APPARATUS AND METHOD FOR ACCESSING TV CONTENTS DATA UTILIZING VIRTUAL DOMAIN SYSTEM, THE MEDIA AND TRANSFERRING SIGNAL CONTAINING THE METHOD
[Technical Field]
The present invention relates to an apparatus and method for processing and accessing television (TV) content data utilizing a virtual domain system, a medium with the method recorded thereon, and a transmission signal. More specifically, the present invention relates to an apparatus and method for processing and accessing television (TV) content data utilizing a virtual domain system, a medium with the method recorded thereon, and a transmission signal, capable of providing users with a channel domain system (CDS) that efficiently processes a number of data broadcasting contents by building the virtual domain system in TV content services, and of incorporating a conventional electronic program guide (EPG) into the channel domain system so that the users can more efficiently and conveniently access channels and broadcasting contents and use the broadcasting contents.
[Background Art]
In recent years, as digital TV broadcasting begins, attentions to a data broadcasting service, which utilizes data, are increasingly paid. The digital broadcasting can provide a variety of services including interactive services that have been impossible so far, since it transmits data in addition to the existing audio and video signals.
In the future, all the broadcasts including territorial, satellite and cable broadcasts will be digitalized within a short time period. This digitalization seems to lead to changes in all environments, around a TV medium, including from the content providers to the advertisement owners and consumers, as well as the broadcasting companies.
With the technical advancement of the data broadcasting, the digital broadcasts will provide much more information and new enjoyment, and the requirements of viewers on these services will be more diversified.
In the data broadcast, an interface called an electronic program guide (EPG) that has been used in a conventional TV system is often used. This interface is an interactive on-screen display function used to display the information similar to a TV program list and contains information needed to make an inquiry about and decode programs.
Meanwhile, an interface in which a process of finding out a desired content is similar to the Internet is recently used in a data broadcasting system that has been recently developed. That is, there is a portal of the data broadcast, and a viewer can view a desired content by sequentially searching for a relevant category in the portal.
Thus, in the case of personal computer (PC)-based Internet contents, even though each of several categories has a number of lower level categories or the depth from a top category to a bottom category is equal to or greater than a third-order depth, the contents can be easily used if category select menus from the top category to the bottom category are displayed on a single screen or if a scroll bar is used such that a desired menu can be clicked with a mouse.
However, since only a simple input device such as a remote control is generally used in the TV system, a viewer should press buttons of the input device several times to find out and select the desired menu. Further, since the viewer generally watches the TV at a position far away from a screen of the TV system, larger and thicker fonts must be used on the screen of the TV system. Therefore, it is very difficult to display several menus or a large amount of contents on a single screen. Of course, since it is difficult for a cursor or selection point at a position on the screen to jump from different select menus or icons at the other positions on the screen, it is further difficult to use a function of the scroll bar. Accordingly, in the case of the TV content service, if a viewer intends to change a content in a lower-level category of a specific category from a content in the other category, he/she should repeatedly go
between upper-level menus and lower-level menus several times and will unnecessarily view the select menus of upper- and lower-level categories several times.
For example, according to a conventional TV system environment, when a viewer wishes to use one content, e.g. 'star makeup catch-up', of the TV content service while viewing the existing broadcasting content of a certain channel on the TV system, the viewer select a portal channel of the TV content service, e.g. presses Channel No.
100, to go merely to the portal channel of the TV content service.
As shown in Fig. 1, a top content category list or menu in the portal is then displayed on a screen, and the viewer operates a direction button of the remote control several times, places a cursor or pointer onto a 'woman' category and then presses a confirmation button.
As shown in Fig. 2, a subcategory list or menu of the 'woman' category is then displayed on the next screen, and the viewer goes to a 'skin beauty' category by again performing the operations of pushing the direction button several times and selecting the confirmation button on this list or menu.
The viewer should again perform the operations of pushing the direction button several times and selecting the confirmation button on the 'skin beauty' category to view the originally desired content 'star makeup catch-up' as shown in Fig. 3.
