Patent Application
20050166227
The present invention relates generally to Program and System Information Protocol (PSIP), and more particularly, to the retrieval of PSIP program data in terrestrial broadcast systems.
As described in the ATSC (Advanced Television Systems Committee) standard, PSIP includes tables that have data describing the digital broadcasted channels and their programs. When retrieving PSIP program data in a terrestrial broadcast system, a device (i.e., set-top box) is tuned to a particular channel's frequency before the PSIP table packets are filtered. This can be a lengthy process since the PSIP table packets come in varying time intervals. The entire process to build a complete program data for the particular channel/frequency could take some time (i.e., 10 seconds) to complete. This means a user has to wait to see the program information for the particular channel and program. The process is repeated for each channel;
therefore, it takes several minutes to complete the process for a whole program guide.
The present invention provides a method to retrieve PSIP program data without having to wait for the device to scan table packets of a particular channel or all the channels.
This is achieved by using a second tuner of the device to do the scanning in the background while a first tuner is tuned to a selected channel for broadcasting its channel information.
The Program and System Information Protocol for terrestrial broadcast and cable specification as described in A/69 by Advanced Television Systems Committee is attached hereto (Appendix A) and incorporated herein by reference.
In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in order not to obscure the understanding of this description.
System Level
The processor 110 represents a central processing unit of any type of architecture, such as embedded processors, mobile processors, micro-controllers, digital signal processors, superscalar computers, vector processors, single instruction multiple data (SIMD) computers, complex instruction set computers (CISC), reduced instruction set computers (RISC), very long instruction word (VLIW), or hybrid architecture.
The processor bus 120 provides interface signals to allow the processor 110 to communicate with other processors or devices, e.g., the MCH 130. The processor bus 120 may support a uni-processor or multiprocessor configuration.
The processor bus 120 may be parallel, sequential, pipelined, asynchronous, synchronous, or any combination thereof.
The MCH 130 provides control and configuration of memory and input/output devices, the system memory 140, and the ICH 150. The MCH 130 may be integrated into a chipset that integrates multiple functionalities such as the isolated execution mode, host-to-peripheral bus interface, and memory control. The MCH 130 interfaces to the peripheral bus 160. For clarity, not all the peripheral buses are shown. It is contemplated that the system memory 140 may also include peripheral buses such as Peripheral Component Interconnect (PCI), accelerated graphics port (AGP), Industry Standard Architecture (ISA) bus, and Universal Serial Bus (USB), etc.
The system memory 140 stores system code (i.e., code to calculate a shared key) and data. The system memory 140 is typically implemented with dynamic random access memory (DRAM) or static random access memory (SRAM). The system memory 140 may include program code or code segments implementing one embodiment of the invention. The system memory includes a user interface management 145. Any one of the elements of the user interface management 145 may be implemented by hardware, software, firmware, microcode, or any combination thereof. The system memory 140 may also include other programs or data, which are not shown, such as an operating system. The user interface management 145 contains program code (i.e., EPG Manager) that, when executed by the processor 110, causes the processor 110 to perform operations as described below.
The ICH 150 has a number of functionalities that are designed to support I/O functions. The ICH 150 may also be integrated into a chipset together or separate from the MCH 130 to perform I/O functions. The ICH 150 may include a number of interface and I/O functions such as PCI bus interface to interface to the peripheral bus 160, processor interface, interrupt controller, direct memory access (DMA) controller, power management logic, timer, system management bus (SMBus), Universal Serial Bus (USB) interface, mass storage interface, low pin count (LPC) interface, etc.
The mass storage device 170 stores archive information such as code, programs, files, data, applications, and operating systems. The mass storage device 170 may include compact disk (CD) ROM 172, a digital video/versatile disk (DVD) 173, floppy drive 174, hard drive 176, flash memory 178, and any other magnetic or optical storage devices. The mass storage device 170 provides a mechanism to read machine-accessible media. The machine-accessible media may contain computer readable program code to perform tasks as described in the following.
