Design of universal set-top box with software and hardware separation based on Fujitsu HD chip

In the past, set-top boxes were designed and produced individually according to the special standard requirements of CA, browsers, etc. adopted by operators, which resulted in set-top boxes having to be customized for a certain operator, high software design costs, and set-top boxes that could not be mass-produced. The closed technical model and industrial chain made it difficult for new advanced set-top box chips to enter the market, resulting in low set-top box performance and high costs. If high-definition set-top boxes are also developed in this way, they will be difficult to popularize. How to break the closure and meet the special needs of operators while reducing costs through mass production seems to be a common problem faced by everyone. Using the latest digital TV hardware and software separation operating system can solve this problem well.

This article introduces a universal HD set-top box solution based on Fujitsu MB86H60 HD set-top box chip, using the Taixin hardware and software separation development platform.

The Origin of the Closed Digital TV Software Development Model

The set-top boxes used by more than 50 million digital TV users in China are almost all customized by operators from set-top box manufacturers. However, the development of digital TV software, which plays a key role in the digitalization process, has always been closed, especially CA software, which has a closed development process and uses a large amount of private black box technology. In addition, all third-party software needs to be integrated by set-top box manufacturers, which greatly increases the software development and testing burden of set-top box manufacturers. The development cycle of set-top boxes is long. Generally, it takes a long time from the advent of a chip to mass production. The "Moore's Law" that promotes the rapid development of the IT industry has lost its effect in the digital TV industry.

In the early days of digital TV development, as long as a few third-party software became market standards, set-top box manufacturers had limited choices for third-party software to integrate, and could only choose from a few CA and browser software that became market standards; conversely, third-party software such as CA and browsers that gained support from more set-top box manufacturers were more likely to consolidate their market position, thus forming a very closed digital TV software industry environment. Other software that did not become market standards, no matter how advanced, could not be recognized by the market and could not participate in the competition. Due to insufficient competition, the development of front-end digital TV CA, browser and other software became a "land grabbing" game between a few companies that entered the market earlier, resulting in serious backwardness of digital TV technology, which has remained at the level of ten years ago.

Digital TV CA, browser and other software standards that have become market standards are basically private, and the promotion of such products is actually the promotion of private standards. The software and hardware structures of various set-top box manufacturers vary greatly. In order to disperse risks, operators generally purchase from multiple set-top box manufacturers. The software and hardware designs of various set-top box manufacturers vary greatly. After operators accepted these dazzling array of set-top boxes and purchased in batches, they caused serious confusion in the set-top boxes used by radio and television operators, difficulty in upgrading, inability to load new services, and security vulnerabilities that could not be remedied. Many operators who are migrating are caught in a dilemma: if they stop, the capital chain may be broken; if they continue, they will get deeper and deeper.

Under such circumstances, some radio and television operators have made positive efforts and attempts. For example, Shaanxi Radio and Television Network has established a "Joint Laboratory for Unified Set-Top Box Solutions" to address problems such as confusion in set-top boxes, difficulty in upgrading set-top box software, and inability to load value-added services. According to Lv Xiaoming, Secretary of the Party Committee and Chairman of Shaanxi Radio and Television Network, the work of the joint laboratory has not only prompted Shaanxi Radio and Television Network to gradually form unified standards and specifications in terms of software and hardware functions, structures, and modularization to guide the company's future standardized development, large-scale application, and universal promotion of set-top box products, but also provided a reference for the establishment and improvement of domestic standards and specifications in the same industry. At the same time, it has effectively reduced the investment cost and operation and maintenance cost of set-top boxes for radio and television network operators, simplified the logistics and distribution process, and enabled suppliers to share functional configurations, technical specifications, and solutions , thereby greatly reducing the cost of set-top box maintenance. What is particularly outstanding is that this measure has opened up all links of radio and television network terminal application equipment research and development, procurement, production, technology, customer service, operation, sales, etc., and created a new model of long-term cooperation for the market competition relationship between operators and suppliers, established a unified, open, competitive and orderly market order for the industrialization process of cable television, and laid a solid foundation for the sustainable development of value-added services after the migration of radio and television network digital TV.

The practice of Shaanxi Radio and Television Network is worth thinking about and learning for our operators. Although this practice is still at the level of software and hardware unification, it is already a great progress for operators. When it comes to core standard software issues such as CA and middleware, software integration is still required, and these standards are still private and irreplaceable. The need for software modules to be integrated and cannot be replaced independently of set-top box manufacturers is the main reason for the closed and backward nature of the current digital TV industry.

In the process of contacting manufacturers, Taixin's hardware-software separation operation platform is worth in-depth study. This open platform is conducive to the initiative of radio and television to grasp the standards. On this platform, even CA can become an open technology, which is very beneficial to the integration and unification of radio and television standards.