Thereafter, if the viewer wishes to change from the relevant content to a 'latest movie' menu, he/she should return to a main screen of Channel No. 100 (Fig. 1), which corresponds to the TV content portal, via the upper-level categories in a reverse sequence to the above, and then should repeat the aforementioned remote control operations in a sequence from a 'movie' menu to the 'latest movie' via a 'culture' menu that corresponds to the top category. Therefore, there is a problem in that the operation should be restarted from Channel No. 100 corresponding to the TV content portal.
In addition, in a case where a single TV content is assigned one-to-one to a general channel of the existing TV, the TV contents are different from one another in view of their transmission capacity in their nature. Further, the above problem remains unsolved when the TV contents include their own lower-level categories.
To solve the aforementioned problems, a new system has been proposed which facilitates retrieving and accessing a content by assigning virtual channel values to the respective contents and causing the assigned virtual channel values to be channel domain values. The above new system has been disclosed in Korean Patent Application No. 2003-78155, entitled "Apparatus and method for processing television content data," and filed in the name of the applicant of the present application. However, since the aforementioned apparatus and method for processing the television content data are configured to be independent from an electronic program guide (EPG), there is a need for a newly upgraded apparatus in which the electronic program guide is incorporated.
[Disclosure] [Technical Problem]
The present invention is conceived to solve the aforementioned problems.
Accordingly, an object of the present invention is to provide an apparatus and method for processing and accessing television (TV) content data, a medium with the method recorded thereon, and a transmission signal, capable of incorporating a data content retrieving and accessing system and an electronic program guide with each other, specifically accessing data including channel and program information, and flexibly moving between channels and between domains when a number of channel services are provided.
[Technical Solution]
According to an aspect of the present invention, there is provided an apparatus for accessing television content data utilizing a virtual domain system, comprising: a demultiplexer for demultiplexing a plurality of desired programs from an input transport stream containing video and audio data; an MPEG decoder for decoding the received
MPEG transport stream into audio, video and other data; a broadcasting data processing unit including an audio processing unit for receiving and pre-amplifying the decoded audio data and delivering the amplified data to an audio output unit, a video processing unit for processing the decoded video data, and a data processing unit for processing additional data other than the audio and video data; a channel domain system (CDS)
managing unit including a CDS data processing unit for processing CDS data received from the data processing unit of the broadcasting data processing unit according to the type of a data structure of a channel domain system, and an EPG data processing unit for translating conventional EPG information into a data structure suitable for the CDS, the CDS managing unit managing both the CDS data processing unit and the EPG data processing unit; a CDS output execution unit for classifying program object information received from the CDS managing unit according to conditions and organizing on-screen display information to output the program object information to a display unit assigned to each channel; an image output unit for reorganizing the screen configuration information delivered from the video processing unit and data processing unit and the screen configuration information delivered from the CDS output execution unit to output the reorganized information to a screen; a memory connected to the CDS managing unit for storing the received channel domain data and additional information produced as the channel domain data are utilized; and a user input interface. According to another aspect of the present invention, there is provided a method of accessing television content data utilizing a virtual domain system, comprising: a first step of receiving a broadcasting stream by a receiving terminal device; a second step of processing audio and video streams by audio and video processing units; a third step of processing system information and additional information for the broadcast other than the audio and video by a data processing unit; a fourth step of delivering channel domain system (CDS) data for a CDS and electronic program guide (RPG) data for an EPG among the other additional information to a CDS managing unit; a fifth step of delivering the CDS data to a CDS data processing unit to classify and process the delivered CDS data according to a data structure of the CDS, when the other additional information delivered from the CDS managing unit is the CDS data; a sixth step of delivering the EPG data to an EPG data processing unit to process the delivered EPG data according to whether the data are channel information or program information and then to translate the EPG data into the CDS data, when the other additional information delivered from the CDS managing unit is the EPG data; a seventh step of delivering the CDS and EPG data processed in the CDS managing unit to a CDS output execution unit; and an eighth
step of outputting the audio, video and additional data and image information of the CDS output execution unit from an image output unit.
[Advantageous Effects] The present invention has the following advantageous effects.
First, it is possible to incorporate a data content retrieving and accessing system and an electronic program guide with each other, specifically access data including a channel and a program, and flexibly move between channels and between domains when a number of channel services are provided. Further, it is possible for a user to manage associated data. That is, schedule information for the associated data can be transmitted to the user, and thus, more detailed requirements of the user can be satisfied and advantages of accessing an event by the user can also be enhanced.