The I/O devices 1801 to 180N may include any I/O devices to perform I/O functions. Examples of I/O devices 1801 to 180N include controllers for input devices (e.g., keyboard, mouse, trackball, pointing device), media cards (e.g., audio, video, graphics), network cards, and any other peripheral controllers. Elements of one embodiment of the invention may be implemented by hardware, firmware, software or any combination thereof. The term hardware generally refers to an element having a physical structure such as electronic, electromagnetic, optical, electro-optical, mechanical, electro-mechanical parts, etc. The term software generally refers to a logical structure, a method, a procedure, a program, a routine, a process, an algorithm, a formula, a function, an expression, etc. The term firmware generally refers to a logical structure, a method, a procedure, a program, a routine, a process, an algorithm, a formula, a function, an expression, etc. that is implemented or embodied in a hardware structure (e.g., flash memory, ROM, EROM). Examples of firmware may include microcode, writable control store, and microprogrammed structure. When implemented in software or firmware, the elements of an embodiment of the present invention are essentially the code segments to perform the necessary tasks. The software/firmware may include the actual code to carry out the operations described in one embodiment of the invention, or code that emulates or simulates the operations. The program or code segments can be stored in a processor or machine-accessible medium or transmitted by a computer data signal embodied in a carrier wave, or a signal modulated by a carrier, over a transmission medium. The processor-readable or accessible medium or machine-readable or accessible medium may include any medium that can store, transmit, or transfer information. Examples of the processor-readable or machine-accessible medium include an electronic circuit, a semiconductor memory device, a read-only memory (ROM), a flash memory, an erasable ROM (EROM), a floppy diskette, a compact disk (CD) ROM, an optical disk, a hard disk, a fiber optic medium, a radio frequency (RF) link, etc. The computer data signal may include any signal that can propagate over a transmission medium such as electronic network channels, optical fibers, air, electromagnetic, RF links, etc. The code segments may be downloaded via computer networks such as the Internet, Intranet, etc. The machine-accessible medium may be embodied in an article of manufacture. The machine-accessible medium may include data that, when accessed by a machine, causes the machine to perform the operations described in the following. The machine-accessible medium may also include program code embedded therein. The program code may include machine-readable code to perform the operations described in the following. The term data here refers to any type of information that is encoded for machine-readable purposes. Therefore, it may include program, code, data, file, etc.
All or part of an embodiment of the invention may be implemented by hardware, software, or firmware, or any combination thereof. The hardware, software, or firmware element may have several modules coupled to one another. A hardware module is coupled to another module by mechanical, electrical, optical, electromagnetic or any physical connections. A software module is coupled to another module by a function, procedure, method, subprogram, or subroutine call, a jump, a link, a parameter, variable, an argument passing, a function return, etc. A software module is coupled to another module to receive variables, parameters, arguments, pointers, etc. and/or to generate or pass results, updated variables, pointers, etc. A firmware module is coupled to another module by any combination of hardware and software coupling methods above. A hardware, software, or firmware module may be coupled to any one of another hardware, software, or firmware module. A module may also be a software driver or interface to interact with the operating system running on the platform. A module may also be a hardware driver to configure, set up, initialize, send and receive data to and from a hardware device. An apparatus may include any combination of hardware, software, and firmware modules.
Program and System Information Protocol (PSIP)
Program and System Information is data that is transmitted along with a station's DTV signal that provides DTV receivers information regarding the station and what is being broadcasted. PSIP provides information for DTV receivers to identify a DTV station and to determine how a receiver can be tuned to it. PSIP informs the receiver whether multiple program channels are being broadcasted and, if so, how to find them. In order for the receivers to correctly identify and tune to the station, broadcasters should properly encode broadcast and program data in their DTV stations signals.
PSIP is collection of tables designed to operate within every Transport Stream (TS) for terrestrial broadcast of digital television. PSIP describes the information at the system and even at levels for all virtual channels carried in a particular transport stream. Additionally, information for analog channels as well as digital channels from other Transport Systems may be incorporated.
