JPWO1999059290A1 - Content provision system - Google Patents

Abstract

(57) [Abstract] A content providing system for efficient data distribution is provided. It comprises a content data storage unit (21) for storing content data, a meta information storage unit (22) for storing meta information, a meta information schema storage unit (23) for storing a meta information schema indicating the data structure of the meta information, a meta information conversion unit (24) for converting the data format of the meta information into a predetermined transmission format, a meta information schema conversion unit (25) for converting the data format of the meta information schema into the predetermined transmission format, and a transmission unit (26) for transmitting the meta information, meta information schema, and content data converted into the predetermined transmission format. The transmission device (21) converts the meta information and meta information schema into the predetermined transmission format and transmits them.

Description

[Detailed Description of the Invention] Content Provision System Technical Field The present invention relates to a content provision system that provides content to an unspecified number of users, a content provision device, a content receiving device, a content signal provision method, and a meta-information reception method.

BACKGROUND ART Many methods have been proposed for content data distribution systems.

For example, on the Internet, content data is distributed via the World Wide Web (WWW) using the HyperText Transfer Protocol (HTTP). Obtaining the desired content data from a vast collection of content data on the WWW can be extremely difficult. Therefore, on the WWW, each piece of content data typically includes metadata that describes the content data. By searching this metadata, a receiving device can select the desired content data from the vast collection of content data.

Examples of meta-information added to the WWW include the Platform for Internet Content Selection (PICS) and the Resource Description Framework (RDF).

Furthermore, for example, digital television broadcasting distributes data using MPEG-2 and other formats. In such digital television broadcasting, meta-information such as program titles and broadcast times is provided in the form of an EIT (Event Information Table) using, for example, an EPG (Electric Program Guide).

In recent years, the integration of transmission media has progressed, and efforts are being made to integrate broadcast networks such as digital television broadcasting with interactive networks such as the Internet.

When information that was previously transmitted over interactive networks such as the Internet is transmitted over broadcast networks such as digital television broadcasting, meta-information developed for interactive networks, such as PICS and RDF, must also be transmitted over the broadcast network. Furthermore, meta-information described in PICS and RDF is expressed in text format, which reduces transmission efficiency.

Furthermore, when information that was previously transmitted over a two-way network such as the Internet is transmitted over a broadcast network such as digital television, the receiving end typically selectively receives the transmitted meta-information, which requires high-speed filtering to select the necessary meta-information. However, high-speed filtering is difficult when the meta-information is presented in text format.

Furthermore, meta-information in the EIT of digital television broadcasts is transmitted in a predetermined data structure, which is difficult to change. Therefore, it is extremely difficult to add meta-information for systems developed on the World Wide Web, such as PICS and RDF, to the EIT.

Disclosure of the Invention The objective of the present invention is to provide a content delivery system that enables efficient content delivery and flexible content selection and reception.

Another object of the present invention is to provide a content providing device that efficiently distributes content.

Another object of the present invention is to provide a content receiving device that allows flexible content selection and reception.

Another object of the present invention is to provide a method for providing content signals that enables efficient content distribution.

Another object of the present invention is to provide a method for receiving meta information that allows flexible content selection and reception.

The content provision system according to the present invention comprises a content provision device and a content receiving device. The content provision device comprises: provision means for providing a content signal to the content receiving device; metainformation storage means for storing metainformation related to the content signal; provider-side metainformation schema storage means for storing a metainformation schema indicating the data structure of the metainformation; and transmission means for transmitting the metainformation and the metainformation schema to the content receiving device via a communication path. The content receiving device comprises reception means for receiving the metainformation and the metainformation schema transmitted from the transmission means of the content provision device via the communication path; receiver-side metainformation schema storage means for storing the metainformation schema received by the receiver; and metainformation data structure detection means for detecting the data structure of the metainformation received by the receiver based on the metainformation schema stored in the receiver-side metainformation schema storage means.

In this content provision system, a content provision device transmits a meta information schema indicating the data structure of meta information related to a content signal to a content receiving device, transmits the meta information to the content receiving device, and provides the content to the content receiving device. In this content provision system, the content receiving device then receives the meta information schema, receives the meta information, detects the data structure of the received meta information based on the meta information schema, and receives a content signal related to the received meta information.

A content providing device according to the present invention comprises providing means for providing a content signal to a content receiving device, meta-information storage means for storing meta-information related to the content signal, meta-information schema storage means for storing a meta-information schema indicating a data structure of the meta-information, and transmission means for transmitting the meta-information and the meta-information schema to the content receiving device via a communication path.

The content providing device transmits a meta information schema indicating the data structure of meta information related to a content signal to a content receiving device, transmits the meta information to the content receiving device, and provides the content to the content receiving device.

A content receiving device according to the present invention comprises: meta information schema storage means for storing a meta information schema indicating a data structure of meta information related to a content signal; receiving means for receiving the content signal and meta information related to the content signal via a communication path; and meta information data structure detection means for detecting the data structure of the meta information received by the receiving means based on the meta information schema stored in the meta information schema storage means.

This content receiving device receives a meta information schema indicating the data structure of meta information related to a content signal, receives the meta information, detects the data structure of the received meta information based on the meta information schema, and receives a content signal related to the received meta information.

A content signal providing method according to the present invention includes the steps of: transmitting a meta information schema indicating a data structure of meta information related to a content signal to a content receiving device via a communication channel; transmitting the meta information to the content receiving device via the communication channel; and providing the content signal to the content receiving device.

A meta information receiving method according to the present invention comprises the steps of receiving a meta information schema indicating a data structure of meta information related to a content signal, receiving the meta information, and detecting the data structure of the received meta information based on the meta information schema.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram illustrating a content distribution system embodying the present invention.

FIG. 2 is a diagram showing the configuration of a broadcasting station in the content distribution system.

FIG. 3 is a diagram showing the configuration of a receiving terminal in the content distribution system.

Figure 4 illustrates a meta-information schema based on the PICS data model.

FIG. 5 is a diagram for explaining a meta information schema of a predetermined transmission format.

Figure 6 shows an example of a meta information schema based on the PICS data model shown in Figure 4 above, converted into a meta information schema for a specified transmission format shown in Figure 5.

