KR20160005663A - MMT apparatus and method for low delay service - Google Patents

Abstract

The present invention relates to an MMT apparatus and a method thereof. According to an embodiment of the present invention, an MMT transmission entity can set the level of ADC information included in an ADC signaling message to one of the asset level, MPU level, and movie fragment level, can include packet ID information for specifying the corresponding asset in the ADC signaling message when the set ADC information level is the asset level, and can include the packet ID information for specifying the asset having the MPU and the MPU serial number information for specifying the MPU in the ADC signaling message when the set ADC information level is the MPU level. The MMT transmission entity can also include the movie fragment serial number information for specifying the corresponding movie fragment, the MPU serial number information for specifying the MPU including the movie fragment, and packet ID information for specifying the asset having the MPU in the ADC signaling message when the set ADC information level is the movie fragment level.

Description

[0001] MMT APPARATUS AND METHOD FOR LOW DELAY SERVICE [0002]

More particularly, the present invention relates to an MMT apparatus and method for a low delay service such as a streaming service. will be.

MMT (MPEG Media Transport) is a new media transmission standard technology which started development in 2010 from ISO / IEC WG11 (MPEG) system subworking group. 2. Description of the Related Art Conventional MPEG-2 systems have standardized MPEG-2 transport stream (TS) technology as a standard for packetization, synchronization, and multiplexing necessary for transmitting AV (Audio Video) contents in a broadcasting network and are now widely used. However, MPEG-2 TS is inefficient in packet transmission environments where the network is based on IP (Internet Protocol). In ISO / IEC WG 11 MPEG, the need for a new media transmission standard was recognized in consideration of the new media transmission environment and the anticipated media transmission environment, and MMT standardization was started.

MMT is a standard related to media transmission, and it defines quality of service (QoS) as well as other transmission standards. In particular, in the current MMT standard, additional standardization is being carried out in a separate document called "ISO / IEC 23008-1 AMD Additional Technologies for MMT" concerning signaling processing related to QoS.

The standardization document specifies an Asset Delivery Characteristics (ADC) signaling message as an example of a signaling process. The ADC signaling message provides the necessary QoS information for the transmission of the asset and is generated by the MMT sending entity and transmitted to the network intermediate entity and / or the MMT receiving entity via the network. Lt; / RTI > The ADC signaling message is used for packet scheduling, bandwidth conservation, resource reservation management, per-flow QoS management and MMT reception in network intermediate nodes (e.g., Media Aware Network Element (MANE), intelligent Content Delivery Network This can be useful for managing buffers in entities.

In the MMT system, in transmitting the ADC information through the ADC signaling message, the QoS control may vary depending on the characteristics of the service. For example, in the case of a relatively less sensitive service, the QoS control may be made up of a relatively large amount of data units, but in the case of services that are relatively sensitive to delay, the QoS control is also a relatively small amount of data . For this purpose, it is necessary to be able to provide ADC information for a large capacity data unit as well as for a small capacity data unit. According to the ADC signaling message defined in the current standardization document, a method for providing ADC information with various capacity data units It is difficult to perform flexible QoS management.

An object of the present invention is to provide an MMT apparatus and method for a low-latency service that enables control of QoS in units of data of various capacities.

Another problem to be solved by the present invention is to provide an MMT apparatus and method which can efficiently and effectively control QoS even in a low-delay service such as a streaming service.

According to another aspect of the present invention, there is provided an MMT apparatus for generating and transmitting an ADC signaling message, the MMT apparatus comprising: MPU level, and movie fragment level. If the level of the set ADC information is the asset level, packet ID information for specifying the asset is included in the ADC signaling message. If the level of the set ADC information is the MPU level, The MPEG signaling message includes MPU serial number information for specifying an MPU and packet ID information for specifying an asset to which the MPU belongs, and if the level of the set ADC information is a movie fragment level, a movie fragment Serial number information, the movie fragment The MPU serial number information for specifying the MPU including the MPU and the packet ID information for specifying the asset to which the MPU belongs are included in the ADC signaling message.

According to the embodiment of the present invention, in transmitting the ADC signaling message to the network intermediate entity or the MMT receiving entity, ADC information is transmitted at a data unit smaller than the MPU, for example, a movie fragment level as well as an asset level or an MPU level Lt; RTI ID = 0.0 > ADC < / RTI > Therefore, the network intermediate entity or the MMT receiving entity can control the QoS in the unit of the asset or the unit of the MPU, or control the QoS in units of a smaller date size (e.g., movie fragment).

1 is a protocol stack including each functional area of the MMT system.
2 is a conceptual diagram for explaining the configuration of the MMT package.
3 is a diagram showing the format of the ADC signaling message defined in the current standardization document.
4 is a diagram illustrating a format of an ADC signaling message according to an exemplary embodiment of the present invention.
5 is a flow chart illustrating a procedure by which an MMT transmitting entity generates an ADC signaling message when using the ADC signaling message shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The terms used in this specification are terms selected in consideration of functions in the embodiments, and the meaning of the terms may vary depending on the user, the intention or custom of the operator, and the like. Therefore, the meaning of the terms used in the following embodiments is defined according to the definition when specifically defined in this specification, and unless otherwise defined, it should be interpreted in a sense generally recognized by those skilled in the art.

