WO2013055149A2 - Apparatus and method for transmitting a packet and apparatus and method for receiving a packet in an mmt system - Google Patents

Abstract

The present invention relates to an apparatus and method for transmitting a packet and to an apparatus and method for receiving a packet in an MMT system. A packet transmission apparatus for transmitting a packet in an MPEG media transport (MMT) system may comprise an encapsulation unit which performs an encapsulation including the information relating to whether the time interval between composition time stamps (CTSs) of all of consecutive access units (Aus) in a media processing unit (MPU) is constant so as to encapsulate the media processing unit. Thus, the amount of timing information which may be contained within one media processing unit is reduced to increase the space practically used in data transmission, thereby improving the transmission efficiency.

Description

Packet transmission apparatus and method, and packet reception apparatus and method in MMT system

The present invention relates to a packet transmission apparatus and method, and a packet receiving apparatus and method in an MPEG Media Transport (MMT) system, and more particularly, to transmit and receive an MMT packet based on timing information of an E layer. It relates to an apparatus and a method.

Research is underway to reduce the overhead of the encapsulation layer (E-layer), which is responsible for packetization, fragmentation, synchronization, and multiplexing of media transmitted in the MMT system. With the recent demand for high quality and high speed media services, it is necessary for the current MMT system to encapsulate and send a large amount of timing information required for synchronization of media data such as pictures or slices to the receiver. It does not meet the situation.

Timing information is a transmission essential element necessary for synchronization between a transmitter and a receiver and expressing a desired picture or data at a desired time in an MMT system. However, as the timing information increases, data to be actually transmitted decreases. Therefore, a structure for efficiently providing timing information must be introduced to the MMT system.

The conventional MMT system encapsulates each timing information in the media processing unit for all access units (AU) or media fragment units (MFUs) present in the encapsulated media processing unit (MPU), thereby overwriting the encapsulated media processing unit. The head has many problems. That is, when there are a plurality of access units in the media processing unit, the composition time stamp (CTS: Composition Time Stamp) and decoding time information (DTS) of each access unit present in the media processing unit are described in full. Therefore, a large amount of timing information in the media processing unit reduces the data space that can actually be used, and also has a problem of decreasing transmission efficiency.

SUMMARY OF THE INVENTION An object of the present invention for solving the above-described problems is to consider the consumption environment of media data, and in a stable consumption environment, it is not necessary to describe all the composition time information of all the access units included in the media processing unit, and An apparatus and method for transmitting an MMT packet and a packet receiving apparatus and method capable of reducing the amount of timing information by providing only a composition time information interval value of an access unit are provided.

Another object of the present invention is to determine whether there is a time difference between the composition time information and the decoding time information of the access unit, and when there is no time difference, the amount of timing information can be reduced by encapsulating only the composition time information excluding the decoding time information. An apparatus and method for transmitting a MMT packet and a packet receiving apparatus and method are provided.

The MMT packet transmission apparatus of the present invention for achieving the above object is a device for transmitting packets in an MPEG Media Transport (MMT) system, the composition of all consecutive access units (AU) belonging to the media processing unit (MPU) It may include an encapsulation unit for generating a media processing unit by performing encapsulation including information related to whether a time interval between time information (CTS: Composition Time Stamp) is constant.

The encapsulation unit compares and determines whether the time intervals between the CTSs of all consecutive access units in the media processing unit are constant or not, and generates the time interval schedule related information, and based on the generated time interval schedule related information. A mode determination unit that determines to encapsulate in at least one of the constant CTS mode and the all-display mode; And a mode encapsulation unit that performs encapsulation based on the determined mode information.

The packet transmission apparatus may include an MMT packetizer configured to generate an MMT packet by performing packetization based on the encapsulated media processing unit; And a transmitter configured to transmit the packetized MMT packet to a receiver.

The mode determiner may determine to encapsulate all the display modes when only one access unit belongs to the media processing unit.

The mode determining unit determines to encapsulate all the display modes in an environment in which packet loss occurs, including at least one of an environment in which frame rate adaptive conversion and frame skipping occur using an application that dynamically changes the frame rate. In a stable environment where no packet loss occurs, it may be decided to encapsulate in a certain CTS mode.