FIG. 7 is a diagram for explaining meta information based on the PICS data model.

FIG. 8 is a diagram for explaining meta information in a predetermined transmission format.

FIG. 9 is a diagram illustrating information described in the meta information filtering mask in the meta information of the predetermined transmission format.

FIG. 10 is a diagram showing a specific example of meta information in the predetermined transmission format.

FIG. 11 shows another example of meta information in the specified transmission format.

FIG. 12 is a diagram illustrating the locator information in the meta information of the predetermined transmission format.

FIG. 13 is a diagram illustrating a dialog box displayed by the profile generation unit of the receiving terminal shown in FIG.

FIG. 14 is a diagram showing the profile information generated by the profile generation unit.

FIG. 15 is a flowchart showing the processing contents of the receiving terminal shown in FIG.

FIG. 16 is a flowchart showing in more detail the data reception process shown in FIG.

FIG. 17 is a diagram for explaining the RDF data model.

Figure 18 shows a program genre hierarchy description and parental guide hierarchy description based on the RDF data model, bit pattern information for generating a filtering mask after converting this information into a predetermined transmission format, and a filtering mask bit pattern for a certain piece of content.

FIG. 19 is a diagram showing an example of a format for storing a filtering mask bit pattern in the section format of the MPEG-2 system.

FIG. 20 is a diagram showing another example of a format for storing a filtering mask bit pattern in the section format of the MPEG-2 system.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the invention will now be described with reference to the drawings.

FIG. 1 shows an example of the configuration of a content distribution system to which the present invention is applied.

A content distribution system 1 embodying the present invention includes a broadcast station 11 that provides content data via a broadcast network 2, such as cable broadcasting or satellite broadcasting, an information provider 12 (12a, 12b) that provides the content data via a bidirectional network 3, such as the Internet, and a receiving terminal 13 (13a, 13b) that acquires the content data from the broadcast station 11 or the information provider 12.

Broadcast station 11 uses a database to manage the content data it provides, meta information related to this content data, and a meta information schema that indicates the data structure of this meta information. Broadcast station 11 provides this content data, meta information, and meta information schema to receiving terminal 13. Information providing device 12 also uses a database to manage the content data it provides, meta information related to this content data, and a meta information schema that indicates the data structure of this meta information. Information providing device 12 provides this content data, meta information, and meta information schema to receiving terminal 13. Note that information providing device 12 may first transmit the content data, meta information, and meta information schema managed in its own database to broadcast station 11 via bidirectional network 3, and then use broadcast station 11 to provide them to receiving terminal 13 via broadcast network 2.

FIG. 2 shows the configuration of the broadcast station 11 of the content distribution system 1.

The broadcast station 11 includes a content data storage unit 21 for storing content data, a meta information storage unit 22 for storing meta information, a meta information schema storage unit 23 for storing meta information schema, a meta information conversion unit 24 for converting meta information into a predetermined transmission format, a meta information schema conversion unit 25 for converting the meta information schema into a predetermined transmission format, a transmission unit 26 for transmitting the content data and the meta information and meta information schema converted into the predetermined transmission format over the broadcast network 2, a data search unit 27 for searching for content data, etc. in response to a request from the receiving terminal 13, and a communication control unit 28 for transmitting the searched content data, etc. over the bidirectional network 3.

The content data storage unit 21 stores content data to be provided to the receiving terminal 13. The content data to be provided may be, for example, television program data for broadcast. Note that the content data storage unit 21 may also store program data written in HTTP or other formats.

The meta information storage unit 22 stores meta information related to the content data stored in the content data storage unit 21.

Here, meta information is information describing the attributes of content data, and is provided to receiving terminal 13 along with the content data. The meta information describes the attributes of the content data by categorizing them into one or more categories. For example, if television program data is provided as content data, the meta information for that content data would describe the attributes by categorizing them into multiple categories, such as the program title of the television program data being "7:00 News," the program genre of the television program data being "News," the broadcast time of the television program data being "7:00-7:30," and the parental rating of the television program data being "G." For example, when program data is provided as content data via a network such as data broadcasting or the Internet, the content data's meta information describes attributes by classifying them into multiple categories, such as the program name of the program data being "XX Game," the program genre being "Game Program," and the target OS (Operating System) being "Windows 95 (trademark)." The meta information storage unit 22 stores this meta information in a data format corresponding to the content data. For example, the meta information storage unit 22 stores meta information in multiple data formats that are incompatible with the content data's data format, such as meta information based on the PICS data model, meta information based on the RDF data model, or meta information in EIT format that describes program titles, broadcast times, etc.

The meta information schema storage unit 23 stores a meta information schema that indicates the data structure of the meta information stored in the meta information storage unit 22.

Here, the meta information schema is information that defines the data structure of the meta information.

This meta information schema is used by the receiving terminal 13 to interpret the meta information accompanying the provided content data. The meta information describes the attributes of the content data, categorized into one or more items. The meta information schema defines the type of attributes and their arrangement for each item in the meta information.

For example, if television program data is provided as content data, the meta information would include attributes such as "Program Name: 7:00 News," "Program Genre: News," "Broadcast Time: 7:00-7:30," and "Parental Guide: G," as described above. The meta information schema defines that the attributes of the meta information are categorized and described under the headings "Program Name," "Program Genre," "Broadcast Time," and "Parental Guide," and further defines the specific content of the attributes described within each heading. For example, the specific attributes described within each heading are attributes such as "Movie," "News," and "Sports" for the heading "Program Genre," or "Broadcast Time" for the heading "7:00-7:30," "7:30-8:00," "8:00-8:30," etc.

For example, if program data is provided as content data, the meta information would describe attributes such as "Program Name: XX Game," "Program Genre: Game Program," and "Target OS: Windows 95™," as described above. In contrast, the meta information schema defines that the meta information attributes are categorized and described under the headings "Program Name," "Program Genre," and "Target OS," and further defines the specific content and arrangement described within each heading. For example, the specific attributes described within each heading would be attributes such as "still image data," "audio data," and "game" for the heading "Program Genre," or "Windows 98™" and "Mac OS™" for the heading "Target OS."

Because the meta information schema is defined in this manner, when the receiving terminal 13 receives content data, it can interpret the contents of the meta information for each category categorized using the meta information schema and determine the attributes of the content data.