1 is a protocol stack including each functional area of the MMT system.

Referring to FIG. 1, the MMT functional area includes three functions including a media processing unit (MPU) functional area, a delivery functional area, and a signaling functional area. (Functional Area).

The media processing unit functional area (MPU Functional Area) outputs the compressed multimedia data in a form similar to the logical structure and physical file format of the media data, which is the transmission and storage entity. The Delivery Functional Area handles a method for transmitting all kinds of data including media data and signaling messages. In addition, the transfer function area may include an AL-FEC function and an MMT protocol because it carries out network flow multiplexing, network packetization, and QoS control of the media transmitted through the network. The Signaling Functional Area generates information necessary for media presentation and consumption and control information for optimizing transmission quality, and transmits the control information through the MMT protocol or through a separate signaling means.

FIG. 2 is a conceptual diagram for explaining the configuration of the MMT package, showing the components of the MMT data model and the relationship between the components.

Referring to FIG. 2, a package is a set of metadata related to media contents, and is composed of at least one presentation information (PI), an asset, and an asset delivery characteristic (ADC). PI is information that explains the temporal and spatial relationship of assets. An asset is an encoded media such as an audio, a video, or a web page, and has an asset ID as an identifier. The asset includes one or more media processing units (MPUs), which can be consumed independently as ISO-BMFF type files. Two consecutive MPUs within an asset can not contain the same media sample. The ADC provides the necessary QoS information for the transmission of the asset. An asset can have only one ADC, but one ADC can be used for multiple assets.

FIG. 3 is a diagram showing the format of the ADC signaling message defined in the standardization document 'ISO / IEC 23008-1 AMD Additional Technologies for MMT' described above. In FIG. 3, a message ID field, a version field, and a length field are header information that is commonly included in the MMT signaling message. The main fields included in the ADC signaling message include an ADC_Level_flag field, an MPU_sequence_number field, a packet_id field, a QoS descriptor (qos_descriptor) field, a service class (class_of_service) field, A stream descriptor (bitstream_descriptor_vbr) field, and a fixed bit stream descriptor (bitstream_descriptor_cbr). Here, ADC_level_flag is a flag indicating whether the corresponding ADC information is an asset level or an MPU level in the asset, and the MPU serial number is a unique sequence number for distinguishing the MPU in one asset. The packet ID is a number that matches the asset ID one-to-one and matches the packets uniquely. In addition, various descriptors are common items required for QoS control and different information according to the bitstream type.

Using the ADC signaling message of the format shown in FIG. 3, the ADC_level_flag field can be used to indicate whether the corresponding ADC information is displayed at the asset level or at a specific MPU level in the asset. When the ADC_level_flag field is set to the MPU level, the MPU serial number field contains the MPU serial number indicating which MPU is for the MPU.

However, when the ADC information is transmitted through the ADC signaling message to the network intermediate entity and / or the MMT receiving entity, control of the QoS is preferably changed according to the characteristics of the service to be provided. For example, in the case of a service in which delay is relatively less sensitive, packetization and transmission are performed after all MPUs are created, and even if the QoS is controlled at the MPU level or the asset level, this is not a big problem. On the other hand, in the case of delay-sensitive services such as low-latency real-time streaming services, the MPU fragment must be packetized and transmitted before all MPUs are created. In this case, For example, a movie fragment (MOOF) unit.

However, when the ADC signaling message of the format shown in FIG. 3 is directly used, ADC information can be provided at the asset level or the MPU level, but ADC information can not be provided at a data unit having a scale smaller than the MPU level. According to this, it is impossible to control the QoS with a scale smaller than the MPU level, and there is a limit to applying the ADC signaling message shown in FIG. 3 directly to a service requiring a precise and flexible QoS control such as a low delay streaming service. Therefore, new format ADC signaling messages are needed that can provide ADC information in smaller units than the MPU.

According to the embodiment of the present invention, the MMT transmitting entity transmits the ADC information to the network intermediate entity and / or the network intermediate entity in units of data level smaller than the MPU level so as to allow flexible QoS control even in a delay sensitive MMT service, e.g., an MMT streaming service. To the MMT receiving entity. The smaller scale level indicates a unit data level that is smaller than the MPU and constitutes one MPU. This scale level may be a movie fragment (MOOF) level, where the name is arbitrary.

To this end, the embodiment of the present invention proposes a new format ADC signaling message that can replace the ADC signaling message of the format shown in FIG. More specifically, in the embodiment of the present invention, in addition to the asset and the MPU, a movie fragment is additionally set as a level of ADC information in an existing ADC signaling message (see FIG. 3). In addition, when the level of the ADC information indicates a movie fragment, movie fragment sequence number information is further included in the ADC signaling message.

4 is a diagram illustrating a format of an ADC signaling message according to an embodiment of the present invention. 4, the ADC signaling message includes a message ID field, a version field, and a length field, which are header information items commonly included in the MMT signaling message, and also include a packet ID field, The format is the same as that of the conventional ADC signaling message in that it includes a QoS descriptor (qos_descriptor) field, a service class (class_of_service) field, a variable bit stream descriptor (bitstream_descriptor_vbr) field and a fixed bit stream descriptor (bitstream_descriptor_cbr) field.