[Description of Drawings]
Figs. 1 to 3 are screen views illustrating a conventional process of accessing a data broadcasting content.
Fig. 4 is a block diagram illustrating an embodiment of an apparatus for accessing television content data utilizing a virtual domain system according to the present invention.
Fig. 5 is a flowchart illustrating an embodiment of a method for accessing television content data utilizing a virtual domain system according to the present invention.
Fig. 6 is a flowchart illustrating a method for processing channel domain system data according to the present invention.
Fig. 7 is a flowchart illustrating a method for processing EPG data according to the present invention.
Figs. 8 and 9 are hierarchy diagrams illustrating a data structure of a channel domain system.
Figs. 10 and 11 are hierarchy diagrams illustrating a structure of an electronic program guide system.
Fig. 12 is a diagram illustrating an example of a method for accessing a domain by a user of the apparatus and method according to the present invention.
Fig. 13 is a diagram illustrating an example of a structure of the channel domain system data.
Fig. 14 is a structure diagram illustrating a state where the channel domain system and electronic program guide have been incorporated with each other.
<Explanation of reference numerals for designating main components in the drawings>
10: Demultiplexing unit 20: MPEG decoder 30: Broadcasting data processing unit 40: Audio output unit 50: CDS managing unit 60: CDS output execution unit 70: Image output unit 80: Memory 90: Input interface
[Best Mode]
AN embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 4 is a block diagram illustrating an embodiment of an apparatus for accessing television content data utilizing a virtual domain system according to the present invention. The configuration of the accessing apparatus according to an embodiment of the present invention will be described as follows.
The apparatus of the present invention is used to receive broadcasting data by a user receiving terminal, e.g. a terminal device used in a set-top box, VOD, AOD, Internet service, digital home service, a multimedia PC or a general PC for use in the digital broadcasting, and to display the received data such that a user can easily use the received data. The apparatus of the present invention includes an MPEG decoder 20 and a demultiplexer 10 for receiving an RF signal from a transmitter of a broadcasting station,
demodulating the received RF signal into a digital signal, and demultiplexing a plurality of desired programs from an input transport stream containing video and audio data.
A broadcasting data processing unit 30, which includes an audio processing unit 31, a video processing unit 32 and a data processing unit 33, processes audio packets, video packets and the other additional data among the received broadcasting data.
That is, the broadcasting data are first processed by both the demultiplexer 10 for processing the broadcasting data through respective services multiplexed according to channels and the MPEG decoder 20 for decoding (or parsing) the received MPEG transport stream into audio, video and other data. The audio data decoded in the MPEG decoder 20 are delivered to the audio processing unit 31 and are subjected to pre-amplifϊcation. The pre-amplified audio data are delivered to an audio output unit 40 of the set-top box and to a relevant audio output interface (not shown). The decoded video data are delivered to an image output unit 70 via the video processing unit 32. Further, the data processing unit 33 processes the additional data other than the audio and video packets or data. These additional data contain CDS information having information about a virtual channel system (hereinafter, referred to as a "channel domain system" (CDS)) for specifying each content as a virtual channel value and processing the specified content; and system and event information of the conventional data broadcasting, such as system information (SI) data constructing an electronic program guide (EPG) for use in the data broadcasting and event information (EI).
Specifying each content as the virtual channel value as described above is named a "channel domain." The virtual channel value becomes each channel domain value of the channel domain system (CDS). By constructing the channel domain system in such a way, a new system for retrieving and accessing contents can be provided, which has been proposed in Korean Patent Application No. 2003-78155 filed in the name of the applicant of the present application.
The CDS and EPG related information is delivered to a CDS managing unit 50. The CDS managing unit 50 includes a CDS data processing unit 51 and an EPG data processing unit 52. The channel domain system (CDS) data received from the data
processing unit 33 are processed by the CDS data processing unit 51, and the EPG data are processed by the EPG data processing unit 52.
The CDS data processing unit 51 and the EPG data processing unit 52 objectify the CDS data and the EPG data, respectively, and process the objectified data according to a depth classified by a hierarchical structure.
