Title of Invention	A DIGITAL DATA COMMUNICATION SYSTEM AND METHOD THEREFOR, A DIGITAL DATA TRANSMITTER AND A DIGITAL DATA RECEIVER
Abstract	A plurality of HTML files having their file names which may directly be recognized by a filtering part 415 in a data receiver are stored in a data storage part 411. File names of the HTML files are assigned to their headers by a data converter 412, and the files converted and multiplexed are repeatedly transmitted by a data multiplexing and transmitting part 413. A filtering part 415 selects the data having exact match with the filtering condition. A data processing part 419 performs data processing required for generating images, and the images thus generated are displayed on a screen of the display part 421. The data processing part 419 provides a switching command to a filtering conditions varying part 417 when an operator enters a file to be linked through an input part 420. The file to be linked is received as a result of changing the filtering conditions. In this way, the files required can be received and be displayed dynamically without storing all the HTML files linked one another even in temporary basis.

Title of Invention

A DIGITAL DATA COMMUNICATION SYSTEM AND METHOD THEREFOR, A DIGITAL DATA TRANSMITTER AND A DIGITAL DATA RECEIVER

Abstract

A plurality of HTML files having their file names which may directly be recognized by a filtering part 415 in a data receiver are stored in a data storage part 411. File names of the HTML files are assigned to their headers by a data converter 412, and the files converted and multiplexed are repeatedly transmitted by a data multiplexing and transmitting part 413. A filtering part 415 selects the data having exact match with the filtering condition. A data processing part 419 performs data processing required for generating images, and the images thus generated are displayed on a screen of the display part 421. The data processing part 419 provides a switching command to a filtering conditions varying part 417 when an operator enters a file to be linked through an input part 420. The file to be linked is received as a result of changing the filtering conditions. In this way, the files required can be received and be displayed dynamically without storing all the HTML files linked one another even in temporary basis.