In the constant CTS mode, the mode encapsulation unit encapsulates only the CTS value of the start access unit of the media processing unit and the CTS time interval value between the consecutive access units, and the CTS value related information of the remaining access units other than the start access unit is Except for encapsulation, in the all display mode, the CTS value of each of all access units in the media processing unit can be encapsulated in the media fragment header.

In the constant CTS mode, the mode encapsulation unit may encapsulate a CTS value of a start access unit in the media processing unit and a CTS time interval value between the consecutive access units into separate media processing unit headers.

In the constant CTS mode, the mode encapsulation unit may encapsulate the CTS value of the start access unit of the media processing unit into a 32-bit length value, and the CTS time interval value between the access units of the media processing unit into a 16-bit length value. Can be.

The encapsulation unit may encapsulate information including whether the CTS values and the Decoding Time Stamp (DTS) values of all the access units in the media processing unit are the same.

The encapsulation unit encapsulates all DTS values of all access units in the media processing unit in a header of a media fragment unit based on whether the CTS value and the DTS value are equal to each other, or DTS of each access unit in the media processing unit. Encapsulation can be done by deciding whether to encapsulate except values.

The encapsulation unit may encapsulate the time interval schedule related information and information on whether the CTS value and the DTS value are the same in a header of the media processing unit.

The access unit may be a media fragment unit.

MMT packet transmission method of the present invention for achieving the above object is a method for transmitting a packet in a MPEG Media Transport (MMT) system, the composition of all consecutive access units (AU) belonging to the media processing unit (MPU) The method may include an encapsulation step of generating a media processing unit by performing encapsulation including information related to whether a time interval between time information (CTS: Composition Time Stamp) is constant.

An apparatus for receiving an MMT packet of the present invention for achieving the above object is an apparatus for receiving a packet in an MPEG Media Transport (MMT) system, comprising: composition time information (CTS) of all consecutive access units (AUs) in a media processing unit; And a decapsulation unit for decapsulating a media processing unit (MPU) including information related to whether a time interval between the composition time stamps is constant.

The decapsulation unit includes: a mode determination unit determining whether a time interval between CTSs of all consecutive access units in the media processing unit is a constant constant CTS mode or a non-uniform all display mode based on the time interval schedule related information; And a mode decapsulation unit configured to decapsulate the media processing unit based on the determined mode information.

The mode decapsulation unit decapsulates only the CTS value of the start access unit of the media processing unit and the CTS time interval value between the successive access units in the constant CTS mode and is related to the CTS value of the remaining access unit other than the start access unit. Decapsulation is performed without information, and in the all display mode, all CTS values of each of all access units in the media processing unit can be decapsulated.

The decapsulation unit may decapsulate the media processing unit including information indicating whether the CTS values and the Decoding Time Stamp (DTS) values of all the access units in the media processing unit are the same.

The apparatus for receiving an MMT packet further includes a decoder which decodes the decapsulated access unit, wherein the decoder is configured to determine whether each of the access units in the media processing unit is based on whether the CTS value and the DTS value are identical. Decoding may be performed by determining a CTS value as a DTS value for the media processing unit from which the DTS value is excluded.

MMT packet reception method of the present invention for achieving the above object is a method for receiving a packet in a MPEG Media Transport (MMT) system, the composition time information (CTS :) of all consecutive access units (AU) in the media processing unit; And decapsulating the media processing unit (MPU) including information related to whether a time interval between the composition time stamps is constant.

According to the MMT packet transmission apparatus and method, and the packet reception apparatus and method of the present invention, without composing all the composition time information of the access unit included in the media processing unit, the start composition time information and the composition time information of the continuous access unit By describing only the time difference value of, and also omitting the decoding time information and encapsulating and transmitting the media processing unit to the receiving side, the amount of timing information included in one media processing unit can be reduced to substantially increase the space used for transmitting data. It is thus possible to improve the transmission efficiency.

