KR102252402B1 - Method and apparatus for transmitting and receiving multimedia service - Google Patents

Abstract

A method for receiving multimedia content is disclosed. A method for receiving multimedia content according to an embodiment of the present disclosure includes receiving a control message for providing information on a package related to the multimedia content, and processing the received control message, , The control message includes a control message payload including a plurality of tables, identification information of the control message, length information of the control message, version information of the control message, and information indicating the number of the plurality of tables. Extended information, wherein the plurality of tables includes a basic table providing information on at least one package related table included in the plurality of tables, and the at least one package related table is included in the package. Includes a first table that provides information on at least one related asset, and the first table provides asset type information indicating a type of asset among the at least one asset and information on a clock used for the asset. Includes a clock reference flag.

Description

Multimedia service transmission/reception method and apparatus {METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING MULTIMEDIA SERVICE}

The present invention relates to a method of providing a multimedia service, and more particularly, to a method for a service provider that provides a broadcast communication convergence service in a heterogeneous network environment to deliver detailed information on a service provided by the service provider.

As the Internet evolves to broadband, not only conventional broadcasting using dedicated channels such as terrestrial, satellite, cable, etc., but also Internet broadcasting that provides multimedia by organizing using the general Internet is becoming possible. In addition, a broadcasting communication convergence multimedia service that provides various services by more organically combining existing broadcasting and Internet broadcasting has emerged as a realistic service.

Broadcast service providers (broadcasters) can deliver content through the Internet as well as a dedicated channel, and even broadcast service providers that deliver content through the Internet without a dedicated broadcasting channel are emerging. Therefore, whether a broadcaster using a dedicated channel and using only the Internet or a broadcaster using only the Internet, by delivering their program programming information along with the program content to the viewers, they promote their program content to the viewers and make the viewers planable. It needs to be made available to watch. Even by providing a'review' service through the Internet, viewers may be able to later watch content that was not viewed during the broadcast. In conventional broadcasting, this type of information is called Electronic Program Guide (EPG), and in the case of the Digital Video Broadcasting (DVB) system standard, PSIP (Program and System Information Protocol) in the North American method, and SI (in the European method) Service Information). Also, in the MPEG-2 system standard widely used in the existing digital TV system, this is called PSI (Program Specific Information). In the North American method, PSI and PSIP are transmitted together, but a program can be selected by viewers only with PSIP. In the European method, PSI and SI are transmitted together, and program selection is possible only with PSI, but various guide information about the program is additionally provided through SI. In this specification, this type of information will be collectively referred to as Service Specific Information (SSI).

Unlike existing broadcasting that uses dedicated channels, Internet broadcasting is provided globally, so it can be accessed through the Internet anywhere in the world where there is a receiver capable of receiving it beyond the regional property of existing broadcasting. Do. Accordingly, in the case of Internet broadcasting, in order to overcome the regionality of the existing broadcasting standards that are largely divided into North America, Europe, and Japan, it is possible to prevent unnecessary increase in the complexity of the receiver only when it is provided in a single method that is unique in the world. From this point of view, SSI also requires a single method of standardization.

It is expected that the future broadcasting and communication convergence broadcasting system will be reorganized centering on the Internet. In other words, not only program contents through existing broadcasting channels, but also guide information on program contents through the Internet are stored together in the SSI in a machine-readable format that can be read and understood by the receiver, and the receiver transmits the SSI through the broadcasting channel or the Internet. It will be acquired through broadcast reception control and displayed in a form that can be read by viewers if necessary. Of course, Internet broadcasters that do not use dedicated broadcasting channels will of course deliver SSI through the Internet.

Therefore, there is a need for an apparatus and method for providing a format for a service provider that provides a broadcast communication convergence service in a heterogeneous network environment including the Internet to deliver detailed information on a service provided by the service provider.

The information is expressed as background information to aid understanding of the present disclosure. No determination or no mention can be made as to whether or not it can be applied as prior art for the present invention.

Features of the present invention solve at least the above-described problems and/or disadvantages, and provide at least the above-described effects hereinafter.

A feature of the present invention is to provide a format for a service provider providing a broadcast communication convergence service in a heterogeneous network environment including the Internet to deliver detail information on a service provided by the service provider.

A method for receiving multimedia content according to an embodiment of the present invention includes receiving a control message for providing information on a package related to the multimedia content, and processing the received control message, The control message includes a control message payload including a plurality of tables, identification information of the control message, length information of the control message, version information of the control message, and information indicating the number of the plurality of tables. Includes extended information, and the plurality of tables includes a basic table providing information on at least one package related table included in the plurality of tables, and the at least one package related table is related to the package A clock that provides information on a clock used for the asset and asset type information indicating a type of an asset among the at least one asset, and the first table includes a first table that provides information on at least one asset to be used. Includes a clock reference flag.

Other features, effects, and remarkable features of the present invention will become apparent to those skilled in the art from the following detailed description in conjunction with the accompanying drawings.

According to the present invention, by applying the format for providing the service detail information proposed in the present invention, the service provider provides the service detail information on the service provided by the service provider, and the receiver uses the service detail information to allow the viewer to watch the broadcast. Make it easy to select content.

1 is a diagram showing a structure of service details and system guide information in an existing broadcast using a dedicated physical channel according to an embodiment of the present invention;
2 is a diagram showing the structure of service detail guide information in Internet broadcasting;
3 is a diagram showing a logical structure of an SSI according to an embodiment of the present invention;
4 is a diagram showing an example of using SSI in MPEG-2 TS-based broadcasting;
5 is a diagram showing an S1 signaling structure according to an embodiment of the present invention;
6 and 7 are diagrams illustrating an operation of receiving multimedia in a receiver according to an embodiment of the present invention;
8 is a diagram showing the structure of a transmission device according to an embodiment of the present invention; And
9 is a diagram showing the structure of a receiving device according to an embodiment of the present invention.
It should be noted that the same reference numerals are used throughout the drawings to represent the same components, features, and structures.

The following description with reference to the accompanying drawings is provided to aid in a comprehensive understanding of embodiments of the invention defined by the claims and their equivalents. It contains various specific details to aid its understanding, but these should be considered as illustrative only. Accordingly, those skilled in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the spirit and scope of the present invention. In addition, descriptions of well-known structures and functions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographic meaning, but are merely used by the inventors to enable a clear and consistent understanding of the present invention. Accordingly, the description of exemplary embodiments of the present invention is not intended to limit the present invention, as defined by the appended claims and their equivalents, but is provided to illustrate the purpose and will be apparent to those skilled in the art.

It is to be understood that the singular forms "a", "an" and "the" include plural referents and the context does not expressly dictate otherwise. Thus, for example, a reference to “a component surface” includes a reference to one or more of such surfaces.

First, before describing the present invention, terms used in the specification are defined as follows.

Media service: A service that delivers information using one or more of a variety of media such as audio, video, images, text, graphics, and interactive applications.

Foreground media service: video service, audio service, electronic program guide service, push video on demand (VoD) service, portal service, etc. Directly to viewers so that one viewer can select and enjoy it at a point in time. Paid or free media products exposed

Background broadcast service: A media delivery service that assists front media services such as, for example, a carousel for file download and pre-download through the Internet, but is not directly exposed to viewers.

Video service: A video service is mainly provided, and audio accompanying it is necessarily provided, and audio in another language, subtitles, interactive applications, and other additional data may be provided together.

Audio service: Audio is the main service, and related video or image, interactive application, and other additional data may be provided.

Interactive application: Software that provides information to viewers by being called as needed while watching video or audio services, controls media services by receiving viewers' reactions, or delivers information to the server of a media provider. , Collectively refers to software in declarative and procedural languages. In connection with the video or audio service being watched, it is sometimes called by a media service provider, or while watching is called by a media service provider regardless of the media service. In addition, an interactive application already stored in the receiver cache and recognized by the viewer may be called at the request of the viewer.

Regular media: Media that must be provided due to media service requirements. For example, audio from an audio service or video and audio from a video service accompanied by audio.

Adjunct media: Media provided as needed, but not necessarily provided due to media service requirements. For example, web documents, widgets, interactive applications, audio clips, video clips, graphics, text, images, auxiliary media components, etc. Sub-media is always consumed with regular media and cannot be consumed independently.

Media component: An element that composes media. For example, in the case of stereoscopic video, the left-eye image and the right-eye image. As another example, in the case of 5.1 channel audio, each channel audio is a media component.

Auxiliary media component: A media component that does not independently compose one media, but composes a media together with other media components. For example, in a situation in which a left-eye image is always provided as a 2D image among left-eye and right-eye images in a 2D/3D temporal hybrid service, a right-eye image provided only in a stereoscopic video section is an auxiliary media component.

Asset: Encoded data for a media component. Here, encoding refers to compression encoding, encoding according to a standard format, and the like.

Regular asset: Coded data for media components of regular media. Here, encoding refers to compression encoding, encoding according to a standard format, and the like.

Adjunct asset: Encoded data for a media component of an adjunct media or an auxiliary media component. Here, encoding refers to compression encoding, encoding according to a standard format, and the like.

Program: An instance of a media service. For example, the entire contents of one logical broadcast channel (logical channel)

Program item: The content of any time period in the program. For example, suppose that the opening advertisement, the intermediate advertisements, and the last advertisement are mixed and transmitted within a movie, the contents of the time period corresponding to the movie including the advertisement. Here, each advertisement is also an individual program item, but is an embedded program item included in another program item. A program is the result of concatenating program items (which may contain nested program items) that are not nested on the time axis.

Package: As coded data for program items, it is composed of assets and control information related to transmission, decoding, and reproduction thereof.

Primary asset: A static asset that may contain synchronization information for secondary assets. For example, as attached information of M units of a video stream, synchronization and control information of an auxiliary asset may be included.

Attached information: Refers to additional information such as control information and description information for an asset. Attachment information is a logical term and is actually included in headers of several layers of the delivery hierarchy, and in this case, it is called header information.

Stream asset: An asset in the form of media compressed data that can be created infinitely in time, such as a video stream and an audio stream.

Non-stream assets: Assets that do not correspond to stream-type assets.

M-unit: The sub-element of an asset. The M unit of the stream-type asset is a minimum data unit that can be input to a media decoder at one time, and the decoding result can be displayed at one point in time or for a certain period of time depending on the media. For example, in the case of a video stream, a result of compressing one frame may be one M unit, and in the case of an audio stream, a result of compressing an audio sample for 24 ms may be one M unit.

Logical channel: refers to a path through which one coded program is transmitted. For example, in an existing digital TV system based on MPEG-2 TS (Transport Stream), a data transmission path designated by a Program Map Table (PMT) or a source address, a destination address, and A data transmission path or the like designated by a port number corresponds to a logical channel.

Physical channel: refers to a path through which one or more logical channels are transmitted. For example, terrestrial TV channels or cable TV channels, satellite broadcasting channels, and the Internet having a bandwidth of 6 MHz correspond to physical channels.

IP application data flow: An IP application data flow is a source address on the Internet, a destination address, and within a destination that specifies the application to process the contents of the IP packet. It is specified by the port number.

Asset Path IDentifier (APID): The identifier of the asset path (eg, information carrying assets). One IP application data flow consists of multiple asset passages, and each asset passage is uniquely identified within one IP application data flow by APID.

Asset Module IDentifier (AMID): When an asset is divided into several modules and transmitted, it is an identifier that identifies these asset modules within one asset path. For example, suppose there is a large table, and if the table is divided into several sub-tables, if the entire table is designated as one asset, each buoy becomes an asset module.

Next, a format of service detail information according to the present invention is presented with reference to the drawings. First, service detail information should consider the following requirements.

Integration of guide information: Service detail information (SSI) delivers the detail information to the receiver for all wired and wireless Internet, terrestrial, satellite, cable, and other broadcast services jointly operated by one broadcaster or multiple broadcasters. You should be able to.

Format of guide information: The SSI must have a format that the receiver can efficiently read and decode (machine-readable). A format that can express the same SSI as a small amount of data as possible should be used.

Target period for guidance information: SSI must be able to provide information on service details in the past, present, and in the future for a certain period of time (eg, for a full moon). However, the details already broadcast in the past may not be directly included in the SSI, and in this case, the receiver may maintain the previously stored service details without deleting them for a certain period (for example, for a period of 15 days).

Validity period of guide information: A specific version of the SSI is valid only for a certain period of time, and should be automatically updated by the receiver when the specified period is over.

Configuration change support: When broadcasting contents different from the contents of the previously announced SSI according to certain needs, the transmitter and the receiver must provide a means to modify the previously announced SSI.

Means of delivery of guide information: All or part of the SSI should be able to be delivered through at least one of the media such as wired and wireless Internet, terrestrial, satellite, cable, etc., as necessary.

Optional structure of guide information: Among the SSI contents, information essential for the operation of the broadcast system must be delivered, but information that is not must have a structure in which information can be selectively delivered. For example, the location information of the program content is essential information for the receiver to read the corresponding program stream, but the plot of the program content can help the viewer decide whether to watch the program, but information essential for the operation of the receiver. Is not.

Minimization of channel acquisition time: SSI must have a structure that can minimize channel acquisition time. Here, the channel acquisition time means a time until video and audio are reproduced after power is applied or after a channel is changed.

Forward compatibility with existing broadcasts: SSI should be able to guide details of existing broadcasts based on MPEG-2 TS.

Backward compatibility with existing broadcasts: SSI should also be used in existing broadcasts based on MPEG-2 TS. Of course, the SSI provided in this way is not used in an existing receiver that does not support it, but it should not affect its operation. A new version of the receiver that supports SSI can utilize SSI.