Full Text	TITLE OF THE INVENTION SYSTEM AND METHOD FOR DIGITAL DATA COMMUNICATION Cross-Reference to Related Application The entire disclosure of Japanese Patent Application No. Hei 10-123193 filed on May 6, 1998, another Japanese Patent Application No. Hei 10-370637 filed on December 25, 1998, and another Japanese Patent Application No. Hei 11-107209 filed on April 14, 1999, including specification, claims, drawings and abstract is incorporated herein by reference in its entirety. BACKGROUND OF INVENTION 1. Field of the Invention This invention relates to a digital data communication system and method therefor, a digital data transmitter and a digital data receiver, more specifically to communications of self-descriptive data. 2. Description of the Related Art Nowadays, a communication method using the internet is known as two-way data communications among computers. The principle of the method will be briefly described hereunder. A plurality of hyper text markup language (hereinafter referred to as HTML) files linked with one another are stored into a world wide web (hereinafter referred to as WWW) server which is connected to the internet. A demand for transmitting the HTML files stored in the WWW server is sent thereto from a gathering information computer which is connected to the internet. The WWW server transmits whole or a part of the HTML files to the gathering computer in response to the demand. As a result, data linked with one another and stored in the WWW server can be transferred. Data communication services using satellite broadcasting, on the other hand, are known as one-way data communications. In satellite broadcasting, data are transmitted through a moving picture experts group 2 (hereinafter referred to as MPEG 2) system standard used for data transmission which has a relatively higher flexibility than the other two standards in the MPEG 2, such as MPEG 2 video standard used for video data and MPEG 2 audio standard used for audio data, out of these three MPEG 2 standards. In order to transmit HTML files to the receivers by using satellite broadcasting, a demand for transmitting desired HTML file(s) need to be sent to the transmitter. To avoid sending the demand, methods described hereunder are employed in actual data communications protocols such as BITCAST and ADAMS (TV-Asahi data and multimedia service). A plurality of files linked with one another are transmitted as one unitized file by the transmitter. In the receiver, all the files are stored in a storage device like a hard disk by sequentially storing each of the files therein. Further, the specified file(s) is displayed in response to operation of the user by browser software installed in the receiver. The browser software performs reference operations by specifying the name of a file(s) stored in a hard disk when there is HTML tag(s) requiring reference of other file(s) in the specified file(s) (details of the technology is disclosed in an article entitled "Special Report from state-of-the-art technology; The Whole Aspect of the Next Generation Digital Television", published by Nikkei Business Publications, Inc.) In this method, however, all the files must be stored in the hard disk as well as storing information needed to manage the directory. In this way, a certain capability for storing this information is required in the receiver, and the receiver can not display a desired file(s) until its retrieval is completed. Further, a number of processing steps need to be performed by the receiving computer's central processing unit (CPU) for retrieving the desired file(s) from the stored files. SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above mentioned drawbacks on the data communication method, and to provide a data communication system and a method thereof capable of selectively receiving selected data out of data consisting of a plurality of files related one another at a high speed with less data storing capacities. It is another object of the present invention to provide a data communication system and a method thereof capable of selectively extracting desired data out of data related with one another even when the receiver has a small data storing capability. In accordance with characteristics of the present invention, there is provided a digital data communication system comprising a transmitter and a receiver, A) the transmitter ßomprising: al) file storing means for storing a plurality of files, and a2) transmission means for repeatedly transmitting the files packetized thereby in accordance with a transmission protocol, the packetized files uniquely assigned identifiers; B) the receiver comprising: bl) selective receiving means for selectively receiving the packetized files having predetermined identifiers in accordance with a selecting condition set therein and outputting data contained in the packetized files. b2) display data generating means for generating display data according to the outputted data and b3) selecting condition varying means for varying the selecting condition; and C) wherein cl) the file storing means stores files formed of self-descriptive data which includes a reference command for referring another file, and wherein the identifier of each file includes characters directly selected by the selecting condition varying means, c2) the display data generating means generates display data according to the self-descriptive data outputted by the selective receiving means, and c3) the selecting condition varying means provides an identifier assigned to a file so as to obtain the file specified by the reference command in the self- descriptive data to the selective receiving means. Also, in accordance with characteristics of the present invention, there is provided a method of communicating digital data, comprising the steps of: repeatedly transmitting a plurality of files after packetizing the files according to a transmission protocol with identifiers uniquely assigned thereto in a transmitting station, each of the files comprising self- descriptive data which include a reference command for referring another file, the identifier of the each file consisting of characters directly selected by a receiving station, and performing the following steps in a receiving station, selectively receiving the packetized files having predetermined identifiers in accordance with a selecting condition set therein, generating display data in accordance with the self-descriptive data contained in the packetized files, outputting the generated data, and varying an identifier of a file as the selecting condition so as to obtain the file specified by the reference command in the self-descriptive data. Further, in accordance with characteristics of the present invention, there is provided a digital data communication system comprising a transmitter and a receiver, A) the transmitter including: al) file storing means for storing a plurality of files, and a2) transmission means for repeatedly transmitting the files packetized thereby in accordance with a transmission protocol, the packetized files uniquely assigned identifiers; B) the receiver including: bl) selective receiving means for selectively receiving the packetized files having predetermined identifiers in accordance with a selecting condition set therein and outputting data contained in the packetized files, b2) received data storing means for storing data contained in the packetized files each having same identifier in one independent file basis, b3) display data generating means for generating display data according to the outputted data, and b4) selecting condition varying means for varying the selecting condition; and C) wherein: cl) the file storing means stores files formed of self-descriptive data which includes a reference command for referring another file, c2) the transmission means assigns one module identifier including characters capable of being read directly with the selective receiving means to both a reference file which refers other files and a referred file which is referred by the reference file, and transmits the reference file and the referred file, and c3) the display data generating means generates display data according to the self-descriptive data contained in the reference file, and generates another display data according to a desired referred file which is read out thereby from the received data storing means. In accordance with characteristics of the present invention, there is provided a method of communicating digital data, comprising the steps of: repeatedly transmitting a plurality of files stored in a transmitting station after packetizing the files according to a transmission protocol with identifiers uniquely assigned thereto in the transmitting station, and performing the following steps in a receiving station, selectively receiving the packetized files having predetermined module identifiers in accordance with a selecting condition set therein, storing data contained in the packetized files each having same identifier in one independent file basis, and generating display data according to the outputted data, wherein one module identifier including characters capable of being read directly with the receiving station is assigned to both a reference file which refers other files and a referred file which is referred by the reference file in the transmitting station, wherein the following steps are performed by the receiving station, the selecting condition is varied so as to selectively receive packetized files each assigned same identifier with that of a specific reference file in order to selectively receive the specific reference file, display data is generated according to self-descriptive data contained in the reference file, and generating another display data according to a desired referred file which is read out thereby. Also, in accordance with characteristics of the present invention, there is provided a digital data communication system comprising a transmitter and a receiver, A) the transmitter including: al) file storing means for storing a plurality of files, and a2) transmission means for repeatedly transmitting the files packetized thereby in accordance with a transmission protocol, the packetized files uniquely assigned identifiers; B) the receiver including: bl) selective receiving means for selectively receiving the packetized files having predetermined identifiers in accordance with a selecting condition set therein and outputting data contained in the packetized files, b2) received data storing means for storing data contained in the packetized files each having same identifier in one independent file basis, b3) display data generating means for generating display data according to the outputted data. and b4) selecting condition varying means for varying the selecting condition; and C) wherein cl) the file storing means stores a plurality of reference files formed of self-descriptive data which includes a reference command for referring a plurality of other files, c2) the transmission means assigns one module identifier including characters capable of being read directly with the selective receiving means to the reference files and transmits the reference files, c3) the display data generating means generates display data according to self-descriptive data contained in the reference files, and generates another display data according to desired referred files which are read out thereby from the received data storing means, and c4) the selecting condition varying means uses the module identifier as the selecting condition. Further, in accordance with characteristics of* the present invention, there is provided a digital data receiver comprising: selective receiving means for selectively receiving packetized files having predetermined identifiers in accordance with a selecting condition set therein and outputting data contained in the packetized files, received data storing means for storing data . contained in the packetized files each having same identifier in one independent file basis; display data generating means for generating display data according to the outputted data; and selecting condition varying means for varying the selecting condition; wherein the packetized files thus received are one of a reference file formed of self-descriptive data which includes a reference command for referring another file and a referred file by the reference file, and one identifier including characters capable of being read directly with the selective receiving means is assigned to these files, and wherein the display data generating means generates display data according to self-descriptive data contained in the reference file, and generates another display data according to a desired referred file which is read out thereby from the received data storing means, and wherein the selecting condition varying means extracts characters directly be selected by the selective receiving means out of absolute path assigned to the referred files and provides the characters to the selective receiving means as the selecting condition so as to selectively receive packetized files each assigned same identifier with that of the reference file in order to selectively receive the reference file. While the novel features of the invention are set forth in a general fashion, both as to organization and content, the invention will be better understood and appreciated, along with other objects and features thereof from the following detailed description taken in conjunction with the drawings. BRIEF DESCRIPTION OF THE ,DRAWINGS/ Fig. 1 is a schematic block diagram showing an overall structure of a data communication system in accordance with the present invention. Fig. 2 is a simplified conceptual view showing a state of sending radio waves in satellite broadcasting. Fig. 3 is a schematic illustration of a transmitter. Fig. 4 is a view showing a data arrangement of a transport stream transmitted in satellite broadcasting. Fig. 5 shows a data structure of packetized data. Fig. 6 shows contents of control data of control data program map table (PMT) 111 for multiplexing the packetized data. Fig. 7 shows contents of control data PMT 114 for multiplexing the packetized data. Fig. 8 shows contents of control data PAT. Fig. 9 shows contents of control data network . information table (hereinafter referred to as NIT). Fig. 10 is a schematic block diagram of a receiver. Fig. 11 is a detailed block diagram illustrating a hardware structure of the transmitter. Fig. 12 shows a file structure stored in an HTML data storage unit. Fig. 13A, Fig. 13B, and Fig. 13C show contents of HTML files. Fig. 14A, Fig. 14B, and Fig. 14C are examples of images displayed on a screen according to the data stored in the HTML files. Fig. 15 is a correspondence table. Fig. 16 is a block diagram showing a typical example of the hardware structure of a data converter 375. Fig. 17A and Fig. 17B show other correspondence tables. Fig. 18 is a flow chart for describing steps for creating the correspondence table with the data converter 375. Fig. 19 is a detailed block diagram illustrating the hardware structure of the receiver. Fig. 20 is a functional block diagram of a transport stream decoder. Fig. 21 is a flow chart for describing steps of a receiving operation control program. Fig. 22 is a flow chart for describing steps of a display program. Fig. 23A, Fig. 23B, and Fig. 23C are tables showing filtering conditions. Fig. 24 shows files names after conversion. Fig. 25A, Fig. 25B, and Fig. 25C show converted contents of HTML files. Fig. 26 is a flow chart for describing steps for changing a file name. Fig. 27 is a block diagram showing an overall structure of a digital broadcasting system used in a third embodiment of the present invention. Fig. 28A and Fig. 28B are views showing the structure of the data in both an HTML file and an U-U object. Fig. 29 shows a data structure of packetized data being transmitted. Fig. 30 is a detailed view for describing filtering conditions. Fig. 31 is a schematic block diagram showing the hardware structure of a data receiver 414. Fig. 32 is an overall view of a communication system using the data receiver 414. Fig. 33 shows data contents of a reference file. Fig. 34 shows an image displayed according to the contents of the reference file. Fig. 35 shows a hierarchial tree structure of a file stored in a transmitting station. Fig. 36 is a flow chart for describing steps of a display program. Fig. 37 shows data contents of an HTML file in which a plurality of files are incorporated with one another. Fig. 38 shows data contents of another HTML file in which a plurality of files are incorporated one another. Fig. 39 shows data contents of another HTML file in which referred files are included therein other than automatic reference tag(s). Fig. 40 shows a typical image displayed in accordance with the reference file depicted in Fig. 39. Fig. 41A and Fig. 41B show data contents of an HTML file which is referred as the referred file in Fig. 39. Fig. 42A and Fig. 42B show images displayed according to the referred file shown in Fig/ 41A and Fig. 41B. Fig. 43 shows a hierarchlal tree structure of a file stored in the transmitter side. Fig. 44 shows data contents of a reference file. Fig. 45 shows another hierarchial tree structure of a file stored in the transmitter side. Fig. 46 is a flow chart for describing steps of storing data into a cache memory. Fig. 47 shows a data structure of packetized data being transmitted. Fig. 48A through Fig. 48C show data structure of the data stored in the cache memory. Fig. 49 shows data contents of an HTML file which is referred as the referred file. Fig. 50A and Fig. 50B show images displayed according to the referred file shown in Fig. 49. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of the present invention will be described herein along with the index shown in below: 1. FUNCTION BLOCK DIAGRAMS 1-1. Outline of satellite broadcasting 1 - 1 - 1. State of sending radio waves in satellite broadcasting 1-1-2. Outline of transmitter 1-1-3. Structure of transport stream 1-1-4. Outline of receiver 1-2. First Embodiment 1-2-1. Transmitter 1 - 2 - 2. Receiver 1 - 2 - 2 - 1. Hardware structure 1 - 2 - 2 - 2. Receiving operation control program 1 - 2 - 2 - 3. Display program 1 - 3. Second embodiment 1-3-1. Data converting operations in transmitter 1 - 3 - 2. Data receiving operations in receiver 1 - 4. Third embodiment 1 - 4 - l. Data transmitter 1 - 4 - 2. Data receiver 1 - 4 - 3. Hardware structure of data receiver 1 - 5. Fourth embodiment 1-6. Other embodiments. 1. FUNCTION BLOCKS The system 1 shown in Fig. 1 comprises a transmitter 3 and a receiver 11. The transmitter 3 includes file storing means 7 and transmission means 5. The file storing means 7 stores a plurality of files comprising self-descriptive data. A part of the files include reference commands for referring another files. Identifiers of the files stored in the file storing means 7 consist of a series of characters which may directly be recognized with selecting means 15 in the receiver 11. The transmission means 5 repeatedly transmits the files with the identifiers according to a protocol after packetizing them. The receiver 11 comprises receiving means 14, selecting means 15, display data generating means 19, and selecting conditions variation means 17. The receiving means 14 receives the packets thus transmitted. The selecting means 15 selects only packets having selective identifiers out of the received packets in accordance with a selecting condition. The display data generating means 19 generates display data in accordance with self- descriptive data included in the selected packets. Further, the selecting conditions variation means 17 varies the selecting condition so as to obtain selected file(s) specified by the reference(s) included in the self-descriptive data. The selecting conditions variation means 17 also varies the selecting condition in the selecting means 15 so as to obtain selected file(s) * specified by the reference command(s) when an operator of the system selects a display region specified by the reference command(s) out of all the region displayed on display means 20. 1-1. Outline of satellite broadcasting One example of applying the present invention to satellite broadcasting will be described herein. The present invention, however, may also be applied to other broadcasting methods such as terrestrial broadcasting, wire broadcasting such as cable television and the like as long as packetized data are transmitted. 1-1-1. State of sending radio waves in satellite broadcasting Fig. 2 shows a simplified conceptual view showing a state of sending radio waves in satellite broadcasting. Radio waves from a ground station 1002 are sent to a plurality of ground receivers (not shown) through a broadcasting satellite 1004. The broadcasting satellite 1004 sends out a plural number of transport streams 1010, 1020, 1030. Each transport stream is distinguished from the others by its frequency, plane of polarization and other factors (well known in the art). A plurality of services (analogous to channels in terrestrial broadcasting) 1011, 1012, 1013, and 1014 being packetized are multiplexed in the transport stream 1010 under a time-sharing manner. Similarly, services 1021, 1022, 1023 and 1024, and services 1031, 1032, 1033 and 1034 are multiplexed respectively in the transport streams 1020 and 1030. Various control data representing service information, the present time, and the like, together are sent out to each of the transport streams in addition to the packetized data (including video data and audio data). While, Fig. 2 shows only three transport streams, many more transport streams may be sent out. Furthermore, while Fig. 2 shows a total of four services multiplexed in each transport stream, in actuality many more services may be multiplexed therein. 1-1-2. Outline of transmitter Fig. 3 is a schematic illustration of a transmitter for generating and transmitting the transport streams described above. While Fig. 3 shows only the transport stream 1010 for simplicity, other transport streams 1020, 1030 are generated thereby in the same manner. Video/audio data of the service 1011 are stored in a data storing unit 171. These data are compressed by an encoder 181, and are provided to a multiplexer 160. Similarly, video/audio data of the services 1012 and 1013 are stored respectively in data storage unit 172 and 173. Video data for the services are compressed under the MPEG 2 video standard, and audio data are compressed under the MPEG 2 audio standard. The data so compressed are provided to the multiplexer 160. In another data storage unit 174, HTML data used for the service 1014 is stored therein. The data are converted into modules having object headers by a data converter 184 in accordance with the MPEG 2 system standard. Module identification (module_id) are assigned to each of the modules. Details of the assignment will be described later. A control data generator 180 generates control data for multiplexing the packetized data, the control data for displaying program information, the control data representing the present time and other such data. The control data for multiplexing is assigned for properly recognizing video/audio data in plural services which are packetized and multiplexed under a time sharing manner. The multiplexer 160 outputs a plurality of packets under a time sharing manner, each consisting of packetized data having a fixed length as a result of carrying out packetization of the data provided from the control data generator 180, the encoder 181 through the encoder 183, and that from the data converter 184, as the transport stream 1010. Further, the multiplexer 160 assigns individual module_ids to section headers of all the packets when the data from the data converter 184 is packetized. In this embodiment, the last four digits of a packet are assigned a table_id_extension region (field) by using the first four digits thereof as a PID because the module identifiers consist of directory_id and filetid for identifying module (a total of eight digits) as described later. Thus, the packets comprising each file can definitely be specified without further consideration in the receiver by distinguishing them using the PID and the table_id_extension. A modulator 164 outputs the packets being provided and modulated thereby as a transport stream. The transport stream thus outputted is broadcasted to the audience. 1-1-3. Structure of transport stream As shown in Fig. 4, services 1011, 1012 and 1013, each including video data 81V, 82V and 83V, and audio data 81A, 82A and 83A respectively, service 1014, including HTML or imaging data 84 and a correspondence table 109 are multiplexed in the transport stream 1010 generated by the transmitter shown in Fig. 3. Details of the correspondence table 109 will be described later. In addition, control data NIT 100, program allocation table (PAT) 101, and program map table (PMT) 111 through PMT 114 for multiplexing the packetized data are multiplexed therein. The data corresponding to the. services 1011, 1012, 1013 and 1014 thus multiplexed can be separated by using these control data as described later. Control data EIT 121 through EIT 124, each representing program information, and control data representing the present time TDT 105, are also multiplexed therein. Other control data such as scrambling information and others are multiplexed therein even though these are not illustrated in the figures.. The control data PMT 111, PMT 112, PMT 113 and PMT 114, and control data EIT 121, EIT 122, EIT 123 and EIT 124 are the control data for the services 1011, 1012, 1013 and 1014 respectively. Packetization of the control data, the video data, the audio data, HTML data and the correspondence table is carried out in the sequence of a line 18a shown in Fig. 4. In other words, packetization of these data is carried out by the following sequence: the control data NIT, PAT, PMTs, EITs, TDT, then the video data 81V, the audio data 81A, the video data 82V, the audio data 82A, the video data 8V, the audio data 83, and the HTML data 84 and the correspondence table 109. Upon completing the packetization in the. first round, further rounds of packetization are,carried out repeatedly under the same sequence starting from the control data NIT (see line 18b). The packetization process is carried out under a certain rule being predetermined (not shown). A basic structure of the packetized data is shown in Fig. 5. Both the control data and the video/audio data being packetized have the structure as shown in Fig. 5. PIDs are assigned to the forefront of each packetized data. PIDs are the references which are uniquely assigned to each of the packetized data to distinguish each packetized data from other packetized data. The data content field shown in Fig. 6 packetized object data (e.g. the control data, video/audio data, HTML data and others). Contents of the control data PMT 111 for multiplexing the packetized data of service 1011 are shown in Fig. 6. PIDs of both the video data 81V and the audio data 81A of the service 1011 are stored in the PMT 1ll. Similar PIDs as to these data in the services 1012, 1013 are stored respectively to in control data PMT 112, PMT 113. As shown in Fig. 7, a PID and a module identifier (described later) of data 84 in the service 1014 are stored in the PMT 114. PIDs Of PMT 111, PMT 112, PMT 113 and PMT 114, each corresponding to the services 1011, 1012, 1013 and 1014, are stored in the control data PAT as shown in Fig. 8. Transmission specifications defined by their frequencies, planes of polarization and the like as to all the transport streams 1010 through 1040, and a list of the services multiplexed in each of the transport streams are described in the control data NIT as shown in Fig. 9. This allows the receiver to learn what kinds of services are included in each of the transport streams. 1-1-4. Outline of receiver Functions of the receiver 11 shown in Fig. 1 are outlined with reference to Fig. 10. In the receiver. 11, a desired transport stream is selected by a tuner 222, and data concerned with a desired service contained in the selected transport stream is separated therefrom with a transport decoder 226. Further, a micro processing unit (hereinafter referred to as MPU) 228 sets PIDs of video/audio data of the desired service into the transport decoder 226. In response to the setting, the transport decoder 226 outputs the video/audio data of the desired service. The control data thus separated are provided to the MPU 228 when PIDs of the control data are set into the transport decoder 226. Operations of the receiver 1 which currently receives the service 1033 contained in the transport stream 1030, and receives a command to switch it to another service 1012 included in the transport stream 1010, will be described herein. The MPU 228 controls the transport decoder 226 to obtain the control data NIT (i.e., by setting a PID of the control data NIT into the transport decoder 226). The description of the control data NIT tells that the service 1012 is multiplexed in the transport stream 1010 (see Fig. 9). In response to the description, the MPU 228 controls the tuner 222 to receive the transport stream 1010. PIDs of video and audio data in the desired service 1012 are obtained as a result of separating the control data PAT and PMT 112 by controlling the transport decoder 226 with the MPU 228. The MPU 228 controls the transport decoder 226 to output the video and the audio data of the desired service 1012 by setting filtering conditions (the conditions for performing filtering) to select these PIDs into the transport decoder 226. Switching of the received service is carried out as described above. The MPU 228, further controls the transport decoder 226 to obtain the control data EIT when a command for displaying a program schedule and program information is provided to the MPU 228. In addition, the MPU 228 controls peripherals to display the program information and related information in accordance with the control data EIT thus obtained. 1-2. First embodiment 1-2-1. Transmitter Fig. 11 is a detailed block diagram illustrating a hardware structure of the transmitter 3 shown in Fig. 3. The transmitter 3 in this embodiment is used for a digital broadcasting system compliant with MPEG 2 standard. Digital Storage Media Command and Control (hereinafter referred to as DSM-CC) specification, and Digital Video Broadcasting (hereinafter referred to as DVB) specification for Services Information (hereinafter referred to as DVB-SI). Definition of MPEG 2 standard is found in the international standards organization documents ISO/IEC 13818-1 and ISO/IEC 13818-2. The document ISO/IEC 13818-6 specifies the DSM-CC specification. Further, the document ETSI ETS 300 468 (which is similar to document of Association of Radio Industries and Businesses STD-B2 version 1.0 in Japan) defines the DVB-SI specification. The transmitter 3 is a satellite digital transmitter capable of transmitting HTML data together with video data and audio data under a multiplexed format. Fig. 11 shows the structureSwithin the transmitter 3 supporting the services 1011 and 1014. The structures of services 1012 and 1013 (not shown) are similar to that of service 1011. The video data of the service 1011 is stored in a video data storage unit 311V. The video data are compressed with a video encoder 331. The video data thus compressed is provided to a first-in first-out (hereinafter referred to as FIFO) memory 342 as an elementary stream at a varied rate. The FIFO memory 342 outputs the elementary stream of video data to a packeting circuit 344 at a fixed rate. The packet circuit 344 segments the elementary stream of the video data into a plurality of packets each having a fixed length (e.g. 188 bytes), and writes the packets into a memory 352 as packetized elementary streams (hereinafter referred to as PES). PIDs are assigned to each of the PESs as they are written into memory 352. Similarly, audio data of the service 1011 is stored in an audio data storage unit 311A. The audio data are compressed with an audio encoder 332, and is provided to another FIFO memory 346. The compressed audio data are segmented into packets by packet circuit 348. Each packet has a fixed length, and is written into another memory 354 with its own PID as described above for the video data. A packet multiplex controller 356 reads out PESs of both the video data and the audio data stored in the memories 352 and 354 in response to its encoding speed. Also, the controller 356 provides the PIDs assigned to the PESs of both the video data and the audio data to a PMT generating circuit 358. The PMT generating circuit 358 generates the control data PMT 111 as a result of receiving the PIDs. The assigned PIDs of both the video data and the audio data contained in the service are listed in the control data PMT. Both the PESs of the video and the audio data being read out from memory 352 and 354 and the corresponding control data PMT are stored in a memory 362 in a multiplex format under a time-sharing manner. Thus, the video and the audio data of the service 1011 are multiplexed under a time-sharing manner and stored in the memory 362. As shown in Fig. 12, the plurality of HTML files include, e.g., such as "forecast.html", "today.html11 through "osaka.html" and the image files include, e.g., "sun.gif" through "rain.gif", both stored in a directory "Vweather". plurality of HTML and image files are stored in a data storage unit 314D. In this way, images such as those shown in Fig. 14A through Fig. 14C, can be displayed in accordance with the HTML files "forecast.html", "today.html" and "osaka.html" depicted respectively in Fig. 13A through Fig. 13C. A data converter 375 sequentially assigns individual file identifiers to each of the files. The file-ids are stored as an object header for each file. Data converter 375 also creates a correspondence table between the file identifiers thus assigned and name of the files. In this embodiment, file-ids consisting of a total