1 is a conceptual diagram illustrating an MMT hierarchical structure;

FIG. 2 is a diagram illustrating a format of unit information (or data or packet) used for each layer of the MMT hierarchical structure of FIG. 1;

3 is a block diagram schematically showing the configuration of an MMT packet transmission apparatus according to an embodiment of the present invention;

4 is a detailed block diagram showing in detail the configuration of the encapsulation unit of the MMT packet transmission apparatus according to an embodiment of the present invention;

5A is a diagram illustrating a CTS and a DTS providing structure in the presence of a plurality of MFUs in all display modes of an MMT packet transmission apparatus according to an embodiment of the present invention;

5b is a view showing a structure of providing CTS and DTS in the presence of a single MFU in all display mode of an MMT packet transmission apparatus according to an embodiment of the present invention;

6 is a diagram illustrating a structure of providing a CTS and a DTS in a certain CTS mode of an MMT packet transmission apparatus according to an embodiment of the present invention;

7 is a view showing the configuration of a separate MPU reference header in a certain CTS mode of the MMT packet transmission apparatus according to an embodiment of the present invention;

8 is a block diagram schematically showing the configuration of an MMT packet receiving apparatus according to an embodiment of the present invention;

9 is a detailed block diagram showing in detail the configuration of a decapsulation unit of an MMT packet receiving apparatus according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating a decapsulation unit of an MMT packet receiving apparatus according to an embodiment of the present invention decapsulating all of a media processing unit in a display mode; FIG.

FIG. 11 is a view for explaining a decapsulation unit of an MMT packet receiving apparatus according to an embodiment of the present invention to decapsulate a media processing unit of a certain CTS mode; FIG.

FIG. 12 is a diagram for describing a state in which a decapsulation unit of an MMT packet receiving apparatus delivers DTS and CTS information to a decoder according to timing information included in a media processing unit according to an embodiment of the present invention.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, the meaning of the term is defined as follows.

The content component or media component is defined as a media of a single type or a subset of the media of a single type. , Video tracks, movie subtitles, or a video enhancement layer of video.

Content is defined as a set of content components, and may be, for example, a movie or a song.

A presentation is defined as an operation performed by one or more devices to allow a user to experience one content component or one service (eg, watch a movie).

A service is defined as one or more content components that are transmitted for presentation or storage.

Service information is defined as metadata describing one service, characteristics and components of the service.

An access unit (AU) is the smallest data entity and may have time information as an attribute.

If coded media data for which decoding and presentation time information is not specified is relevant, the AU is not defined.

An MMT asset is a logical data entity consisting of at least one MPU with the same MMT asset ID or a specific chunk of data with a format defined by other standards. The MMT asset is the largest data unit to which the same composition information and transmission characteristics apply.

MMT Asset Delivery Characteristics (MMT-ADC) is a description related to QoS requirements for delivering MMT assets. MMT-ADC is expressed without knowing the specific transmission environment.

MMT Composition Information (MMT CI) describes spatial and temporal relationships between MMT assets.

Media Fragment Unit (MFU) is a general container, which is independent of any particular codec, and accommodates encoded media data that can be consumed independently by a media decoder. It has information that is less than or equal to the access unit (AU) and can be used at the transport layer.

An MMT package is a collection of logically structured data and includes at least one MMT asset, MMT composition information, MMT asset asset, and descriptive information.

The MMT packet is a format of data generated or consumed by the MMT protocol.

The MMT payload format is a format for payload of an MMT package or MMT signaling message to be delivered by an MMT protocol or an internet application layer protocol (eg, RTP).

The MMT Processing Unit is a generic container that is independent of any particular media codec and holds at least one AU and information related to additional transmission and consumption. For non-temporal data, the MPU accepts a portion of data that does not fall within the AU range. MPU is encoded media data that can be processed completely and independently. In this context, processing means encapsulation or packetization into an MMT package for transmission.

Non-timed data defines all data elements that are consumed without specifying time. Non-timed data can have a time range within which the data can be executed or started.

Timed data defines data elements associated with a particular time to be decoded and presented.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

1 is a conceptual diagram illustrating an MMT hierarchical structure.

Referring to FIG. 1, the MMT layer includes an encapsulation layer, a delivery layer, and an S layer. The MMT layer operates on a transport layer.

The encapsulation layer (E-layer) may be responsible for, for example, packetization, fragmentation, synchronization, multiplexing, and the like of transmitted media.

The encapsulation functional area defines the logical structure of the format of the media content, the MMT package, and the data units to be processed by the MMT compliant entity. In order to provide the necessary information for adaptive delivery, the MMT package specifies the components that contain the media content and the relationships between them. The format of the data units is defined to encapsulate the encoded media to be stored or transmitted in the payload of the transport protocol and to be easily converted between them.

Encapsulation layer (E-layer), as shown in Figure 1, MMT E.1 Layer (MMT E.1 Layer), MMT E.2 Layer (MMT E.2 Layer) and MMT E.3 Layer (MMT) E.3 Layer).