There are two main categories of information in PSIP Standard: system information and program data. System information allows navigation and access of the channels within the DTV transport stream, and the program data provides necessary information for efficient browsing and event selection. Some tables of the PSIP announce future events and some are used to locate the digital streams that make up an event. The PSIP data are carried via a collection of hierarchically arranged tables.
As stated earlier, the PSIP is a collection of tables such as a system time table (STT), master guide table (MGT), virtual channel table (VCT), rating region table (RRT), event information table (EIT), extended text table (ETT), etc. These tables are designed to operate within every Transport Stream (TS) for terrestrial broadcast of digital television. Each table describes elements of typical digital television services. Although information for analog channels as well as digital channels from other TS may be incorporated, it is noted that not all of these tables are required for terrestrial and cable applications. Since the present application applies to terrestrial application, only information related to this application is discussed.
The STT is a small data structure that fits one transport stream packet and serves as a reference for time-of-day functions. The STT is sent in packets every second with the based PID. Receivers can use this table to manage various operations and scheduled events, as well as display time-of-day.
The MGT contains data pointers to the identification number of the packets that contain all other tables (with the exception of the STT). The MGT controls the versions of all broadcasting program tables. The MGT provides indexing information for the other tables that comprise the PSIP standard. The MGT lists key information about other tables including version numbers, table sizes, and packet identifiers (PIDs). It defines table sizes necessary for memory allocation during decoding and version numbers to identify those tables that need to be updated, and generates the packet identifiers that label the tables. The MGT allows simpler decoder designs for receivers because any change in PSIP status is flagged in this table. Only the base PID needs to be monitored by a receiver to detect changes in PSIP status.
The VCT, also referred to as the terrestrial VCT (TVCT), provides attributes of all virtual channels in the transport stream. The VCT contains a list of channels in the transport steam. The VCT stores the information for all channels. These channels and their attributes are or will be online. Among the attributes given are the channel name and channel number. This table contains a set of data that enables a receiver to tune and locate the service being broadcast. In other words, it contains information on each service that a broadcaster creates or has announced that will be created within the DTV channel assignment. Even though it may also include the broadcaster's analog, the present invention applies only to digital channels (e.g., terrestrial broadcasting). For terrestrial broadcasting, the terrestrial VCT is used (TVCT). The information contained in the VCT includes the channel numbers (major and minor) and transport stream identification (TSID), pointers to the component streams that make up a program, and descriptive information.
The EIT provides program titles and technical data about the planned events on the virtual channels and events. The EIT provides the information on the current broadcasting programs and future broadcasting programs. Each EIT covers a period of time (i.e., three hours). The starting time for each EIT may be constrained to be one of the CUT (Coordinated Universal Time), the current local time, 00:00 (midnight), 3:00, 6:00, 9:00, 12:00 (noon), 15:00, 18:00, and 21:00. EIT-0 represents the current three hours of programming. For terrestrial PSIP, the first four EIT's (EIT-0, EIT-1, EIT-2, and EIT-3), representing 9 to 12 hours of programming, are required. The maximum number of EIT's is 128, permitting up to 16 days' worth of program information to be delivered to receivers.
The RRT provides rating information for each geographic region and/or country. The RRT is where a rating table of each program is listed. The RRT has been designed to transmit the rating system in use for each country using the ratings. The content advisory descriptor, which may appear in the EIT and PMT, indicates, for a given event, the ratings for any or all of the rating dimensions defined in the RRT.
The ETT provides the detailed information on the current broadcasting programs and future broadcasting programs. It provides detailed descriptions of virtual channels and events. The PID of the ETT is defined in the MGT. Although ETT is optional for terrestrial applications, it is used when additional information about the entire event is desired. However, receivers may have limited support for descriptive text so there may be a trade-off between covering more events and more data about each event. Furthermore, the rate the information is sent can be adjusted by setting the time interval between ETT's to make more efficient use of bandwidth.