That is, the CDS data received from the data processing unit 33 are delivered to the CDS data processing unit 51 and will be organized into a CDS data structure composed of root (portal) nodes, sub portal nodes, terminal nodes, etc.
Further, the EPG data received from the data processing unit 33 are delivered to the EPG data processing unit 52 where an EPG data structure is parsed. The parsed data are subjected to a step of converting the EPG data into the CDS data. That is, channel configuration information and program configuration information is translated into a root, a sub portal domain and a terminal node suitable for the channel domain system (CDS). The EPG data that are received and converted into a CDS data format are delivered from the CDS managing unit 50 to a CDS output execution unit 60. If desired, data may be read out from a memory 80 to create display information for electronic program information and update new data on the memory.
The memory 80 stores data produced when utilizing provided additional functions such as domain reservation, bookmark, favorite channel, and program use information.
The CDS output execution unit 60 arranges the CDS data delivered from the CDS managing unit 50 in an order according to a control condition inputted from an input interface 90 such as a user's input device and organizes on-screen display information for outputting information to be displayed.
The CDS output execution unit 60 causes a certain number of objects to be displayed on the image output unit according to a length upon the display of the objects, thereby making it possible to adjust the number of displayed objects in accordance with the length of each object. Therefore, when displaying the objects, this is substituted for
a concept of a grid represented by a time axis that has been used in a conventional EPG, and does not depend on the size or length of a program object display area.
The screen configuration information delivered from the video processing unit 32 and the data processing unit 33 and the information delivered from the CDS output execution unit 60 are delivered to the image output unit 70.
In the meantime, the apparatus may further comprise a data receiving unit (not shown) connected to the data processing unit 33 to receive channel domain system (CDS) data, electronic program guide (EPG) data or the other additional data via the Internet, so that the CDS data, the EPG data or the other additional data can be preferably received via the Internet instead of a broadcast.
Fig. 5 is a flowchart illustrating an embodiment of a method for accessing television content data utilizing a virtual domain system according to the present invention. This figure shows a method of using the above apparatus.
The method of using the access apparatus according to the present invention comprises a first step (Sl) of receiving a broadcasting stream by a receiving terminal device; a second step (S2) of processing audio and video streams by audio and video processing units; a third step (S3) of processing system information and additional information, which are used for the broadcast, other than the audio and video by a data processing unit; a fourth step (S4) of delivering CDS data for a channel domain system (CDS) and EPG data for an electronic program guide (EPG) among the other additional information to a CDS managing unit; a fifth step (S5) of delivering the CDS data to a CDS data processing unit to classify and process the delivered CDS data according to a data structure of the channel domain system (CDS), when the other additional information delivered from the CDS managing unit is the CDS data; a sixth step (S6) of delivering the EPG data to an EPG data processing unit to process the delivered EPG data according to whether they are channel information or program information and then to convert the EPG data into the CDS data, when the other additional information delivered from the CDS managing unit is the EPG data; a seventh step (S7) of delivering the CDS and EPG data processed in the CDS managing unit to a CDS output execution
unit; and an eighth step (S 8) of outputting the audio, video and additional data and image information of the CDS output execution unit from an image output unit.
Furthermore, the method of the present invention may further comprise, between the first and second steps, a step (Sl-I) of receiving the CDS data, the EPG data or the other additional data via the Internet such that the CDS data, the EPG data or the other additional data can be received in other ways than the broadcast.
Fig. 6 is a flowchart illustrating a method for processing the channel domain system (CDS) data according to the present invention. The processing of the channel domain system data in the CDS data processing unit will be performed in the following manner.
That is, the method for processing the CDS data according to the present invention comprises a step (S5-1) of processing linkage information for a lower level structure and storing highest level root domain data into a memory, when it is determined that the type of a structure (node) of a channel domain is of a root (portal node) type by parsing a CDS stream corresponding to the broadcasting data having CDS structure information; a step (S5-2) of processing linkage information for higher and lower level structures and storing sub portal type data into the memory, when it is determined that the type of the structure of the channel domain is of a sub type; a step (S5-3) of processing linkage information for a higher level structure and storing terminal type data into the memory, when it is determined that the type of the structure of the channel domain is of a terminal type; and a step (S 5 -4) of verifying the integrity of the data stored in the memory.