The E.3 layer encapsulates a Media Fragment Unit (MFU) provided from the Media Codec (A) layer to create a Media Processing Unit (MPU).

Encoded media data from the upper layer is encapsulated in MFU. The type and value of the encoded media can be abstracted to allow the MFU to be generally used in a particular codec technology. This allows the lower layer to process the MFU without access to the encapsulated encoded media. The lower layer retrieves the required encoded media data from the network or storage buffer and sends it to the media decoder. The MFU has enough information media subunits to perform this operation.

The MFU may have a format, independent of any particular codec, that can carry data units that can be consumed independently in the media decoder. The MFU can be, for example, a picture or slice of the video.

One or a group of multiple MFUs that can be independently transmitted and decoded create an MPU. Non-temporal media that are independently transportable and executable also create an MPU. MPUs describe internal structures such as the arrangement and pattern of MFUs that allow for quick access and partial consumption of MFUs.

The E.2 layer encapsulates the MPUs created in the E.3 layer to generate MMT assets.

An MMT asset is a data entity made up of one or more MPUs from a single data source, and is a data unit in which composition information (CI) and transport characteristics (TC) are defined. Multiplexed by load format and transmitted by MMT protocol. MMT assets can correspond to packetized elementary streams (PES), for example video, audio, program information, MPEG-U widgets, JPEG images, MPEG 4 file format, M2TS (MPEG transport stream), etc.

The E.1 layer creates an MMT package by encapsulating the MMT asset generated in the E.2 layer.

The MMT asset is packaged with MMT composition information (MMT-CI) for later response of the same user experience together or separately with other functional areas—transmission area and signal area. The MMT package is also packaged with a transmission characteristic that selects an appropriate transmission method for each MMT asset to satisfy the haptic quality of the MMT asset.

The MMT package may be composed of one or more MMT assets together with additional information such as composition information and transport characteristics. Composition information includes information about a relationship between MMT assets, and when one content consists of a plurality of MMT packages, it indicates a relationship between a plurality of MMT packages. It may further include information. The transport characteristics may include transmission characteristic information necessary for determining a delivery condition of an MMT asset or an MMT packet, and may include, for example, a traffic description parameter and a QoS descriptor. ) May be included. The MMT package may correspond to a program of MPEG-2 TS.

The delivery layer may perform, for example, network flow multiplexing, network packetization, and QoS control of media transmitted through a network.

The delivery functional area defines the application layer protocol and format of the payload. The application layer protocol in the present invention provides enhanced features for the delivery of MMT packages as compared to conventional application layer protocols for the transmission of multimedia including multiplexing. The payload format is defined to carry coded media data regardless of the media type or encoding method.

The transport layer (D-layer), as shown in Figure 1, MMT D.1 Layer (MMT D.1 Layer), MMT D.2 Layer (MMT D.2 Layer) and MMT D.3 Layer (MMT) D.3 Layer).

The D.1 layer receives the MMT package generated in the E.1 layer and generates an MMT payload format. The MMT payload format is a payload format for carrying MMT assets and for transmitting information for consumption by the MMT application protocol or other existing application transport protocol such as RTP. The MMT payload may include a fragment of the MFU along with information such as AL-FEC.

The D.2 layer receives the MMT payload format generated in the D.1 layer and generates an MMT transport packet or an MMT packet. The MMT transport packet or MMT packet is a data format used in an application transport protocol for MMT.

D.3 layer (D.3-layer) supports QoS by providing the function of exchanging information between layers by cross-layer design. For example, the D.3 layer may perform QoS control using QoS parameters of the MAC / PHY layer.

The S layer performs a signaling function. For example, signaling functions for session initialization / control / management of transmitted media, server-based and / or client-based trick modes, service discovery, synchronization, etc. Can be done.

The signaling functional area defines the format of the message that manages the delivery and consumption of the MMT package. The message for consumption management is used to transmit the structure of the MMT package, and the message for delivery management is used to transmit the structure of the payload format and the configuration of the protocol.

As illustrated in FIG. 1, the S layer may include an MMT S.1 layer and an MMT S.2 layer.

S.1 layer includes service discovery, media session initialization / termination of media, media session presentation / control of media, delivery (D) layer and encapsulation (E). The interface function with the layer can be performed. The S.1 layer may define the format of control messages between applications for media presentation session management.