Introduction to the open software and hardware separation operating platform

Both set-top box manufacturers and broadcasting and television operators hope that set-top boxes can have a unified and open software and hardware platform, and standardize them as much as possible so that set-top boxes can be universal and easy to mass produce. However, due to the confusion of standards, digital television has now entered the Warring States period, and it is not easy to unify. In the absence of a standard hardware platform, it is very important and feasible to first unify the software and hardware development platform. The aforementioned contribution of Shaanxi Radio and Television in the industry lies in this. However, it is far from enough to unify the software and hardware of the set-top box part. If standard software such as CA and middleware still integrate private standards and continue to use this closed and non-open development model, the joint laboratory will only replace the R&D department of the set-top box manufacturer and will not change the long-term closed industry outlook. To achieve openness, a newer development model and concept is needed.

The digital TV software and hardware separation development platform used in this design is provided by Shandong Taixin, which is similar to the iPhone SDK development kit of Apple Inc. Its API is very close to the low level and completely open, allowing any digital TV software engineer to develop set-top box software on this platform, and can independently compile and debug, and then independently download to the set-top box for operation. It does not need to be developed according to the traditional set-top box software development model, breaking the tradition that all third-party software is integrated and tested by the set-top box manufacturer, thereby greatly reducing the software workload of the set-top box manufacturer, reducing the set-top box cost, and expanding the source of software channels. The following is an open software and hardware development platform block diagram:

This open platform has a rich set of platform software API interfaces , including commonly used software modules , such as network, SI information analysis, etc.

Downloadable CA is the prerequisite for implementing an open software and hardware separation development platform

In the process of developing digital TV conditional access software, for security reasons, CA companies must sign confidentiality contracts with set-top box manufacturers. The integration test of CA software is all carried out in a confidential manner. CA companies rely on this confidentiality to ensure security, which is the main reason for the closed development of digital TV software. If digital TV software is to be open, the closed nature of digital TV CA software development must be broken. In order to resolve this contradiction, Taixin proposed the concept of downloadable CA, which cleared the obstacles to the implementation of the software and hardware separation platform.

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Downloadable CA means that the CA software can be downloaded from the front end to the set-top box for operation without software integration. Since CA is downloadable, the risk of complete collapse once the CA algorithm and key are cracked can be avoided. This is the long-standing curse of "death in the light" that has entangled CA, and it is also the reason why various radio and television operators are very cautious when choosing CA and keep the CA development process confidential. Downloadable CA technology can immediately replace the "exposed" algorithm and key, or even the entire CA system, getting rid of the fate of traditional CA "death in the light", so this downloadable CA can be open. The security and openness of this CA are self-evident, because it completely changes the traditional model of CA as a black box technology, making the development process of digital TV software open and possible. Downloadable CA has the following two forms:

If the algorithm or key is downloaded, it is cardless CA technology. The security of this technology depends on the unique ID number and encryption engine in the main chip of the set-top box, as well as the FLASH with the ID number .

If only the set-top box CA part is downloaded and a smart card is inserted, it is the traditional smart card CA technology. At this time, when there is no card CA, it is possible to replace the CA without entering the house or replacing the set-top box. It is almost impossible for the traditional smart card CA to switch to other CAs in order to solve its own security vulnerabilities, which is also the main reason why smart card CA is bundled with operators.

On an open platform with separated software and hardware, CA companies can independently develop set-top box CA and then download it to the set-top box. In this way, the closed nature of CA can be limited to the CA company, so that this closed nature will not affect the development of other software. The development of other similar software and the spread of source code are also limited to their own scope, thus protecting their respective intellectual property rights, increasing the enthusiasm for software development, and ensuring the openness of the entire platform.

Universal HD set-top box using MB86H60 under the hardware-software separation development platform

To facilitate future upgrades, we plan to unify the HD set-top box hardware onto the Fujitsu MB86H60 platform. The block diagram of the MB86H60 set-top box chip is as follows. It is compatible with the upcoming MB86H61 and has AVS and VC1 decoding capabilities:

Fujitsu MB86H60 HD set-top box chip uses ARM1176JZF-S CPU , which is the same as the CPU in the iPhone mobile phone we usually use . Its biggest advantages are high speed, low power consumption and high reliability. The chip works at 324MHz, which can achieve the efficiency of other chips working at 450MHz clock. It has high-definition H.264/MPEG2 decoding; integrated HDMI high-definition interface, HDCP anti-copy function; built-in Ethernet and USB; built-in encryption engine for DRM control; program register space is 128MB, two independent high-speed DDR 2 channels, system software operation and high-definition decoding do not affect each other; the normal power consumption of the whole chip is 1.2W, and no external heat sink is required. In particular, the chip has a NAND FLASH controller, which can be matched with a low-cost large-capacity NAND FLASH to meet the needs of Taixin software and hardware open platform for large-capacity storage space, and can also be hung with a large-capacity NAND FLASH to achieve high-definition PUSH VOD. The universal ARM1176CPU makes the high-definition solution more open on the Taixin platform, which can easily meet the needs of many third-party software developers to develop application software on the platform in the future, including CA, middleware and other software. It can even be easy to transplant mobile games to set-top boxes, because 90% of the mobile phone CPUs in the market are using ARM CPUs, and now the proportion of high-end functional mobile phones using ARM11 CPUs is even higher. In addition, because MB86H60 can have a high network speed, it can also be designed as an IPTV/DVB dual-mode set-top box.