Furthermore, meta information may vary in description format and data content depending on the receiving device to which the content is delivered and the content itself, and it can also be updated. For example, even if the same content changes over time and the meta information changes, because the meta information has the same data structure, it can be updated in response to changes in the content itself.

The meta information schema storage unit 23 stores multiple meta information schemas, identifying each meta information schema with an identifier to accommodate, for example, updates to such meta information and differences in the meta information description format. For example, the meta information schema storage unit 23 stores multiple meta information schemas, such as a meta information schema that defines that the attributes categorized under the above-mentioned "Program Name," "Program Genre," "Broadcast Time," and "Parental Guide" are described in the meta information, and a meta information schema that defines that the attributes categorized under the above-mentioned "Program Name," "Program Genre," and "Target OS" are described in the meta information. Each of these meta information schemas is identified by an identifier. Furthermore, the meta information storage unit 22 stores meta information in a format that includes the same identifier as the identifier assigned to the associated meta information schema.

Furthermore, meta information is provided in a form accompanying the content data provided to the receiving terminal 13. In contrast, the meta information schema may be provided to the receiving terminal 13 accompanying the content data, or may be provided to the receiving terminal 13 independently prior to the provision of the content data. If the meta information schema is provided to the receiving terminal 13 independently prior to the provision of the content data, it may be provided via communications over the broadcast network 2 and the two-way network 3, or by other means, such as using a recording medium such as an optical disc or a memory card.

The meta-information conversion unit 24 converts the meta-information stored in the meta-information storage unit 22 into a predetermined transmission format. The description format of the meta-information stored in the meta-information storage unit 22 may differ for each piece of content data or for each information providing device 12. For example, the meta-information storage unit 22 stores meta-information in multiple different description formats, such as meta-information based on the PICS data model and meta-information based on the RDF data model. However, this meta-information is converted into a predetermined transmission format by the meta-information conversion unit 24 and provided to the receiving terminal 13.

The meta information schema conversion unit 25 converts the meta information schema stored in the meta information schema storage unit 25 into a predetermined transmission format. The description format of the meta information schema stored in the meta information schema storage unit 25 may differ for each piece of content data or for each information providing device 12 providing the content data. For example, the meta information schema storage unit 25 stores meta information schemas with multiple different description formats, such as a meta information schema based on the PICS data model and a meta information schema based on the RDF data model. However, the meta information schema conversion unit 25 converts the description format of the meta information schema into the same predetermined transmission format and provides it to the receiving terminal 13.

The transmission unit 26 transmits the meta information converted into a predetermined transmission format by the meta information conversion unit 24, the meta information schema converted into a predetermined transmission format by the meta information schema conversion unit 25, and the content data stored in the content data storage unit 21 to the receiving terminal 13 via the broadcast network 2, for example, by multiplexing them.

The data search unit 27 searches for content data, meta information, and meta information schemas requested for transmission from the receiving terminal 13 via the bidirectional network 3.

The communication control unit 28 extracts the content data, meta information, and meta information schema searched by the data search unit 27 and transmits them to the receiving terminal 13 via the bidirectional network 3. Similar to the transmission unit 26, the communication control unit 28 multiplexes the meta information converted into a predetermined transmission format by the meta information conversion unit 24, the meta information schema converted into a predetermined transmission format by the meta information schema conversion unit 25, and the content data stored in the content data storage unit 21, and transmits them to the receiving terminal 13.

A broadcast station 11 configured in this manner can convert the description formats of meta information and meta information schemas, which vary for each piece of content data or each information providing device 12, into a single, predetermined transmission format and transmit this information to the receiving terminal 13 along with the content data.

Furthermore, the information providing device 12 of the content distribution system 1 uses a database to manage the content data it provides, meta information related to this content data, and a meta information schema that indicates the data structure of this meta information. The content data provided by the information providing device 12 may be, for example, a World Wide Web page. The information providing device 12 provides this content data, meta information, and meta information schema to the broadcast station 11 and the receiving terminal 13 via the two-way network 3. The information providing device 12 can also supply the content data, meta information, and meta information schema managed in the database to the broadcast station 11 via the two-way network 3, which then provides them to the receiving terminal 13 via the broadcast network 2. In addition, the broadcast station 11 and the information providing device 12 may transmit the meta information and meta information schema to the receiving terminal 13 via the broadcast network 2 or the bidirectional network 3, and then transmit content data stored in the content data storage unit 21 of the broadcast station 11 or the information providing device 12 in response to a request from the receiving terminal 13 that has received the meta information and meta information schema.

The information providing device 12 has the same configuration as the broadcasting station 11, except that it does not have, for example, a transmission unit 26 that transmits data to the broadcasting network 2.

This information providing device 12 can convert meta information and meta information schemas that have different description formats for each piece of content data or for other information providing devices 12 into a single predetermined transmission format and transmit this information to the receiving terminal 13 along with the content data.

FIG. 3 shows the configuration of the receiving terminal 13 of the content distribution system 1.

The receiving terminal 13 includes a receiving unit 31 that receives content data, meta information, and meta information schema provided via the broadcast network 2; a communication control unit 32 that receives content data, meta information, and meta information schema provided via the bidirectional network 3; a meta information schema storage unit 33 that stores the received meta information schema; a profile generation unit 34 that generates profile information based on user input; a user profile storage unit 35 that stores the generated profile information; a meta information filter unit 36 that filters the received meta information based on the profile information; a meta information storage unit 37 that stores the filtered meta information; a content data receiving unit 38 that acquires content data corresponding to the filtered meta information; and a content data storage unit 39 that stores the acquired content data. The profile generation unit 34 includes a monitor 34a and an input unit 34b.

The receiving unit 31 receives content data, meta information, and meta information schema provided from the broadcast station 11 via the broadcast network 2.

The communication control unit 32 requests the broadcast station 11 or the information providing device 12 to provide content data and the like via the bidirectional network 3, and receives the content data, meta information, and meta information schema provided by the broadcast station 11 or the information providing device 12 in response to the request.

The meta information schema storage unit 33 stores the received meta information schema.