The S.2 layer is responsible for flow control, delivery session management, delivery session monitoring, error control, and hybrid network synchronization control. It is possible to define the format of the control message exchanged between delivery end-points of the D-layer.

The S.2 layer supports delivery session establishment and release, delivery session monitoring, flow control, error control, resource scheduling for established delivery sessions, and synchronization in a complex delivery environment to support the behavior of the delivery layer. Signaling for adaptive delivery, and signaling for adaptive delivery. Required signaling may be provided between a sender and a receiver. That is, the S.2 layer may provide signaling required between the sender and the receiver in order to support the operation of the transport layer as described above. In addition, the S.2 layer may be responsible for interfacing with the transport layer and the encapsulation layer.

FIG. 2 illustrates a format of unit information (or data or packet) used for each layer of the MMT hierarchical structure of FIG. 1.

The media fragment unit (MFU) 130 may include coded media fragment data 132 and a media fragment unit header (MFUH) 134. The media fragment unit 130 has a general container format independent of a specific codec and may carry the smallest data unit that can be consumed independently in a media decoder. The MFUH 134 may include additional information such as media characteristics-for example, loss-tolerance. MFU) 130 may be, for example, a picture or slice of a video.

The Media Fragment Unit (MFU) may define a format that encapsulates a portion of the AU in the transport layer to perform adaptive transmission in the range of the MFU. The MFU may be used to transmit certain types of encoded media so that portions of the AU can be independently decoded or discarded.

The MFU has an identifier for distinguishing one MFU from other MFUs and may have general relationship information between MFUs in a single AU. The dependency relationship between MFUs in a single AU is described, and the relative priority of the MFUs can be described as part of such information. The information can be used to handle the transmission at the lower transport layer. For example, the transport layer may omit the transmission of MFUs that may be discarded to support QoS transmission in insufficient bandwidth. Detailed description of the MFU structure will be given later.

The MPU is a collection of media fragment units including a plurality of media fragment units 130. The MPU may have a general container format independent of a specific codec and may include media data equivalent to an access unit. The MPU may have a timed data unit or a non-timed data unit.

MPU is data that is independently and completely processed by an entity following the MMT, and the processing may include encapsulation and packetization. An MPU may consist of at least one MFU or have a portion of data having a format defined by another standard.

A single MPU may accommodate the integral number or non-time data of at least one AU. For time data, an AU may be delivered from at least one MFU, but one AU may not be divided into multiple MPUs. In non-time data, one MPU receives a portion of non-time data that has been independently and completely processed by an entity that complies with the MMT.

An MPU may be uniquely identified within an MMT package with a sequence number and an associated asset ID that distinguishes it from other MPUs.

The MPU may have at least one random access point. The first byte of the MPU payload can always start with a random access point. In time data, this fact means that the decoding order of the first MFU in the MPU payload is always zero. In the time data, the presentation period and decoding order of each AU can be sent to inform the presentation time. The MPU does not have its initial presentation time, and the presentation time of the first AU of one MPU may be described in the composition information. The composition information may specify the first presentation time of the MPU. Details will be described later.

The MMT asset 150 is a collection of MPUs composed of a plurality of MPUs. The MMT asset 150 is a data entity composed of multiple MPUs (timed or non-timed data) from a single data source, and the MMT asset information 152 is an asset packaging metadata (Asset). additional information such as packaging metadata) and data type. MMT asset 150 may include, for example, video, audio, program information, MPEG-U widgets, JPEG images, MPEG 4 FF (File Format), packetized elementary streams (PES), and MPEG transport (M2TS). streams).

MMT Assets (MMT Assets) are logical data entities that contain encoded media data. The MMT asset may be composed of an MMT asset header and encoded media data. The encoded media data may be a collective reference group of MPUs with the same MMT asset ID. Types of data that can be individually consumed by an entity directly connected to the MMT client may be considered as separate MMT assets. Examples of data types that can be considered as individual MMT assets include MPEG-2 TS, PES, MP4 files, MPEG-U Widget Package, and JPEG files.

The encoded media of the MMT asset may be time data or non-time data. Temporal data is audiovisual media data that requires synchronized decoding and presentation of specific data at specified times. Non-timed data is data of a data type that can be decoded and provided at any time in accordance with the provision of a service or user interaction.