Support for multiple small screens within one screen: SSI must be able to support multiple small screens within one screen. This includes the function of specifying the space-time location of the small screen. For example, when broadcasting a baseball game, it should be possible to include all of the small screens showing pitchers, batters, specific infielders, and the entire stadium within the full screen.

Support for receivers of various capabilities: SSI must support content guidance for receivers of various capabilities, such as mobile devices, SDTV (Standard Definition Television), HDTV (High Definition TV), and UHDTV (Ultra-High Definition).

Multilingual, subtitle, screen commentary broadcast, sign language broadcast guide support: SSI provides supplementary content that can increase accessibility, such as audio, subtitle, screen commentary broadcast (commentary channel), and sign language broadcast in various languages. If included, you should be able to guide them.

Content Use Restrictions Guidance: SSI should be able to guide several restrictions on the use of content. These restrictions include content rating (prohibition of viewing under a certain age), recording availability, random access availability, high-speed playback/reverse playback availability, payment per flight, and monthly payment.

Content data location guidance: SSI must guide the location of the content data. It should be possible to efficiently guide both the case where the entire contents are at the same location and the case where the contents are at different locations for each content component. In addition, the SSI must be able to guide the delivery of content by using one or more dedicated broadcast physical channels and the Internet alone or at the same time in part or all of the Internet.

Alternative content data location guidance: SSI must be able to guide the location of the alternative content data. Substitute content data refers to a different location from which content identical or similar to the original content data can be read in place of the content data originally intended for the content selected by the viewer.

Ancillary Data Guidance: SSI provides guidance on the main video and audio, as well as accompanying web documents, widgets, interactive applications, audio clips, video clips, graphics, text, images, and partial media streams. For example, an additional finite-length stream for displaying binocular 3D video for a certain period of time) should be able to be guided.

Meanwhile, service detail information (SSI) is provided for each broadcaster or broadcaster group. Since terrestrial broadcasters, cable broadcasters, satellite broadcasters, and Internet broadcasters each run their own businesses, they have no choice but to deliver their respective service details independently unless they agree to share service details and deliver integrated delivery. However, if there is such an agreement, a group of broadcasters, which is a group of broadcasters participating in the agreement, may provide information on service details in an integrated manner. If the amount of information in the service history guide is large, it takes a lot of time to download it to the receiver, so the delay before the viewer reads the service history guide becomes longer, and the burden is increased even when downloading the changed service history guide. There is a need for a way to overcome the dots.

In the existing MPEG-2 standard-based broadcasting system, since the PSI (Program Specific Information) provided by the MPEG-2 system standard (ISO/IEC 13818-1) was insufficient for the service details guidance, additional service and system guidance information were specified and implemented. I'm doing it. These are ATSC's Program and System Information Protocol (PSIP) and DVB's SI. In the case of ATSC PSIP, since it contains information that replaces PAT (Program Association Table) or PMT (Program Map Table) among MPEG-2 PSI, it is designed to receive programs without necessarily decoding PAT or PMT by the receiver. .

Unlike broadcasting through a dedicated channel that multiplexes and transmits multiple programs within one physical channel, in the case of Internet broadcasting using only the Internet, it is not necessary to multiplex multiple programs within one IP application data flow. is average. Of course, it can be done if necessary, but in the method proposed by the present invention, it is assumed that only one program is sent in one IP application data flow. In addition, due to the bandwidth limitation of the physical channel, the case where program components are transmitted by dividing them into several different physical channels is not applicable in Internet broadcasting. Under such conditions, SSI for Internet broadcasting can be greatly simplified.

1 is a structure of a service specific information (SSI) of an existing broadcast using a dedicated physical channel according to an embodiment of the present invention.

The receiver checks the details of the physical channel from ATSC PSIP or DVB SI, and when tuning a specific physical channel, it checks the program details in the corresponding physical channel from the PAT among MPEG-2 PSIs, and when a specific program is selected, MPEG- Among the 2 PSIs, program components can be identified from the PMT. In the ATSC system, it is also possible to directly check the components of a specific program from the PSIP information.

2 is a structure of service detail information required for Internet broadcasting according to another embodiment of the present invention.

The receiver can play a program by checking a path identifier of a program component from service detail information transmitted through a specific path within the same IP application data flow. Since it is not possible to know in advance when the receiver will be powered on, when to access this Internet broadcast, etc., service detail information must be transmitted periodically. The shorter the period, the better. Usually it is desirable to keep it within 500 ms. If the amount of service detail information is large, in order to transmit it in a short period, as many packets have to be delivered in the same time period, it is inefficient. Therefore, information transmitted in a short period should be designed to be as small as possible. It is good to have the additional guidance information transmitted at a longer period or at the request of the receiver.

3 shows a logical structure of an SSI according to an embodiment of the present invention. For example, FIG. 3 is a logical structure of an SSI for broadcast communication convergence broadcasting using the Internet and a dedicated physical channel proposed in the present invention.

Referring to FIG. 3, the described structure is basically an integrated structure of FIGS. 1 and 2, and the Service Map Table for Multiple Packages (SMT-M) 301 provides multiple logical channels through a dedicated broadcast physical channel. It is used when broadcasting, and SMT-S (Service Map Table for a Single package) 309 is used when broadcasting one logical channel through a dedicated broadcasting physical channel, using only the Internet, or mainly using the Internet. . As an example of broadcasting mainly using the Internet, when a broadcaster using a dedicated physical channel and the Internet performs Internet broadcasting, when necessary, the data transmitted through the dedicated physical channel is used in Internet broadcasting. For example, due to the bandwidth limitation of the dedicated channel, when a content is broadcast on the Internet, ancillary data to be additionally used for this content may allow the content transmitted through the dedicated channel to be used jointly. In this case, a receiver that can only access the Internet cannot utilize auxiliary data, but a smart TV receiver that has both a tuner for a dedicated channel and an Internet access device receives the main content through the Internet and the auxiliary data through the dedicated channel. It can be received and provided to viewers in a comprehensive manner.

SMT-M refers to the location of the PPT (Package Packing Table) (307-1…307-n), which contains brief information on all programs in the physical channel through which this information is transmitted and information on each program item currently being broadcast. It includes information, and includes location reference information and version information for the PGT (Package Guide Table) 305 that contains guide information for all programs provided by the corresponding broadcaster.

In order to minimize the channel acquisition time, since the SMT is periodically transmitted in a very short period (eg, 500 ms), the amount of information included is also minimized if possible.

The PGT includes guide information for a certain amount of time (for example, between the past and the future for a full moon based on the present) among all physical channels operated by a broadcaster and all program items serviced through the Internet. The amount of information is much more than that of SMT, and the transmission period is also much larger (eg, 1 minute). If necessary, the PGT may allow the receiver to download through the Internet. The PGT guides program items according to the broadcast schedule, and even if it is a broadcast schedule that is known in advance, it can be changed, so it must have a structure capable of efficient updating. Therefore, the information included in the PGT is modularized and configured by type, and the receiver can download only the updated module. Of course, you can collect only the updated modules and download them all at once. This is called an integrated delta module.

For example, if the PGT version difference is 1 to N (N is a number corresponding to one or two days), if various integrated delta modules are provided together, the download burden on the receiver can be significantly reduced. . If the version of the PGT included in the SMT is different from the version of the PGT currently stored by the receiver, since at least one module among the PGTs has been added/updated/deleted, the receiver downloads the added or updated module and deletes the contents to be deleted. And, if the version of the PGT is the same, the receiver does not need to download or decrypt the PGT newly.

Each module of the PGT contains guidance information on one or more program items or packages corresponding thereto, or an additional associated table necessary for decryption of the PGT (e.g., a viewer rating table). table)). The guide information for the package included in the PGT includes location reference information for the PPT, so that the viewer can select a program to watch or reserve recording using the PGT. By guiding the program home page URL (Uniform Resource Locator) on the Internet, instead of guiding the outline of the program contents by long text information, the amount of information that must be included in the PGT is reduced, and various programs by HTML pages are deviated from the program content guidance that relies only on text. It is possible to provide information and services such as'preview' and'review'.

Although PPT is information similar to MPEG-2 Program Map Table (PMT), while MPEG-2 PMT is information on the configuration of a program logical channel that does not classify program items, PPT guides each program item. PPT can guide only one package corresponding to one program item. The PPT includes information on the auxiliary data elements as well as all program item elements constituting the program item. In other words, not only regular assets such as video and accompanying audio, but also web documents, widgets, interactive applications, audio clips, video clips, graphics, text, and images provided at the time of need. , It may include information on an adjunct asset such as an auxiliary media component and location reference information on the resource. It provides information and resources of auxiliary assets in a form that multiple packages can share auxiliary assets commonly used in multiple packages.

Referring to Figure 3, the structure and function of the SMT-S has similar aspects to those of the PPT. In the case of Internet broadcasting, since only one program is usually present in one IP application data flow, it is not necessary to acquire program access information in two steps of SMT and PPT. Also, the same applies to the case where only one program item is broadcast in one dedicated physical channel for broadcasting. SMT-S shortens the channel acquisition time by combining the functions of SMT and PPT into one. In the SMT-S, a simple guide for the Internet broadcasting channel or the logical channel itself, location reference information of the PGT, the version of the PGT, a simple guide for the program item corresponding to the package currently being broadcast, and assets that constitute the package 311- 1,..., 311-K) and various information. Therefore, the SMT-S integratedly delivers logical channel guidance, program item guidance, and program item component information.

The PGT used in Internet broadcasting may include a guide for all Internet broadcasting channels operated by an Internet broadcaster or a group of broadcasters, that is, all programs included in data flows of multiple IP applications. Viewers can use this to navigate and select a program of an Internet broadcaster or a group of broadcasters.

If real-time Internet broadcasting is performed by MPEG-DASH, SMT-S may not guide each program item included in the Internet broadcasting. For example, this is live streaming in which the length of a program item (actual content is a program in which several program items are consecutive) is not specified. However, in this case, the PGT must guide each program item.

The location of the PGT provided by the SMT-M may be one of a stream in a physical channel through which the SMT-M is transmitted, a stream in another physical channel, a stream in an IP application data flow, and an Internet URL.

The location of the asset corresponding to each program item component provided by PPT is one of the stream in the physical channel through which the PPT is loaded, the stream in the other physical channel, the stream in the Internet IP application data flow, and the URL (including MPEG-DASH URL). It can be eggplant. If a program item transmitted through a broadcast-dedicated physical channel broadcasts live only a part of an event that a viewer wants to see for various reasons, information on an alternative program item for viewing the entire event may be included. For example, if live HDTV baseball game broadcasting is stopped due to regular programming, an alternative program item based on MPEG-DASH, which is a low-resolution video but can be viewed subsequently, may be guided.

The location of the PGT provided by the SMT-S and the location of the program item components are the stream in the broadcast-dedicated physical channel through which the SMT-S is transmitted, the stream in the Internet IP application data flow, the stream in the other broadcast-only physical channel, It may be one of a stream in an IP application data flow or an Internet URL. When a broadcaster using both the dedicated channel and the Internet conducts Internet broadcasting, the location of some program item components of the Internet broadcasting may be a stream in the dedicated broadcasting channel.

When the location of the PGT is an Internet URL, the receiver accesses the URL whenever necessary or at a specified period to download the entire PGT or some of the updated or added modules among the PGTs.

Only one of SMT-M and SMT-S is included at one point in one physical channel. However, if the number of logical channels in a physical channel is changed from several to one, it is possible that a physical channel including only SMT-M includes only SMT-S. In this case, since the SMT-M and SMT-S have different table_id values, the receiver can easily distinguish them.

One of the main functions of SMT-M and SMT-S is to deliver the latest version information of the PGT and location reference information of the PGT. The receiver downloads the latest PGT using the latest version information of the PGT and the location reference information of the PGT contained in the SMT-M and SMT-S. If the latest version of the PGT contained in the SMT-M and SMT-S is the same version as the PGT already stored by the receiver, the receiver allows the viewer to select a program item based on the previously stored PGT contents. If the latest version of the PGT contained in SMT-M and SMT-S is different from the PGT contents already stored by the receiver, the viewer can download the program item by the PGT until the updated PGT is downloaded and stored in the receiver. Do not let them choose.

PGT may not be transmitted in the actual system. In this case, the viewer's selection of program items is entirely based on SMT-M or SMT-S.

When the receiver is initially installed, since there is no PGT downloaded, the physical channels for broadcasting and logical channels included therein are searched one by one by automatic channel search. At this time, if this broadcasting system provides a PGT, after downloading the PGT using the PGT location reference information of the SMT-M or SMT-S identified for the first time, the viewer can select the program item by the PGT. . If this broadcasting system does not provide a PGT, the automatic channel search is continued, and after checking all logical channels provided by the broadcasting system, the viewer can navigate the channels in the order of logical channels.

If the power is turned on again while the receiver being used is turned off, the program item of the previously viewed logical channel is played first, and in this process, the PGT information of the SMT-M or SMT-S is checked and the PGT is updated. . The viewer navigates the channel in the order of logical channels or retrieves PGT information and selects a desired program item from among the program items currently being broadcast.

In the case of Internet broadcasting, the broadcast server address already stored when the receiver is manufactured, the broadcast server address input to the receiver afterwards, the broadcast server address obtained by the PGT, etc. are stored inside the receiver, and then stored in the viewer's channel navigation. It can be selected through the selection process by selection by the PGT or by the PGT program item guidance.