The meta information schema stored in the meta information schema storage unit 33 may be pre-stored prior to the provision of content data. Note that the meta information schema stored in the meta information schema storage unit 33 prior to the provision of content data may be provided via the broadcast network 2 and the two-way network 3, or may be provided by other means, such as using a recording medium such as an optical disc or a memory card.

The profile generation unit 34 displays information defined in the meta information schema stored in the meta information schema storage unit 33 on the monitor 34a, and generates user-specific profile information from the meta information schema by accepting user input via the input unit 34b. For example, the profile generation unit 34 classifies multiple attributes of the meta information defined in the meta information schema, for example, by category, and displays them on the monitor 34a. The user selects the attribute of the content data they wish to acquire from the multiple attributes of the displayed meta information using the input unit 34b, which may be, for example, a pointer. The profile generation unit 34 then generates profile information that identifies the attribute of the selected content data.

For example, in a metadata schema defining the data structure of meta information related to television program data, the "program genre" attribute may be defined as "movie," "news," or "sports," and the "broadcast time" attribute may be defined as "7:00-7:30," "7:30-8:00," etc. The profile generation unit 34 classifies these attributes, for example, by category, and displays them on the monitor 34a. Based on the displayed information, the user selects the "program genre" and time period of the television program data they wish to watch. The profile generation unit 34 then generates profile information indicating the attributes selected by the user, such as "program genre: news" and "broadcast time: 7:00-7:30."

The profile generation unit 34 may generate profile information using a mechanical automatic selection device, etc., rather than selecting profile information in response to a user selection.

The user profile storage unit 35 stores the profile information generated by the profile generation unit 34.

The meta information filter unit 36 filters and extracts only the meta information that matches the conditions specified in the profile information from the received meta information. For example, it filters and extracts only the meta information that describes "program genre: news" and "broadcast time: 7:00-7:30."

The meta-information storage unit 37 stores the meta-information extracted by the meta-information filter unit 36.

The content data receiving unit 38 receives content data received by the receiving unit 31 or the communication control unit 32, and acquires, from the received content data, content data corresponding to the meta information stored in the meta information storage unit 37.

The content data storage unit 39 stores the content data acquired by the content data receiving unit 38.

As described above, receiving terminal 13 obtains content data, meta information related to this content data, and meta information schema indicating the data structure of this meta information provided by broadcast station 11 and information provider device 12 via broadcast network 2 and bidirectional network 3. Because the meta information and meta information schema are converted into a predetermined transmission format, receiving terminal 13 always receives the meta information and meta information schema in the same transmission format, regardless of the content data or information provider device. Users of content distribution system 1 can use receiving terminal 13 to access the provided content, such as television programs and the World Wide Web.

Furthermore, by transmitting meta information and meta information schemas with improved filtering and transmission efficiency, the receiving terminal 13 can efficiently distribute data and flexibly select and receive it.

Next, a specific example will be described in which the meta information conversion unit 24 and meta information schema conversion unit 25 of the broadcast station 11 convert meta information and meta information schema based on the PICS data model into meta information and meta information schema in a predetermined transmission format, and then distribute the content data.

FIG. 4 shows an example of a meta information schema based on the PICS data model.

As shown in Figure 4, a meta information schema based on the PICS data model consists of multiple categories for classifying the attributes of content data and multiple labels for specifically identifying the attributes of the content data.

The PICS data model provides categories such as "genre" and "parental guide" to classify the attributes of content data.

The PICS data model defines labels identifying attributes of categories classified by "genre": "Movies or Dramas (Value 1)," "News or Current Affairs (Value 2)," "Shows or Game Shows (Value 3)," "Sports (Value 4)," "Children's or Youth Programs (Value 5)," "Music, Ballet, or Dance (Value 6)," "Arts or Culture (Value 7)," "Education, Science, Events, or Topics (Value 8)," and "Leisure or Hobbies (Value 9)." The PICS data model also provides labels specifying attributes of categories classified in the "Parental Guide": "G (value 1)," "PG (value 2)," "PG-13 (value 3)," "R (value 4)," and "NC-17 (value 5)." The combinations of letters and numbers such as G and PG shown as parental guide attributes represent the age limit for viewing a television program.

The meta information schema based on such a PICS data model is interpreted by the meta information schema conversion unit 25 and converted into a meta information schema in a predetermined transmission format.

FIG. 5 shows a specific example of a meta information schema in a predetermined transmission format converted by the meta information schema conversion unit 25.

As shown in FIG. 5, a meta information schema for a given transmission format may include, for example, information type data 40, a schema ID 41, an item name 42, an attribute name 43 indicating the attribute of the content data within that item name, a mask pattern 44 representing the attribute name 43 as a bit string, and bit length information 45 indicating the bit length of the mask pattern 44.

The information type data 40 is a header indicating that the data following this information type data 40 is a metadata schema.

The schema ID 41 is an identifier assigned to identify the type of meta information schema.

Item name 42 is the name of an item that classifies the attributes indicated in the meta information. For example, when converting a meta information schema of the PICS data model into this specified transmission format, this item name 42 would describe a specific category name (such as "genre" or "parental guide").

The attribute name 43 is the name of an attribute indicated in the meta information. For example, when converting a meta information schema of the PICS data model to this predetermined transmission format, the attribute name 43 describes a specific label name (e.g., "Movie/Drama" or "G"). The attribute name 43 is provided in association with each item name 42 described above, and is information located below the item name 43.

The mask pattern 44 is binary data that indicates each attribute name 43. At least one mask pattern 44 is written for each attribute name 43, and each mask pattern 44 has a unique value that differs from the binary data of other attribute names 43. Note that a mask pattern 44 of the same bit length is written for each attribute name 43 grouped under the same item name 42.

The bit length information 44 indicates the bit length of the bit string of the mask pattern 44. One bit length information 44 is provided for each item name 42. The bit length information 44 may have a different value for each item name 42. For example, in the PICS data model, the bit length of the mask pattern 44 may be different for each category.

Specifically, Figure 6 shows an example in which a meta information schema based on the PICS data model shown in Figure 4 is converted into a meta information schema in a specified transmission format shown in Figure 5.