A service provider may create a multimedia service by integrating MMT assets and putting MMT assets on a space-time axis.

The MMT package 160 is a collection of MMT assets including one or more MMT assets 150. MMT assets in an MMT package may be multiplexed or concatenated.

The MMT package is a container format for MMT asset and configuration information. The MMT package provides a repository of MMT assets and configuration information for the MMT program.

The MMT program provider generates configuration information by encapsulating the encoded data into MMT assets and describing the temporal and spatial layout of the MMT assets and their transmission characteristics. MU and MMT assets can be sent directly in the D.1 payload format. The configuration information may be sent by the C.1 Presentation Session Management message. However, MMT program providers and clients that allow relaying or future reuse of MMT programs store them in MMT package format.

In parsing the MMT package, the MMT program provider determines which transmission path (eg, broadcast or broadband) the MMT asset will be provided to the client. Configuration information in the MMT package is transmitted in a C.1 presentation session management message along with transmission related information.

The client receives the C.1 Presentation Session Management message to know which MMT programs are available and how to receive the MMT assets for the corresponding MMT program.

The MMT package can also be transmitted by the D.1 payload format. The MMT package is packetized and delivered in D.1 payload format. The client receives the packetized MMT package and configures all or part of it, where it consumes the MMT program.

The package information 165 of the MMT package 160 may include configuration information. The configuration information may include additional information such as a list of MMT assets, package identification information, composition information 162, and transport characteristics 164. Composition information 162 includes information about a relationship between MMT assets 150.

The composition information 162 may further include information for indicating a relationship between a plurality of MMT packages when one content includes a plurality of MMT packages. Composition information 162 may include information about temporal, spatial and adaptive relations in an MMT package.

Like information to assist in the transmission and presentation of the MMT package, Composition Information in the MMT provides information about the spatial and temporal relationships between MMT assets in the MMT package.

MMT-CI is an explanatory language that extends HTML5 to provide such information. If HTML5 is designed to describe page-based presentations of text-based content, MMT-CI mainly represents spatial relationships between sources. In order to support the presentation of the temporal relationship between MMT assets, information related to MMT assets in an MMT package, such as presentation resources, time information for determining the order in which MMT assets are sent and consumed, and various MMT assets are consumed in HTML5. It can be extended to have additional properties of media elements. Detailed description will be described later.

The transport characteristics information 164 may include information on transmission characteristics and may provide information necessary for determining a delivery condition of each MMT asset (or MMT packet). The transmission characteristic information may include a traffic description parameter and a QoS descriptor.

The traffic description parameter may include bitrate information, priority information, or the like for the media fragment unit (MFU) 130 or the MPU. The bitrate information is for example information about whether the MMT asset is Variable BitRate (VBR) or Constant BitRate (CBR), guaranteed bitrate for the Media Fragment Unit (MFU) (or MPU). ), The maximum bit rate for the media fragment unit (MFU) (or MPU). The traffic description parameter may be used for resource reservation between servers, clients, and other components on a delivery path, for example, maximum size information of a media fragment unit (MFU) (or MPU) in an MMT asset. It may include. The traffic description parameter may be updated periodically or aperiodically.

The QoS descriptor includes information for QoS control and may include, for example, delay information and loss information. The loss information may include, for example, a loss indicator of whether delivery loss of the MMT asset is allowed or not. For example, if the loss indicator is '1', it may represent 'lossless', and if it is '0', it may represent 'lossy'. The delay information may include a delay indicator used to distinguish the sensitivity of the transmission delay of the MMT asset. The delay indicator may indicate whether the type of the MMT asset is conversation, interactive, real time, and non-realtime.

One content may consist of one MMT package. Alternatively, one content may consist of a plurality of MMT packages.

When one content consists of a plurality of MMT packages, composition information or composition information indicating temporal, spatial, and adaptive relations between the plurality of MMT packages ( configuration information) may exist inside one MMT package or outside the MMT package.

For example, in the case of hybrid delivery, some of the content components are transmitted through a broadcast network and the rest of the content components are transmitted through a broadband network. Can be. For example, in the case of a plurality of audio visual streams constituting one multi-view service, one stream may be transmitted to a broadcasting network and the other stream may be transmitted to a broadband network, and each AV stream may be multiplexed and transmitted to a client terminal. Can be individually received and stored. Alternatively, there may be a scenario in which application software such as a widget is transmitted to a broadband network and an AV stream (AV program) is transmitted to an existing broadcasting network.