When a viewer selects a program item according to the PGT's program item guidance, the receiver actually accesses the logical channel through which the program item is transmitted and shows the program item currently being broadcast through the logical channel. Although very rarely, the contents of the PGT may be updated from the point when a viewer selects a program item by referring to the program item guide of the PGT until immediately before decoding the SMT-M or SMT-S of the corresponding program item. In this case, the PGT is updated using the PGT information included in the SMT-M or SMT-S, and if the program item currently being viewed by the viewer is different from the program item guided in the previous version of the PGT due to emergency scheduling, The guide should be displayed on the screen so that the viewer can recognize the program item currently being viewed.

Referring to FIG. 3, an asset referenced by SMT-S or PPT may actually be a media asset or another PPT. However, a double recursive reference in which a PPT referenced by SMT-S or PPT refers to another PPT again is not allowed. When SMT-S or PPT refers to another PPT as an asset, MMT composition information must be transmitted for screen layout. If the screen layout is not changed over time in one program item and is fixed and the amount is not large, the MMT (MPEG Media Transport) composition information may be included in the descriptor in the PPT and transmitted. If the screen layout changes over time within one program item, the time information is transmitted as a timed asset. In addition, if the screen arrangement does not change over time in one program item, but the amount of composition information is large, the MMT composition information may be transmitted as an asset without time information.

The SSI proposed by the present invention can be used interchangeably in a broadcasting system based on the existing MPEG-2 system standard.

4 shows an example of SSI in an MPEG-2 Transport Stream (TS) based on broadcast according to an embodiment of the present invention.

For example, FIG. 4 is an example of an MPEG-2 TS that can be interpreted by both an existing broadcast receiver and a receiver supporting MMT. Referring to FIG. 4, in this example, two programs exist in one TS. Existing broadcast receivers decode MPEG-2 PAT, MPEG-2 PMT 1, and MPEG-2 PMT 2 to receive programs. A receiver supporting MMT decodes MMT SMT-M, MMT PPT 1, and MMT PPT 2 to receive a program. Of course, the PID of the TS packet carrying the MMT SMT-M must be allocated in advance as a fixed value, and the SMT-M and PPT must be encapsulated in an MPEG-2 section structure and then transmitted.

Next, the specification of the SSI information format proposed by the present invention will be described.

SMT-M (Service Map Table for Multiple packages) is a version of the PPT location and program guide corresponding to all program items currently being broadcast as a physical channel dedicated to the broadcast when multiple logical channels are broadcast through a dedicated broadcast physical channel. And is used to convey the location. It is preferable that the SMT-M is transmitted in a period of less than 500 ms, and when the receiver approaches a physical channel dedicated to broadcasting, it is possible to quickly find a package corresponding to the program item.

The APID (asset path identifier) of SMT-M is always fixed to a specific value (eg, 0x0000). If SMT-M is transmitted through MPEG-2 TS, the PID of the TS packet carrying it must be designated as a fixed value.

The syntax of SMT-M is as defined in <Table 1>. The definition of the content in the "Type" column of <Table 1> follows that of the MPEG-2 system standard. In addition, loop counts not displayed in the "Value" column of <Table 1> are values derived from values representing lengths. This principle also applies to other tables in the embodiments of the present invention.

The semantics of each syntax element in <Table 1> are as follows.

table_id : Identifier indicating the type of table. A unique and unique value corresponding to SMT-M is assigned.

version_id : An identifier indicating the composition of this table. If the composition of the table changes due to the revision of the standard, this value also changes. The receiver looks at this value and determines if this table is structured so that it can be understood. Increase this value only when the contents of the table have been revised incompatible with the existing one.

table_length : Number of bytes from after this field to the last byte of service_map_table_type_I(). A value of 0 is not used.

service_id : This is a unique identifier for a broadcast service using a dedicated broadcast channel. A unique identifier must be assigned to each broadcaster's dedicated broadcast channel through a registration authority.

SMT_update_version : Since the SMT-M is transmitted periodically, if the content of the SMT-M is different from the content of the SMT-M having the same service_id transmitted immediately before, this value is increased by one. After the maximum value of 255, it is changed to 0. When this value is changed, the receiver reads and decodes the contents of SMT-M.

SMT_prefix_count : Indicates the number of SMT_prefixes following. SMT_prefix is concatenated in front of the character string included in SMT-M to form a URL. When referring to SMT_prefix, refer to SMT_prefix using the order of appearance of SMT_prefix as an index. The value 0xFF of this field is not used. Therefore, up to 255 SMT_prefixes can be included.

SMT_prefix_length : indicates the length of the SMT_prefix character string.

SMT_prefix_byte : Represents an SMT_prefix character. It does not include the null byte at the end of the string.

SMT_M_descriptors_length : Indicates the length of the SMT_M_descripor syntax loop immediately below this field as the number of bytes from the next byte of this field to the last byte of the SMT_M_descripor syntax loop. In the place of SMT_M_descripor(), various descriptors including PGT_reference_descriptor(), which will be described later, can be entered.

number_of_packages : Indicates the number of packages currently being delivered through this broadcast channel.

package_path_number : represents a package path number that identifies a logical channel within a certain broadcast channel. A value of '0' is not used. The package_path_number is uniquely assigned within a physical channel by a broadcaster or a group of broadcasters.

package_id : This is the identifier of the package currently delivered through this virtual channel. package_id is a value assigned by a broadcaster for each package and has a unique value for packages provided by a broadcaster or a group of broadcasters for a certain period of time. This value can be reused after a certain period of time.

simple_location_type : Specifies the format of location reference information for PPT corresponding to the currently delivered package. All of the PPT referenced by SMT-M are delivered in the same IP application data flow as the IP application data flow carrying SMT-M or in the same MPEG-2 TS as the MPEG-2 TS carrying SMT-M. If the value of this field is '0', the asset path carrying PPT is designated as APID, and if '1', the MPEG-2 TS carrying PPT is designated as PID defined in MPEG-2.

PPT_APID : The identifier of the asset path carrying PPT within the IP application data flow.

PPT_PID : PID of TS packet carrying PPT in MPEG-2 TS

CRC_32 : Same field as CRC_32 defined in section syntax of MPEG-2 system standard

SMT-S (Service Map Table for a Single package) is a simple guide information for program items and corresponding packages when broadcasting one logical channel through a dedicated broadcasting physical channel, using only the Internet or mainly using it. , It is used to convey location reference information for more detailed program guide information, configuration of a program item, and location reference information of its components. SMT-S must be transmitted in a period within 500 ms, and the APID of SMT-S is always fixed to a specific value (eg, 0x0000). Therefore, SMT-M and SMT-S are transmitted through a path having the same APID, but are distinguished by table_id.

The syntax of SMT-S is shown in <Table 2>.

The meaning of each syntax element in <Table 2> is as follows.

table_id : Identifier indicating the type of table. A unique and unique value corresponding to SMT-S is assigned.

version_id : An identifier indicating the composition of this table. If the composition of the table changes due to the revision of the standard, this value also changes. The receiver looks at this value and determines if this table is structured so that it can be understood. Increase this value only when the contents of the table have been revised incompatible with the existing one.

table_length : Number of bytes from after this field to the last byte of service_map_table_type_II(). A value of 0 is not used.

service_id : This is a unique identifier for an Internet broadcasting service. A unique identifier must be assigned to each broadcaster's IP application data flow through the registration authority.

SMT_update_version : Since the SMT-S is transmitted periodically, if the content of the SMT-S is different from the content of the SMT-S having the same service_id transmitted immediately before, this value is increased by one. After the maximum value of 255, it is changed to 0. When this value is changed, the receiver reads and decodes the contents of SMT-S.

CRC_32 : Same field as CRC_32 defined in section syntax of MPEG-2 system standard

PPT_body() : A group of syntax elements corresponding to the body of the PPT in MMT, and its syntax is shown in <Table 3>.

The meaning of each syntax element in <Table 3> is as follows.

short_channel_name_length : The number of bytes of the logical channel name expressed as a string using UTF-8 encoding.

short_channel_name_byte : byte data constituting the logical channel name

package_id : This is the identifier of the package currently delivered through this virtual channel. package_id is a value assigned by a broadcaster for each package and has a unique value for packages provided by a broadcaster or a group of broadcasters for a certain period of time. This value can be reused after a certain period of time.

prefix_count : Shows the number of prefixes following. The prefix is concatenated in front of the string to form a URL. To refer to the prefix, refer to the prefix by using the order of appearance of the prefix as an index. The value 0xFF of this field is not used. Therefore, up to 255 prefixes can be included.

prefix_length : Indicates the length of the prefix string.

prefix_byte: Represents the prefix character. It does not include the null byte at the end of the string.

descriptors_length : Indicates the length of the descriptor syntax loop immediately below this field as the number of bytes from the next byte of this field to the last byte of the descriptor syntax loop. Various descriptors can be placed in the descriptor() place. When the PPT_body() syntax element group in <Table 3> is included in SMT-S, PGT_reference_descriptor() can be placed in this descriptor() place.

parental_guidance_flag : If the value of this flag is '1', the receiver does not play the restored content from the package until it decodes the PGT and checks the correct viewer rating applied to this package. If this value is '0', the receiver plays back content restored from the package even before checking the viewer rating.

recording_flag : If the value of this flag is '1', the receiver can store this package in a storage medium in the receiver.

random_access_flag : If the value of this flag is '1', the viewer can perform random access to this package.

fast_forward_play_flag : If the value of this flag is '1', the viewer can perform high-speed playback on this package.

fast_reverse_play_flag : If the value of this flag is '1', the viewer can perform fast reverse playback for this package.

timescale_flag : If the value of this field is '1', it indicates that the timescale field appears below.

protection_scheme_id_flag : If the value of this field is '1', it indicates that the protection_scheme_id field is shown below.

timescale : The time unit applied to various timestamps of the asset, expressed as the number of time units per second. The default value is 90,000. The timescale field appears in two places in PPT_body(), the first one is the value applied to all assets belonging to the package, and the later one in the syntax loop for the asset is the value applied to each asset. If there is a value applied to each asset, this value takes precedence over the value applied to all assets that appear first.

protection_scheme_id : A value specifying the encryption method of the asset. The protection_scheme_id field appears in two places within PPT_body(), the first one is the value applied to all assets belonging to the package, and the later one in the syntax loop for the asset is the value applied to each asset. If there is a value applied to each asset, this value takes precedence over the value applied to all assets that appear first.

clock_reference_id : The identifier of the clock used by the asset encoder. The clock_referece_id field appears in two places within PPT_body(), the first one is the value applied to all assets belonging to the package, and the later one in the syntax loop for the asset is the value applied to each asset. If there is a value applied to each asset, this value takes precedence over the value applied to all assets that appear first.

number_of_asset_groups : Number of asset groups. Assets belonging to the same asset group are mutually exclusive. That is, the receiver plays only one asset among assets belonging to the same group. For example, for multilingual support, audio in language A and audio in language B belong to the same asset group.

level_of_mandatory_playing : A value indicating whether one asset in the asset group should be played. If the value of this field is '0', one asset in this asset group must be played. If the value of this field is '0', assets belonging to this asset group may not be played according to the capabilities of the receiver. However, the larger the value of this field, the lower the importance, and the asset group with a smaller value of this field should not be omitted and an asset group with a larger value of this field should not be played.

number_of_assets_in_group : Number of assets belonging to this asset group

asset_type: Represents the asset type. It is similar to stream_type in MPEG-2 PMT, but is an extended field. If the asset_type is PPT, this asset becomes a PPT asset. However, a double recursive reference referring to another PPT asset within the PPT asset included in the SMT-S or PPT is not allowed.

asset_id : Asset identifier. This identifier is used to refer to an asset in MMT_package_composition_descriptor.

default_selection_flag : If the value of this field is '1', this indicates that the asset is a preferentially recommended asset within the asset group to which it belongs. Among assets belonging to the same asset group, the value of this field should be set to '1' for only one asset. If this field value is '0' for all assets belonging to the same asset group, the receiver regards the asset that appears first as the first recommended asset.

clock_reference_flag : If the value of this field is '1', it indicates that the clock_reference_id field is shown below.

asset_timescale_flag : If the value of this field is '1', it indicates that a timescale field is displayed below.

asset_protected_flag : If the value of this field is '1', this indicates that the asset is encrypted.

scheme_id_flag : When the value of this field is '1', it indicates that the protection_scheme_id field appears below.

MMT_general_location_info() : As general location reference information for MMT, it designates the location of an asset. Its contents are shown in <Table 5>.

asset_descriptors_ length : Number of bytes from after this field to the last byte of the descriptor syntax loop

asset_descriptor() : Descriptor for the asset

PPT_asset() is a group of syntax elements used to include another package within a package. The syntax is as shown in <Table 4>, and the meaning of each syntax element is as defined in <Table 3>.

MMT_general_location_info() is a syntax element group that provides location reference information of an asset in MMT. The syntax is shown in <Table 5>.

The meaning of each syntax element in <Table 5> is as follows.

location_type : Designates the type of location reference information as shown in <Table 6>.

AMID : The module's identifier within the asset passage.

