. The importance of managing SDI-DVR is self-evident. I think the future SDI-DVR can go further in the following aspects.
1, picture clarity
Sharpness has always been a key indicator for customers to choose products. Image quality is a core issue in evaluating the quality of digital video recorders. With the development of high-definition technology and the popularity of high-definition cameras, HD DVR will be the research and development target of the next generation of DVR manufacturers.
2. More efficient compression algorithm
In order to meet the needs of high-definition storage, improve image storage time, and reduce the bandwidth occupied during transmission, manufacturers are developing a more efficient compression algorithm. The currently widely used compression algorithm is a simplified H.264.
3, centralized storage
With the advancement of digital technology, the amount of data that needs to be stored is increasing, and meeting the requirements of high storage is an important issue that DVR vendors need to face. Video surveillance systems from data collection, transmission, storage to digital data collection, transmission, storage, from the original space constraints to the current remote monitoring, remote storage, remote recovery technology applications, with the improvement of the system, are also undergoing Step by step evolution and perfection, in the future will integrate NAS, SAN, ISCSI and other technologies, the data directly through the network to complete storage, which is an inevitable trend of storage technology development.
4, the operation interface
Improving the software operating interface and increasing the added value of software profits is a direction that every DVR vendor is looking forward to. Starting from the details of appearance, interface, and operating habits, we will change the image of China's manufacturing, and make the interface closer to the user's use. The application of graphical interface and the clarity of color will bring people a new feeling, which is the basic indicator for customers to choose products.
5, smart technology
The intelligent technology enables the video surveillance system to make the identification and processing of the personnel who need to be on duty to be completed by the computer, thereby greatly reducing the workload of the on-duty personnel and improving the security quality. With the advancement of projects such as “Safe Cityâ€, massive video information has made SDI-DVR to solve storage problems on the one hand, and to provide strong support for remote or local retrieval on the other hand.
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