With the development of digital TV technology, many digital devices have appeared in the TV monitoring industry. Digital systems have become the current hotspot, so the concept of digital video matrix has appeared, and some manufacturers have also launched pure digital video matrix devices.

 

Digital video matrix technology principle

 

    At present, digital systems mainly have the following two situations:

 

    First, according to the concept of an analog video matrix, a channel-type connection (how many inputs to many outputs) is established for the input digital video signals (data streams). Such equipment is mainly used in television studios, and the system it adapts to ( The network) structure is lumped, but it is rarely used in the TV monitoring system of the security industry.

 

    Another way is to use DVR, video gateway or IP camera to digitize the image source in the LAN environment, and switch the digital stream through the network switch. At this time, the output of the system can be considered as B / S or C / S. The client in the structure, it does not establish a transmission channel between the input and output signals, but essentially performs multiple image transformation and codec processing in parallel. The connection between the input and output is not direct (there is a transformation ), Nor is it real-time (with delay). In addition, the input signal is usually an analog video signal, and the output may be a digital signal or an analog signal. This is a distributed structure, which is characterized by:

 

    Digital video signals will not be degraded during multiple transmissions, recordings, and processing. At the same time, it can not only realize distributed storage and local control, but also centralized image calling, recording, and unified management. Image retrieval processing is more convenient, such as multi-screen segmentation, license plate number recognition, etc. These image processing uses simulation Technology is difficult or impossible to implement;

 

    The network wiring is convenient, and the data network reserved in the building can be fully utilized. Easy to connect with WAN for remote monitoring;

 

    The system has good scalability and upgradeability and strong confidentiality.

 

    However, there are still some problems that need to be improved urgently: the central monitoring room cannot obtain all the real-time images of the system at the same time. The image quality (resolution, sharpness, continuity, and image reproducibility) has not reached the level of analog systems. The more important point is that the product is not yet fully mature and the interface relationship is not unified (especially the video codec algorithm) has not yet formed a basic standard and uniformity. Nevertheless, this approach will be the best and inevitable way for TV surveillance systems to transition from analog to digital.

 

    A large part of the video matrix host currently on the market is still the traditional analog video matrix, and the digital matrix is ​​only a small part of it. With the advancement of technology and the digitalization of security products, it is undeniable that the digital matrix host will be the future development trend. Until many problems are faced with digital matrices, analog and digital matrices will coexist on the market.

 

Digital video matrix application advantages

 

    1. Cost advantage: video matrix and DVR are combined into one

 

    Using digital video matrix solution, only one device can realize the functions of video matrix and DVR at the same time, which greatly saves costs. The control of the matrix and the control of the DVR are integrated together, which is convenient and flexible. If you use an analog matrix, you need at least one matrix host and one DVR host. Installation and commissioning are complicated. In addition to the cost of the DVR, you must pay a high cost for the analog matrix. In addition, for the control of the analog matrix, you may need to connect other devices, such as display devices, matrix controllers, matrix control keyboards, etc. Some complex functions even require a special PC to configure. The analog matrix solution also requires video signal distribution and multiplexing equipment to implement the DVR recording function. With the digital matrix, you only need to add a simple matrix module on the basis of the DVR. The cost is relatively low, and the digital The integration of matrix and video recording system is high, the stability is enhanced, and the maintenance cost is reduced.

 

    2. Functional advantages: flexible configuration, powerful functions, simple and easy to use

 

    In the simulation matrix + DVR solution, the matrix and the DVR are independent and need to be controlled separately. The operation method provided by the simulation matrix is ​​complicated, the operability is very poor, and the function is single. If you want to implement more complex functions, you need a very complicated operation process; With the digital matrix, simultaneous control of the switching matrix and DVR can be achieved through a control platform. The operation interface can be freely developed by secondary developers under Windows or Linux. You can customize applications and customize various functions according to your customers' needs. The system built depends entirely on the developer's own software.

 

    In the digital matrix, based on the digital processing of the image: you can perform a lot of processing on the image while implementing video switching, such as superimposed characters, superimposed images, area masking, etc. These are the functions that are currently common in DVRs. But for the analog matrix, since its core is based on the processing of analog signals, it seems to be inadequate when facing these functions. Here, the character superposition function is taken as an example. The simulation matrix often requires an external character superposition chip to implement. Usually, only AS CII codes, that is, the superposition of English characters, can be implemented, and the simulation that can implement the superposition of Chinese characters can be said to be very few. , Not to mention support for Simplified, Traditional, and even Japanese. As for image superimposition and other functions, it is basically impossible to achieve in the analog signal layer.

 

    The digital matrix can provide richer image display modes. The traditional analog matrix can only perform the simplest 1: 1 image output; on the basis of this, the digital matrix can also achieve N → 1 (by scaling the image, multiple channels of images can be displayed in a window) and 1 → N (an input image is displayed on multiple outputs at the same time), even advanced features such as picture-in-picture.

 

    Finally, the system stability, the digital matrix + DVR scheme, has high system integration, low power consumption, and high stability; while the analog matrix scheme requires multiple devices, the probability of problems is greatly increased.

 

    3. Potential: huge development space

 

    The simulation matrix control system is currently very mature. The structure and function of its products have not changed greatly in recent years, even more than ten years, and the potential that can be tapped is very limited.

 

    The digital matrix is ​​completely different. The current development of digital technology can be described by the rapid change and broad prospects. First of all, with the improvement of hardware performance, in terms of high-speed buses: the 66M PCI bus has become very mature and popular, such as PCI-E or other high-speed serial buses. 720M is even a 1GHz high-performance DSP. It can be said that thanks to the continuous improvement of the performance of the hardware platform, the functions of the digital matrix will inevitably be continuously improved, and it will continue to develop to the high end. At the same time, the progress of the software cannot be ignored. New image compression and processing algorithms are constantly being proposed, and the efficiency of image compression is constantly improving. More sophisticated and smarter image processing algorithms are also being applied, such as intelligent motion detection, Intelligent recognition technologies (face recognition, fingerprint recognition, license plate recognition, signature recognition) have already been more mature applications. These higher-level image processing technologies, using the current hardware platform, can already be applied to our digital video system. in. Therefore, with the rapid improvement of the software and hardware levels, we have reason to believe that the development space of digital matrix will be very wide, and it will inevitably exceed the analog matrix comprehensively in terms of performance and function.

 

    4. Simple and convenient secondary development

 

    Unlike the previous H and D cards, which used separate SDKs, the new SDK will support H, HC, and MD cards at the same time. Encoding, decoding, and matrix control can be achieved at the same time through only one SDK. The encoding and decoding parts in the new SDK are compatible with the encoding and decoding parts in the original SDK. Users only need to add the matrix control part. Reduces the complexity of the user's secondary development. At the same time: H cards, HC cards, and MD cards can be mixed to facilitate maintenance and expansion of existing projects.