APID : The identifier of the asset path within the IP application data flow.

ipv4_src_addr : IP version 4 source address of the IP application data flow

ipv4_dst_addr : IP version 4 destination address of the IP application data flow

dst_port : IP application data flow destination port number

ipv6_src_addr : IP version 6 source address of the IP application data flow

ipv6_dst_addr : IP version 6 destination address of IP application data flow

network_id : Broadcasting network identifier that delivers MPEG-2 TS

MPEG_2_transport_stream_id : MPEG-2 TS identifier

MPEG_2_PID : PID of MPEG-2 TS packet

prefix_index : An index that designates one of the prefixes stored in the receiver before decoding this field. If the value of this field is 0xFF, it indicates that there is no prefix.

URL_length : The length of the URL. The null (0x00) byte at the end of the string is not included.

URL_byte : The byte of the URL. The null byte at the end of the string is not included.

byte_offset : Byte offset from the beginning of the file

length: length in bytes

The Package Packing Table (PPT) is for broadcasting using a physical channel exclusively for broadcasting, simple guide information for program items and corresponding packages, location reference information for more detailed program guide information, program item configuration and components thereof. It is used to convey location reference information. It is preferable that the PPT is transmitted in a period within 500 ms.

The syntax of PPT is almost the same as the syntax of SMT-S except that the service_id syntax element is replaced by the package_path_number syntax element in the syntax of SMT-S. The syntax of PPT is shown in <Table 7>. Since most of the syntax elements have the same meaning as SMT-S, only other cases are defined.

The meaning of each syntax element in <Table 7> is as follows.

table_id : Identifier indicating the type of table. Assign a unique value for PPT.

package_path_number : represents a package path number that identifies a logical channel within a certain broadcast channel. A value of '0' is not used. The package_path_number is uniquely assigned within a physical channel by a broadcaster or a group of broadcasters.

The Package Guide Table (PGT) is program guide information, and can guide programs organized for all broadcasts operated by one broadcaster or a group of broadcasters. It is desirable that the PGT is transmitted in a period of less than 1 minute.

PGT basically provides guide information in units of program items. It is the responsibility of the receiver to classify and provide this for each physical channel or logical channel. Of course, information that enables such sorting is included in the PGT. The transmission side may arrange and deliver program item guide information according to a certain rule.

Program items are identified by package_id, which is the identifier of the package, which is the encoding type. The package_id uniquely identifies a program item provided by a broadcaster or a group of broadcasters. A broadcaster or group of broadcasters is uniquely identified by the PGT_provider_id. PGT_provider_id must be assigned at the request of each broadcasting service provider or group of broadcasting service providers by designating the registration authority. The package_id is uniquely assigned to each broadcaster or group of broadcasters to their own program items. Since package_id is a 16-bit value, only a finite number of program items can be identified, so it must be reused after a certain period of time. When reused, the package_id_recycle_number (which is 8 bits as one of the syntax elements included in PGT_package_info()) is increased by one. The pair of three pieces of information consisting of (PGT_provider_id, package_id_recycle_number, package_id) becomes a unique identifier for a program item or corresponding package in the world during the period until all of the package_id_recycle_number is exhausted. For example, if it takes about one year to run out of package_id, since package_id_recycle_number is 8 bits, uniqueness is guaranteed for about 256 years.

The PGT is composed of the identifier of the broadcaster or group of broadcasters providing it, the updated version, the URL of the homepage of the broadcaster or group of broadcasters providing the same, update module information, logical channel information, package information, and annexed table information. The update module information is in the form of delta information, and is information including only different parts of the current PGT version and the past PGT version as a reference. If update module information corresponding to about one or two days is included in the PGT, the PGT update process in the receiver can be performed very efficiently.

The syntax of the PGT is shown in <Table 8>.

The meaning of each syntax element in <Table 8> is as follows.

table_id : Identifier indicating the type of table. Assign a unique value corresponding to the PGT.

version_id : An identifier indicating the composition of this table. If the composition of the table changes due to the revision of the standard, this value also changes. The receiver looks at this value and determines if this table is structured so that it can be understood. Increase this value only when the contents of the table have been revised incompatible with the existing one.

PGT_provider_id : Unique identifier of the organization providing the PGT. One institution can provide one PGT, and the PGT_provider_id is assigned by the corresponding registration authority.

PGT_update_version : This is the version number indicating whether the PGT contents are changed. When the contents of the PGT are changed, this value is increased by one. After the maximum value of 255, it is changed to 0. If the version number of the PGT stored by the receiver is different from this value, the receiver reads the PGT again and decodes the contents.

table_length : Number of bytes from after this field to the last byte in package_guide_table(). A value of 0 is not used.

PGT_prefix_count : Shows the number of prefixes used in PGT. prefix is concatenated before the string included in the PGT. To refer to the prefix, refer to the prefix by using the order of appearance of the prefix as an index. The 0xFF value is not used as an index value. Therefore, up to 255 prefixes can be included.

PGT_prefix_length : indicates the length of the prefix.

PGT_prefix_byte : Indicates the character of prefix. It does not include the null byte at the end of the string.

PGT_provider_homepage_URL_prefix_index : Index of the prefix of the homepage URL of the organization providing the PGT. A value that designates one of the prefixes preceding it. If the value of this field is 0xFF, it indicates that there is no prefix string.

PGT_provider_homepage_URL_length : The length of the postfix among the URLs of the homepage of the organization providing the PGT immediately following.

PGT_provider_homepage_URL_byte : ASCII character value of postfix among homepage URLs of organizations providing PGT

PGT_descriptors_length : Length of the next descriptor syntax loop

PGT_descriptor() : Descriptor related to PGT

redirect_flag_for_delta_update_info : If this flag value is '0', the PGT update information is directly included in the PGT, and if it is '1', it is located elsewhere.

redirect_flag_for_logical_channel_info : If this flag value is '0', the logical channel information is directly included in the PGT, and if it is '1', it is located elsewhere.

redirect_flag_for_package_info : If this flag value is '0', the package information is directly included in the PGT, and if it is '1', it is located elsewhere.

redirect_flag_for_associated_table_info : If this flag value is '0', table information attached to the PGT is directly included in the PGT, and if it is '1', it is located elsewhere.

PGT_delta_update_info_molude_count : number of PGT_delta_update_info_module

PGT_update_delta: Value corresponding to the difference between the past PGT version and the current PGT version, which is the standard when creating the PGT_delta_update_module. MMT_general_location_info() immediately following specifies the location of PGT_delta_update_module().

PGT_delta_update_info_module() : A data module that contains only different contents between the PGT of the previous version as much as PGT_update_delta and the current PGT

PGT_logical_channel_info_update_version : Version of PGT_logical_channel_info() defined in <Table 10>. MMT_general_location_info() immediately following designates the location of PGT_logical_channel_info().

PGT_logical_channel_info() : Logical channel information defined in <Table 10>

PGT_package_info_module_count : Number of PGT_package_info_module()

PGT_package_info_module_id : Identifier of PGT_package_info_module()

PGT_package_info_module_update_version : The version of PGT_package_info_module(). MMT_general_location_info() immediately following specifies the location of PGT_package_info_module().

PGT_package_count : number of packages

PGT_package_info() : Package information defined in <Table 11>. One package information contains information about only one package.

PGT_associated_table_info_module_count : Number of PGT_associated_table_info_module()

PGT_associated_table_info_module_id : Identifier of PGT_associated_table_info_module()

PGT_associated_table_info_module_update_version : The version of PGT_associated_table_info_module(). Immediately following MMT_general_location_info() designates the location of PGT_associated_table_info_module().

PGT_associated_table_count : The number of tables associated with the PGT. Tables with the same table_id are regarded as one table.

PGT_associated_sub_table_count : The number of sub-tables in the table associated with the PGT

PGT_associated_sub_table() : A buoy in the table attached to the PGT

PGT_delta_update_info_module() is a group of syntax elements that includes only updated information among the contents of the PGT. PGT_delta_update_info_module() may selectively include updated logical channel information, updated package information, and updated associated sub-tables.

If the PGT_update_version is different from the PGT version stored by the receiver, the receiver decrypts the PGT_descriptor() loop among the contents of the PGT, and then searches for the same PGT_update_delta as the difference minus the PGT version stored by the PGT_update_version. By decrypting PGT_delta_update_info_module(), the PGT update can be completed.

The syntax of PGT_delta_update_info_module() is shown in <Table 9>.

The meaning of each syntax element in <Table 9> is as follows.

PGT_update_delta: Value corresponding to the difference between the past PGT version and the current PGT version, which is the standard when creating the PGT_delta_update_module

PGT_delta_update_info_molude_length : Number of bytes from after this field to the last byte of PGT_delta_update_info_module()

update_logical_channel_info_flag : When this flag is '1', it indicates that update information on logical channel information is included.

update_package_info_flag : When this flag is '1', it indicates that update information on package information is included.

update_associated_table_flag : When this flag is '1', it indicates that update information for table information attached to the PGT is included.

PGT_logical_channel_info() : Logical channel information defined in <Table 10>

PGT_package_update_count : The number of updated package information included in the syntax loop below.

PGT_package_info() : Package information defined in <Table 11>

PGT_associated_table_update_count : The number of sub-tables among the updated tables appended to the PGT included in the syntax loop below.

PGT_associated_sub_table() : A sub-table among the tables attached to the PGT

PGT_logical_channel_info() is a group of syntax elements corresponding to metadata for all logical channels provided by the PGT provider among the contents of the PGT.

The syntax of PGT_logical_channel_info() is shown in <Table 10>. Here, it should be noted that the syntax loop index, PGT_logical_channel_index, is an index used in package information.

The meaning of each syntax element in <Table 10> is as follows.

PGT_logical_channel_info_update_version : The version of PGT_logical_channel_info(). Each time the content of the logical channel information is changed, it increases by one, and changes to 0 at 255.

PGT_logical_channel_info_length : Number of bytes from after this field to the last byte of PGT_logical_channel_info()

PGT_logical_channel_count : The number of logical channels guided by the PGT

short_channel_name_length : The number of bytes of the logical channel name expressed as a string using UTF-8 encoding.

short_channel_name_byte : byte data constituting the logical channel name

physical_channel_type : The type of physical channel carrying the logical channel. It indicates whether it is Internet (0), terrestrial (1), satellite (2), or cable (3).

major_channel_number : Major channel number

minor_channel_number : minor channel number

service_id : MMT service identifier

package_path_number : represents a package path number that identifies a logical channel within a certain broadcast channel. A value of '0' is not used. The package_path_number is uniquely assigned within a physical channel by a broadcaster or a group of broadcasters.

test_channel_flag : This logical channel indicates that it is a test logical channel. If the value of this flag is '1', the general receiver does not provide this logical channel information in the program guide.

nvod_channel_flag: Indicates that this logical channel is for Near Video On Demand (NVOD).

relay_broadcast_flag : This logical channel indicates that it is a retransmission channel of another logical channel. For example, when terrestrial broadcasting is retransmitted by cable, this flag is set to '1' for the corresponding logical channel.

channel_protection_type : This indicates the type of encryption applied to this logical channel. If this value is '0', it means that it is not encrypted, if it is '1', all packages in this logical channel are encrypted, if it is '2', it means that only some assets belonging to the package within this logical channel or only some/all of the assets are , '3' indicates that only some packages are encrypted. When this field value is '2', it indicates that, for example, only video is encrypted or only the first 10 minutes of the package are encrypted. When this field value is '3', it indicates that only a few packages delivered through this logical channel are encrypted.

original_physical_channel_type : Original physical channel type

original_major_channel_number : Original major channel number

original_minor_channel_number : Original subchannel number

MMT_general_location_info() : Designates the location of the PPT or SMT-S corresponding to this logical channel.

descriptors_length : The length of the next descriptor syntax loop

descriptor() : Descriptor related to logical channel information

PGT_package_info() is a group of syntax elements corresponding to metadata about a package among the contents of the PGT. The syntax of PGT_package_info() is shown in <Table 11>.

The meaning of each syntax element in <Table 11> is as follows.

package_id : This is the identifier of the package currently delivered through this logical channel. package_id is a value allocated by a broadcaster for each package and has a unique value for packages for a certain period of time. This value can be reused after a certain period of time.

PGT_package_info_update_version : The version of PGT_package_info(). Each time the content of the package information is changed, it is incremented by one, and at 255, it is changed to 0.

PGT_package_info_length : Number of bytes from after this field to the last byte of PGT_package_info()

package_id_recycle_number : A value that is incremented by one each time allocation of a 16-bit package_id number is completed, and becomes a unique package identifier along with package_id.

start_time : Indicates the start time of the program item corresponding to this package in UTC.

duration: Indicates the duration of the program item corresponding to this package in seconds. If the duration is '0', it means'not knowing the duration'.

title_text_language_count : The number of languages representing the title of the program item corresponding to this package.

title_text_language : A 3-byte language identifier according to the ISO 639 standard indicating the title language of the program item corresponding to this package.

title_text_length : It informs the length of the UTF-8 string representing the title of the program item corresponding to this package in bytes.

title_text_byte : Title string byte of program item corresponding to this package

package_homepage_URL_prefix_index : Index of the prefix of the homepage URL of the program item corresponding to this package. A value that designates one of the prefixes previously defined in PGT_header(). If the value of this field is 0xFF, it indicates that there is no prefix.

package_homepage_URL_length : The length of the postfix in the homepage URL of the program item corresponding to this package immediately following.

package_homepage_URL_byte : ASCII character value of postfix among homepage URL of program item corresponding to this package

format_type : Specifies the format of PGT_package_info(). If the format_type is '0' ㅇP, l is included, if it is '1;, only'review' information on the already broadcast program item is included, and if it is '2', all information on the program to be broadcast in the future is included. 'Review' is a service that allows users to download or stream previously broadcast program items for free from an Internet server and watch them.

