Digital set-top box

Saturday, 13 January 2007

Set-top boxes (STB) are microprocessor-based controllers that control the operation of media systems. Set-top boxes are used to process televisions signals provided, for example, from a cable, into various consumer devices, particularly television sets. Consumers are beginning to have access to a large number of television programs over an increasing number of television channels. Set top boxes such as satellite receivers, cable boxes, and digital video recorders or combinations thereof are becoming more popular because they provide features to consumers that were not previously available. Set-top boxes are used to control the conversion of the media signal transmitted from a content provider into the images and sounds that are provided by a corresponding media display device. Set top boxes allow users to digitally record programming content such as television programs, lock certain channels from being accessed without permission, view electronic program guide data, and set personal preferences that control how the program guide data and/or the programming content is presented to the user. Set-top boxes such as cable television boxes and Internet terminal boxes, are increasingly being used with consumer home entertainment equipment such as television sets. Typically, a set top box connects to a television set and interfaces various media such as cable television broadcasts, satellite signals, stereo components, internet connections via a telephone line, DVD and VCR devices, and other types of electronics and communication media. Digital video recorders, for example, provide the capability of concurrently recording incoming streaming video data using hard disk drive technology and playing back previously recorded video data. A digital video recorder receives incoming streaming video data from the output interface of a standard set-top box configured to receive the broadcast signals from a multiple-service operator (MSO), and the output of the digital video recorder is transmitted directly to a display device, such as a television.

Television set-top boxes are used to provide tuning capabilities for cable and satellite television systems. Generally, a subscriber signal conversion apparatus is required to receive a cable broadcasting signal or a satellite broadcasting signal or use a next generation two-way multimedia telecommunication service, such as a video-on-demand through a TV set, home shopping, a network game, etc. Such subscriber signal conversion apparatus coupled to the TV set and is called a set-top box. Traditional broadcast television systems broadcast the same television signal to each person viewing a particular station. Thus, each person viewing a particular channel will necessarily view the same programming content as well as the same advertisements embedded in the programming content. The emerging technology of digital television systems holds a promise of allowing a television set to provide a vast array of new services. Digital technology provides higher quality television reception as well as the availability of additional services such as electronic program guides and interactivity. Digital television systems, such as cable television systems and satellite television systems, are capable of displaying text and graphic images in addition to typical video program streams. An example of digital television services which make use of text and graphic image display is interactive television. Features of interactive television accommodate a variety of marketing, entertainment and educational capabilities such as allowing a user to order an advertised product or service, compete against contestants in a game show, or request specialized information regarding a televised program. With digital television media, the total viewing audience may be divided into many subgroups based on common interests or common demographic descriptors. An on-screen user interface (UI) is commonly used with televisions and television set-top boxes for cable and satellite television systems to support numerous features. Features such as menus of favorite channels, locks and limits, timed recording, etc. as well as electronic program guides, pay-per-view (PPV) or video-on-demand (VOD) and other menus and guides are typically provided through such a user interface. Users of the interactive television systems will be able to access movies on demand, pay bills, bank, shop, place orders, make reservations, participate in interactive games and forums, access informational data bases and perform numerous other functions in addition to accessing the traditional television stations. Typically, the interactive functionality is controlled by a set top box connected to a television set. The goal of the systems is to provide a user friendly interface at the user end. The systems require that the user have a computer/decoder similar to the need for having a cable decoder in traditional cable systems. These computer/decoders for the interactive television systems have become known as set top boxes referring to the fact that these boxes will be set on top of the television set. The set top box executes an interactive program written for a television broadcast. The interactive functionality is displayed upon the television set screen and may include icons or menus to allow a user to make selections via the television's remote control. These set top boxes also can reside inside the television housing itself in a fashion similar to the cable boxes which originally resided outside in a separate box but now are incorporated inside the television housing. Each set top box will include a remote control which will provide for the user interface and interaction between the user and the interactive television system. The set-top box typically allows the user to select between channels, perform programming functions, etc. Consequently, television set-top boxes are becoming an integral part of home entertainment equipment.