In addition, MB86H60 also has built-in Taixin's CA and DRM engines, which can effectively protect the copyrights of program providers.

Product reliability and stability design and guarantee

Fujitsu's MB86H60 high-definition set-top box chip is jointly designed by Fujitsu Japan and Fujitsu Germany. The rigorous and meticulous work of Japanese and German engineers laid the foundation for the high-quality research and development of this high-definition chip. Through the following optimized design and professional configuration, this high-definition interactive set-top box has more stable performance, more perfect quality, and higher cost performance.

MB86H60 high-definition decoding dedicated main chip, each chip has a unique ID number that cannot be tampered with, and Taixin dedicated encryption engine, which ensures the security of CAS used in this solution. In addition, high-quality image and audio decoders are configured to ensure high-quality audio and video effects and high software running speed.

High-frequency head Using the internationally renowned brand ALPS TDAE, it achieves a lower reception threshold and ensures stable signal reception.

We use large-capacity DDR2 and NAND FLASH from regular brands to ensure the stability of software operation and future function expansion.

Adopt SST's NOR FLASH. This NOR FLASH has fast read and write speed, and each chip has a unique ID number that cannot be tampered with. When used with MB86H60, the CAS used in this solution can be more secure.

Software Structure Overview

The software of this solution is layered, from bottom to top: the underlying driver, operating system, application software layer, and hardware and software separation adaptation layer.

Software separation is an important development direction of digital TV software in recent years. It breaks the closed development mode of digital TV centered on CA and allows various software companies to develop digital TV software on an open platform. The openness, scalability and standardization of digital TV software require such a platform. This software and hardware separation platform technology is open, allowing various software companies to independently develop software modules on this platform. Each software module is independent of each other. Broadcasting and television operators only need to download it from the front end to the set-top box, saving the integration time of individual modules, facilitating the standardization of digital TV software, and avoiding the disadvantages of any software upgrade and improvement caused by the software and hardware bundling of the set-top box, which requires reintegration and testing, as well as the inconvenience caused by the upgrade of the set-top box. This disadvantage is more obvious when there are many types of set-top boxes for broadcasting and television. It is worth noting that this platform does not need to provide CA library files to set-top box manufacturers, and the security is greatly improved. It allows broadcasting and television to change CA algorithms and keys at any time, and the operating environment of CA can also be changed at any time. Various functions can be expanded based on CA, which can realize the platformization of CA and facilitate the independent modularization and standardization of software.

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Software Development Process

It is very convenient to develop software on this hardware-software separation platform. After defining the interfaces between modules, each module can be developed and tested in parallel. When the development is completed, it becomes a standardized software module, which also reduces a lot of software integration and testing time. The software development process is as follows:

The biggest advantage of adopting this open software development model is that each module can be developed and replaced independently, which is convenient for the standardization of software modules, expands the software source of digital TV, and facilitates the unified upgrade of set-top box software and the random loading of value-added services. It is the development direction of digital TV software and can be said to have brought a revolution to the radio and television industry. Yueqing Radio and Television, from leaders to grassroots engineering and technical personnel, is open-minded and dares to accept new things and new technologies, which is also the reason why Yueqing Radio and Television appreciates the hardware and software separation operation platform. If its shortcomings are that it is not easy to be accepted by conservative radio and television that adheres to mainstream consciousness, and there are relatively few application cases, but objectively speaking, this is not unrelated to the technical level of radio and television operators.

Summarize

The development of high-definition set-top boxes using Taixin's open software and hardware separation platform and high-performance MB86H60 high-definition set-top box chips can enable software engineers to quickly master digital TV technology and knowledge, which is of great help in popularizing digital TV software knowledge. The development of digital TV software is no longer limited to a few companies in the past, and the source of software has also been broadened. The separation of software and hardware allows software development and hardware production to be undertaken by different companies. The open software development platform allows many software companies to develop software for set-top boxes, and it is not integrated by set-top box manufacturers, but downloaded independently by operators. Therefore, set-top box manufacturers can get rid of the different needs of each operator, and can mass-produce universal set-top boxes, greatly reducing the cost of set-top boxes. At present, there are plans for radio and television to use this solution for high-definition two-way translation. This is a good choice for relatively wealthy areas like Yueqing that have not yet been digitized, and it is also in line with the development direction of digital TV.

At present, the software and hardware separation technology is still a very new technology, and most radio and television operators have not really realized the convenience brought by this advanced technology. In the "Several Opinions on Accelerating the Development of Radio and Television Cable Networks" issued by the State Administration of Radio, Film and Television, it is clearly required that provincial radio and television departments should actively seek government support, organize the formulation of practical integration plans, clarify the integration roadmap and timetable, promote specific implementation, and ensure that all provinces basically complete the integration before the end of 2010 , laying the foundation for the scale and industrialization of the national radio and television cable network in the future. With the promotion of policies, the pace of provincial network integration will be further accelerated. Taixin's open software and hardware separation platform is conducive to radio and television to establish independent standards, avoid the constraints brought by the use of private closed standards, and is very beneficial to the integration and unification of radio and television standards. I believe that the open software and hardware separation operation platform will play its due role.