As shown in Figure 6, the meta information schema converted to a specified transmission format contains a schema ID of, for example, "0." The item name 42 contains "Genre" and "Parental Guide." The attribute names 43 below the item name "Genre" contain the following: "Movies/Dramas," "News/Current Affairs," "Shows/Game Shows," "Sports," "Children's/Youth Programs," "Music/Ballet/Dance," "Arts/Culture," "Education/Science/Events/Topics," and "Leisure/Hobbies." The attribute names 43 below the item name "Parental Guide" contain the following: "G," "PG," "PG-13," "R," and "NC-17."

Furthermore, for example, "9" is written in the "Genre" bit length information 45, and the bit length of the mask pattern 44 indicating the attribute name of the "Genre" item is set to 9 bits. Furthermore, for example, "5" is written in the "Parental Guide" bit length information 45, and the bit length of the mask pattern 44 indicating the attribute name of the "Parental Guide" item is set to 5 bits.

The mask patterns 44 corresponding to the attribute names 42 classified by “genre” are, for example, as follows:

"Movies/Dramas" is "000000001" "News/Current Affairs" is "000000010" "Shows/Game Shows" is "000000100" "Sports" is "000001000" "Children's/Youth Programs" is "000010000" "Music/Ballet/Dance" is "000100000" "Arts/Culture" is "001000000" "Education/Science/Events/Topics" is "010000000" "Leisure/Hobbies" is "100000000" The mask patterns 44 corresponding to each attribute name 42 classified in the "Valentine's Guide" are, for example, as follows:

"G" is "00001" "PG" is "00010" "PG-13" is "00100" "R" is "01000" "NC-17" is "10000" As described above, the description format of a meta information schema based on the PICS data model is converted by the meta information conversion unit 25. Note that the binary data described in the mask pattern 44 is not limited to the above; any bit length or specific value may be used. For example, when the transmission unit 26 transmits content data, meta information, and meta information schema via an MPEG transport stream, a PID (Packet Identification) is generally added to identify each piece of information. In this case, the information type data 40 does not need to be added to the transmitted meta information schema.

Figure 7 shows an example of meta information based on the PICS data model. This meta information based on the PICS data model indicates the attributes of the content data by describing one label per category. For example, if the attribute of the content data to be transmitted to the user is movie or drama and its parental guide is R, then the meta information "Genre: Movie/Drama" and "Parental Guide: R" as shown in Figure 7 would be attached to the content data.

The meta information based on such a PICS data model is interpreted by the meta information conversion unit 24 and converted into a predetermined transmission format.

An example of meta information in a predetermined transmission format converted by the meta information conversion unit 24 is shown in FIG.

As shown in FIG. 8, meta information in a predetermined transmission format is composed of, for example, information type data 50, a meta information filtering mask 51, additional meta information 52, an additional meta information locator 53, and a content locator 54.

The information type data 50 is a header indicating that the data following this information type data 50 is metadata.

The meta-information filtering mask 51 is information indicating the attributes of the content data. This meta-information filtering mask 51 is information in which the attributes of the content data are converted into binary data using the metadata schema of the predetermined transmission format described above.

Specifically, the meta-information filtering mask 51 is composed of a schema ID 55 and a filtering mask pattern 56 following the schema ID 55, as shown in FIG.

The schema ID 55 is information that indicates which meta-information schema the meta-information filtering mask 51 corresponds to. For example, this schema ID 55 is the same value as the schema ID 41 described in the meta-information schema of a given transmission format.

The filtering mask pattern 56 describes the attributes of the content data represented by this meta information using mask patterns 44 defined in the meta information schema. This filtering mask pattern 56 is described by listing as many mask patterns 44 as there are categories, corresponding to the attributes of the content data that are classified and specified for each category.

For example, if the meta information schema for the specified transmission format shown in FIG. 6 is referenced and meta information for this specified transmission format is generated from meta information 57a based on the PICS data model, such as "Genre: Movie/Drama" and "Parental Guide: R," as shown in FIG. 10, the filtering mask pattern 56 will be meta information 57b for the specified transmission format, in which the schema ID 55 is "0" and the filtering mask patterns 56 are "000000001" and "01000."

For example, if meta information 57c based on the PICS data model with "Genre: News/Current Affairs" and "Parental Guide: G" as shown in FIG. 11 is generated by referencing the meta information schema of the predetermined transmission format shown in FIG. 6, the filtering mask pattern 56 will be meta information 57d of the predetermined transmission format with a schema ID 55 of "02" and a filtering mask pattern 56 consisting of "000000010" and "00001."

Additional meta information 52 defines attributes of content data that are not defined by the mask pattern of the meta information schema for a given transmission format. For example, meta information for television program data typically includes attributes such as "genre" and "parental guide," as well as attributes such as "program title." Since it is difficult to define an attribute such as "program title" in advance using the meta information schema, this attribute is included as additional meta information 52. Additional meta information 52 can be included as needed, for example, when there are attributes that cannot be included in the meta information schema.

The additional meta information locator 53 is information that points to the location where the attribute information that cannot be described in the additional meta information 52 is stored, for example, if the data size of the attribute information is too large to be described in the additional meta information 52. This additional meta information locator can also be written as needed.

The content locator 54 is information that indicates the location of the content data defined in the meta information of this specified transmission format.

As shown in FIG. 12, the additional meta information locator 53 and the content locator 54 each consist of a locator type 58 and a locator 59. The locator 59 stores, for example, the uniform resource locator (URL) where the indicated content is stored, the MPEG transport stream identification ID (transport_ID, PID, service_ID, event_ID, table_ID) containing the indicated content, and the carousel ID and module ID of the DVB (Digital Video Broadcasting) data carousel containing the indicated content. The locator type 58 is information indicating the data type of the locator 59.

As described above, meta information for a given transmission format describes the attributes of content data using mask patterns defined in the meta information schema for that transmission format. This allows for the transmission of meta information and meta information schema with improved filtering and transmission efficiency, enabling efficient data distribution and flexible selective reception. Furthermore, when filtering this meta information on the receiving side, necessary meta information can be quickly obtained from a large amount of meta information.

Next, a method for generating profile information in the receiving terminal 13 and the contents of the data reception processing in the receiving terminal 13 will be described in more detail.

