KR20090026707A - The method to send meta data through mpeg-2, and the decoder, encoder - Google Patents

Abstract

A method for transmitting the metadata by using MPEG-2 TS regardless of an application and an encoder and a decoder is provided to transmit metadata regardless of the application by transmitting metadata through MPEG(Moving Picture Expert Group) - 2TS(Transport Stream). A logic encoder includes RDFT encoder. The RDFT encoder converts the triple of the RDF form into an RDFT(RDF Table) of the private section of MPEG-2. The triple of the RDF form is metadata generated for the application of the receiving side. The section encoder produces the section based on RDFT. The binary encoder converts the section into the binary data. The TS encoder converts binary data into the MPEG-2 TS. A MUX(multiplexer) multiplexes the MPEG-2 TS in which RDFT is included. A DVB(Digital Video Broadcasting) ASI(Asynchronous Serial Interface) encoder converts the multiplexed MPEG-2 TS into the ASI signal.

Description

METHOD TO SEND META DATA THROUGH MPEG-2, AND THE DECODER, ENCODER}

The present invention relates to transmitting metadata in real time using MPEG-2 TS (Transport Stream), and in particular, using the Resource Description Framework (RDF) format, which is a standard of the Graph Database. It is about transmitting metadata. It also relates to an encoder and a decoder using the method.

MPEG-2 TS is a standard for transmitting multimedia data and is used in various media.

On the other hand, for additional services by application programs (applications) in addition to video and audio signals, data transmission technologies specialized for each medium are used. In general, data has a characteristic of additional information, that is, metadata, for efficiently utilizing the content rather than the content itself. DTV (digital television) uses ATSC ACAP, TV-Anytime, etc. to send metadata. However, these technologies are designed without considering the Internet environment and have an inefficient structure.

In the case of ACAP, Java-based applications and all data are transferred using a technology called object carousel. Java applications are large and have inherent inefficiencies by sending data and applications repeatedly. In addition, the use of a very complicated transmission standard called object carousel puts a heavy burden on both transmission and reception.

TV-anytime has an additional feature to help you use your content in a variety of ways. It is written based on XML and adopts object carousel for transmission method in DTV. This standard defines the detailed grammar of transmission contents like general standards in advance and the receiver must comply exactly with this. Therefore, it is impossible to provide new services other than the previously defined methods, and the transmitting and receiving party has a big burden because the data must be processed using an XML parser.

The present invention seeks to compensate for the above problems of the prior art. That is, the meta data type uses RDF triple (Resource Description Framework triple) that can contain rich meaning without being fixed to a specific service and proposes a method for transmitting the data in real time. Existing methods are inefficient because they transfer data and applications together or require a separate XML parser.

In order to solve the above problems, the present invention transmits metadata through MPEG-2 TS, and describes metadata in RDF.

To this end, the metadata required by the application program on the receiving side is generated as a triple in RDF format, converted into RDFT (RDF Tabel) of the private_section of MPEG-2, inserted into PSIP, and transmitted through MPEG-2 TS. It provides a method for generating and transmitting metadata. Here, it further comprises data indicating the change of the triple, wherein the change is characterized in that no change, add, update and delete.

In addition, a logical encoder including an RDFT encoder for converting triple in RDF format, which is metadata generated for an application on the receiving side, to RDFT (RDF Tabel) of private_section of MPEG-2, and based on the RDFT A section encoder for generating a section, a binary encoder for converting the section into binary data, and a TS encoder for converting the binary data into MPEG-2 TS. And a mux for multiplexing the MPEG-2 TS including the RDFT, and a DVB ASI encoder for converting the multiplexed MPEG-2 TS into an Asynchronous signal (Asynchronous Serial Interface). A serial interface encoder) is provided.

In addition, an RF tuner for converting an RF signal including an RDFT (RDF Tabel) of a private_section of MPEG-2 into a triple of RDF format, which is metadata generated for an application program on the receiving side, is converted into an MPEG-2 TS. A TS parser that receives the MPEG-2 TS and separates the packetized elementary stream TS into a PES PS and a private-section TS, and an MPEG-2 decoder that restores an RDFT section from the private-section TS. And an RDFT processor for recovering RDF data from the RDFT section and storing the RDF data in an RDF buffer that can be read by an application program. Here, the meta data further includes data indicating a change of the triple, and the change is characterized by no change, no addition, no update, and no deletion.

In addition, the present invention is a receiver including the decoder, in which the data indicating the change of the triple ignores the triple if there is no change, adds the triple if it is an addition, changes the triple if it is an update, and deletes it. Provided is a receiver which deletes the triple.

