DVB is a cooperative organization, consisting of more than 260 members from more than 30 countries around the world. The core organization is the DVB Steering Committee, which is responsible for certifying all DVB standards and technical specifications. MHP project follows the convention of DVB and divides the project into two modules, namely, technical module and commercial module. Develop technical solutions and commercial solutions respectively.
MHP project team has set up two working groups for two modules:
① Market-oriented working group, which mainly defines users and market demand (including Internet access, etc.). Enhanced and interactive TV broadcasting based on local network.
② Technology-oriented Working Group -DVB-TAM (Technology
MHP-related issues) to solve the problems of DVB programming interface (API) specification.
Digital TV software platform-middleware has no unified definition and standard because of incompatible solutions put forward by various manufacturers. Generally speaking, middleware refers to the software part between the real-time operating system and application programs in the digital TV set-top box, which exists in the form of application program interface API, and the whole API set is stored in the flash memory of the set-top box. MHP project team is committed to introducing a unified middleware standard. Table 1 lists some typical digital TV systems and middleware providers, and the statistics are up to the beginning of 200 1.
Table 1 Comparison of some companies' middleware: OpenTV Canal+ NDS Integrator Network No.43, 20 unknown application software, Such as audio and video, games, stocks, network broadcasting, Chinese electronic program guide, etc., boot interface, games, electronic program guide, stock information, webpage broadcasting and other unknown audio and video, electronic program guide, stock information, webpage broadcasting and other CA Nagra Vision CAS MediaGuard open video guard Nagra Vision CAS middleware and related parts EN2 MediaHighway need not develop language standard C language special scripting language standard C language to integrate with other middleware providers. Say whether there is a virtual machine, whether there are development tools provided by Open Author Pro and SDK Studio+I-Frame editor, and the development direction of MHP.
Java MHEG-5
The Java Java MHP project team considered the following candidate reference APIs:
MHEG-5
Expressway+
OpenTV
HTML/Java
Java TV
Multimedia and Hypermedia Expert System (MHEG-5) is a format to enhance broadcasting services. It can run basic applications on terminals with limited resources. It uses an open attitude to describe programming objects, so that these objects can be applied to standardized programming to meet specific programming requirements.
Mediahighway+ and OpenTV systems will be introduced in detail in the application examples of this paper, and will not be described here.
HTML is a universal standard language on the Internet. It is a purely explanatory language and needs to run an interpreter on this machine.
Ava is a new generation programming language developed by SUN Company. Originally intended for smart home appliances, it has now become the mainstream of Internet programming language. It is an object-oriented programming language, similar to C++, but it abandons the parts that are rarely used and not easy to use in C++. Its characteristics are cross-platform, multi-thread and distributed. It can be used to develop software under the network environment of various machines and different operating platforms, compile at one time and run everywhere. It completely changed the development mode of application programs and brought another technological revolution since PC.
Java applications can only realize their functions through a Java virtual machine closely related to the operating system. Embedded Java virtual machine developed for real-time operating systems (such as HOPEN, VXWORKS, PSOS) can provide a supporting environment for Java programs. Real-time operating system supports personal Java application environment of consumer electronic products. This means that ordinary consumers, whether at home, in the office or on the road, can experience the colorful life patterns of interactive TV sets, refrigerators, toast boxes, burglar alarms and other aspects on the real-time operating system and Java API through Java virtual machine technology, and exchange information through TCP/IP to realize family informationization and intelligence.
Java TV API is a product developed by SUN Company and major digital TV companies on the basis of Java platform through open research, and it is one of the giants in the computer field. Sun company's fist product in the field of digital TV broadcasting. With the help of Java, a cross-platform language, enhanced TV and interactive TV are strengthened and optimized. Major manufacturers of electronic consumer products have publicly stated that their products will support Java TV API as the global digital TV software platform standard.
Java TV API is designed for the unique functions of digital TV receiver, including:
Audio/video media control
Broadcast data access
Service information data access
Tuner and decoder control
Screen graphics processing
DVB organizations adopt an open attitude when considering API candidates, which can meet the requirements of different levels of operators (called horizontal market). The choice of API has nothing to do with conditional access system, but it can also support multi-secret applications.