First, the meta information schema storage unit 33 of the receiving terminal 13 stores the meta information schema converted into a predetermined transmission format by the meta information schema conversion unit 25 of the broadcasting station 11.

The profile generation unit 34 receives a meta information schema in a predetermined transmission format stored in the meta information schema storage unit 33. For example, a meta information schema such as that shown in FIG. 6, which is a meta information schema based on the PICS data model converted into a predetermined transmission format, is supplied. The profile generation unit 34 references this supplied meta information schema and displays on the monitor 34a, for example, a dialog box 60 titled "Received Content Settings," as shown in FIG. 13, for inputting selection information.

Area 60a of this dialog box 60 displays information for setting the genre of the television program to be received. Area 60b of this dialog box 60 displays a slider for setting the parental guide for the television program to be received. Also displayed in the lower right display area of this dialog box 60 (see FIG. 13), for example, is an execute button 60c for starting the generation of profile information based on the settings, and a cancel button 60d for canceling the settings.

The user uses this dialog box 60 to select attributes of the television program they wish to view and inputs the selection information into the profile generation unit 34. The profile generation unit 34 generates profile information based on the selection information input by the user.

For example, suppose a user uses this dialog box 60 to select "Movies/Dramas" as the television program genre and "PG" as the parental guide. In this case, when the user clicks the selection button 60c in this dialog box 60, the profile generation unit 34 compares the information selected by the user (here, "Genre: Movies/Dramas" and "Parental Guide: PG") with the meta information schema of the specified transmission format (e.g., the meta information schema shown in FIG. 6) and generates profile information for filtering the meta information selected by the user. Specifically, as shown in FIG. 14, this profile information consists of a schema ID 61 for identifying the meta information schema of the referenced specified transmission format and a filtering mask pattern 62 described in this meta information schema. For example, in this example, "0" is entered as the schema ID 61, and the filtering mask pattern 61 contains a binary bit sequence of "000000001" corresponding to "Genre: Movie/Drama" and a binary bit sequence of "00010" corresponding to "Parental Guide: PG."

This profile information shares the same description format as meta information in a predetermined transmission format (the meta information shown in FIG. 9). Therefore, the profile information generated in this manner can be sent to the user profile storage unit 35, and the meta information filter unit 36 can filter the meta information by referencing the stored profile information.

FIG. 15 is a flowchart showing the processing performed by the receiving terminal 13.

First, when some data is transmitted to the receiving terminal 13 from the broadcast network 2 or the bidirectional network 3, the receiving unit 31 or the communication control unit 32 receives the data transmitted from the broadcast station 11 or the information providing device 12 (step S1).

Next, the receiving unit 31 or the communication control unit 32 references the information type 40 to determine whether the received data is a meta-information schema (step S2). If the received data is a meta-information schema, the receiving unit 31 or the communication control unit 32 sends the received data to the meta-information schema storage unit 33, which then stores the meta-information schema (step S3).

Next, the receiving unit 31 or the communication control unit 32 refers to the information type 50 to determine whether the received data is meta-information (step S4).

If the received data is meta information, the receiving unit 31 or the communication control unit 32 sends the received data to the meta information filter unit 36. The meta information filter unit 35 compares the sent meta information with the profile information stored in the user profile storage unit 35 to determine whether they match (step S5). If the comparison results in the sent meta information matching the profile information, the meta information filter unit 36 sends the matching meta information to the meta information storage unit 37, which stores the meta information (step S6).

Next, if the received data is not meta-information, the receiving unit 31 or the communication control unit 32 determines whether the received data is content data (step S7).

If the received data is content data, the receiving terminal 12 performs data reception processing for the content data (step S8). If the received data is neither a meta information schema, meta information, nor content data, or if the data is meta information but does not match the profile information, the receiving terminal 12 terminates processing.

The content data reception process shown in step S8 will be described in more detail with reference to the flowchart shown in FIG.

If the receiving unit 31 or the communication control unit 32 determines that the received data is content data, the content data receiving unit 38 acquires the content locator (content locator 54 shown in FIG. 8) described in the meta information (step S11).

Next, the content data receiving unit 38 references the locator type of the content locator (locator type 58 shown in FIG. 12) and determines whether the locator type is a URL (step S12).

Next, if the locator type is a URL, the content data receiving unit 38 retrieves the content data specified by the URL described in the locator (locator 59 shown in FIG. 12) from the information providing device 12, for example, via the communications control unit 32 (step S13).

The content data receiving unit 38 then sends the acquired content data to the content data storage unit 39, which then stores the content data (step S14).

As described above, in the content distribution system 1 according to an embodiment of the present invention, a meta-information schema indicating the data structure of the metadata is transmitted to the receiving terminal 13 in advance, and this meta-information schema is transmitted in a predetermined transmission format, enabling smooth reception regardless of the type of meta-information associated with the content being received. Furthermore, in the content distribution system 1, meta-information is expressed using a simple bit mask, thereby reducing the amount of information transmitted as meta-information. Furthermore, the content distribution system generates profile information using a meta-information schema in a predetermined transmission format, and uses this profile information to filter meta-information expressed in a bit mask in the predetermined transmission format, enabling rapid filtering of the meta-information to be selectively received.

In this content distribution system 1, the meta information conversion unit 24 and meta information schema conversion unit 25 are provided in the broadcast station 11 and the information providing device 12, but they may also be provided in the receiving terminal 13. In this case, the broadcast station 11 and the information providing device 12 transmit the meta information and meta information schema stored in the meta information storage unit 22 and the meta information schema storage unit 23 without converting them into a predetermined transmission format. In the receiving terminal 13, the meta information schema conversion unit 25 is provided between the meta information schema storage unit 33 and the profile generation unit 34, and the meta information conversion unit 24 is provided between the receiving unit 31 and the meta information filter unit 36, whereby these conversions can be performed.

The above description of an embodiment of the present invention has focused on an example of converting meta information and meta information schema based on the PICS data model into a predetermined transmission format. However, this content distribution system 1 can also convert meta information and meta information schema based on the RDF data model. Below, we will describe an example of converting meta information and meta information schema based on this RDF data model into a predetermined transmission format.