As described above, the CDS data processing unit classifies the channel domain system data according to the type of the structure (node) when processing the CDS data. The type of the node is classified into root, sub portal and terminal. The root refers to the highest level root domain and means that the channel domain data designate the highest level root (portal), the terminal typically becomes the lowest level node having a content, and the sub portal indicates an intermediate step between the root and the terminal.
The step of processing the linkage information for the higher level structure connected to the terminal node in the step (S5-3) includes an object ID storing step of storing a channel domain object ID into a memory; a depth storing step of storing channel domain depth (or level) information into the memory; a flat ID storing step of storing information indicating a sequence of domains at the same depth into the memory; a higher level ID storing step of storing an ID value of a higher level linkage structure into the memoiy; and a data storing step of storing own structure object content data into the memory.
Further, the step of processing the linkage information for the higher and lower level structures connected to the sub node in the step (S5-2) includes an object ID storing step of storing a channel domain object ID into the memory; a depth storing step of storing channel domain depth information into the memory; a flat ID storing step of storing information indicating a sequence of domains at the same depth into the memory; a higher level ID storing step of storing an ID value of a higher level linkage object into the memory; a lower level ID storing step of storing an ID value of a lower level linkage object into the memory; and a data storing step of storing own structure object content data into the memory.
The objects are created as described above, and the respective objects are then examined for the integrity. This is a process of confirming whether an actual stream to be broadcast is identical to an original stream obtained after the processing of an input stream received at a receiving terminal device.
Fig. 7 is a flowchart illustrating a method for processing the EPG data according to the present invention. The processing of the EPG data in the EPG data processing unit will be specifically performed in the following manner. That is, the step of processing the EPG data and translating the processed data into channel domain system (CDS) data in the EPG data processing unit comprises a step (S6-1) of receiving and parsing the EPG data; a step (S6-2) of processing linkage information for higher and lower level structures and storing the processed information into the memory, when it is determined that the EPG data are channel information; a step (S6-3) of determining whether the EPG data are program information having additional
data, when it is determined that the EPG data are program information; a step (S6-4) of processing linkage information for higher and lower level structures and storing the processed information into a sub portal structure memory, when it is determined that the
EPG data are the program information having the additional data; a step (S6-5) of processing linkage information for the higher level structure and storing the processed information into a terminal structure memory when it is determined that the EPG data are the program information having no additional data; and a step (S6-6) of verifying the integrity of the information stored in the memory.
A concept of the structure (or node) does not apply to the data broadcast scheduling information when processing the EPG data, but the broadcast scheduling information has the same configuration as the above concept. Thus, the concept of a node (or object) is introduced and applied to the CDS.
To maintain the compatibility of the existing EPG in the CDS, a process of parsing the EPG data to be received is necessary. That is, thee EPG data processing unit parses the received EPG information as it is and translates the EPG information into
CDS object information based on the parsed data.
That is, the root domain object is created based on data obtained by parsing the
EPG data and then performing the translation of all the lower level domains thereof into the CDS, in a reverse order to the CDS. Channel related information among the EPG information is assigned ID, depth or Linklnfo and translated into a sub portal domain object. The channel information such as a channel name is stored as content information into the memory in the form of the domain object.
In a case where the EPG information is the program information and its lower level additional information is a sub portal type provided in an associated form, the ID, depth and Linklnfo structure is first assigned thereto and the content information of the associated additional information is then stored in the memory.
In a case where the higher level additional information containing only the program information among the EPG information is a program and a terminal node object, the DD, depth or Link Info structure is assigned in a terminal node object type and
the content information of the program is stored in the memory of the terminal node object.
Thereafter, the respective objects are organized and then examined for the integrity. This is a process of confirming whether an actual stream to be broadcast is identical to an original stream obtained after the processing of an input stream received at the receiving terminal device.
Figs. 8 and 9 are hierarchy diagrams illustrating a data structure of a channel domain system, and Figs. 10 and 11 are hierarchy diagrams illustrating a structure of an electronic program guide system. These figures indicate that the channel domain system (CDS) and the electronic program guide (EPG) can be incorporated with each other.