A set-top box performs a number of functions associated with processing a broadcast digital signal. The rapid gains in digital technology and telecommunications have increased the desirability of having a network in the home to interconnect a multitude of products in the home with each other and to the outside world. The range of available outside services includes interactive services, cable video and audio services, satellite networks, telephone company services, video on demand, and other types of information services. Digital electronics and, in particular, digital video systems are becoming ubiquitous in today's electronic world. Digital broadcast systems include direct broadcast digital satellite systems, interactive internet access systems, and digital cable systems. Digital broadcasting provides a number of advantages to subscribers, such as variety and flexibility of programming, useful and comprehensive support services, and superior audio and video quality. Subscribers receive broadcast digital signals via set-top boxes or other similar consumer electronic equipment located in the subscriber's home. A digital video system generally includes a processor, memory, a hardware graphics system for generating graphics, an application that provides system functionality including graphics creation, and an application program interface (API) for communicating between the application and graphics system. The digital video system can provide various functions relative to the digital television services, such as television programming information, games, internet browsing and other multimedia in a graphical format on a television display. A digital set top box may be used as an interface between the digital broadcast systems and a television set, computer or other type of remote user terminal. The set top box typically provides functions such as input/output processing of video, audio and other data, audio and video demultiplexing and decompression, graphics overlay processing for use in electronic program guides and the like, entitlement control for video on demand (VOD), near video on demand (NVOD) and pay-per-view (PPV) applications, and remote control user interfaces. As the internet communication has become prevalent and the number of people using the internet has increased, the development of TV sets capable of connecting to the internet, so called an internet TV, has been launched and some products are already commercially available in the market. Advanced set-top boxes, which are those that have the ability to access the Internet or to provide other information or entertainment services beyond conventional television, provide the ability to control the information viewed on a television screen and to interactively respond thereto, offer the potential for television viewers to use their television sets to purchase goods, receive customized news, send and receive electronic mail, and perform substantially any other activity that can be performed over the Internet.

In general, set-top boxes include signal processing devices to process the particular digital (and/or analog) audio and/or video signals, one or more microprocessors that handle supervisory and control functions, and one or more volatile and non-volatile memories designed to store short-term and long-term information. In detail, the STB includes a power supply, a remote controller signal receiver for receiving and decoding the command signals from the remote controller, video processor for processing the list of the service items transferred in the form of image data into still images, an MPEG (motion picture experts group) decoder for recovering original video data from compressed MPEG data which is transmitted from the server and corresponds to a particular service item selected by the user, a video encoder for receiving the recovered data from the MPEG decoder and for transferring the received data to the TV as picture data and an audio processor for processing audio data contained in the video on demand (VOD) service program. A central processing unit CPU of the set-top box controls the above components. In a digital set-top box, information and instructions associated with receiving and processing digital broadcast signals are stored in a memory unit of the set-top box and executed by a processor. With a bi-directional set-top box, in addition to receiving broadcast signals, a subscriber can transmit messages to the digital broadcast system operator. The non-volatile memory (i.e. EPROM, NVRAM, ROM, etc.) for storing program instructions that controls media signal conversion when the set-top box is off, and the main memory (i.e. SDRAM, DRAM, etc.) provides fast processor access to the program instructions when the set-top box is on. The microprocessors are controlled by firmware that includes control sequences and sub-sequences for all the functions provided by the set-top box. The set top box may comprise an application specific integrated circuit (ASIC), which performs decoding and processing functions, and a memory for storing video signal information. The compressed signals may be received over cable from a cable TV source or from any telecommunications source including, for example, satellite broadcast. A digital cable set-top box is connected to a cable head end through a cable and produces a program for a digital cable. Television set-top boxes are used to provide tuning capabilities for cable and satellite television systems. While these devices still provide that fundamental function, digital set-top boxes now often incorporate powerful computers which expand the usefulness of the television set-top box beyond that of merely providing tuning functions for cable and satellite systems. Many set-top boxes now provide users with the ability to navigate the Internet using their television sets rather than a computer. The digital cable set-top box makes a bidirectional communication with the cable head end in a manner that it receives an A/V broadcast program from the cable head end through an inband (IB), and transmits a user's request to the cable head end through an out of band (OOB) and receives a corresponding service to be displayed.

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