The present invention has the effect of transmitting meta data regardless of the application by transmitting the meta data through the MPEG-2 TS using the newly designed RDF table.

For example, in the present invention, since data and an application are separated and only data is transmitted through the TS, and other images and applications can be transmitted to the IP network, it is possible to transmit a lot of information even in a small communication band. It works.

In addition, data can be easily extracted without a separate parser, reducing the burden on the receiver.

In addition, if only the RDF triple is transmitted from the transmitting side, the receiving side application can extract and efficiently use only data necessary for itself.

In addition, the RDF table is based on the private_section of MPEG-2 so that new data can be sent while complying with the standard of the existing MPEG-2 system. The use of the private_section_derivative region defined in MPEG-2 ensures backward compatibility with existing devices, that is, backwards-compatibility of existing services.

      EXAMPLE

First, the form of data will be described.

The form of meta data uses the RDF Triple (http: //www.w3.ort/RDF/) of the World Wide Web Consortium (W3C).

The most widely used form of data storage is a relational database. This approach is easy to predefine data types in a specific form and to store a lot of data. However, when the format of the data needs to be changed, the processing is very difficult, and it is difficult to find the correlation between the data. The technique designed to solve this is a graph database. The database does not predefine tables, and data is stored in association with each other.

The basic form of storing data in a graph database is an RDF triple. This type of data can transmit data in the same type of format even if the service is diversified, enabling precise retrieval. In addition, since the form is simple, it places little load on the receiving end and the transmitting end.

This concept of RDF is shown in FIG. 2 shows specific data in the form of RDF.

In Fig. 1, for example, Dog is a subclass of Mammal, Mammal means a subclass of Animal, and Mammal means 4 legs and 2 eyes. hasPet is a subproperty of owns, meaning its range is Mammal.

Also, at the bottom of the figure, Robbie is Jan's petOf, Mr.Aasman is the same as Jans.

If this is expressed concretely, it will become a form as shown in FIG. That is, in Figure 2, person2 means that the kind is a person, the name is Rose Elizabeth Fitgerald, and the job is a home-maker.

The RDF triple consists of three words, a subject predicate object, and serves as a subject, predicate, and object. For example, Lee's triple actor means "Lee's career is an actor." The words used are given meaning according to a predefined ontology.

When data is transmitted in the above RDF format, there is no need to make a standard according to a service or a function. In other words , it can be called general-purpose metadata . If only the RDF triple is transmitted from the transmitting side, the receiving side extracts and uses only the data necessary for itself.

Describes an RDF table for transmitting RDF triples.

First, the grammar will be described.

An RDF table consists of a plurality of RDF sections. RDF sections conform to MPEG-2 private_section. The maximum size of a section is 4096 bytes and the maximum number of sections in a table is 255. In the PMT (Program Map Table), a separate elementary stream is input and stream_type is 0x05 (private_section derivative). Table_id table_id is 0x0A. PID (Packet ID) used for transmission is used within the range that does not collide with other PID between 0x0020 ~ 0x1FFA. A maximum of 255 can be transmitted (recommended range: 0x0100 to 0x01FF). RDF triples transmit data according to a predefined ontology. The triple that is required is a triple that tells which web page to access when the receiver selects a particular channel. The receiver parses the RDF section to extract triples and store / maintain them in a buffer. As the triple is changed, add / delete / update is performed and the contents of the buffer are updated.

Fig. 3 shows a diagram summarizing the grammar.

This will be described in detail as follows.

tabel id: 0xA0 (this is undefined)

transport_stream_id: ID of broadcasting station (SBS: 0x1411)

ontology_version: indicates which version of ontology are currently used symbols

abbrev_length: Length of namespace abbreviation

abbrev: Abbreviation for namespace. Multiple string structure format.

namespace_length: Namespace length

namespace: Use URL type and the end must be a string ending with #. MMS (multiple string structure) format. For example, http: //www.sbs.co.kr#.

modify: show changes for the next triple

       0: unchanged

       1: add

       2: updated

       3: deleted

When the receiver is powered on and the channel is tuned to receive the rdf table for the first time, it receives all triples and processes them. After that, when receiving the rdf table, the triple that is 0 is ignored and processed only when 1, 2, and 3. If it is 1, 2 means update, and 3 means delete. If the sender indicates and sends it once, the receiver deletes the triple and then the sender also deletes the triple and transmits it.

triple_id: Positive number of 32 bits, one RDF table has a maximum of 2 ³² triples. Unique within the same version number.

triple_length: the length of the triple

triple: Starting with “(” and ending with “)”, each element takes the form namaspace: symbol. (subject predicate object) in the form of a multiple string structure.

private_data_length: Length of binary data

private_data_byte: Binary data

The private_data_length and private_data_byte are used when sending arbitrary binary data such as an executable program or an image file in addition to the RDF data, together with the RDF data.