Figure 17 shows the RDF data model. As shown in Figure 17, the RDF data model is represented as a directed graph consisting of two nodes, Resource 63 and Value 64, and PropertyType 65, which represents the relationship between those nodes. Based on this RDF data model, it is also possible to describe hierarchical relationships between nodes.

FIG. 18 shows a program genre hierarchy description and a parental guide hierarchy description based on the RDF data model, a bit pattern representing a mask pattern 44 used to generate a filtering mask pattern 56 after converting this information into a predetermined transmission format by the meta information schema conversion unit 25, and a filtering mask bit pattern 56 for a certain content (aContent).

The program genre (genre) based on the RDF data model has four classes 71: movie, news, sports, and music. Furthermore, movie has three subclasses 72: mystery, action, and science fiction, and music has two subclasses 73: pop and rock, each of which has a hierarchical structure.

In addition, parental guides based on the RDF data model have five classes 74: G, PG, PG-13, R, and NC-17.

The class hierarchy structure based on this RDF data model is interpreted and converted into a meta information schema of a predetermined transmission format by the meta information schema conversion unit 25. Furthermore, the meta information conversion unit 24 converts the meta information based on this RDF data model into meta information of a predetermined transmission format using the meta information schema of the predetermined transmission format.

The information required to convert meta information based on the RDF data model into meta information in a specified transmission format is the bit pattern representing each node and an offset value indicating the location where that information is stored within the entire filtering mask pattern 56. An example of these values is shown in Figure 18 as "offset" and "bit pattern."

Consider a case in which the meta information converter 24 converts metadata indicating that the program genre of a certain content (aContent) is rock and its parental guide is NC-17 into a filtering mask bit pattern 56.

First, the meta information of the RDF data model is interpreted by the meta information schema conversion unit 25, and a bit pattern and offset value are assigned to each node in advance, as shown in Figure 18.

Specifically, for a bit pattern representing meta information for a given piece of content (aContent), 1) because the genre is rock, the bit pattern "10" is stored starting at offset 3, which is assigned to the rock node. This offset value indicates the location within the entire filtering mask pattern 56 where the information is stored, so the bit pattern "10" is arranged as follows: Note that "XXX" indicates a portion where the bit pattern to be stored at that location has not yet been determined.

--> XXX 10 2) The parent class of the program genre "rock" exists, and it is "music." Therefore, the bit pattern "100" is stored starting from the offset value "0."

--> 100 10 3) The parental guide is NC-17, so the bit pattern "101" is stored starting from offset "5."

-> 100 10 101 In this way, the meta information of acontent is converted to "10010101," which is the information to be stored in the filtering mask pattern 56.

Such a filtering mask pattern 56 is stored in the meta information filtering mask 51 shown in FIG. 9 together with the schema ID 55. The pattern 56 is then used as meta information for digital broadcasting in MPEG2, for example.

As described above, content distribution system 1 can convert metadata based on the RDF data model into a predetermined transmission format. Therefore, content distribution system 1 can unify and transmit meta information with incompatible description formats.

Next, Figure 19 shows an example of the format for storing a filtering mask bit pattern in an MPEG-2 system section format, particularly in a private section format data stream. Note that the numbers "8" and "1" in Figure 19 indicate the byte length of the data to be stored. The numbers in Figure 20 are similar.

The table_id contains the identification ID of this metadata_package_section. The section_syntax_indicator contains a flag indicating whether this metadata_package_section is in use. The private_indicator contains a flag indicating that user-defined information is stored in this metadata_package_section. The section_length contains the entire code length information for this metadata_package_section. The current_next_indicator contains a flag indicating whether the metadata_package_section described here is currently valid. The section_number is the section number of this metadata_package_section. The last_section_number is the number of the last section.

The filtering_mask_schema_id (shown in Figure 19, item a) stores an ID for identifying the meta information schema. The structure of the meta information schema identified by this ID can be used to identify which part of the filtering mask bit string contains which meta information. The filtering_mask_1, filtering_mask_2 (shown in Figure 19, item b) and filtering_mask_length through filtering_mask_byte (shown in Figure 19, item c) store the information for the filtering mask 56 in separate parts.

The filtering_mask_1 and filtering_mask_2 areas are areas where hardware filtering is possible using a demultiplexer. By storing meta-information that requires particularly fast filtering here, you can configure the filtering to be even more efficient.

The area for(i=0;i<N;i++) to CRC_32 (shown as d in Figure 19) stores pointer information to the content to which the meta information is attached, such as information equivalent to the additional meta information locator 53 and content locator 54 shown in Figure 8.

Next, FIG. 20 shows another example of a format for storing a filtering mask bit pattern in a data stream in the section format of the MPEG-2 system, particularly in the private section format.

The metadata_packagede_scriptor() is stored in the PMT (Program Map Table) in the PSI (Program Specific Information) of the MPEG-2 system, and indicates information about the stream in which the metadata_package_section is transmitted.

The filtering_mask_schema_id (shown in Figure 20, item e) contains an ID for identifying the meta information schema. The filtering_mask_length (shown in Figure 20, item h) contains the bit length information for the filtering mask.

Then, identify the meta information schema to which the metadata_package_section refers.

This eliminates the need to add a filtering_mask_schema_id to each metadata_package_section, as in the case shown in Figure 19, and improves coding efficiency. However, the format of the metadata_package_section that flows in a single stream is limited to one.

The filtering mask 56 information is divided and stored in the filtering_mask (shown as f in Figure 20) and filtering_mask_length to filtering_mask_byte (shown as c in Figure 20) areas. The filtering_mask area is an area that can be filtered by hardware using a demultiplexer. By storing meta-information that requires particularly high-speed filtering here, filtering can be configured to be more efficient.

The area for(i=0;i<N;i++) to CRC_32 (shown in item d in Figure 20) stores pointer information to the content to which the meta information is attached, such as information equivalent to the additional meta information locator 53 and content locator 54 shown in Figure 8. The length of the filtering mask in this area for(i=0;i<N;i++) to CRC_32 is indicated by the filtering_mask_length field of the meta_package descriptor (shown in item h in Figure 20).