of four digits such as id = "0001" (expressed in hexadecimal) are sequentially assigned to the files in the directory "weather" as shown in Fig. 15. The sequential assignment is made from the top (Yforecast.html) through the bottom file (not shown) of the directory "Vweather" as described later. Similarly, directory identifiers consisting of four digits such as id = "0001" are assigned to the directory "Yweather" which includes each of the files. Together, the directory_id and file_id make up the module identifier. This is to definitely specify each of the files with an absolute path including name of the directory as shown in Fig. 15. For example, a file "¥forecast.html" can definitely be specified as "¥weather¥forecast.html" can definitely be specified as "weatherforecast.html" or "0001/0001". In this way, a correspondence table shown in Fig. 15 is created by assigning both the directory_id and the file_id to each module as its module identifier. The data converter 375 consists of a combination of hardware and software structures in this embodiment. Fig. 16 shows a typical example of the hardware structure of the data converter 375. A corresponding chart shown in Fig. 17A is stored in a ROM 375r. Steps performed in a software structure for data conversion used by the CPU 375c will be described with reference to Fig. 18. The CPU 375c initializes the counter i (step S201, in Fig. 18). Then, the file corresponding to the counter i is stored into the corresponding chart (step S203) . For example, the top file "¥forecast.html" of the directory "¥weather" is stored into a region representing module number 1. Thus, the file "¥weatherYforecast.html" is assigned the module_id "0001/0001" as shown in Fig. 17B. In this embodiment, the module identifiers consist of the four digit file_id = "0001" and the four digit directory_id = "000l" as described above. Next, the CPU 375c determines whether or not all the files are stored in the corresponding chart (step S207). If files have not been so stored, the CPU 375c increments the counter i by one (step S209), and stores the next file in the corresponding chart (step S203). Creation of the corresponding chart is completed when the step S203 is carried out to all the files. The corresponding chart thus created is provided to a packeting component 377, shown in Fig. 11, together with each of the modules, and is stored in a memory 382 after packetization. The data from the data converter 375 is packetized into packets having a fixed length by the packeting component 377. The packeting component 377 assigns individual PIDs to the section headers of all the packets generated. In this embodiment, the first four digits and the last four digits are respectively assigned as the PID and the table_id_extension region (field) because the module identifiers consist of the directory_id and the file_id (a total of eight digits). In this way, the packets making up each file can definitely be specified without further consideration in the receiver by distinguishing them using the PID of each packet and the table_id_extension as a result of distinguishing the modules by the PID and the table_id_extension of each packet. Further, the packeting component 377 also packetizes the corresponding chart created by the data converter 375 into packets having a fixed length. In other words, the corresponding chart is multiplexed as the correspondence table 109 depicted in Fig. 4. There are table_id regions (fields) for setting own table_id, each having a predetermined data length, and table_id_extension regions (fields) for setting own table_id_extensions in the sections heads of each packet. Their own module identifiers are stored in the table_id_extension fields as the table_id_extensions. The details of this relationship will be described later. A packet multiplex controller 384 reads out the data stored in the memory 382 in response to, its encoding speed. Also, the controller 384 provides PIDs assigned to the data to a PMT generating circuit 386. The PMT generating circuit 386 generates a control data PMT 114 (see Fig. 4) as a result of receiving the PIDs. The PIDs for each packet related to contained in the service 1014 are listed in the control data PMT 114. Both the data thus read out from the memory 382 and the corresponding control data PMT are stored in a memory 364 in a multiplex format under a time-sharing manner. Additionally, the PMT 114 contains the module_id into an additional information field by the circuit 386, the module_id corresponding to an HTML file comprising a front page displayed initially in the service 1014 as shown in Fig. 7. In this way, a table_id_extension "0x0001" is written to an additional information field in the PMT of the service 1014 as a file_id of the front page when the front page is represented by file "¥weather¥forecast.html", because the file "YweatherYforecast.html11 is replaced with a file_id "0001" during the packetization. Also, the file "YweatherYforecast.html" is replaced respectively with a PID "0x0001" and a table_id "0x0001" during the packetization. 1 - 2 - 2. Receiver 1-2-2-1. Hardware structure The hardware structure of the receiver 11 depicted in Fig. 1 is shown in Fig. 19. The receiver 11 functions as a receiver of satellite broadcasting as well as a device for displaying HTML data on a monitor. The function of the receiver 11 in receiving satellite broadcasting is similar to that of the conventional broadcasting receiver, as briefly described below. Radio waves transmitted by the transmitter are caught with an antenna 131, and the radio waves are supplied to a tuner 132. The tuner 132 selects one of the transport streams in accordance with a command of the CPU 147. Further, the tuner 132 carries out demodulation and error-correction and other relevant operations, and outputs the resultant signals to a transport decoder 141. The transport decoder 141 only selects (i.e., filters) predetermined packets out of the packets multiplexed within the selected transport stream in accordance with PIDs set therein by the CPU 147. PacketIzed data for the system are contained in the multiplexed packets other than control data, video data and audio data because the system data are also multiplexed together with the video data and the audio data. The transport decoder 141 identifies these data in accordance with the data stored in the headers in each of the files, and both the control data and the system data are stored in a RAM 144. The RAM 144 stores the packetized data under the file basis so that the packetized data thus stored forms to one independent file. Filtering procedure carried out in the transport decoder 141 will be described with reference to Fig. 20. Conditions for performing filtering of data (hereinafter referred to as filtering conditions) are stored in a filtering conditions storing unit 154. For example, PIDs, the table_id and table_id_extensions of * the packets to be selected are stored therein. A PID selecting unit 156 selects the packets having predetermined PIDs in accordance with the filtering conditions stored in the filtering conditions storing unit 154. The packets of video data and that of audio data, are respectively outputted to a video decoder 137 and an audio decoder 134. Packets of HTML or image data in a selection format with the selected packets are outputted to a section data selecting unit 155 shown in Fig. 20. The section data selecting unit 155 only outputs the packets having predetermined table_id_extensions in accordance with the filtering conditions stored in the filtering conditions storing unit 154. A conditions varying unit 153 varies filtering conditions stored in the filtering conditions storing unit 154 in accordance with a rewrite command outputted by the CPU 147 (as shown in Fig. 19). The video data are provided to the video decoder 137 through the FIFO memory 136 depicted in Fig. 19, and are decompressed or expanded thereby. The video data are converted into analog signals with a digital/analog converter (hereinafter referred to as D/A converter) 138, and the analog signals are displayed on a monitor 140 such as a liquid crystal display, a cathode ray tube and the like through a video synthesizer 139. The data representing characters stored in a video RAM (hereinafter referred to as VRAM) are converted into analog signals with another D/A converter 145, and the analog signals are provided to the video synthesizer 139. In this way, characters can be overlapped on images displayed on the monitor. The audio data, on the contrary, are provided to the audio decoder 134 through another FIFO memory 133, and are decompressed or expanded thereby. The audio data are outputted through a speaker 135 as actual sound. A remote controller 149 stores the following commands such as initialization of watching, designation of services, instruction for category search for the program information or the like, and the controller 149 outputs them to a microcomputer 148 installed in the main part of the receiver 11. The CPU 147 controls the tuner 132, the transport decoder 141 and relevant cpmoonents In accordance with a receiving operation control program 142c and a display program 142a both stored in a ROM 142/ These programs may be capable of stand alone operation, or may require an operating system (such as Windows CE by Microsoft Inc.) as a premise. 1 - 2 - 2 - 2. Receiving operation control program An embodiment of the receiving operation control program 142c used for carrying out receiving operations will be described with reference to Fig. 19 and Fig. 21. Operations necessary to switch the receiver 11 from receiving the service 1013 contained in the transport stream 1010, to receiving another service 1011 included in the transport stream 1010, will be described herein. A switching command is sent by the remote controller 149 or a control panel (not shown) to the CPU 147. The switching command is provided to the CPU 147 through a microcomputer 148 (as shown in Fig. 19). In response to the switching command, the CPU 147 sets PIDs of the control data PAT into a register (not shown) for separating the control data in the transport decoder 141. The PID of the control data PAT has a fixed value such as "0x0000". In this way, contents of the control data PAT being separated are stored in the RAM 144 under the control of the transport decoder 141 (step Sll, in Fig. 21). A list of the services multiplexed in the transport stream currently received are shown in the contents of the control data PAT (see Fig. 8). The CPU 147 determines that the desired service 1011 is multiplexed in the transport stream 1010 currently received by referring the list. The CPU 147 continues processing from step S12. to step S18. In the step S18, the CPU 147 obtains PIDs of the control data PMT in the desired service 1011 in accordance, with the contents of the control data PAT. As a result, the CPU 147 recognizes that id "0x0011" is for a PID of the control data PMT in the desired service 1011 as shown in Fig. 8. Further, the CPU 147 sets the PID "0x0011" of the control data PMT into the register for separating the control data in the transport decoder 141 (step S19). Hence, the control data PMT 111 in the service 1011 can be separated from other data, and contents of which can be stored in the RAM 144. Next, the CPU 147 recognizes PIDs "0x0022" and "0x0024" of the video data 81V and the audio data 81A respectively, in accordance with the PMT for the service 1011 as shown in Fig. 6 (step S20). Then, the CPU 147 sets both the PIDs "0x0022" and "0x0024" into the filtering conditions storing unit 154 (see Fig. 20) in the transport decoder 141 (step S22). In this way, the transport decoder 141 can selectively output both the video data 81V and the audio data 81A, both being required. The CPU 147 proceeds its processing to step S13 if the desired service is not multiplexed in the transport stream currently received in step S12. Further, the CPU 147 obtains PIDs of the control data NIT assigned in the control data PAT. In accordance with the PIDs thus obtained, the CPU 147 obtains the control data NIT, and determines whether the desired service contained in any of the transport streams (step S14, step S15). * The CPU 147 switches a setting of the tuner 34 so as to receive the transport stream which contains the desired service (step S16). Then, the CPU 147 obtains the control data PAT of the transport stream (step S17). Hereafter, steps following to step S18 may be performed, as described above. 1-2-2-3. Display program The function for displaying HTML data on the monitor is accomplished by the CPU 147 and the display program 142a stored in the ROM 142. Data obtained is stored in the RAM 144 when the data is system data under the control of the transport decoder 141. The CPU 147 starts performing the display program 142a when the system data is supplied by the transport decoder 141 because the CPU 147 recognizes data written in a section format as system data in this embodiment. Steps performed by the display program 142a for displaying HTML files will be described with reference to Fig. 19 and Fig. 22. At first, a switching command, for switching the operations to a service in which the HTML files are received, is outputted by the remote controller 149 in accordance with input of the operator who refers a program table. As a result of receiving the command, the CPU 147 varies filtering conditions in the tuner 132 and the transport decoder 141 respectively. For example, the operator selects a service id = "001" with the remote controller 149 when he/she find out a weather forecast which provides interactive service can be specified by the service id = "001" by referring to the program table. Control data PAT is obtained by varying the filtering conditions of the transport decoder 141 to PID = "0x0000" with the CPU 147 because the PID of the PAT is a fixed value "0x0000". Steps for obtaining the control data PAT are performed after switching the tuner 132 so as to receive a transport stream in which a service specified by the service id = "001" is multiplexed as a result of obtaining the control data NIT thereof when the service having the service id = "001" is multiplexed in the transport stream other than the transport stream currently received. A PMT of the service specified by the service id = "001" can be obtained once the control data PAT is obtained. As a result of obtaining the PMT, an id of the transport stream in which the service is multiplexed, PIDs of packets in which data related to the service is stored, and table_id_extensions of the file which are displayed at first can automatically be obtained. Under this logic, the CPU 147 varies filtering conditions in the transport decoder 141 while switching the tuner 132 in order to receive the service. In this way, receipt of a service specified by a service id "001" is started. For instance, the CPU 147 varies filtering conditions in the transport decoder 141 so as to select packets of a PID "0x0001", that of a table_id "0x3C", and that of a table_ld_extension "0x0001" shown in Fig. 23A when the PID, the table_id, and the table_id_extension of the service specified by the service id = "001" are respectively "0x0001", "0x3C", and "0x0001" according to the PMT. The table_id is a fixed value of "0x3C". Further, the numbers "Ox" means that the numbers following thereto are expressed in hexadecimal in this embodiment. Consequently, the transport decoder 141 selects the packets having their PIDs, table_id, and table_id_extension as "0x0001", "0x3C", and "0x0001" respectively. Selective reception of the HTML files shown in Fig. 13A according to the filtering conditions will be described below as an example. The CPU 147 judges whether or not the system data stored in the RAM 144 comes to one independent file (step S101, in Fig. 22). In a concrete form, the judgement can be carried out by detecting whether or not the last block of the system data is received. The counter i is initialized once the one independent file is received (step S103). The CPU 147 detects existence of an automatic reference tag in the HTML data of the file located in 1 th row thereof (step S105). The automatic reference tag is defined as image tags for referring other file(s) regardless of the operations by the operator. Operations related to the automatic reference tag will be described later. Since the counter i was initially set to 0, the first time CPU 147 executes step S105, it will move onto step S1ll and generate display data according to. the data located in the i th row. The display data is stored to a VRAM 146, then converted into analog data by the D/A converter 145. After conversion to analog data, the display data is provided to the video synthesizer 139. The video synthesizer 139 outputs display data which is synthesized with the data from the video decoder 137 thereby to the monitor 140. Hence, a image according to the data located i th row is displayed on the monitor 140. Next, the CPU 147 increments the counter i by one (step S113), and judges whether or not a tag "