Fig. 12 illustrates an example of a method for accessing a domain by a user of the apparatus and method according to the present invention, Fig. 13 is a diagram illustrating an example of a data structure of the channel domain system data, and Fig. 14 is a structure diagram illustrating a state where the channel domain system and electronic program guide have been incorporated with each other.
Hereinafter, the operation and advantageous effects of the present invention will be described with reference to Figs. 4 to 14.
Fig. 8 illustrates how to organize a channel of the CDS in a two-dimensional hierarchical structure. The channel structure of the CDS is a tree structure in which the portal is a root and all the channels are terminals (leaf nodes). Each structure (or node) has the following attributes.
1. Root domain (portal domain)
A portal node provides an entry point for an entire content. The portal node is the only node in the CDS and becomes a root of an entire tree structure.
Such a root domain is allowed for direct access from another type of node to the portal node through external key input or specific signal transmission, wherein the portal node may include other sub portals or channel nodes.
2. Sub portal domain
This provides an entry point for a specific content category and may include other sub portal domains or terminal domains.
3. Terminal domain
This is a node having information about service where content is directly provided. This node is the lowest level node (leaf node) that cannot include any other type of node.
Fig. 9 shows another representation of Fig. 8 having the same meaning. That is, Fig. 9 indicates that it has the same data structure as that of the EPG.
The CDS can be used even for general broadcasting capable of porting the EPG, but is more effective in indicating additional information such as a data portal channel in which the data broadcasting is primarily made.
CDS data are composed of the highest level portal domain of the CDS data serving as a root, lower level sub portals, channels directly linked to the highest level portal domain, and terminal domain objects containing content data. The domain object constructing the sub portal has information about a higher level portal and is composed of a terminal domain object including channels and content data of lower level sub portals or the sub portal (one's own domain).
The terminal (last end) domain objects serving as the channels and content data have link information on higher level parent domain objects and actual information (text, , image and other binary files) on the channels and contents.
By using the linkage information about the respective domains, the CDS system can be extended and used without limitation.
Meanwhile, a data stream constructing the scheduling information in the actual broadcast is composed of a Program Association Table (PAT), a Program Map Table (PMT), an Event Information Table (EIT), a Service Description Table (SDT) and other additional data. In such a case, these data constitute channel information, program information and other additional information, as conceptually illustrated in Fig. 10.
EPG data (scheduling information) contains the scheduling information on the current channel and lower level program belonging thereto. Programs that are
broadcast on the relevant channel have a schedule within a certain period of time. The internally scheduled programs are arranged in time order.
The objects contained in the relevant program are composed of various kinds of additional information and contents (text information, image information, file information, etc.). The contents include associated additional digital contents such as viewing information, advertisement information and PPL information of the program, and the additional information contained in each content may be lower level additional information according to the features of the contents.
The EPG data having channel and time axes may be translated into a structure with data having association between the higher and lower level objects using a concept of a depth (or level) of a tree type.
This structure of the EPG data is identical to that of the CDS data. By using this feature, the EPG data can be converted into the CDS data to thereby build the domain system. Fig. 11 schematically shows a part of a process of translating five programs of a certain channel (e.g., channel no. 100) into the CDS data, which corresponds to the information on the EPG scheduled and broadcast as described above.
To translate the EPG data into the CDS data, it is necessary to parse the EPG data and reorganize the CDS data. That is, in order to construct the CDS linkage structure, the above process should be performed in a reverse order, i.e. an order from the terminal domain to the sub portal domain and then from the sub portal domain to the portal domain, as follows:
1. Domains of additional information at Level 4 are organized.
2. Domains of additional information at Level 3 are organized. Linkage information about lower level objects thereof is stored using the information on domain objects at Level 4. Information about the linkage to higher level domains thereof among the domain information at Level 4 is stored as the additional information at Level 3.
3. As for information at Level 2 (program information), domain objects thereof are organized using the EPG data, and the respective organized data are stored using other received table information.
4. As for information at Level 1 (channel information), the channel information is organized and stored using the information about the domains of the program information at Level 2.
5. As for information at Level 0 (a root domain), a virtual root domain is organized and stored using the domains of the channel information.