In the multi-view service scenario and / or widget scenario as described above, the entire plurality of AV streams may be a single MMT package, and in this case, one of the plurality of streams may be stored in only one client terminal. The storage content becomes part of the MMT package, and the client terminal needs to rewrite the composition information or the configuration information, and the rewritten content becomes a new MMT package independent of the server. .

In the multi-view service scenario and / or widget scenario as described above, each AV stream may be one MMT package, and in this case, a plurality of MMT packages constitute one content, and storage Storage is recorded in MMT package units and requires composition information or configuration information indicating a relationship between MMT packages.

The composition information or configuration information included in one MMT package may refer to an MMT asset in another MMT package, and may refer to an outside of an MMT package that refers to the MMT package in an out-band situation. I can express it.

Meanwhile, in order to inform the client terminal of a list of MMT assets 160 provided by a service provider and a possible path for delivery of the MMT package 160, the MMT package 160 is controlled through a control (C) layer. Translated into service discovery information, the MMT control message may include an information table for service discovery.

The server dividing the multimedia content into a plurality of segments allocates URL information to a plurality of segments divided into a predetermined number, and stores URL information about each segment in a media information file and transmits the URL information to the client.

The media information file may be called various names such as 'Media Presentation Description (MPD)' or 'Manifest file' according to a standardization mechanism for standardizing HTTP streaming. Hereinafter, the media information file is referred to and described as a media presentation description (MPD).

The cross-layer interface is described below.

The Cross Layer Interface (CLI) provides a means for supporting QoS in a single entity by exchanging QoS related information between lower layers including the application layer and the MAC / PHY layer. The lower layer provides bottom-up QoS information such as network channel state, while the application layer provides information related to media characteristics as top-down QoS information.

The cross layer interface provides an integrated interface between the application layer and various network layers including IEE802.11 WiFi, IEEE 802.16 WiMAX, 3G, 4G LTE, etc. Common network parameters of popular network standards are extracted as NAM parameters for static and dynamic QoS control of real-time media applications over various networks. The NAM parameter may include a BER value that is a bit error rate. BER can be measured at the PHY or MAC layer. The NAM also provides the identification of the underlying network, possible bit rates, buffer conditions, peak bit rates, service unit sizes, and service data unit loss rates.

Two different methods can be used to provide the NAM. The first way is to provide an absolute value. And the second is to provide relative values. The second method can be used to update the NAM while connected.

The application layer provides top-down QoS information related to media characteristics for lower layers. There are two types of top-down information such as MMT asset level information and packet level information. MMT asset information is used for capacity exchange and / or resource (re) allocation at lower layers. Packet level top down information is recorded in the appropriate field of every packet for the lower layer to identify the QoS level it supports.

The lower layer provides bottom-up QoS information to the application layer. The lower layer provides information regarding network conditions that change over time, enabling faster and more accurate QoS control at the application layer. Bottom-up information is expressed in an abstracted form to support heterogeneous network environments. These parameters are measured at the lower layer and read at the application layer periodically or at the request of the MMT application.

3 is a block diagram schematically showing the configuration of an MMT packet transmission apparatus according to an embodiment of the present invention. As shown in FIG. 3, the MMT packet transmission apparatus according to an embodiment of the present invention may include an encapsulation unit 310, a packetization unit 320, and a transmission unit 330.

Referring to FIG. 3, the encapsulation unit 310 receives an i-th access unit (AU) as an input and encapsulates it to generate a media processing unit (MPU). Throughout this specification, an access unit may be replaced with a media fragment unit (MFU). That is, the i-th media fragment unit may be input to the encapsulation unit 310. The access unit has the timing information attribute as the smallest data entity, as described above. Accordingly, when the encapsulation unit 310 generates the media processing unit based on the access unit, consideration is given to how to process the timing information. This is because when the data amount of the timing information is allotted and encapsulated, the space on which the coded data is to be loaded is reduced, and the space occupied by the header including the timing information is increased. Accordingly, the encapsulation unit 310 needs to effectively reduce the amount of timing information to improve data transmission efficiency. However, if encapsulation is focused on only reducing the amount of timing information, there may be a case in which the proper access unit cannot be represented in a desired space-time because there is no timing information required by the receiver. Therefore, it is desirable to simplify and encapsulate the timing information to such a level that it is possible to infer the timing information for each access unit.