PGT_logical_channel_index : An index specifying information about the logical channel carrying this package. This index value is an index for logical channels provided by PGT_logical_channel_info() in <Table 10>.

post_event_replay_URL_flag : Indicates that there is a'replay' URL for this package.

post_event_replay_URL_prefix_index : The index for the prefix of the'replay' URL for this package. A value that designates one of the prefixes defined in PGT_header() previously. If the value of this field is '0', it indicates no prefix. If the value of this field is'N' instead of '0', designates the Nth prefix.

post_event_replay_URL_length : The length of the postfix in the'replay' URL of this package immediately following.

post_event_replay_URL_byte : ASCII character value of postfix in'replay' URL of this package

package_protection_type : Shows the encryption type applied to this package. If this value is '0', it means that it is not encrypted, if it is '1', all assets in this package are encrypted, if it is '2', it indicates that only some assets or parts of certain assets in this package are encrypted, and a value of '3' Do not use. When this field value is '2', it indicates that, for example, only the video asset is encrypted, or only the first 10 minutes of the video asset and the audio asset are encrypted.

pay_type : This field has no meaning if package_protection_type is '0', so it is ignored by the receiver. If it is '1' or '2', it has meaning. If pay_type is '0', it means'paid subscription is required', and if '1', it indicates'pay-per-view per program item'. Related payment guide information must be provided using a descriptor in the PGT_descriptor() syntax loop of <Table 8> or the PGT_package_info_descriptor() syntax loop of <Table 11>. When payment guidance information is present in both the PGT_descriptor() syntax loop and the PGT_package_info_descriptor() syntax loop, the one in the PGT_package_info_descriptor() syntax loop takes precedence.

content_id_flag : Indicates that a globally unique content identifier for a program item corresponding to this package is included.

genre_flag : Indicates that genre information of a program item corresponding to this package is included. If this flag value is '1', the genre table must be transmitted to one of the PGT_associated_tables.

parental_guidance_flag : Indicates that viewer rating information is included. If this flag value is '1', a viewer rating table must be transmitted to one of the PGT_associated_tables.

live_flag: Indicates that this package is by live broadcasting, that is, does not broadcast recorded or recorded data.

serial_flag : Indicates that the program item corresponding to this package is one of a series such as a serial drama.

rebroadcast_flag: Indicates that a program item corresponding to this package is'rebroadcast' for a program item that has already been broadcast.

rebroadcast_exist_flag : Indicates that there is a'rebroadcast' plan for a program item corresponding to this package.

recording_flag : Indicates that this package can be recorded.

multilingual_flag : Indicates that multilingual audio is supported.

commentary_channel_flag : Indicates that there is a'screen commentary broadcast' for this package.

sign_language_flag : Indicates that there is a'sign language broadcast' for this package.

subtitles_flag : Indicates that there is a'subtitle broadcast' for this package. Subtitles are in UTF-8 encoding.

multivew_flag: This indicates that the entire package is'multi-view broadcast' or that some'multi-view broadcast' is included in this package. 'Multi-view broadcasting' includes binocular stereoscopic broadcasting, multi-view 3D broadcasting, and multi-view broadcasting.

picture_size_grade_count : The number of size grades on the screen. A value of '2' or more indicates that the video is provided by spatial scalability encoding.

picture_size_grade : Represents the grade of the size of the screen. For example, based on the horizontal resolution, it represents at least one of 240 pixel class, 480 pixel class, 720 pixel class, 1,920 pixel class, 3,840 pixel class, and 7,680 pixel class. If picture_size_grade is more than one, it indicates that the video is provided by spatial scalability encoding.

audio_language : 3-byte language identifier according to ISO 639 standard indicating the language of audio

audio_grade : Represents the type of audio. For example, it represents one of mono, stereo, 5.1 channels, and 22.2 channels.

additional_audio_count : The number of additional other language audio

additional_audio_language : A 3-byte language identifier according to the ISO 639 standard indicating the language of additional other language audio

additional_audio_grade : Indicates the type of additional audio in another language. For example, it represents one of mono, stereo, 5.1 channels, and 22.2 channels.

content_originator_id : A globally unique identifier representing the main content author of the program item corresponding to this package. This identifier must be used after registration with the registrar.

content_id : The content identifier for the program item corresponding to this package. This identifier is managed by each author. The pair of content_originator_id and content_id becomes an identifier that uniquely identifies a content in the world.

content_major_version : The major version of the program item for this package.

content_minor_version : The minor version index of the program item corresponding to this package.

genre_system_id : The identifier of the system that classifies the genre. It actually corresponds to the sub_table_id of the genre table.

major_genre : Index of the main genre of the program item corresponding to this package. This index is an index for the main genre entry listed in the genre table. For example, the main genre is sports.

minor_genre : The sub-genre of the program item corresponding to this package. This index is an index for the sub-genre entry in major_genre listed in the genre table. For example, the sub-genre is soccer among sports.

rating_system_id : An identifier of a system for classifying viewer ratings. It actually corresponds to the sub_table_id of the audience rating table.

rate_index : Index indicating the viewer rating of the program item corresponding to this package. This index is an index for the audience rating entry listed in the audience rating table.

season_number : represents the season of the series. If the value of this field is '0', it indicates that there is no season classification.

serial_number_minus1: Represents a value that is one less than the number of episodes within the season of the series.

prequel_package_id : The package_id of the package immediately preceding the program item corresponding to this package. If the value of this field is '0', it indicates that the program item corresponding to this package is the first episode of the corresponding season of the series.

sequel_package_id : The package_id of the next package of the program item corresponding to this package. If the value of this field is '0', it indicates that the program item corresponding to this package is the last episode of the corresponding season of the series.

rebroadcast_package_id : The identifier of the package corresponding to'rebroadcast' for this package.

commentary_channel_count : The number of languages for'screen commentary broadcasts' for this package.

commentary_language : A 3-byte language identifier according to the ISO 639 standard that designates the language of'screen commentary broadcasting'

subtitle_count : Number of'subtitles' languages for this package

subtitle_language : A 3-byte language identifier according to the ISO 639 standard that designates the language of'subtitle broadcasting'

karaoke_flag : Flag indicating whether the subtitle is karaoke style

multiview_coverage_type : If this field value is '0', this indicates that the entire package is multiview video. If it is '1', only part of this package is multiview video.

multiview_scheme_type : The method of'multiview broadcasting' is binocular stereoscopic broadcasting (1), multi-view 3D broadcasting (2), introverted multi-view broadcasting (3), outward multi-view broadcasting (4), and multi-view multi-view broadcasting (5). ).

PGT_package_info_descriptors_length : Length of the PGT_package_info_descriptor() syntax loop that follows

PGT_package_info_descriptor() : Area where additional descriptors can be put

The syntax of PGT_associated_sub_table() follows the syntax of a general MMT table as shown in <Table 12>. The meaning of each syntax element is defined below it.

table_id : Identifier indicating the type of table

version_id : An identifier indicating the composition of this table. If the composition of the table changes due to the revision of the standard, this value also changes. The receiver looks at this value and determines if this table is structured so that it can be understood. Increase this value only when the contents of the table have been revised incompatible with the existing one.

table_sub_id : The identifier of the sub-table

update_version : This is a version number indicating whether or not the contents of this field are changed from the end of this field to the end of this buoy. After the maximum value of 255, it is changed to 0. If the version number of this buoy stored by the receiver is different from this value, the receiver reads the buoy again and decodes the contents.

table_length : Number of bytes from after this field to the last byte of this buoy

sub_table_contents() : Contents that are different for each buoy

CRC_32 : Same field as CRC_32 defined in section syntax of MPEG-2 system standard [8]

PGT_package_info_module() is a data structure that includes guidance for one or more packages when the PGT does not directly include package guidance information, but includes it indirectly by referring to an external path or file in which the package guidance information exists.

The syntax of PGT_package_info_module() is as shown in <Table 13>, and the meaning of each syntax element is as defined below.

PGT_package_info_module_id : The identifier of PGT_package_info_module(). This identifier is reusable, and unless this identifier is reused, this module always contains information about the same packages.

PGT_package_info_module_update_version : The version of PGT_package_info(). Whenever the content after this field is changed, it is incremented by one regardless of whether the identifier is reused, and at 255, it is changed to 0.

PGT_package_info_module_length : Number of bytes from after this field to the last byte of PGT_package_info()

reallocation_flag : If this field value is '1', it indicates that this module contains information on packages different from the packages included in the previously received module that have the same identifier as the identifier of this module. That is, it indicates that the identifier is reused.

PGT_package_count_in_this_module : Number of package information included in this module

CRC_32 : Same field as CRC_32 defined in section syntax of MPEG-2 system standard

The Adjunct Asset Table (AAT) delivers information on an adjunct asset. AAT is periodically delivered as a separate asset constituting a package in which a primary asset corresponding to a target for synchronizing the sub-assets included in the AAT is included.

The definition of the synchronization method of the main asset and the sub-assets, and AAT is given in the domestic application number P2011-0095458. In this specification, for convenience of description, the syntax of the AAT and the meaning of each field are included below.

The syntax of AAT is as shown in <Table 14>, and the meaning of each field is as defined below.

table_id : Identifier indicating the type of table. Assign a unique value corresponding to the AAT.

version_id : An identifier indicating the composition of this table. If the composition of the table changes due to the revision of the standard, this value also changes. The receiver looks at this value and determines if this table is structured so that it can be understood.

sub_table_id : When the entire table is transmitted by dividing the contents into several sub-tables, each sub-table is classified.

update_version : Since the AAT is transmitted periodically, if the contents of the AAT are different from the contents of the AAT having the same sub_table_id transmitted immediately before, this value is increased by one. After the maximum value of 255, it is changed to 0. When this value changes, the receiver reads and decodes the contents of the AAT.

table_length : The number of bytes from after this field to the last byte of the AAT. A value of 0 is not used.

locator_prefix_count : This is the number of locator_prefixes that follow. The locator_prefix is concatenated in front of the locator string provided by adjunct_asset_locator to form a URL. In adjunct_asset_locator, the locator_prefix appearance order is used as an index to refer to locator_prefix. The value 0xFF of this field is not used. Therefore, up to 255 locator_prefixes can be included.

locator_prefix_length : Represents the length of the locator_prefix character string.

locator_prefix_byte : Represents a locator_prefix character. It does not include the null byte at the end of the string.

adjunct_asset_type : This indicates what type of auxiliary asset it is. For example, unique values are assigned for different formats for web documents, widgets, interactive applications, audio clips, video clips, graphics, text, images, and auxiliary media components. The adjuct_asset_type value is equally applied to the sub-assets in the syntax loop that follows.

adjunct_asset_count_minus1 : A value that is one less than the number of adjunct assets described in the syntax loop that follows. Up to 256 sub-assets can be displayed. If the number of auxiliary assets with the same adjuct_asset_type exceeds 256, use two or more syntax loops to describe them.

adjunct_asset_id : A unique 48-bit global identifier that designates an adjunct asset. Here, the uniqueness is maintained only for a certain period of time, and the identifier value can be reused after a certain period of time. To become a global identifier, this field is divided into two parts: a 32-bit provider identifier (provider_identifier) and a 16-bit asset identifier (asset_identifier), and the provider identifier designates a registration authority to register each provider, and the asset identifier is a provider. Take care of yourself.

execution_attribute : When the receiver receives this auxiliary asset, it contains several fields indicating how to execute.

execution_on_reception : A flag indicating whether to execute "immediately" after storing the received auxiliary asset in the auxiliary asset cache inside the receiver. If not executed immediately, it is implemented at a specified time point by the synchronization method proposed in the present invention, or by a user's selection or a call from another auxiliary asset. If this flag is 1, execution_entry_point must also be set to 1.

media_service_bound : Flag indicating whether to belong to this media service (media_service_bound). If this flag is 1, it indicates that it belongs to this media service, and the corresponding sub asset is automatically terminated when the broadcast channel is switched.

execution_entry_point : Flag indicating that it is a sub asset that can be executed directly. If the value of this flag is 0, it is indirectly enforced by other auxiliary assets.

visible_to_user : A 2-bit field indicating whether the user can select and enforce using the sub asset navigation function, or whether another sub asset is visible when searching the sub asset list through the API provided by the receiver. The meaning of visible_to_user is as in <Table 15>.

secure_execution : 2-bit information indicating whether the auxiliary asset is secure. The meaning of secure_execution is shown in <Table 16>.

adjunct_asset_priority : A field indicating the execution priority of an adjunct asset. The higher the value of adjunct_asset_priority, the higher the priority. When resources of the receiver for executing the sub-assets are insufficient, the sub-assets that are currently being executed are paused or terminated from the lowest priority.

adjunct_asset_locator_count_minus1 : A value that is one less than the number of places to read sub-assets. As 2 bits, it can represent up to 4 places in all. If more than one location is provided, priority is given according to the order in which adjunct_asset_locator appears below. There must be more than one adjunct_asset_locator.

adjunct_asset_locator : It informs the information of the place to read the auxiliary asset.

adjunct_asset_descriptor_loop_length : Number of bytes from after this field to the last byte of the descriptor syntax loop

adjunct_asset_descriptor : Various descriptors to be described later may be included in this descriptor syntax loop.

CRC_32 : Same field as CRC_32 defined in section syntax of MPEG-2 system standard

The resource data location information adjunct_asset_locator tells where to read the sub asset. Adjunct assets are delivered through the carousel of the broadcasting network or downloaded through the Internet. AAT must include at least one adjunct_asset_locator per sub asset. The receiver reads the adjunct asset from the position designated by the adjunct_asset_locator that appears first, and if an error occurs, the adjunct asset is read from the position designated by the next adjunct_asset_locator.