The three main tables (VCT, EIT, STT) contain information to facilitate suitably equipped receivers to find the components needed to present a program (event). Although receivers are expected to use stored information to speed channel acquisition, sometimes parameters must change and the VCT is the table that must be accurate each instant as it provides the actual connection path. If nothing has changed since an EIT was sent for an event, then the anticipatory use of data is expected to proceed, and when there is a change, the new parts would be used. There are certain must have items and must do rules of operations. If the PSIP elements are missing or wrong, there may be consequences, which will vary depending on the type of receiver. However, the key elements that must be set and/or checked will not be discussed since it is beyond the scope of the present invention. It is contemplated that the information contained herein applies, but is not limited to, broadcasters, network operators, infrastructure manufacturers, and receiver manufacturers.
The plurality of streams of digital source data is retrieved via tuners 220 and 225. Each stream represents a video, an audio, or an ancillary data services component, such as PSIP data of a television program. As stated above, the PSIP data from the transport stream may include control data and data associated with program audio and video services such as system information for a program guide. The data is retrieved from a filter (i.e., PID packet identifier filter), which scans the incoming stream for particular types of data (i.e., PSIP data). The PID filter may be implemented by hardware, firmware or software. The EPG Manager receives the PSIP data then parses the data for channel information. The channel information is embedded in the above-described tables of the PSIP transport stream. The data is then stored in a database (i.e., Program Guide Database). The database is used by a monitor application (i.e., any EPG which users see onscreen).
The demodulator 355 coupled to the tuners 220 and 230, and the demultiplexer 335. The demodulator 355 demodulates the digital signal (i.e., the transport stream 109) carried in the physical channel selected by the tuner 230. The demultiplexer 335 receives the demodulated transport stream, extracts the video, audio, and data programs from the transport stream, depacketizes and demultiplexes the transport stream into video, audio, and ancillary data bit streams (i.e., AC bitstream, MPEG bitstream and PSIP data). It is noted that although the disclosed system is described in the context of a system for receiving terrestrial broadcast video signals incorporating ancillary program specific and timing information in MPEG compatible format, it is exemplary only. The MPEG data format is widely adopted and detailed in the MPEG-2 (Moving Pictures Expert Group) image standard. The program specific and timing information may be of a variety of types. The demultiplexer 335 separates the transport bit stream into streams of transport packets, which include data streams for video, audio and PSIP data. The demultiplexer 335 directs the data in each of the transport packet data streams to a decoder for that stream. These bitstreams may be stored in a buffer (not shown). The decoders 340 and 345 decode and reassemble the video and audio bitstreams respectively into data streams. The video decoder 340 decodes a video bit stream, which corresponds to the ATSC Digital Television Standard. The audio decoder 345 decodes an audio bit stream, which provides audio signals at output ports (i.e., speakers). The decoders cause the flow of data to be regulated so that data can be presented in synchronization with an instant of audio or visual information of the program. The video information is broadcasted via the display processing unit 315 and the audio stream is forwarded to a sound generation unit (i.e., speakers) (not shown). The decoding and the presentation of program data are coordinated by the clock recovery and synchronization 350. The clock recovery/synchronization 350 synchronizes the video and audio bit-streams. The clock recovery/synchronization 350 is used to generate timing signals to synchronize the operations between the video and audio decoders 340 and 345. The desired program is processed not only for display but also for recording or playback.
The EPG manager 310 retrieves data (i.e., PSIP data) from the transport streams of different channels, parses the data for channel information before storing the information into the program guide database 305. The database 305 may be a memory area, which is separate from the memory, used to decode the audio and video programs. The EPG manager 310 continues to retrieve data from the transport stream and parses the data for all channel information and stores the information into the database 305. While tuner 220 is used entirely to scan the entire channel for program data in the background, tuner 230 is used to tune a particular channel to broadcast that particular channel. When a channel/program is selected (i.e., by a user), tuner 230 tunes to that particular channel and retrieves the broadcast data from the transport stream via demodulator 355.
While certain embodiments are illustrated in the drawings and have been described herein, it will be apparent to those skilled in the art that many modifications can be made to the embodiments without departing from the inventive concepts described.