Without description, the definition follows the definition of MPEG-2 private_section.

An example based on the above grammar is shown below.

namespace abbreviation: SBS

Full name of the namespace full name: http: //www.sbs.co.kr#

Example of actual RDF triples sent

(sbs: apple rdf: type sbs: fruit)

In SBS, apple is defined as a kind of fruit.

(sbs: music space sbs: producer sbs: Shim Sung Min)

This means that the producer of "Music Space" defined by SBS is Shim Sung Min.

Hereinafter, an example of applying the above data transmission method will be described.

First, application examples in DTV will be described.

In order to transmit an rdf_ table (hereinafter referred to as RDFT) in DTV, a PSIP (Program Specific Information Protocol) encoder is used.

First, the structure of an encoder and a transmitter for generating and transmitting an RDF table using a PSIP encoder will be described.

5 shows an example of a PSIP encoder for generating and transmitting RDF data.

An application to service generates RDF data according to its purpose. When generating data, it must be created according to a predefined ontology for efficient retrieval and storage. Ontology definition, modification and management use separate management tool. The data generated in this way is stored in the RDF storage (see FIG. 6). The RDF triple at this time is stored in the form of a normal string and input to the PSIP encoder.

The logic encoder is composed of a PSIP table encoder and an RDFT encoder. The RDFT encoder reads an RDF triple stored in an RDF store to generate an RDFT composed of an RDF section as shown in FIG.

The PSIP table encoder in the logic encoder generates a program association table (PAT), a program map table (PMT), a master guide tab (MGT), and the like based on channel information, organization information, and the like.

The section encoder reads each table to create a section, in which the RDF triples stored in the RDFT are converted from a uni-code string form to a string in the form of a multiple string structure (MSS). . Each section is created based on MPEG-2 private_section. The output from this process consists of several RDF sections, for example in the case of RDF.

Next, a binary encoder converts the generated section into binary data.

The TS encoder divides binary data into small 188 byte MPEG-2 Transport Packets. The data passed through this process has the data in the form described in FIG. Each of these tables is input to the MUX via a buffer and merged into one MPEG-2 TS.

Here, the PID to which the RDFT is transmitted should be designated as a separate elementary stream in the PMT. The element must also be included in the Service Location Descriptor (SLD) of the VCT (Virtual Channel Table).

The DVB ASI encoder converts the multiplexed binary data into an ASI signal and transmits it to an external RE-Multiplexer (REMUX).

REMUX remuxes the ASI signal received from the PSIP encoder and the ASI signal (AV TS) received from the AV encoder to generate a final TS (see FIG. 6) and transmits the result through an RF modulator.

4 shows in detail that the data output from the TS encoder in the PSIP encoder is output to the TS through the mux.

PAT, PMT, MGT, VCT, Vent Information Table (EIT), and System Time Table (STT) are data generated by PSIP encoder for DTV broadcasting. Each is based on MPEG-2 private_section. These data must be input to the MPEG-2 TS in a constant cycle. Each table in the figure has its own buffer, which sends data to the MUX (multiplexer) at regular intervals.

For example, in case of RDFT, 5000 ms can be considered, but the present invention is not limited thereto.

MUX synthesizes the input data and creates an appropriate MPEG-2 TS.

Next, a receiver structure such as an RDF table will be described.

7 shows an example of a receiving system for receiving RDF data and the like.

The content including the RDFT is transmitted in the form of MPEG-2 TS. In the case of DTV, the RF tuner receives the RF signal and extracts the TS signal. This TS is divided into a PES (packetized elementary stream) containing AV information and a private_section stream containing additional information such as an RDFT. The private_section stream contains PSIP tables, RDF tables, and so on. The PSIP table is processed by the PSIP processor. The RDFT containing the RDF data is first input to the RDFT processor. Here, the RDF triple containing the actual data is extracted and stored in the receiver's RDF buffer. The RDFT contains control signals in addition to the data, so that it is possible to update / delete already received data. Update the contents of the RDF buffer using the data and control signals from the RDFT. Receiver-side applications use RDF data from the buffer for their purpose.