Full Text

TITLE OF THE INVENTION
SYSTEM AND METHOD FOR DIGITAL DATA
COMMUNICATION
Cross-Reference to Related Application
The entire disclosure of Japanese Patent
Application No. Hei 10-123193 filed on May 6, 1998,
another Japanese Patent Application No. Hei 10-370637
filed on December 25, 1998, and another Japanese Patent
Application No. Hei 11-107209 filed on April 14, 1999,
including specification, claims, drawings and abstract is
incorporated herein by reference in its entirety.
BACKGROUND OF INVENTION
1. Field of the Invention
This invention relates to a digital data communication system and
method therefor, a digital data transmitter and a digital data receiver, more
specifically to communications of self-descriptive data.
2. Description of the Related Art
Nowadays, a communication method using the
internet is known as two-way data communications among
computers. The principle of the method will be briefly
described hereunder. A plurality of hyper text markup
language (hereinafter referred to as HTML) files linked
with one another are stored into a world wide web
(hereinafter referred to as WWW) server which is
connected to the internet. A demand for transmitting the
HTML files stored in the WWW server is sent thereto from
a gathering information computer which is connected to
the internet. The WWW server transmits whole or a part
of the HTML files to the gathering computer in response
to the demand. As a result, data linked with one another
and stored in the WWW server can be transferred.
Data communication services using satellite
broadcasting, on the other hand, are known as one-way
data communications. In satellite broadcasting, data are
transmitted through a moving picture experts group 2
(hereinafter referred to as MPEG 2) system standard used
for data transmission which has a relatively higher
flexibility than the other two standards in the MPEG 2,
such as MPEG 2 video standard used for video data and
MPEG 2 audio standard used for audio data, out of these
three MPEG 2 standards.
In order to transmit HTML files to the
receivers by using satellite broadcasting, a demand for
transmitting desired HTML file(s) need to be sent to the
transmitter.
To avoid sending the demand, methods described
hereunder are employed in actual data communications
protocols such as BITCAST and ADAMS (TV-Asahi data and
multimedia service). A plurality of files linked with
one another are transmitted as one unitized file by the
transmitter. In the receiver, all the files are stored
in a storage device like a hard disk by sequentially
storing each of the files therein. Further, the
specified file(s) is displayed in response to operation
of the user by browser software installed in the
receiver. The browser software performs reference
operations by specifying the name of a file(s) stored in
a hard disk when there is HTML tag(s) requiring reference
of other file(s) in the specified file(s) (details of the
technology is disclosed in an article entitled "Special
Report from state-of-the-art technology; The Whole Aspect
of the Next Generation Digital Television", published by
Nikkei Business Publications, Inc.)
In this method, however, all the files must be
stored in the hard disk as well as storing information
needed to manage the directory. In this way, a certain
capability for storing this information is required in
the receiver, and the receiver can not display a desired
file(s) until its retrieval is completed. Further, a
number of processing steps need to be performed by the
receiving computer's central processing unit (CPU) for
retrieving the desired file(s) from the stored files.
SUMMARY OF THE INVENTION
It is an object of the present invention to
overcome the above mentioned drawbacks on the data
communication method, and to provide a data communication
system and a method thereof capable of selectively
receiving selected data out of data consisting of a
plurality of files related one another at a high speed
with less data storing capacities.
It is another object of the present invention
to provide a data communication system and a method
thereof capable of selectively extracting desired data
out of data related with one another even when the
receiver has a small data storing capability.
In accordance with characteristics of the
present invention, there is provided a digital data
communication system comprising a transmitter and a
receiver,
A) the transmitter ßomprising:
al) file storing means for storing a
plurality of files, and
a2) transmission means for repeatedly
transmitting the files packetized thereby in accordance
with a transmission protocol, the packetized files
uniquely assigned identifiers;
B) the receiver comprising:
bl) selective receiving means for selectively
receiving the packetized files having predetermined
identifiers in accordance with a selecting condition set
therein and outputting data contained in the packetized
files.
b2) display data generating means for
generating display data according to the outputted data
and
b3) selecting condition varying means for
varying the selecting condition; and
C) wherein cl) the file storing means stores
files formed of self-descriptive data which includes a
reference command for referring another file, and wherein
the identifier of each file includes characters directly
selected by the selecting condition varying means,
c2) the display data generating means
generates display data according to the self-descriptive
data outputted by the selective receiving means, and
c3) the selecting condition varying means
provides an identifier assigned to a file so as to obtain
the file specified by the reference command in the self-
descriptive data to the selective receiving means.
Also, in accordance with characteristics of the
present invention, there is provided a method of
communicating digital data, comprising the steps of:
repeatedly transmitting a plurality of files
after packetizing the files according to a transmission
protocol with identifiers uniquely assigned thereto in a
transmitting station, each of the files comprising self-
descriptive data which include a reference command for
referring another file, the identifier of the each file
consisting of characters directly selected by a receiving
station, and
performing the following steps in a receiving
station, selectively receiving the packetized files
having predetermined identifiers in accordance with a
selecting condition set therein, generating display data
in accordance with the self-descriptive data contained in
the packetized files, outputting the generated data, and
varying an identifier of a file as the selecting
condition so as to obtain the file specified by the
reference command in the self-descriptive data.
Further, in accordance with characteristics of
the present invention, there is provided a digital data
communication system comprising a transmitter and a
receiver,
A) the transmitter including:
al) file storing means for storing a
plurality of files, and
a2) transmission means for repeatedly
transmitting the files packetized thereby in accordance
with a transmission protocol, the packetized files
uniquely assigned identifiers;
B) the receiver including:
bl) selective receiving means for selectively
receiving the packetized files having predetermined
identifiers in accordance with a selecting condition set
therein and outputting data contained in the packetized
files,
b2) received data storing means for storing
data contained in the packetized files each having same
identifier in one independent file basis,
b3) display data generating means for
generating display data according to the outputted data,
and
b4) selecting condition varying means for
varying the selecting condition; and
C) wherein: cl) the file storing means stores
files formed of self-descriptive data which includes a
reference command for referring another file,
c2) the transmission means assigns one module
identifier including characters capable of being read
directly with the selective receiving means to both a
reference file which refers other files and a referred
file which is referred by the reference file, and
transmits the reference file and the referred file, and
c3) the display data generating means
generates display data according to the self-descriptive
data contained in the reference file, and generates
another display data according to a desired referred file
which is read out thereby from the received data storing
means.
In accordance with characteristics of the
present invention, there is provided a method of
communicating digital data, comprising the steps of:
repeatedly transmitting a plurality of files
stored in a transmitting station after packetizing the
files according to a transmission protocol with
identifiers uniquely assigned thereto in the transmitting
station, and
performing the following steps in a receiving
station, selectively receiving the packetized files
having predetermined module identifiers in accordance
with a selecting condition set therein, storing data
contained in the packetized files each having same
identifier in one independent file basis, and generating
display data according to the outputted data,
wherein one module identifier including
characters capable of being read directly with the
receiving station is assigned to both a reference file
which refers other files and a referred file which is
referred by the reference file in the transmitting
station,
wherein the following steps are performed by
the receiving station, the selecting condition is varied
so as to selectively receive packetized files each
assigned same identifier with that of a specific
reference file in order to selectively receive the
specific reference file, display data is generated
according to self-descriptive data contained in the
reference file, and generating another display data
according to a desired referred file which is read out
thereby.
Also, in accordance with characteristics of the
present invention, there is provided a digital data
communication system comprising a transmitter and a
receiver,
A) the transmitter including:
al) file storing means for storing a
plurality of files, and
a2) transmission means for repeatedly
transmitting the files packetized thereby in accordance
with a transmission protocol, the packetized files
uniquely assigned identifiers;
B) the receiver including:
bl) selective receiving means for selectively
receiving the packetized files having predetermined
identifiers in accordance with a selecting condition set
therein and outputting data contained in the packetized
files,
b2) received data storing means for storing
data contained in the packetized files each having same
identifier in one independent file basis,
b3) display data generating means for
generating display data according to the outputted data.
and
b4) selecting condition varying means for
varying the selecting condition; and
C) wherein cl) the file storing means stores a
plurality of reference files formed of self-descriptive
data which includes a reference command for referring a
plurality of other files,
c2) the transmission means assigns one module
identifier including characters capable of being read
directly with the selective receiving means to the
reference files and transmits the reference files,
c3) the display data generating means
generates display data according to self-descriptive data
contained in the reference files, and generates another
display data according to desired referred files which
are read out thereby from the received data storing
means, and
c4) the selecting condition varying means
uses the module identifier as the selecting condition.
Further, in accordance with characteristics of*
the present invention, there is provided a digital data
receiver comprising:
selective receiving means for selectively
receiving packetized files having predetermined
identifiers in accordance with a selecting condition set
therein and outputting data contained in the packetized
files,
received data storing means for storing data .
contained in the packetized files each having same
identifier in one independent file basis;
display data generating means for generating
display data according to the outputted data; and
selecting condition varying means for varying
the selecting condition;
wherein the packetized files thus received are
one of a reference file formed of self-descriptive data
which includes a reference command for referring another
file and a referred file by the reference file, and one
identifier including characters capable of being read
directly with the selective receiving means is assigned
to these files,
and wherein the display data generating means
generates display data according to self-descriptive data
contained in the reference file, and generates another
display data according to a desired referred file which
is read out thereby from the received data storing means,
and wherein the selecting condition varying
means extracts characters directly be selected by the
selective receiving means out of absolute path assigned
to the referred files and provides the characters to the
selective receiving means as the selecting condition so
as to selectively receive packetized files each assigned
same identifier with that of the reference file in order
to selectively receive the reference file. While the
novel features of the invention are set forth in a
general fashion, both as to organization and content, the
invention will be better understood and appreciated,
along with other objects and features thereof from the
following detailed description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE ,DRAWINGS/
Fig. 1 is a schematic block diagram showing an
overall structure of a data communication system in
accordance with the present invention.
Fig. 2 is a simplified conceptual view showing
a state of sending radio waves in satellite broadcasting.
Fig. 3 is a schematic illustration of a
transmitter.
Fig. 4 is a view showing a data arrangement of
a transport stream transmitted in satellite broadcasting.
Fig. 5 shows a data structure of packetized
data.
Fig. 6 shows contents of control data of
control data program map table (PMT) 111 for multiplexing
the packetized data.
Fig. 7 shows contents of control data PMT 114
for multiplexing the packetized data.
Fig. 8 shows contents of control data PAT.
Fig. 9 shows contents of control data network .
information table (hereinafter referred to as NIT).
Fig. 10 is a schematic block diagram of a
receiver.
Fig. 11 is a detailed block diagram
illustrating a hardware structure of the transmitter.
Fig. 12 shows a file structure stored in an
HTML data storage unit.
Fig. 13A, Fig. 13B, and Fig. 13C show contents
of HTML files.
Fig. 14A, Fig. 14B, and Fig. 14C are examples
of images displayed on a screen according to the data
stored in the HTML files.
Fig. 15 is a correspondence table.
Fig. 16 is a block diagram showing a typical
example of the hardware structure of a data converter
375.
Fig. 17A and Fig. 17B show other correspondence
tables.
Fig. 18 is a flow chart for describing steps
for creating the correspondence table with the data
converter 375.
Fig. 19 is a detailed block diagram
illustrating the hardware structure of the receiver.
Fig. 20 is a functional block diagram of a
transport stream decoder.
Fig. 21 is a flow chart for describing steps of
a receiving operation control program.
Fig. 22 is a flow chart for describing steps of
a display program.
Fig. 23A, Fig. 23B, and Fig. 23C are tables
showing filtering conditions.
Fig. 24 shows files names after conversion.
Fig. 25A, Fig. 25B, and Fig. 25C show converted
contents of HTML files.
Fig. 26 is a flow chart for describing steps
for changing a file name.
Fig. 27 is a block diagram showing an overall
structure of a digital broadcasting system used in a
third embodiment of the present invention.
Fig. 28A and Fig. 28B are views showing the
structure of the data in both an HTML file and an U-U
object.
Fig. 29 shows a data structure of packetized
data being transmitted.
Fig. 30 is a detailed view for describing
filtering conditions.
Fig. 31 is a schematic block diagram showing
the hardware structure of a data receiver 414.
Fig. 32 is an overall view of a communication
system using the data receiver 414.
Fig. 33 shows data contents of a reference
file.
Fig. 34 shows an image displayed according to
the contents of the reference file.
Fig. 35 shows a hierarchial tree structure of a
file stored in a transmitting station.
Fig. 36 is a flow chart for describing steps of
a display program.
Fig. 37 shows data contents of an HTML file in
which a plurality of files are incorporated with one
another.
Fig. 38 shows data contents of another HTML
file in which a plurality of files are incorporated one
another.
Fig. 39 shows data contents of another HTML
file in which referred files are included therein other
than automatic reference tag(s).
Fig. 40 shows a typical image displayed in
accordance with the reference file depicted in Fig. 39.
Fig. 41A and Fig. 41B show data contents of an
HTML file which is referred as the referred file in Fig.
39.
Fig. 42A and Fig. 42B show images displayed