On the other hand, the ADC signaling message according to the embodiment of the present invention not only includes the ADC level indicator (ADC_Level_indicator) field but also includes only the MPU sequence number (MPU_sequence_number) field according to the value of the ADC level indicator field, And differs from the format of the existing ADC signaling message in that it includes a movie_fragment_sequence_number field. Here, the ADC level indicator field is an extension of the existing 1-bit ADC level flag (ADC_level_flag) field to a size of 2 bits and indicates whether the level of the ADC information to be transmitted is an asset level, MPU level, or MOOF level Table 2 shows an example of 2-bit information that can be used as the value of the ADC level indicator. The movie fragment serial number field is a serial number for identifying the movie fragment to which the ADC information to be transmitted is valid when the ADC level indicator indicates a movie fragment, for example, can be represented by 32 bits of information.

According to the embodiment of the present invention, the MMT transmitting entity can generate an ADC signaling message at the existing asset level or MPU level and transmit it to the network intermediate entity and / or the MMT receiving entity, It is possible to generate and transmit an ADC signaling message at a movie fragment level, which is a unit of data constituting the MPU. Therefore, according to the embodiment of the present invention, more efficient and fine QoS control is possible by transmitting the ADC information at the asset level, the MPU level and, if necessary, at the movie fragment level in the case of a delay sensitive service such as a streaming service.

5 is a flow chart illustrating a procedure by which an MMT transmitting entity generates an ADC signaling message when using the ADC signaling message shown in FIG.

Referring to FIG. 5, the MMT transmitting entity sets a value of the ADC level indicator (ADC_level_indicator) field to a predetermined value (S10). For example, the MMT transmitting entity sets the value of the ADC level indicator to '00' to indicate the asset level, or to '01' to indicate the MPU level, or to '10' to set the movie fragment level to (See Table 1). At this time, there is no particular limitation in this embodiment regarding the criterion that the MMT transmitting entity determines the value of the ADC level indicator. For example, the value may be determined based on the degree of maximum delay allowed by the provided service, The value may be determined based on the characteristics of the data, and / or the value may be determined based on the degree of quality of service provided.

According to the embodiment of the present invention, the information included in the ADC signaling message can be changed according to the value of the ADC level indicator set in step S10. More specifically, if the ADC level indicator (ADC_level_indicator) is set to '00' and the ADC information level indicates the asset (S11), the ADC signaling message includes the packet ID (packet_id) of the corresponding asset (S17) . If the ADC level indicator (ADC_level_indicator) is set to '01' and the level of the ADC information indicates the MPU (S12), the ADC signaling message includes the MPU serial number (MPU_sequence_number) indicating the specific MPU of the corresponding asset The packet ID (packet_id) of the packet is included (S14 & S17). If the value of the ADC level indicator (ADC_level_indicator) is set to '10' and the level of the ADC information indicates the movie fragment MOOF (S13), the ADC signaling message includes a specific movie fragment belonging to a specific MPU of the corresponding asset (MPU_sequence_number) of the MPU including the movie fragment, and a packet ID (packet_id) of the asset in which the MPU is included (S15, S16 & S17). The movie_fragment_sequence_number

Thereafter, common QoS descriptor information is included in the ADC signaling message (S18). The variable bit stream descriptor (bitstream_descriptor_vbr) field is set (S20) or the fixed bit stream descriptor (bitstream_descriptor_cbr) field is set in accordance with the type of the service class (class_of_service) set in step S19 (S21). The process of steps S18 to S21 is the same as the existing procedure and is not directly related to the technical concept of the present invention, so a detailed description thereof will be omitted here.

According to this method, the MMT transmitting entity transmits an ADC signaling message, that is, an ADC signaling message including different types of ADC information depending on whether a unit to provide ADC information is an asset level, an MPU level, or a movie fragment level And also transmits ADC messages generated by the network intermediate entity and / or the MMT receiving entity.

The above description is only an example of the present invention, and the technical idea of the present invention should not be interpreted as being limited by this embodiment. The technical idea of the present invention should be specified only by the invention described in the claims. Therefore, it is apparent to those skilled in the art that the above-described embodiments may be modified and embodied in various forms without departing from the technical spirit of the present invention.

Claims (1)

An MMT transmitting entity for generating and transmitting an ADC signaling message,
The level of the ADC information included in the ADC signaling message may be set to one of an asset level, an MPU level, and a movie fragment level,
If the level of the set ADC information is an asset level, packet ID information for specifying the asset is included in the ADC signaling message. If the level of the set ADC information is MPU level, MPU serial number information for specifying the MPU and MPU serial number information Includes the packet ID information for specifying the asset in the ADC signaling message, and if the level of the set ADC information is the movie fragment level, the movie fragment serial number information for specifying the movie fragment, the MPU including the movie fragment And includes packet ID information for specifying MPU serial number information for the MPU and an asset to which the MPU belongs in the ADC signaling message.

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