The syntax of adjunct_asset_locator is as in <Table 17>, and the meaning of each field is as defined below. <Table 17> includes only the Internet, and in the case of carousel, since it varies according to the carousel method described in ISO/IEC 13818-6:1998, specific matters are not included.

locator_type : An 8-bit field indicating whether the secondary asset is read from the Internet or the carousel of the broadcasting network, and if various types of carousel are used together, it is an 8-bit field.

locator_prefix_index : An index specifying one of the locator_prefixes in <Table 14>. If the value of this field is 0xFF, it indicates that there is no locator_prefix.

directory_path_length : The length of the next directory path string. It does not include the null byte at the end of the string. If the value of this field is 0, the directory path is not used.

directory_path_byte : The bytes in the directory path. The null byte at the end of the string is not included.

entry_path_length : The length of the path to the first page file that follows. It does not include the null byte at the end of the string. It has meaning only in the case of an auxiliary asset composed of several files, such as a web page. For sub-assets in a single file, the value of this field is 0.

entry_path_byte : The bytes of the first page file path. The null byte at the end of the string is not included.

object_count : The number of next file paths. If this field value is 0, the entire directory is designated.

object_path_length : The length of the next file path string. It does not include the null byte at the end of the string.

object_path_byte : The bytes of the file path. The null byte at the end of the string is not included.

Meanwhile, as described above, various descriptors can be included in adjuct_asset_descriptor of <Table 14>. Handler_capability_descriptor() indicating the receiver's ability to process auxiliary assets, adjunct_asset_cache_descriptor() indicating the amount of memory required for auxiliary asset cache management, expiration date, etc., display_position_descriptor() indicating the position on the display of the auxiliary asset to be displayed on the screen, These include adjunct_asset_name_descriptor(), which informs the name of the auxiliary asset to be displayed to the user, and adjunct_asset_icon_descriptor(), which informs the icon of the auxiliary asset to be displayed to the user.

PGT_reference_descriptor delivers PGT version and location reference information. It may be included in the SMT_M_descriptor syntax loop or in the SMT_S_descriptor (when PPT_body() is used in SMT-S, the descriptor in PPT_body() will be referred to as SMT_S_descriptor) syntax loop. If PGT_reference_descriptor is not included in SMT, the service is considered to not provide program guide.

The syntax of PGT_reference_descriptor is as shown in <Table 18>, and the meaning of each field is as defined below.

descriptor_tag : A unique value representing the kind of this descriptor

descriptor_length : Number of bytes from after this field to the last byte of this descriptor

PGT_provider_id : Unique identifier of the organization providing the PGT. One institution can provide one PGT, and the PGT_provider_id is assigned by the corresponding registration authority.

PGT_update_version : This is the version number indicating whether the PGT contents are changed. When the contents of the PGT are changed, this value is increased by one. After the maximum value of 255, it is changed to 0. If the version number of the PGT stored by the receiver is different from this value, the receiver reads the PGT again and decodes the contents.

number_of_locations: indicates the number of PGT location reference information. The locations where the PGT of the same version is stored are shown below as much as this field value.

MMT_general_location_info() : Designates the location of the PGT.

MMT_general_location_info() is general location reference information, and its contents are shown in <Table 5>. If more than one MMT_general_location_info() appears, the receiver tries to access in the order of first occurrence.

MMT_composition_descriptor provides spatial screen arrangement information of assets (including PPT assets) belonging to a certain package based on SMIL. When the screen layout does not change during the playback period of a certain package, the screen layout information can be provided using this descriptor. This descriptor may be included in the SMT_S_descriptor syntax loop or in the PPT_descriptor (when PPT_body() is used in PPT, the descriptor in PPT_body() is referred to as PPT_descriptor) syntax loop.

The syntax of MMT_composition_descriptor is as in <Table 19>, and the meaning of each field is as defined below.

descriptor_tag : A unique value representing the kind of this descriptor

descriptor_length : Number of bytes from after this field to the last byte of this descriptor

version : When package composition information is changed, this field value increases by one, and changes to 0 after 255.

compression_type : Represents a method of compressing package composition information. If the value of this field is '0', it indicates no compression, and if it is '1', it indicates that it is compressed by GZIP. The remaining values are reserved for future definition.

XML_length : Represents the length of package composition information in bytes.

XML_package_composition_byte : byte of package composition information. The definition of package composition information is given in ISO/IEC JTC 1/SC 29/WG 11 m19266.

alternate_package_descriptor is a descriptor that allows you to watch the live broadcast interrupted by the regular schedule using an alternative package or if you broadcast only the second half of the entire event (for example, golf broadcast), the event can be watched using an alternative package from the beginning. . It can also be used to specify an alternative package for all packages, from start to finish, regardless of whether they are broadcast live.

MMT_package_descriptor may be included in the SMT_S_descriptor syntax loop or the PPT_descriptor syntax loop. If there are multiple alternate package locations, multiple alternate_package_descriptors can be included in this.

The purpose, usage scenario, definition and method of use of this descriptor are given in national application number P2011-0095665. In this specification, for convenience of explanation, the syntax of alternate_package_descriptor is shown in Table 20, and the meaning of each field is included below it.

descriptor_tag : An 8-bit field indicating which descriptor it is. In order to distinguish it from other descriptors defined in the MPEG-2 system standard or a broadcast standard using the same, a unique value indicating that it is a substitute program descriptor is assigned.

descriptor_length : An 8-bit field indicating the length of this descriptor in bytes. This field indicates the length from the next byte to the last byte of the descriptor.

alternate_program_id : An 8-bit field corresponding to the alternate program identifier. If the alternate programs described by alternate_program_descriptor are different, different alternate_program_ids are allocated. In the case of guiding to watch an alternate program before the actual live broadcast starts, information about the same alternate program may be periodically transmitted several times. In this case, the same alternate_program_id is used continuously. If all values from 0 to 255 are used, the values that have already been used are reused.

reserved : This field is reserved for future use, and its value is filled with 0x7F.

just_alternate_flag : Indicates that the content contained in this descriptor is for an alternative package for the package containing this descriptor (regardless of whether it is intended for live broadcast). If this flag is '1', future_flag has no meaning, and text_length is always '0'.

future_flag : A 1-bit field indicating whether the content included in this descriptor is for an alternative program to be viewed from before or after the current program is ended. If the value of this field is '1', it indicates a program to be watched from beforehand, and if it is '0', it indicates a substitute program to be watched after completion.

time_to_future_live_program : When future_flag is '1', a 16-bit field indicating the time until live broadcast starts through this program channel in seconds. If the value of this field is 0x0000, it means that the live broadcast starts immediately or has already started. This value can be used when returning to a live broadcast program of a broadcast channel from an alternative package Internet live broadcast service. If the value of this field is 0xFFFF, it indicates that the time until live broadcast starts through this channel is unknown. This value is used when an event scheduled to be broadcast live through this program channel is watched through the Internet live broadcast service, but is not known when the live broadcast will start through this program channel.

MMT_general_location_info() : This is general location reference information defined in MMT, and its contents are shown in <Table 5>.

text_length : An 8-bit field indicating the number of text_bytes to appear next. A value of 0x00 indicates that there is no character string describing the replacement program.

text_byte : As bytes constituting a character string describing the replacement program, they do not include a null byte at the end.

extension_descriptor() : Descriptors corresponding to an option to deliver additional information. The 8-bit tag value that distinguishes the type is uniquely distinguished within alternate_package_descriptor, and is the first byte of this descriptor. The 8-bit value indicating the length of the descriptor follows immediately.

The alternate_program_descriptor is the same as the contents of the alternate_package_descriptor whose sizes are 16 bits, except that the sizes of descriptor_tag and descriptor_lenth are 8 bytes, and the descriptor_tag value is allocated as the MPEG-2 descriptor tag value. That is, alternate_program_descriptor is a transformation of alternate_package_descriptor into MPEG-2 descriptor.

The alternate_program_descriptor is used for a similar purpose to the alternate_package_descriptor, but puts it in the descriptor syntax loop following program_info_length of MPEG-2 PMT. In the case of MPEG-2 TS based MPEG-DASH, this descriptor may be directly put in the PMT.

language_descriptor is used to specify the language for assets that need to specify the language to be used. For example, it is necessary to specify in which language the assets corresponding to audio, subtitles, and screen commentary broadcasts are produced. The language_descriptor may be included in the PPT_descriptor syntax loop or asset_descriptor syntax loop of PPT, and the SMT_S_descriptor syntax loop or asset_descriptor syntax loop in SMT-S. When this descriptor enters the PPT_descriptor or SMT_S_descriptor syntax loop, the language of all assets in the package is specified by this descriptor. When this descriptor enters the asset_descriptor syntax loop, the language of the asset is specified by this descriptor. The content of the descriptor applied to the asset takes precedence over the content of the descriptor applied to all assets in the package. In this specification, for convenience of description, the syntax of language_descriptor is shown in <Table 21>, and the meaning of each field is included below it.

descriptor_tag : A unique value representing the kind of this descriptor

descriptor_length : Number of bytes from after this field to the last byte of this descriptor

ISO_639_language_code : 3-byte language identifier according to ISO 639 standard

The clock_reference_descriptor is used to inform the receiver of the relationship between the encoder clock for media synchronization and the MMT system clock. In MMT, UTC in the NTP (Network Time Protocol) format is used as the system clock, and the asset encoder clock allows different clocks to be used for each asset. The clock used by the asset encoder is identified by clock_reference_id.

The clock_reference_descriptor must be delivered periodically in a period within 100 ms, and is delivered as a separate asset. In this specification, for convenience of description, the syntax of clock_reference_descriptor is shown in <Table 22>, and the meaning of each field is included below it.

descriptor_tag : A unique value representing the kind of this descriptor

descriptor_length : Number of bytes from after this field to the last byte of this descriptor

clock_reference_id : The identifier of the clock used by the asset encoder

encoder_clock_sample : Asset clock sample value corresponding to system_clock_time shown below

encoder_clock_sample : The MMT system clock time corresponding to the encoder_clock_sample shown above, which is a UTC time value in NTP format.

5 shows an S1 signaling structure according to another embodiment of the present invention.

The six S1 layer messages according to another embodiment of the present invention are summarized as follows.

(1) Messages for Information on Tables and Notice (ITN) : These messages carry the ITN Table 505 and additionally other tables that can be used for high-speed access to the package. The role of ITN is similar to MPEG-2, but has other MMT-specific functions. The ITN table contains pool information for all other S1 tables. In addition, the ITN has information on receiving notifications. Typical examples of notifications are emergency alerts, emergency notifications, and the like.

(2) MMT composition information (MMT Composition Information: MCI) message : This message transmits the MMT CI. It carries full CI as well as layered CIs.

(3) Message to Clock Reference Descriptors (CRD) : These messages are between the MMT system clock (i.e., NTP clock) and any other clock (e.g., MPEG-2 or MPEG-4 clock). It transmits clock reference information to be used for mapping.

(4) Messages for Security Information : These messages transmit security information used for MMT content protection. The security system is DRM, downloadable DRM and downloadable condition evaluation system (D-CAS) information.

(5) Messages for MMT Package Table (MPT) : These messages transmit MMT Package Table (MPT). The complete or layer-0 MPT corresponds to the MMT package. This includes a globally unique identifier of the package, the location of the MMT synthesis information (MCI), and a complete or partial (possibly, a layered MPT used) list of MMT assets belonging to the MMT package. In addition, it includes package type, package name, short description of the package, parallel rating, language of audio, language of text, target user profile, required device capabilities, package policies such as recording permission and high-speed play permission, and the like. The role of MPT is similar to MPEG2 PMT, but has more functions for MMT purposes.

(6) Messages for Device Capability Information Table (DCIT): This message transmits a device capability information table (DCIT). The device capability information provides a request for MPEG media content consumption and/or a recommended device capability.

In addition, the following three descriptors are defined according to another embodiment of the present invention.

(1) Language descriptor

(2) Clock reference descriptor

(3) D-CAS descriptor D-CAS descriptor

Hereinafter, syntax and semantics of an S1 layer message, table, and descriptor according to another embodiment of the present invention will be defined with reference to FIG. 5.

1. Syntax and semantics of S1 layer messages, tables, and descriptors

1.1 Information tables and messages for information in notifications (ITN)

This message carries the ITN table 505. The role of ITN is similar to that of MPEG-2 PAT, but has other MMT-specific functions. The ITN table contains pool information for all other S1 tables.

In addition, the ITN has information on receiving notifications. Typical examples of notifications are emergency alerts, emergency notifications, and the like.

The ITN message, that is, the message including the ITN, may additionally include one or more MMT package tables (MPT) corresponding to the MMT package. The MPT includes a globally unique identifier of the package, the location of the MMT synthesis information (MCI), and a complete or partial (possibly, a layered MPT used) list of MMT assets belonging to the MMT package. In addition, MP[T includes package type, package name, short description of package, parallel rating, language of audio, language of text, target user profile, required device capability, package policy such as recording permission and high-speed play permission, etc. Includes.

If the ITN message contains only one MPT, the media delivery service provides only one package to the user at any fixed time instant. If the ITN table contains multiple MPTs with any redundancy in the timeline, the media delivery service provides the user with multiple packages at any fixed time instant. If the ITN table does not have time overlap and the corresponding packages include multiple MPTs associated with the same logical channel, the media delivery service provides multiple packages to the user in sequential time order.