according to the referred file shown in Fig/ 41A and Fig.
41B.
Fig. 43 shows a hierarchlal tree structure of a
file stored in the transmitter side.
Fig. 44 shows data contents of a reference
file.
Fig. 45 shows another hierarchial tree
structure of a file stored in the transmitter side.
Fig. 46 is a flow chart for describing steps of
storing data into a cache memory.
Fig. 47 shows a data structure of packetized
data being transmitted.
Fig. 48A through Fig. 48C show data structure
of the data stored in the cache memory.
Fig. 49 shows data contents of an HTML file
which is referred as the referred file.
Fig. 50A and Fig. 50B show images displayed
according to the referred file shown in Fig. 49.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the present
invention will be described herein along with the index
shown in below:
1. FUNCTION BLOCK DIAGRAMS
1-1. Outline of satellite broadcasting
1 - 1 - 1. State of sending radio waves in
satellite broadcasting
1-1-2. Outline of transmitter
1-1-3. Structure of transport stream
1-1-4. Outline of receiver
1-2. First Embodiment
1-2-1. Transmitter
1 - 2 - 2. Receiver
1 - 2 - 2 - 1. Hardware structure
1 - 2 - 2 - 2. Receiving operation control program
1 - 2 - 2 - 3. Display program
1 - 3. Second embodiment
1-3-1. Data converting operations in transmitter
1 - 3 - 2. Data receiving operations in receiver
1 - 4. Third embodiment
1 - 4 - l. Data transmitter
1 - 4 - 2. Data receiver
1 - 4 - 3. Hardware structure of data receiver
1 - 5. Fourth embodiment
1-6. Other embodiments.
1. FUNCTION BLOCKS
The system 1 shown in Fig. 1 comprises a transmitter 3
and a receiver 11.
The transmitter 3 includes file storing means 7
and transmission means 5. The file storing means 7
stores a plurality of files comprising self-descriptive
data. A part of the files include reference commands
for referring another files. Identifiers of the files
stored in the file storing means 7 consist of a series of
characters which may directly be recognized with
selecting means 15 in the receiver 11. The transmission
means 5 repeatedly transmits the files with the
identifiers according to a protocol after packetizing
them.
The receiver 11 comprises receiving means 14,
selecting means 15, display data generating means 19, and
selecting conditions variation means 17. The receiving
means 14 receives the packets thus transmitted. The
selecting means 15 selects only packets having selective
identifiers out of the received packets in accordance
with a selecting condition. The display data generating
means 19 generates display data in accordance with self-
descriptive data included in the selected packets.
Further, the selecting conditions variation means 17
varies the selecting condition so as to obtain selected
file(s) specified by the reference(s) included in the
self-descriptive data. The selecting conditions
variation means 17 also varies the selecting condition in
the selecting means 15 so as to obtain selected file(s) *
specified by the reference command(s) when an operator of
the system selects a display region specified by the
reference command(s) out of all the region displayed on
display means 20.
1-1. Outline of satellite broadcasting
One example of applying the present invention
to satellite broadcasting will be described herein. The
present invention, however, may also be applied to other
broadcasting methods such as terrestrial broadcasting,
wire broadcasting such as cable television and the like
as long as packetized data are transmitted.
1-1-1. State of sending radio waves in
satellite broadcasting
Fig. 2 shows a simplified conceptual view
showing a state of sending radio waves in satellite
broadcasting. Radio waves from a ground station 1002 are
sent to a plurality of ground receivers (not shown)
through a broadcasting satellite 1004. The broadcasting
satellite 1004 sends out a plural number of transport
streams 1010, 1020, 1030. Each transport stream is
distinguished from the others by its frequency, plane of
polarization and other factors (well known in the art).
A plurality of services (analogous to channels
in terrestrial broadcasting) 1011, 1012, 1013, and 1014
being packetized are multiplexed in the transport stream
1010 under a time-sharing manner. Similarly, services
1021, 1022, 1023 and 1024, and services 1031, 1032, 1033
and 1034 are multiplexed respectively in the transport
streams 1020 and 1030. Various control data representing
service information, the present time, and the like,
together are sent out to each of the transport streams in
addition to the packetized data (including video data and
audio data). While, Fig. 2 shows only three transport
streams, many more transport streams may be sent out.
Furthermore, while Fig. 2 shows a total of four services
multiplexed in each transport stream, in actuality many
more services may be multiplexed therein.
1-1-2. Outline of transmitter
Fig. 3 is a schematic illustration of a
transmitter for generating and transmitting the transport
streams described above. While Fig. 3 shows only the
transport stream 1010 for simplicity, other transport
streams 1020, 1030 are generated thereby in the same
manner.
Video/audio data of the service 1011 are stored
in a data storing unit 171. These data are compressed by
an encoder 181, and are provided to a multiplexer 160.
Similarly, video/audio data of the services 1012 and 1013
are stored respectively in data storage unit 172 and 173.
Video data for the services are compressed under the MPEG
2 video standard, and audio data are compressed under the
MPEG 2 audio standard. The data so compressed are
provided to the multiplexer 160.
In another data storage unit 174, HTML data
used for the service 1014 is stored therein. The data
are converted into modules having object headers by a
data converter 184 in accordance with the MPEG 2 system
standard. Module identification (module_id) are assigned
to each of the modules. Details of the assignment will
be described later.
A control data generator 180 generates control
data for multiplexing the packetized data,
the control data for displaying program information, the
control data representing the present time and other such
data. The control data for multiplexing is assigned for
properly recognizing video/audio data in plural services
which are packetized and multiplexed under a time sharing
manner.
The multiplexer 160 outputs a plurality of
packets under a time sharing manner, each consisting of
packetized data having a fixed length as a result of
carrying out packetization of the data provided from the
control data generator 180, the encoder 181 through the
encoder 183, and that from the data converter 184, as the
transport stream 1010.
Further, the multiplexer 160 assigns individual
module_ids to section headers of all the packets when the
data from the data converter 184 is packetized. In this
embodiment, the last four digits of a packet are assigned
a table_id_extension region (field) by using the first
four digits thereof as a PID because the module
identifiers consist of directory_id and filetid for
identifying module (a total of eight digits) as described
later.
Thus, the packets comprising each file can
definitely be specified without further consideration in
the receiver by distinguishing them using the PID and the
table_id_extension.
A modulator 164 outputs the packets being
provided and modulated thereby as a transport stream.
The transport stream thus outputted is broadcasted to the
audience.
1-1-3. Structure of transport stream
As shown in Fig. 4, services 1011, 1012 and
1013, each including video data 81V, 82V and 83V, and
audio data 81A, 82A and 83A respectively, service 1014,
including HTML or imaging data 84 and a correspondence
table 109 are multiplexed in the transport stream 1010
generated by the transmitter shown in Fig. 3. Details of
the correspondence table 109 will be described later.
In addition, control data NIT 100, program
allocation table (PAT) 101, and program map table (PMT)
111 through PMT 114 for multiplexing the packetized data
are multiplexed therein. The data corresponding to the.
services 1011, 1012, 1013 and 1014 thus multiplexed can
be separated by using these control data as described
later. Control data EIT 121 through EIT 124, each
representing program information, and control data
representing the present time TDT 105, are also
multiplexed therein. Other control data such as
scrambling information and others are multiplexed therein
even though these are not illustrated in the figures..
The control data PMT 111, PMT 112, PMT 113 and PMT 114,
and control data EIT 121, EIT 122, EIT 123 and EIT 124 are
the control data for the services 1011, 1012, 1013 and 1014
respectively.
Packetization of the control data, the video data, the
audio data, HTML data and the correspondence table is carried
out in the sequence of a line 18a shown in Fig. 4. In other
words, packetization of these data is carried out by the
following sequence: the control data NIT, PAT, PMTs, EITs,
TDT, then the video data 81V, the audio data 81A, the video
data 82V, the audio data 82A, the video data 8V, the audio
data 83, and the HTML data 84 and the correspondence table
109. Upon completing the packetization in the. first round,
further rounds of packetization are,carried out repeatedly
under the same sequence starting from the control data NIT
(see line 18b). The packetization process is carried out
under a certain rule being predetermined (not shown).
A basic structure of the packetized data is shown in
Fig. 5. Both the control data and the video/audio data being
packetized have the structure as shown in Fig. 5. PIDs are
assigned to the forefront of each packetized data. PIDs are
the references which are uniquely assigned to each of the
packetized data to distinguish each packetized data from
other packetized data. The data content field shown in
Fig. 6 packetized object data (e.g. the control data,
video/audio data, HTML data and others).
Contents of the control data PMT 111 for multiplexing
the packetized data of service 1011 are shown in Fig. 6.
PIDs of both the video data 81V and the audio data 81A of the
service 1011 are stored in the PMT 1ll. Similar PIDs as to
these data in the services 1012, 1013 are stored respectively
to in control data PMT 112, PMT 113.
As shown in Fig. 7, a PID and a module identifier
(described later) of data 84 in the service 1014 are stored
in the PMT 114.
PIDs Of PMT 111, PMT 112, PMT 113 and PMT 114, each
corresponding to the services 1011, 1012, 1013 and 1014, are
stored in the control data PAT as shown in Fig. 8.
Transmission specifications defined by their
frequencies, planes of polarization and the like as to all
the transport streams 1010 through 1040, and a list of the
services multiplexed in each of the transport streams are
described in the control data NIT as shown in Fig. 9. This
allows the receiver to learn what kinds of services are
included in each of the transport streams.
1-1-4. Outline of receiver
Functions of the receiver 11 shown in Fig. 1
are outlined with reference to Fig. 10. In the receiver.
11, a desired transport stream is selected by a tuner
222, and data concerned with a desired service contained
in the selected transport stream is separated therefrom
with a transport decoder 226.
Further, a micro processing unit (hereinafter
referred to as MPU) 228 sets PIDs of video/audio data of
the desired service into the transport decoder 226. In
response to the setting, the transport decoder 226
outputs the video/audio data of the desired service. The
control data thus separated are provided to the MPU 228
when PIDs of the control data are set into the transport
decoder 226.
Operations of the receiver 1 which currently
receives the service 1033 contained in the transport
stream 1030, and receives a command to switch it to
another service 1012 included in the transport stream
1010, will be described herein.
The MPU 228 controls the transport decoder 226
to obtain the control data NIT (i.e., by setting a PID of
the control data NIT into the transport decoder 226).
The description of the control data NIT tells that the
service 1012 is multiplexed in the transport stream 1010
(see Fig. 9). In response to the description, the MPU
228 controls the tuner 222 to receive the transport
stream 1010. PIDs of video and audio data in the desired
service 1012 are obtained as a result of separating the
control data PAT and PMT 112 by controlling the transport
decoder 226 with the MPU 228. The MPU 228 controls the
transport decoder 226 to output the video and the audio
data of the desired service 1012 by setting filtering
conditions (the conditions for performing filtering) to
select these PIDs into the transport decoder 226.
Switching of the received service is carried
out as described above.
The MPU 228, further controls the transport
decoder 226 to obtain the control data EIT when a command
for displaying a program schedule and program information
is provided to the MPU 228. In addition, the MPU 228
controls peripherals to display the program information
and related information in accordance with the control
data EIT thus obtained.
1-2. First embodiment
1-2-1. Transmitter
Fig. 11 is a detailed block diagram
illustrating a hardware structure of the transmitter 3
shown in Fig. 3. The transmitter 3 in this embodiment is
used for a digital broadcasting system compliant with
MPEG 2 standard. Digital Storage Media Command and
Control (hereinafter referred to as DSM-CC)
specification, and Digital Video Broadcasting
(hereinafter referred to as DVB) specification for Services
Information (hereinafter referred to as DVB-SI). Definition
of MPEG 2 standard is found in the international standards
organization documents ISO/IEC 13818-1 and ISO/IEC 13818-2.
The document ISO/IEC 13818-6 specifies the DSM-CC
specification. Further, the document ETSI ETS 300 468 (which
is similar to document of Association of Radio Industries and
Businesses STD-B2 version 1.0 in Japan) defines the DVB-SI
specification.
The transmitter 3 is a satellite digital transmitter
capable of transmitting HTML data together with video data
and audio data under a multiplexed format. Fig. 11 shows the
structureSwithin the transmitter 3 supporting the services
1011 and 1014. The structures of services 1012 and 1013 (not
shown) are similar to that of service 1011.
The video data of the service 1011 is stored in a video
data storage unit 311V. The video data are compressed with a
video encoder 331. The video data thus compressed is
provided to a first-in first-out (hereinafter referred to as
FIFO) memory 342 as an elementary stream at a varied rate.
The FIFO memory 342 outputs the elementary stream of video
data to a packeting circuit 344 at a fixed rate.
The packet circuit 344 segments the elementary
stream of the video data into a plurality of packets
each having a fixed length (e.g. 188 bytes), and
writes the packets into a memory 352 as packetized elementary
streams (hereinafter referred to as PES). PIDs are
assigned to each of the PESs as they are written into
memory 352.
Similarly, audio data of the service 1011 is
stored in an audio data storage unit 311A. The audio
data are compressed with an audio encoder 332, and is
provided to another FIFO memory 346. The compressed
audio data are segmented into packets by packet circuit
348. Each packet has a fixed length, and is written into
another memory 354 with its own PID as described above
for the video data.
A packet multiplex controller 356 reads out
PESs of both the video data and the audio data stored in
the memories 352 and 354 in response to its encoding
speed. Also, the controller 356 provides the PIDs
assigned to the PESs of both the video data and the audio
data to a PMT generating circuit 358. The PMT generating
circuit 358 generates the control data PMT 111 as a
result of receiving the PIDs. The assigned PIDs of both
the video data and the audio data contained in the
service are listed in the control data PMT. Both the
PESs of the video and the audio data being read out from
memory 352 and 354 and the corresponding control data PMT
are stored in a memory 362 in a multiplex format under a
time-sharing manner.
Thus, the video and the audio data of the
service 1011 are multiplexed under a time-sharing manner and
stored in the memory 362.
As shown in Fig. 12, the plurality of HTML files
include, e.g., such as "forecast.html", "today.html11 through
"osaka.html" and the image files include, e.g., "sun.gif"
through "rain.gif", both stored in a directory "Vweather".
plurality of HTML and image files are stored in a data
storage unit 314D. In this way, images such as those shown
in Fig. 14A through Fig. 14C, can be displayed in accordance
with the HTML files "forecast.html", "today.html" and
"osaka.html" depicted respectively in Fig. 13A through Fig.
13C.
A data converter 375 sequentially assigns individual
file identifiers to each of the files. The file-ids are
stored as an object header for each file. Data converter 375
also creates a correspondence table between the file
identifiers thus assigned and name of the files. In this
embodiment, file-ids consisting of a total of four digits