As described above, the content distribution system 1 according to an embodiment of the present invention transmits a metainformation schema indicating the data structure of metainformation to the receiving terminal 13, thereby enabling smooth reception regardless of the type of metainformation accompanying the received content. Furthermore, by converting the metainformation and metainformation schema based on the RDF data model into a predetermined transmission format, the content distribution system 1 can achieve compatibility with metainformation description formats, for example, on the Internet. Furthermore, by converting the metainformation into a bitmap with high transmission and filtering efficiency and storing it in the private section of the MPEG-2 system, transmission of the metainformation via digital broadcasting becomes possible. Furthermore, storing this bitmap in the private section of the MPEG-2 system enables high-speed filtering of the metainformation using the hardware filtering function of a demultiplexer.

───────────────────────────────────────────────────── Continued from the front page (72) Inventor: Yasuaki Yamagishi Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo (72) Inventor: Yasushi Katayama Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo (Note) This publication is based on the publication published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act) and is unrelated to this publication.

Claims (22)

[Claims] 1. A content provision system including a content provision device and a content receiving device, wherein the content provision device comprises: a providing means for providing a content signal to the content receiving device; a meta-information storage means for storing meta-information related to the content signal; a provider-side meta-information schema storage means for storing a meta-information schema indicating the data structure of the meta-information; and a transmitting means for transmitting the meta-information and the meta-information schema to the content receiving device via a communication path; and the content receiving device comprises: a receiving means for receiving the meta-information and the meta-information schema transmitted from the transmitting means of the content provision device via the communication path; a receiver-side meta-information schema storage means for storing the meta-information schema received by the receiving means; and a meta-information data structure detection means for detecting the data structure of the meta-information received by the receiving means based on the meta-information schema stored in the receiver-side meta-information schema storage means. 2. The content providing system described in claim 1, wherein the meta information schema includes an identifier for identifying itself and data structure information indicating the data structure of the metadata including multiple items. 3. The content providing system of claim 1 further comprises: a metainformation schema conversion means for converting the metainformation schema into transmission information in a predetermined transmission format; and a metainformation conversion means for converting the metainformation into a transmission format corresponding to the metainformation schema converted into the transmission information in the predetermined transmission format; and the transmission means transmits the metainformation schema converted by the metainformation schema conversion means and the metainformation converted by the metainformation conversion means. 4. The content providing system of claim 3, wherein the meta information schema includes an identifier for identifying itself and data structure information indicating the data structure of the meta information including multiple items. 5. The content providing system according to claim 4, wherein the meta information schema conversion means converts the meta information schema into an identifier that identifies the meta information schema and a filtering mask value for the plurality of items in the predetermined transmission format. 6. The content receiving device according to claim 1 further comprises: a profile generating means for generating a profile for selecting desired meta information from a plurality of pieces of meta information based on the meta information schema stored in the receiver-side meta information schema storage means and input selection information; a meta information selecting means for selecting metadata associated with the profile from the plurality of pieces of meta information received by the receiver means; and a content signal selecting means for selecting a content signal associated with the meta information selected by the meta information selecting means from the plurality of content signals received by the receiver means. 7. The content providing system according to claim 6, wherein the content receiving device further comprises a content signal storage means for storing the content signal selected by the content signal selection means. 8. The content providing system according to claim 6, wherein the content receiving device further comprises analysis means for analyzing the content of the meta information based on the data structure of the meta information detected from the meta information schema by the meta information structure detection means. 9. A content providing device comprising: providing means for providing a content signal to a content receiving device; meta-information storage means for storing meta-information related to the content signal; meta-information schema storage means for storing a meta-information schema indicating the data structure of the meta-information; and transmission means for transmitting the meta-information and the meta-information schema to the content receiving device via a communication path. 10. The content providing device according to claim 9, wherein the providing means transmits the content signal to the content receiving device via the communication path. 11. The content providing device according to claim 9, further comprising a content signal storage means for storing the content signal. 12. The content providing device described in claim 9, wherein the meta information schema includes an identifier for identifying itself and data structure information indicating a data structure for the meta information including multiple items. 13. The content providing device according to claim 9, further comprising: a meta information schema conversion means for converting the meta information schema into transmission information in a predetermined transmission format; and a meta information conversion means for converting the meta information into the predetermined transmission format, wherein the transmission means transmits the meta information schema converted into the predetermined transmission format by the meta information schema conversion means and the meta information converted into the predetermined transmission format by the meta information conversion means. 14. The content providing device described in claim 13, wherein the meta information schema includes an identifier for identifying itself and data structure information indicating a data structure for the meta information including multiple items. 15. The content providing device according to claim 14, wherein the meta information schema conversion means converts the metadata schema into an identifier of the metadata schema and filtering mask values for the plurality of items in the predetermined transmission format. 16. A content receiving device comprising: a meta-information schema storage means for storing a meta-information schema indicating the data structure of meta-information related to a content signal; a receiving means for receiving the content signal and meta-information related to the content signal via a communication path; and a meta-information data structure detection means for detecting the data structure of the meta-information received by the receiving means based on the meta-information schema stored in the meta-information schema storage means. 17. The content receiving device according to claim 16, wherein the receiving means receives the meta information schema transmitted via a communication path, and the meta information schema storage means stores the meta information schema received by the receiving means. 18. The content receiving device of claim 16 further comprising: profile generation means for generating a profile for selecting desired meta information from a plurality of pieces of meta information based on the meta information schema stored in the meta information schema storage means and input selection information; meta information selection means for selecting metadata associated with the profile from the plurality of pieces of meta information received by the receiving means; and content signal selection means for selecting a content signal associated with the meta information selected by the meta information selection means from the plurality of content signals received by the receiving means. 19. The content receiving device according to claim 18, further comprising a content signal storage means for storing the content signal selected by the content signal selection means. 20. The content receiving device according to claim 16, further comprising analysis means for analyzing the content of the meta information based on the data structure of the meta information detected from the meta information schema by the meta information structure detection means. 21. A method for providing a content signal, comprising the steps of: transmitting a meta information schema indicating the data structure of meta information related to a content signal to a content receiving device via a communication path; transmitting the meta information to the content receiving device via the communication path; providing the content signal to the content receiving device. 22. A method for receiving meta information, comprising the steps of: receiving a meta information schema indicating the data structure of meta information related to a content signal; receiving the meta information; and detecting the data structure of the received meta information based on the meta information schema.