S-layer messages with MessageID=0x00 MUST contain an ITN table. In addition, the payload id of the asset path in the IP application data flow transmitting the S-layer message having MessageID=0x00 is fixed to '0x0000'. The receiver must read and parse the ITN message before reading any other messages.

ITN messages are typically transmitted periodically in a very short period, for example 500 ms, in a broadcast environment to ensure a short power-up delay or low zapping time.

1.1 1 ITN message syntax and semantics

The syntax of the ITN message is defined in Table 23, and the semantics of its syntax elements are provided in Table 23 below. The syntax definition method is based on the method of the MPEG-2 system standard (ISO/IEC 13818-1). The indication of no loop count in the "Value" column can be deduced from the length of the table. The same rules apply to other tables in this specification.

message_id : This indicates the type of S layer message. The length of this field is 8 bits. The ITN message has a fixed message_id with a value of 0x00.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted over a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S1 layer message. The length of this field is 16 bits. This indicates the length of the ITN message counted in bytes starting from the next field to the last byte of the ITN message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time at the NPT of ITN message transmission.

retransmission_period : This indicates the retransmission time of the ITN message. The unit of retransmission_period is 10ms.

number_of_tables : This represents the number of tables included in this ITN message.

table_id : This represents the table identifier of the table included in this ITN message. This is a copy of the table_id field in the table included in the payload of this ITN message.

table_version : This indicates the version of the table contained in this ITN message. This is a copy of the version field in the table contained in the payload of this ITN message.

table_length : This indicates the length of the table included in this ITN message. This is a copy of the length field in the table contained in the payload of this ITN message. The actual length of the table is the length of the table + 4.

table() : This represents an S-layer table. Tables in the payload appear in the same order as table_Id in the extended field.

1.1. 2 ITN table syntax and semantics

The syntax of the ITN table is defined in Table 24, and the semantics of its syntax elements are provided below Table 24.

table_id: The table identifier of the ITN table.

version: The version of the ITN table. As soon as a newer version is received, it overrides the old version.

length: The length of the ITN table counted in bytes starting from the next field to the last byte of the ITN table. The value '0' is never used for these fields.

method_flag: This indicates how to receive notifications. If this flag is '0', the notification is delivered by IP broadcast delivery. If this flag is '1', the notification is delivered through the interactive channel. For IP broadcast delivery, an IP address and IP port number are provided. For delivery over the interactive channel, a URL is provided through which the client can poll the notification through the interactive channel.

MMT_general_location_info(): This is general location reference information defined in Table 25 in Section 1.1.3. The actual location depends on the syntax element location_type in MMT_general_location_info().

MMT_general_location_info() for IP_broadcast_delivery: For IP_broadcast_delivery, only location_type = 0x14 and 0x15 are allowed.

MMT_general_location_info() for poll_URL: For poll_URL, only location_type = 0x0E is allowed.

poll_period: While polling the notification, it is expected that the client or receiver polls the notification URL, poll_URL, every poll_period seconds.

number_of_tables: This indicates the number of information tables for which the information is provided in this ITN table.

information_table_id: The identifier of the information table for which the information is provided in this ITN table. ITN's table_id never appears here.

information_table_version: The version of the information table for which the information is provided in this ITN table.

package_path_number: The identifier for the logical channel to which the information table belongs. The broadcaster uniquely assigns an identifier to a logical channel within a physical channel. The value '0' has a special use and is not used as an identifier. If this field is '0', the information table is channel independent, that is, the information table has service-wide information.

MMT_general_location_info() for location: The address at which the client obtains an information table. Only location_type = 0x0F~0x13 is allowed.

second_location_flag: If this flag is set, an alternative address is provided for the client to obtain the information table.

table_filter_code_flag: When this flag is set, one or more table filter codes are provided. The table filter code specifies the criteria for grouping tables. If several criteria for grouping exist at the same time, all grouping criteria are applied to the information table.

MMT_general_location_info() for second_location: an alternative address from which the client obtains an information table. Only 0x0F~0x13 are allowed.

number_of_table_filter_codes: Number of table filter codes for information tables.

language_for_all_table_filter_codes: The language of all immediately following table_filter_codes. The language code is a 3-byte language identifier defined in the ISO 639 standard.

table_filter_code_language_flag: If this flag is '1', the language for the subsequent table_filter_code is specified separately and overrides the language provided by language_for_all_table_filter_codes. The language code is a 3-byte language identifier defined in the ISO 639 standard.

table_fileter_code_language: The language of the immediately following table_filter_code. The language code is a 3-byte language identifier defined in the ISO 639 standard.

table_fileter_code_length: The length in bytes of table_filter_code.

table_fileter_code_byte: byte in table_filter_code.

private_extension_flag: If this flag is '1', there is a private extension.

private_extension(): A group of syntax elements that act as a container for ownership or application specific extensions.

1.1.3 MMT_general_location_info() syntax element group

The MMT_general_location_info() syntax element group is used to provide location information. The syntax of MMT_general_location_info() is defined in Table 25, and the semantics of its syntax elements are provided below Table 25.

location_type: This field represents the type of location information as defined in Table 26.

payload_id : Unique asset path identifier within the IP application data flow.

ipv4_src_addr : IP version 4 source address of the IP application data flow.

ipv4_dst_addr : IP version 4 destination address of the IP application data flow.

dst_port : The destination port number for IP application data flow.

ipv6_src_addr : IP version 6 source address of the IP application data flow.

ipv6_dst_addr : IP version 6 destination address of the IP application data flow.

network_id : A broadcast network identifier for transmitting MPEG-2 TS.

MPEG_2_transport_stream_id : MPEG-2 TS identifier.

MPEG_2_PID : PID of MPEG-2 TS packet.

prefix_index : The index for the prefix defined before this syntax element group. If this field is 0xFF, the prefix is not used.

URL_length : The length of the URL in bytes. The terminating null (0x00) should not be counted.

URL_byte : byte data in URL. The terminating null (0x00) must not be included.

byte_offset : The byte offset from the first byte of the file.

length: The length in bytes.

message_id : S layer message identifier.

ipv4_addr : IP version 4 address of the IP application data flow.

ipv6_addr : IP version 6 address of the IP application data flow.

1.2.1 MMT synthesis information (CI) message

MMT synthesis information (CI) is delivered by a CI message for out-of-band signaling. CI messages can carry complete CIs or layered CIs. When a layered CI is delivered, it is highly recommended to send the layer-0 CI by ITN message to reduce the time required for package consumption in a broadcast scenario. When a layer-0 CI is transmitted in an INT message, such as 510, the CI must be encapsulated in the MCI (MMT synthesis information) table before being included in the INT message.

When a layered CI mechanism is used, layer-N CIs (where N is not 0) are generally transmitted in CI messages with changed repetition periods and different message identifiers.

1.2.1 CI message syntax and semantics

The syntax of the CI message is defined in Table 27, and the semantics of its syntax elements are provided below Table 27.

message_id : This indicates the type of S layer message. The length of this field is 8 bits. The S layer message must have a separate message_id when CI is transmitted from a separate CI layer for a separate package.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted through a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S layer message. The length of this field is 16 bits. This indicates the length of the CI message counted in bytes starting from the next field to the last byte of the CI message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time in the NPT of sending the CI message.

retransmission_period : This indicates the retransmission time of this CI message. The unit of retransmission_period is 10ms.

CI_byte : byte in CI.

1.2.2 MCI Table Syntax and Semantics

The syntax of the MCI table is defined in Table 28, and the semantics of its syntax elements are provided below Table 28. The MCI table should be used only for complete CIs or layer-0 CIs.

table_id : Table identifier of the MCI table.

version : The version of the MCI table. As soon as a newer version is received, it overrides the old version.

length : The length of the MCI table counted in bytes starting from the next field to the last byte of the MCI table. The value '0' is never used for these fields.

CI_byte : byte in CI.

1.3 Message to the clock reference descriptor (CRD)

The clock reference descriptor defined in 1.7.2 is carried in the CRD message. One CRD message may contain multiple clock reference descriptors.

When clock reference descriptors, such as 520, are transmitted within an INT message, they must be encapsulated in a table structure called a CRD table.

1.3.1 CRD message syntax and semantics

The syntax of the CRD message is defined in Table 29, and the semantics of its elements are provided below Table 29.

message_id : This indicates the type of S layer message. The length of this field is 8 bits.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted through a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S layer message. The length of this field is 16 bits. This indicates the length of the CI message counted in bytes starting from the next field to the last byte of the CI message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time at the NPT of CRD message transmission.

retransmission_period : This indicates the retransmission time of this CRD message. The unit of retransmission_period is 10ms.

clock_reference_descriptor() : This is defined in 1.7.2.

1.3.2 CRD Table Syntax and Semantics

The syntax of the CRD table is defined in Table 30, and the semantics of its syntax elements are provided below Table 30. The MCI table should be used only for complete CIs or layer-0 CIs.

table_id : The identifier of the CRD table.

version : The version of the CRD table. As soon as a newer version is received, it overrides the old version.

length : The length of the CRD table counted in bytes starting from the next field to the last byte of the CRD table. The value '0' is never used for these fields.

clock_reference_descriptor() : This is defined in 1.7.2.

1.4 Message about security

Security information is conveyed in a security message or ITN message. When security information is transmitted within an ITN message, such as 525, it must be encapsulated before being included in the ITN message.

1.4.1 Secure Message Syntax and Semantics

The syntax of the security message is defined in Table 31, and the semantics of its syntax elements are provided below Table 31.

message_id : This indicates the type of S layer message. The length of this field is 8 bits.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted through a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S layer message. The length of this field is 16 bits. This indicates the length of the CI message counted in bytes starting from the next field to the last byte of the CI message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time at the NPT of sending a secure message.

retransmission_period : This indicates the retransmission time of this secure message. The unit of retransmission_period is 10ms.

Security_descriptor() : This is defined in 1.7.3.

1.4.2 Security Table Syntax and Semantics

The syntax of the security table is defined in Table 32, and the semantics of its syntax elements are provided below Table 32.

table_id : The identifier of the security table.

version : The version of the security table. As soon as a newer version is received, it overrides the old version.

length : The length of the security table counted in bytes starting from the next field to the last byte of the security table. The value '0' is never used for these fields.

security_descriptor() : This is defined in 1.7.2.

Message for 1.5 MPT (MMT Package Table)

Referring to FIG. 5, an MMT package table (MPT) conveys all information on a single package. The S layer message for transmitting the MPT is referred to as "MPT message". The MPT may be included in an ITN message having different tables, such as 515, or may be transmitted in a separate MPT message.

For layered delivery of a package with layered CI, the MPT can be partitioned into multiple layered MPTs. The layer-0 MPT is the default MPT, and if layered delivery is not used, only the layer-0 MPT is delivered. In the latter case, the layer-0 MPT is a complete MPT. MPTs in different layers should have different table identifiers (table_ids). In this standard, 8 different values for the MPT tabe-id were assigned to allow up to 8 MPT layers. The smaller the value of the MPT table_id, the closer the MPT layer is to the base MPT.

In the case where a layered MPT is used in the ITN message to reduce the package acquisition time in a broadcast scenario, it is highly recommended to transmit a complete MPT or layer-0 MPT.

1.5.1 MPT Message Syntax and Semantics

The syntax of the MPT message is defined in Table 33, and the semantics of its syntax elements are provided below Table 33. The MPT message transmits only one complete MPT or layer-N MPT when MPT layering is used.

message_id : This indicates the type of S layer message. The length of this field is 8 bits.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted through a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S layer message. The length of this field is 16 bits. This indicates the length of the MPT message counted in bytes starting from the next field to the last byte of the MPT message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time at the NPT of MPT message transmission.

retransmission_period : This indicates the retransmission time of this MPT message. The unit of retransmission_period is 10ms. When layered MPTs are used, the retransmission_period of the higher layer MPT is generally longer than the retransmission_period of the MPT layer below the higher layer MPT.

MMT_package_table() : This is defined in 1.5.2.

1.5.2 MPT Syntax and Semantics

The syntax of MPT() is defined in Table 34, and the semantics of its syntax elements are provided below Table 34.

table_id: Table identifier of MPT. MPTs in different layers should have different table identifiers (table_ids). For MPT table_id, 8 different values are assigned. Among the eight MPT table_ids, the table_id for the perfect MPT or the layer-0 MPT is the smallest when layered MPTs are used. For the remaining MPT table_ids, a smaller value means a lower layer MPT.

version: The version of the MPT. As soon as a newer version is received, it overrides the old version.

length: The length of the MPT counted in bytes starting from the next field to the last byte of the ITN table. The value '0' is never used for these fields.

MMT_package_id: Globally unique identifier of the MMT package

MPT_descriptors_length: The length of the descriptor syntax loop. This length is counted from the next field to the end of the descriptor syntax loop. Several descriptors can be inserted into this syntax loop.