such as id = "0001" (expressed in hexadecimal) are
sequentially assigned to the files in the directory "weather"
as shown in Fig. 15. The sequential assignment is made from
the top (Yforecast.html) through the bottom file (not shown)
of the directory "Vweather" as described later. Similarly,
directory identifiers consisting of four digits such as id =
"0001" are assigned to the directory "Yweather" which
includes each of the files. Together, the directory_id and
file_id make up the module identifier. This is to definitely
specify each of the files with an absolute path including
name of the directory as shown in Fig. 15. For example, a
file "¥forecast.html" can definitely be specified as
"¥weather¥forecast.html" can definitely be specified as
"weatherforecast.html" or "0001/0001". In this way, a
correspondence table shown in Fig. 15 is created by assigning
both the directory_id and the file_id to each module as its
module identifier.
The data converter 375 consists of a combination of
hardware and software structures in this embodiment. Fig. 16
shows a typical example of the hardware structure of the data
converter 375. A corresponding chart shown in Fig. 17A is
stored in a ROM 375r. Steps performed in a software
structure for data conversion used by the CPU 375c will be
described with reference to Fig. 18.
The CPU 375c initializes the counter i (step S201, in
Fig. 18). Then, the file corresponding to the counter i is
stored into the corresponding chart (step S203) . For
example, the top file "¥forecast.html" of the directory
"¥weather" is stored into a region representing module number
1. Thus, the file "¥weatherYforecast.html" is assigned the
module_id "0001/0001" as shown in Fig. 17B. In this
embodiment, the module identifiers consist of the four digit
file_id = "0001" and the four digit directory_id = "000l" as
described above.
Next, the CPU 375c determines whether or not all the
files are stored in the corresponding chart (step S207). If
files have not been so stored, the CPU 375c increments the
counter i by one (step S209), and stores the next file in the
corresponding chart (step S203). Creation of the
corresponding chart is completed when the step S203 is
carried out to all the files.
The corresponding chart thus created is provided to a
packeting component 377, shown in Fig. 11, together with each
of the modules, and is stored in a memory 382 after
packetization.
The data from the data converter 375 is packetized into
packets having a fixed length by the packeting component 377.
The packeting component 377 assigns individual PIDs to the
section headers of all the packets generated. In this
embodiment, the first four digits and the last four digits
are respectively assigned as the PID and the
table_id_extension region (field) because the module
identifiers consist of the directory_id and the file_id (a
total of eight digits).
In this way, the packets making up each file can
definitely be specified without further consideration in the
receiver by distinguishing them using the PID of each packet
and the table_id_extension as a result of distinguishing the
modules by the PID and the table_id_extension of each packet.
Further, the packeting component 377 also packetizes the
corresponding chart created by the data converter 375 into
packets having a fixed length. In other words, the
corresponding chart is multiplexed as the correspondence
table 109 depicted in Fig. 4.
There are table_id regions (fields) for setting own
table_id, each having a predetermined data length, and
table_id_extension regions (fields) for setting own
table_id_extensions in the sections heads of each packet.
Their own module identifiers are stored in the
table_id_extension fields as the table_id_extensions. The
details of this relationship will be described later.
A packet multiplex controller 384 reads out the data
stored in the memory 382 in response to, its encoding speed.
Also, the controller 384 provides PIDs assigned to the data
to a PMT generating circuit 386.
The PMT generating circuit 386 generates a control data
PMT 114 (see Fig. 4) as a result of receiving the PIDs. The
PIDs for each packet related to contained in the service 1014
are listed in the control data PMT 114. Both the data thus
read out from the memory 382 and the corresponding control
data PMT are stored in a memory 364 in a multiplex format
under a time-sharing manner. Additionally, the PMT 114
contains the module_id into an additional information field
by the circuit 386, the module_id corresponding to an HTML
file comprising a front page displayed initially in the
service 1014 as shown in Fig. 7. In this way, a
table_id_extension "0x0001" is written to an additional
information field in the PMT of the service 1014 as a file_id
of the front page when the front page is represented by file
"¥weather¥forecast.html", because the file
"YweatherYforecast.html11 is replaced with a file_id "0001"
during the packetization. Also, the file
"YweatherYforecast.html" is replaced respectively with a PID
"0x0001" and a table_id "0x0001" during the packetization.
1 - 2 - 2. Receiver
1-2-2-1. Hardware structure
The hardware structure of the receiver 11 depicted in
Fig. 1 is shown in Fig. 19. The receiver 11 functions as a
receiver of satellite broadcasting as well as a device for
displaying HTML data on a monitor.
The function of the receiver 11 in receiving satellite
broadcasting is similar to that of the conventional
broadcasting receiver, as briefly described below. Radio
waves transmitted by the transmitter are caught with an
antenna 131, and the radio waves are supplied to a tuner 132.
The tuner 132 selects one of the transport streams in
accordance with a command of the CPU 147. Further, the tuner
132 carries out demodulation and error-correction and other
relevant operations, and outputs the resultant signals to a
transport decoder 141.
The transport decoder 141 only selects (i.e.,
filters) predetermined packets out of the packets
multiplexed within the selected transport stream in
accordance with PIDs set therein by the CPU 147.
PacketIzed data for the system are contained in the
multiplexed packets other than control data, video data
and audio data because the system data are also
multiplexed together with the video data and the audio
data. The transport decoder 141 identifies these data in
accordance with the data stored in the headers in each of
the files, and both the control data and the system data
are stored in a RAM 144. The RAM 144 stores the
packetized data under the file basis so that the
packetized data thus stored forms to one independent
file.
Filtering procedure carried out in the
transport decoder 141 will be described with reference to
Fig. 20. Conditions for performing filtering of data
(hereinafter referred to as filtering conditions) are
stored in a filtering conditions storing unit 154. For
example, PIDs, the table_id and table_id_extensions of *
the packets to be selected are stored therein. A PID
selecting unit 156 selects the packets having
predetermined PIDs in accordance with the filtering
conditions stored in the filtering conditions storing
unit 154. The packets of video data and that of audio
data, are respectively outputted to a video decoder 137
and an audio decoder 134. Packets of HTML or image data in a
selection format with the selected packets are outputted to a
section data selecting unit 155 shown in Fig. 20. The
section data selecting unit 155 only outputs the packets
having predetermined table_id_extensions in accordance with
the filtering conditions stored in the filtering conditions
storing unit 154.
A conditions varying unit 153 varies filtering
conditions stored in the filtering conditions storing unit
154 in accordance with a rewrite command outputted by the CPU
147 (as shown in Fig. 19).
The video data are provided to the video decoder 137
through the FIFO memory 136 depicted in Fig. 19, and are
decompressed or expanded thereby. The video data are
converted into analog signals with a digital/analog converter
(hereinafter referred to as D/A converter) 138, and the
analog signals are displayed on a monitor 140 such as a
liquid crystal display, a cathode ray tube and the like
through a video synthesizer 139. The data representing
characters stored in a video RAM (hereinafter referred to as
VRAM) are converted into analog signals with another D/A
converter 145, and the analog signals are provided to the
video synthesizer 139. In this way, characters can be
overlapped on images displayed on the monitor.
The audio data, on the contrary, are provided to the
audio decoder 134 through another FIFO memory 133, and are
decompressed or expanded thereby. The audio data are
outputted through a speaker 135 as actual sound.
A remote controller 149 stores the following commands
such as initialization of watching, designation of services,
instruction for category search for the program information
or the like, and the controller 149 outputs them to a
microcomputer 148 installed in the main part of the receiver
11.
The CPU 147 controls the tuner 132, the transport
decoder 141 and relevant cpmoonents In accordance with a
receiving operation control program 142c and a display
program 142a both stored in a ROM 142/ These programs may be
capable of stand alone operation, or may require an operating
system (such as Windows CE by Microsoft Inc.) as a
premise.
1 - 2 - 2 - 2. Receiving operation control program
An embodiment of the receiving operation control program
142c used for carrying out receiving operations will be
described with reference to Fig. 19 and Fig. 21. Operations
necessary to switch the receiver 11 from receiving the
service 1013 contained in the transport stream 1010, to
receiving another service 1011 included in the transport
stream 1010, will be described herein. A switching command
is sent by the remote controller 149 or a control panel (not
shown) to the CPU 147. The switching command is provided to
the CPU 147 through a microcomputer 148 (as shown in Fig.
19). In response to the switching command, the CPU 147 sets
PIDs of the control data PAT into a register (not shown) for
separating the control data in the transport decoder 141.
The PID of the control data PAT has a fixed value such as
"0x0000". In this way, contents of the control data PAT
being separated are stored in the RAM 144 under the control
of the transport decoder 141 (step Sll, in Fig. 21). A list
of the services multiplexed in the transport stream currently
received are shown in the contents of the control data PAT
(see Fig. 8). The CPU 147 determines that the desired
service 1011 is multiplexed in the transport stream 1010
currently received by referring the list. The CPU 147
continues processing from step S12. to step S18.
In the step S18, the CPU 147 obtains
PIDs of the control data PMT in the desired
service 1011 in accordance, with the contents of the
control data PAT. As a result, the CPU 147
recognizes that id "0x0011" is for a PID of the
control data PMT in the desired service 1011 as shown
in Fig. 8. Further, the CPU 147 sets the PID
"0x0011" of the control data PMT into the register
for separating the control data in the transport decoder
141 (step S19). Hence, the control data PMT 111 in the
service 1011 can be separated from other data, and
contents of which can be stored in the RAM 144.
Next, the CPU 147 recognizes PIDs "0x0022" and
"0x0024" of the video data 81V and the audio data 81A
respectively, in accordance with the PMT for the service
1011 as shown in Fig. 6 (step S20).
Then, the CPU 147 sets both the PIDs "0x0022"
and "0x0024" into the filtering conditions storing unit
154 (see Fig. 20) in the transport decoder 141 (step
S22). In this way, the transport decoder 141 can
selectively output both the video data 81V and the audio
data 81A, both being required.
The CPU 147 proceeds its processing to step S13
if the desired service is not multiplexed in the
transport stream currently received in step S12.
Further, the CPU 147 obtains PIDs of the control data NIT
assigned in the control data PAT. In accordance with the
PIDs thus obtained, the CPU 147 obtains the control data
NIT, and determines whether the desired service contained
in any of the transport streams (step S14, step S15). *
The CPU 147 switches a setting of the tuner 34
so as to receive the transport stream which contains the
desired service (step S16). Then, the CPU 147 obtains
the control data PAT of the transport stream (step S17).
Hereafter, steps following to step S18 may be performed,
as described above.
1-2-2-3. Display program
The function for displaying HTML data on the
monitor is accomplished by the CPU 147 and the display
program 142a stored in the ROM 142.
Data obtained is stored in the RAM 144 when the
data is system data under the control of the transport
decoder 141. The CPU 147 starts performing the display
program 142a when the system data is supplied by the
transport decoder 141 because the CPU 147 recognizes data
written in a section format as system data in this
embodiment.
Steps performed by the display program 142a for
displaying HTML files will be described with reference to
Fig. 19 and Fig. 22.
At first, a switching command, for switching
the operations to a service in which the HTML files are
received, is outputted by the remote controller 149 in
accordance with input of the operator who refers a
program table. As a result of receiving the command, the
CPU 147 varies filtering conditions in the tuner 132 and
the transport decoder 141 respectively.
For example, the operator selects a service id
= "001" with the remote controller 149 when he/she find
out a weather forecast which provides interactive service
can be specified by the service id = "001" by referring
to the program table.
Control data PAT is obtained by varying the
filtering conditions of the transport decoder 141 to PID
= "0x0000" with the CPU 147 because the PID of the PAT is
a fixed value "0x0000". Steps for obtaining the control
data PAT are performed after switching the tuner 132 so
as to receive a transport stream in which a service
specified by the service id = "001" is multiplexed as a
result of obtaining the control data NIT thereof when the
service having the service id = "001" is multiplexed in
the transport stream other than the transport stream
currently received.
A PMT of the service specified by the service
id = "001" can be obtained once the control data PAT is
obtained. As a result of obtaining the PMT, an id of the
transport stream in which the service is multiplexed,
PIDs of packets in which data related to the service is
stored, and table_id_extensions of the file which are
displayed at first can automatically be obtained. Under
this logic, the CPU 147 varies filtering conditions in
the transport decoder 141 while switching the tuner 132
in order to receive the service. In this way, receipt of
a service specified by a service id "001" is started.
For instance, the CPU 147 varies filtering
conditions in the transport decoder 141 so as to select
packets of a PID "0x0001", that of a table_id "0x3C", and
that of a table_ld_extension "0x0001" shown in Fig. 23A
when the PID, the table_id, and the table_id_extension of
the service specified by the service id = "001" are
respectively "0x0001", "0x3C", and "0x0001" according to
the PMT. The table_id is a fixed value of "0x3C".
Further, the numbers "Ox" means that the numbers
following thereto are expressed in hexadecimal in this
embodiment.
Consequently, the transport decoder 141 selects
the packets having their PIDs, table_id, and
table_id_extension as "0x0001", "0x3C", and "0x0001"
respectively. Selective reception of the HTML files
shown in Fig. 13A according to the filtering conditions
will be described below as an example.
The CPU 147 judges whether or not the system
data stored in the RAM 144 comes to one independent file
(step S101, in Fig. 22). In a concrete form, the
judgement can be carried out by detecting whether or not
the last block of the system data is received. The
counter i is initialized once the one independent file is
received (step S103). The CPU 147 detects existence of
an automatic reference tag in the HTML data of the file
located in 1 th row thereof (step S105). The automatic
reference tag is defined as image tags for referring
other file(s) regardless of the operations by the
operator. Operations related to the automatic reference
tag will be described later. Since the counter i was
initially set to 0, the first time CPU 147 executes step
S105, it will move onto step S1ll and generate display
data according to. the data located in the i th row. The
display data is stored to a VRAM 146, then converted into
analog data by the D/A converter 145. After conversion
to analog data, the display data is provided to the video
synthesizer 139. The video synthesizer 139 outputs
display data which is synthesized with the data from the
video decoder 137 thereby to the monitor 140. Hence, a
image according to the data located i th row is displayed
on the monitor 140.
Next, the CPU 147 increments the counter i by
one (step S113), and judges whether or not a tag
"