The receiver structure assumes a situation of directly receiving an RF signal.

The RF signal finally generated at the transmitting side is input to the RF tuner of the receiver through the antenna. Here, the RF signal is converted to MPEG-2 TS. The TS is first made up of meaningful data by merging the packets that have been broken up by the TS parser. This data can be classified into two types.

There is a PES (Packetized Elementary Stream) containing AV information and a private section containing data and additional information other than AV information. The AV PES is delivered to the AV decoder, which is displayed on the screen or output as voice after MPEG-2 decoding.

The TS packet containing the private_section is input into the MPEG-2 section decoder to make a section.

The section corresponding to the PSIP is passed to the PSIP processor for processing.

On the other hand, the RDF section is passed to the RDFT processor for processing. Here, RDF data in the RDFT is first extracted and stored in the RDF buffer. The type of storage can be freely defined depending on the implementation. The RDF data in this buffer is delivered to the application through a predefined application programming interface (API).

The application performs its own service using the received RDF data. Such an application may include, for example, T-commerce, securities information provision, weather information provision, user customized broadcasting, and the like.

Such an application itself is built into the receiver from the beginning or can be downloaded via the Internet, for example.

8 is a diagram illustrating an operation mode of a broadcast using airwaves and the Internet and related applications.

The receiver receives voice / video, PSIP, and RDF in RF form over the airwaves, and displays the broadcast on the display using voice / video and PSIP.

On the other hand, the application is already loaded in the receiver, or download the application via the Internet at the same time as the reception of the broadcast information. This application can deploy various services using the RDF. At this time, if necessary, bidirectional information such as purchase information is transmitted to the transmitter through the Internet.

When an application provides a service based on RDF data, it can read and modify RDF data to add, delete, update, or ignore triples depending on its status.

For example, if modify means uncahanged, the triple can be ignored to speed up processing. In addition, if modify means delete, the triple can be deleted, and the sender can send the triple by not sending the triple again.

In this way, the processing can be made faster by reducing the transmission / reception burden on the transmission / reception side.

The present invention as described above can be applied to various broadcasting methods, media such as DTV broadcasting, IPTV broadcasting, DMB broadcasting, satellite broadcasting.

1 is a diagram for explaining the concept of RDF.

2 is a diagram illustrating an RDF triple.

Fig. 3 shows the grammar of the RDF triple of the present invention.

4 is a diagram illustrating a method of multiplexing a PSIP and an RDFT.

5 is a diagram showing the internal structure of the PSIP to which the RDFT function is added.

6 shows an example of a transmission system for generating and sending RDF data.

7 shows an example of a receiving system for receiving RDF data.

8 is a diagram illustrating a transceiver for transmitting RDF meta data through MPEG-2 PS and transmitting and receiving application programs and bidirectional information through the Internet.

Claims (6)

Generate the metadata required by the application on the receiving side in triple in RDF format, A method of generating and transmitting meta data which is converted to RDFT (RDF Tabel) of private_section of MPEG-2 and inserted into PSIP and transmitted through MPEG-2 TS. The method of claim 1, Further comprising data representing changes in the triples, And said change is change free, add, update and delete. A logical encoder including an RDFT encoder for converting triple in RDF format, which is metadata generated for an application on the receiving side, to RDFT (RDF Tabel) of private_section of MPEG-2, and A section encoder for generating a section based on the RDFT; A binary encoder for converting the section into binary data, A TS encoder for converting the binary data into MPEG-2 TS; MUX for multiplexing MPEG-2 TS including RDFT, The DVB ASI encoder converts the multiplexed MPEG-2 TS into an ASI signal (Asynchronous Serial Interface). An encoder, characterized in that made. RF tuner for receiving RF signal including RDFT (RDF Tabel) of private_section of MPEG-2, which is triple format of RDF format which is metadata for application program of receiving side, and converts it into MPEG-2 TS. , A TS parser for receiving the MPEG-2 TS and separating the packetized elementary stream TS into a private-section TS; An MPEG-2 decoder for recovering an RDFT section from the private-section TS; The RDFT processor restores RDF data from the RDFT section and stores the RDF data in an RDF buffer that can be read by an application program. Decoder, characterized in that made. The method of claim 4, wherein The metadata further includes data indicating changes of the triples, Such changes shall be made without change, additions, updates and deletions. Decoder, characterized in that. A receiver comprising the decoder of claim 5, The data representing the change of the triple is If no change, ignore the triple, If it is an addition, add the triple, If it is an update, the triple is changed. If delete, delete the triple Receiver characterized in that.

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