MPT_descriptors_byte: 1 byte in descriptor loop.

package_type: This indicates the type of package. The allowable values are in Table 35.

package_name : If possible, the name of the package in multiple languages. The language code is a 3-byte language identifier defined in the ISO 639 standard. The first language in the list is the default.

package_description : If possible, the syntax description language code of a package in multiple languages is a 3-byte language identifier defined in the ISO 639 standard. The first language in the list is the default.

audio_languages : The audio language(s) used in the package. The language code is a 3-byte language identifier defined in the ISO 639 standard. The first language in the list is the default.

text_languages : The text language(s) used in the package. The language code is a 3-byte language identifier defined in the ISO 639 standard. The first language in the list is the default.

target_user_profiles : Profile(s) of users targeting the package

required_device_capability_profiles : Profile(s) of the required device capabilities for package consumption.

parental_guidance_flag : If this flag is '1', it can be made clear from the rating information (its delivery method is not currently specified in this standard) that the receiver is allowed to indicate content for what is set by the viewer for child protection. It shouldn't provide what is decoded until there is. If this flag is '0', the receiver just provides what is decoded from this package without checking the rating.

recording_flag : If this flag is '1', the receiver can store this package in its internal storage for later use.

fast_play_flag : If this flag is '1', the receiver causes the viewer to command the fast play of this package.

clock_reference_flag : If this flag is '0', clock_reference_id is not provided and by default the MMT system clock is an NTP clock, that is, the time base of all assets in this package is an NTP clock. If this flag is '1', the clock_reference_id field is included next.

protection_scheme_id_flag : If this flag is '1', the protection_scheme_id field is included next.

clock_reference_id : Clock reference identifier. This field is used to reference the clock passed by clock_reference_descriptor() as the default time base for all assets in this package. A value of 0 is not allowed for these fields. There are two placeholders for the clock reference identifier in the NPT syntax. One (this field) applies to all assets in this package, while the other applies only to the asset entry in the syntax loop. When both fields are included in the MPT syntax, the latter takes precedence.

timescale_flag : If this flag is '1', the timescale field is included next.

timescale : The unit of time for all timestamps used for all assets in these packages expressed in units of 1 second. The default value is 90,000. There are two placeholders for the timescale field in the MPT syntax. One (this field) applies to all assets in this package, while the other applies only to the asset entry in the syntax loop. When both fields are included in the MPT syntax, the latter takes precedence.

protection_scheme_id : This field represents the protection scheme used for all assets in this package. There are two placeholders for the protection scheme identifier field in the MPT syntax. One (this field) applies to all assets in this package, while the other applies only to the asset entry in the syntax loop. When both fields are included in the MPT syntax, the latter takes precedence. The value of this field is one of the DCAS_types specified by the D-CAS descriptors in 3.7.3.

protection_scheme_id_flag : If this flag is '1', the protection_scheme_id field is included next.

MMT_general_location_info() for the CI location : General location reference information for the MMT defined in 1.1.3. Only location_type = 0x0F~0x13 is allowed for the CI location.

number_of_assets : The number of assets in this MPT.

asset_type : The type of assets. This field is similar to steam_type defined in MPEG-2 PMT, but is an extension of it.

asset_id : Asset identifier. In CI, asset_id is used to refer to an asset. The asset_id defined in the CI is globally unique. These fields are short aliases for globally unique asset identifiers. Aliasing is automatically performed by mapping the order of appearance of assets in the list of assets (LoA) in the CI. When CI layering is used, aliasing is performed within the ordered concatenation of all LoAs from layer 0 to layer N. In the asset information syntax in MPT, the asset_id alias must appear incrementally.

asset_clock_reference_flag : If this flag is '1', the asset_clock_reference_id field is included in the following syntax.

asset_clock_reference_id : The clock reference identifier for the asset. This field is used to refer to the clock passed by clock_reference_descriptor() as the asset's time base. If this field is '0', the NTP clock is used for the asset. If this field is not '0', the value of this field is one of the clock_reference_id values provided by the clock reference descriptors.

asset_timescale_flag : If this value is '1', the asset_timescale field is included in the following syntax.

asset_timescale : A unit of time for all timestamps used for an asset expressed in multiple units from 1 second. The default value is 90,000.

asset_protected_flag : If this flag is '1', this asset is protected.

asset_protection_scheme_id_flag : If this flag is '1', the asset_protection_scheme_id field is included in the following syntax.

MMT_general_location_info() for the asset location : General location reference information for MMT defined in Table 3 in 1.1.3. Only location_type = 0x03, 0x05, and 0x07 to 0x0D are allowed for the asset location.

asset_descriptors_length : The number of bytes counted from the next field to the end of the asset descriptor syntax loop

asset_descriptors_byte : The bytes in the asset descriptor.

Message for Device Capability Information Table (DCIT)

DCIT provides device capability information.

When DCITs, such as 530, are transmitted in an INT message, they must be encapsulated in a table structure called a DCIT table.

1.6.1 DCIT message syntax and semantics

The syntax of the DCIT message is defined in Table 36, and the semantics of its syntax elements are provided below Table 36.

message_id : This indicates the type of S layer message. The length of this field is 8 bits.

version : This represents the version of the S layer message. The MMT client may check whether the received S layer message is new. In particular, this field is useful when an S-layer message is repeatedly transmitted through a broadcasting network. The length of this field is 8 bits.

length : This indicates the length of the S layer message. The length of this field is 16 bits. This indicates the length of the MPT message counted in bytes starting from the next field to the last byte of the DCIT message. The value '0' is never used for these fields.

start_time_flag : If this flag is '1', an additional syntax element start_time is used.

start_time : This represents the start time at the NPT of DCIT message transmission.

retransmission_period : This indicates the retransmission time of this DCIT message. The unit of retransmission_period is 10ms. When layered MPTs are used, the retransmission_period of the higher layer MPT is generally longer than the retransmission_period of the MPT layer below the higher layer MPT.

MMT_package_table() : This is defined in 1.5.2.

DCIT() : This is defined in 1.6.2.

1.6.2 DCIT Syntax and Semantics

The syntax and semantics of DCIT are defined in Table 37.

1.7. Descriptors

Descriptors related to S-tier tables are defined here.

1.7.1 Language descriptor

Language descriptors are used to specify media assets such as audio, commentary channels, subtitles, etc. The language descriptor may be included in an MPT descriptor syntax loop or an asset descriptor syntax loop in MPT. When a language descriptor is included in the MPT descriptor syntax loop, it specifies the language of all assets in the package. When a language descriptor is included in the asset descriptor syntax loop in MPT, it specifies the language of the asset. The language descriptor included in the asset descriptor syntax loop in MPT has priority over the language descriptor included in the MPT descriptor syntax loop in MPT.

The syntax of language_descriptor() is defined in Table 38, and the semantics of its syntax elements are provided below Table 38.

descriptor_tag : Tag value indicating the type of descriptor.

descriptor_length : The length in bytes counted from the next byte after this field to the last byte of the descriptor.

ISO_639_language_code : 3-byte ISO 639 language identifier.

1.7.2 Clock reference descriptor

The clock reference descriptor is used to specify the relationship between the encoder clock for media synchronization and the MMT system clock. UTC in Network Time Protocol (NTP) format is used as the MMT system clock time. MMT allows different clocks to be used for different assets. The clock used by the asset encoder is specified by clock_reference_id.

Clock_reference_descriptors should be transmitted periodically in a clock reference message having a short period, for example, 100 ms.

The syntax of clock_reference_descriptor() is defined in Table 39, and the semantics of its syntax elements are provided below Table 39.

descriptor_tag : A tag value indicating the type of descriptor.

descriptor_length : The length in bytes counted from the next byte after this field to the last byte of the descriptor.

clock_reference_id : The identifier of the media clock used by the asset encoder. The value '0' is reserved for other purposes and is not used for clock_reference_id.

encoder_clock_sample : The sampled value of the media clock used by the asset encoder corresponding to the MMT_system_clock_time below.

MMT_system_clock_time : UTC time value in NTP format corresponding to the preceding encoder_clock_sample.

1.7.3 Security descriptor

The security descriptor is used to specify a security system that can be used to protect an MMT asset or package.

Securtiy_descriptor should be transmitted periodically in a security message or an ITN message.

The syntax of security_descriptor() is defined in Table 40, and the semantics of its syntax elements are provided below Table 40.

descriptor_tag : Tag value indicating the type of descriptor.

descriptor_length : The length in bytes counted from the next byte after this field to the last byte of the descriptor.

Security_type : Type of security solution. It represents a solution of access control, digital rights management, downloadable CAS or downloadable DRM.

Solution : This indicates which security solution is used for access control, DRM, DCAS or DDRM.

Access_control_server_address : The address of the access control security solution server to which the client is authenticated and authorized.

DRM_server_address : The address of the DRM solution server to which the client is authenticated and authorized.

DCAS_server_address : The address of the DCAS server to which the client can download DCAS SW after authentication and authorization.

DDRM_server_address : The address of the DDRM server from which the client can download DDRM SW after authentication and authorization.

6 and 7 are flowcharts illustrating a multimedia reception operation in a receiver according to an embodiment of the present invention.

Referring to FIG. 6, first, in step 615, the receiver finds an S1 message transmitted on a current channel. The S1 message is a message for managing all functions required for consumption of MMT assets and MMT items.

The receiver determines whether it is an ITN message included in the S1 message found based on the message ID in step 617. If the message is other than the ITN message, it is determined in step 627 whether the other message has been updated. If it is the updated other message, the receiver stores the updated other message and version information of the updated other message in the memory of the receiver in step 629.

Meanwhile, as a result of the determination in step 617, in the case of the ITN message, the receiver determines whether the ITN message included in the S1 message found in step 619 based on the version information has been updated. If updated, the receiver determines in step 621 whether at least one table (i) in the ITN message has been updated. If updated, the receiver stores at least one table updated in step 623 and its version information in the memory of the receiver.

Thereafter, the receiver checks all tables in step 625.

As a result of the inspection, the receiver determines whether the CI layer 0 has been updated in step 631 described in FIG. 7.

If updated, the receiver sets CI layer 0 as an integrated CI in step 633.

In step 635, the receiver determines whether the version of CI layer i is the same as the version of CI layer 0.

If they are the same, the receiver combines the CI layer i with the integrated CI in step 637. In step 639, the receiver determines whether all CI layers have been checked. When all checks are completed, the receiver transmits the integrated CI to the CI analyzer in step 641.

Meanwhile, the receiver determines whether the MPT layer 0 has been updated in step 643.

If updated, the receiver sets MPT layer 0 as an integrated MPT in step 645.

In step 647, the receiver determines whether the version of the MPT layer i is the same as the version of the MPT layer 0.

If they are the same, the receiver combines the MPT layer i with the integrated MPT in step 649. In step 651, the receiver determines whether all MPT layers have been checked. When all checks are completed, the receiver searches for an asset in the package using asset references in the integrated MPT in step 653, and transmits the found asset to a corresponding asset decoder or asset handler.

8 is a block diagram of a transmission device according to an embodiment of the present invention.

As an example of the transmission device, the service providing server includes a service data providing unit 801, a package generating unit 803, and a transmitting unit 805. Although not shown in the drawings, it is natural that a control unit capable of controlling the components of the transmission device is provided in order to perform the operation of the present invention.

The service data providing unit 801 has all service sources.

The package generation unit 803 generates a package using the table described with reference to FIGS. 3 and 5.

The transmission unit 805 transmits the generated package to the terminal.

In addition, the transmission unit 805 may transmit the generated package to the terminal using a network having two different physical characteristics, such as a broadcasting network and a broadband network.

9 is a block diagram of a receiving device according to an embodiment of the present invention.

The receiving device, for example, may be a terminal, but is not limited thereto.

The receiving device includes a receiving unit 901, a package analyzing unit 903, and a decoder/reproducing unit 905. Although not shown in the drawings, it is natural that a control unit capable of controlling components of the receiving device is provided in order to perform the operation of the present invention.

The receiving unit 901 receives a package generated by using the table described with reference to FIGS. 3 and 5 according to an embodiment of the present invention.

The package analysis unit 903 analyzes the received package component.

The decoder/playback unit 905 decodes and reproduces content based on the analyzed package component.

In addition, although not shown in the drawings, data may be recorded, stored, and reproduced according to the package generated according to the embodiment of the present invention. Includes MMT assets, Configuration information, Composition information, Transport Characteristics, Package Identification Information, Asset list Information, Rights Management Information, and Transport Timeline Information in one package in a storage medium (e.g., CD, DVD, BD, USB, etc.) It is stored so that the content can be played by analyzing the package components during playback. In the case of storing and playing back through a storage medium, the URL can be more easily stored and played back by replacing the URL with storage location information (eg, memory address) in the description of the embodiment.

The above-described embodiments will be understood as examples of the present invention. All features described in connection with any one of the above embodiments may be used alone or in combination with other described features, and used in combination with one or more features of other embodiments among the embodiments. It will be appreciated that the embodiments may be used in combination with other embodiments. While the present invention has been shown and described with reference to specific embodiments, those skilled in the art may make various changes in form and detail without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. You will understand that it can be done.

Claims (2)

As a method for receiving multimedia content,
Receiving a control message for providing information on a package related to the multimedia content; And
Processing the received control message,
The control message is:
A control message payload including a plurality of tables;
Identification information of the control message;
Length information of the control message;
Version information of the control message; And
Includes extended information including information indicating the number of the plurality of tables and identification information for each of the plurality of tables,
The plurality of tables includes a basic table providing information on at least one package related table included in the plurality of tables,
The at least one package related table includes a first table providing information on at least one asset related to the package,
The first table includes asset type information indicating a type of an asset among the at least one asset and a clock reference flag providing information on a clock used for the asset,
Method for receiving multimedia content. The method of claim 1,
The basic table above is,
Location information providing an address for obtaining the package related table; And
Includes flag information indicating whether replacement address information providing a replacement address for obtaining the package related table is included in the basic table,
Method for receiving multimedia content.

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