Documents:

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Patent Number

225656

Indian Patent Application Number

IN/PCT/2000/00001/KOL

PG Journal Number

47/2008

Publication Date

21-Nov-2008

Grant Date

19-Nov-2008

Date of Filing

05-Jan-2000

Name of Patentee

MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.

Applicant Address

1006, OAZA KADOMA, KADOMA-SHI, OSAKA

Inventors:

#	Inventor's Name	Inventor's Address
1	OASHI MASAHIRO	61-6, TANABEDOUJOU KYOTANABE-SHI KYOTO 610-0331
2	SHIMOJI TATSUYA	30-3-1102 MIIMINAMIMATI NEYAGAWA-SHI OSAKA 572-0019
3	SONODA YASUYUKI	22-1, SHINOMIYAI-WAKUBOTYOU YAMASINAKU, KYOTO-SHI KYOTO 607-8028
4	YAMAMURO KEISEI	2-2-2-207 MINAMITERA-KATAKITADOORI MORIGUCHI-SHI OSAKA 570-0046

PCT International Classification Number

G06F 17/30

PCT International Application Number

PCT/JP99/02365

PCT International Filing date

1999-05-06

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	HEI10-123193	1998-05-06	Japan
2	HEI10-170637	1998-12-25	Japan
3	HEI10-107209	1999-04-14	Japan