A method of accessing the user domain so organized will be described by way of example.
A domain can be indicated as a label composed of character or number according to a unique level (depth), and portions between the levels can be indicated as a character or symbol, in a similar way as [001.123.456].
Nodes at the same level of which parent nodes are the same as each other basically have the same size of the label indicating the node. It is apparent that nodes at the same level of which parent nodes are different from each other can have a different size of the label.
Ex) 001.123.456, 001.124.1, 001.999.8765
When each label is represented as a decimal number, a digit value of zero may be indicated or not to represent the cipher thereof.
Ex) 001.123.456 = 1.123.456
Fig. 13 shows an example of a CDS data structure that is composed of the following elements.
1. NodeJQD: This is a unique ID assigned to a node corresponding to an object that organizes the CDS. Even though an internal ID is changed, the user has a label in addition to the ID. Thus, the ID independence can be maintained when in use.
2. Node Type: This is a field which indicates the type of domain. The type of domain may include a root portal domain, a sub portal domain and a terminal domain.
3. Service Type: This is a field which indicates a transmitting method. Examples of the transmitting method include a multicast broadcasting method and a unicast on-demand method.
4. Node Vision: This is a field which indicates whether a transmitted node is used as a main object of the interface or represents supplemental data and link information of the main object.
5. Node Level: This indicates a depth of the domain. The root portal domain has a value of 0, a lower level sub portal domain and a terminal domain has a value of 1, and the lower level has a value of 2. That is, the value increments by one. 6. Node Flat DD: This is a field which has information to identify domains at a level with the same depth. By using this field, it is possible to rapidly find out the information on the nodes at the same level.
7. Node Flat Priority: This is a priority assigned to each node at the same depth
(level) such that the high-speed processing can be made by using this priority. 8. Version value: This is a field which indicates information on domain version.
The receiving terminal device compares this value with a newly received value to receive new domain information when it is determined that the value is directed to a new version. 9. Link Info: This is a structure which indicates the linkage information of a domain and contains information on domains linked to higher and lower level domains. Here, a linkage domain is linked using Node ID (unique value) and a domain linking method is expressed as Link Type.
For example, when the Link Type is 1 in case of a lower linkage, the lower level domain becomes a domain object indicating internal and link information of the higher level domain but not an actual main domain. 10. MetaData Type: This is a field which indicates a format of a content of a node object. This field indicates a conventional EPG and broadcast system when it has a value of 1, while this field indicates the transmission of CDS information when it has a value of 0.
11. Label Size: This is a maximum label digit which the domains at the same depth (level) may have.
12. Label: This is a field which indicates a label value of a domain. The value corresponds to a value inputted by a user or a value outputted onto a screen, which is indication information of the actual domain.
13. Title: This is a field which indicates a title of domain. 14. Description: This is a field that explains a domain.
15. Keyword: This is a field that is used to retrieve a domain.
16. Category: This is a field that is used to indicate the type of domain. It is also used while retrieving the domain.
17. Time Value: This indicates a point of time of transmission. 18. URI: This is a field which indicates URL and is utilized as on-demand URL information.
19. Parameter: This is used together with the URI field.
20. Certification: This indicates certification information for a domain.
(The following fields apply when the metadata indicate a conventional data broadcasting system such as EPG.)
21. TablelD: This indicates TableJD that is table information of the EPG and broadcast system when the MetaData Type is one (1). NIT = 0x40, SDT = 0x42, and EIT = 0x4E.
22. FIELD_VALUE: This is a field which generally indicates a value of existing broadcast information.
23. Descriptor_tag: This is a field which indicates the type of descriptors among the existing broadcast information.
24. Descriptor(): This a structure which indicates information about a descriptorO among the existing broadcast information. The metadata are actual information that respective nodes will have. Linldnfo of the metadata is structure information for linkage between the upper and lower nodes and is a key element which indicates link information of the CDS.
Through the aforementioned process, the electronic program guide (EPG) data can be incorporated into the channel domain system (CDS), as shown in Fig. 14.
The aforementioned embodiment has been described as an example of specifically explaining the technical spirit of the present invention. Therefore, the true spirit and scope of the present invention is not limited to the embodiment or accompanying drawings.