According to an embodiment of the present invention, the timing information encapsulated by the encapsulation unit 310 may include composition time stamp (CTS) and decoding time stamp (Decode Time Stamp). The composition time information CTS means a time when the corresponding access unit (or media fragment unit) is displayed on the screen. Decoding time information (DTS) refers to the time that the corresponding access unit (or media fragment unit) is spent in the decoder. According to an embodiment of the present invention, when the access units are displayed at regular intervals, the composition time information (CTS) has a form of constantly increasing, so that only the starting CTS value and the CTS increment are provided to provide the CTS value of the access unit. Can provide. In addition, since the DTS often has the same value as the CTS, the DTS value may be substituted for the CTS value. The encapsulation unit 310 according to an embodiment of the present invention may generate the media processing unit by encapsulating the access unit in consideration of the above matters and thereby reducing the data amount of the timing information.

The packetizer 320 generates an MMT packet by performing packetization based on the media processing unit encapsulated by the encapsulation unit 310. According to an embodiment of the present invention, the packetizer 320 may generate an MMT asset based on the media processing unit, and generate an MMT packet based on the MMT asset. The MMT packet may include additional information such as composition information (CI) and transport characteristics (TC).

The transmitter 330 transmits the packetized MMT packet to the receiver through the network 340. The network 340 includes at least one of a broadcasting network and an IP network.

4 is a detailed block diagram showing in detail the configuration of the encapsulation unit 310 of the MMT packet transmission apparatus according to an embodiment of the present invention. As shown in FIG. 4, the encapsulation unit 310 according to an embodiment of the present invention may include a mode determination unit 410 and a mode encapsulation unit 420.

Referring to FIG. 4, the mode determiner 410 according to an embodiment of the present invention determines whether a time interval between composition time information of all consecutive access units belonging to a media processing unit is constant. The mode determiner 410 may generate information related to whether the time interval is scheduled through the determination and encapsulate it in the header of the media processing unit. The mode determining unit 410 is a constant CTS mode if the time interval between the CTSs of all consecutive access units in the media processing unit is constant based on the generated time interval schedule related information, and if not, all The encapsulation mode is determined to encapsulate in Full Descriptive Mode. For example, the mode determiner 410 determines the number of access units included in the media processing unit and grasps the CTS values of the determined number of access units. The mode determiner 410 then searches the CTS values of consecutive access units belonging to the media processing unit to determine whether the difference between the CTS values is constant. However, if only some of the consecutive access units belonging to the media processing unit have a constant CTS increment and some do not have a constant CTS increment, the encapsulation should be performed in the display mode instead of the constant CTS mode. For example, the media processing unit includes the first to sixth access units, where the difference between the CTS values is constant at 1 m sec until the first to fourth access units, and the difference in the CTS values with the fifth access unit is 2 msec. If so, the mode determination unit 410 should determine the encapsulation mode so that the media processing unit is encapsulated in the display mode. According to the exemplary embodiment of the present invention, the mode determining unit 410 determines that all the access units belong to the media processing unit to be encapsulated in the display mode.

Specifically, the encapsulation mode, in relation to the all display mode, every access unit or media fragment unit has a corresponding CTS value of 1: 1. Thus, the full display mode can be used when transmitting on a transport channel in which packet loss occurs, such as UDP. Alternatively, the present invention can be used in an application that dynamically changes the frame rate, for example, an environment in which frame rate adaptive conversion of a SVS (Scalable Video Stream), frame skipping, or the like occurs.

In constant CTS mode, all access units have the same CTS increment. That is, the CTS values of all access units can be inferred only by the increment and the start value. Therefore, by using the constant CTS mode, it is possible to reduce the header overhead in a stable environment without loss.

According to another embodiment of the present invention, the mode determiner 410 may determine to encapsulate including information indicating whether the CTS values and the Decoding Time Stamp (DTS) values of all the access units in the media processing unit are the same. The mode determiner 410 may encapsulate the information related to whether the CTS value and the DTS value are equal to each other in a media processing header.

According to an embodiment of the present invention, the mode encapsulation unit 420 performs encapsulation of the media processing unit or the access unit and the media fragment unit along the encapsulation mode determined by the mode determination unit 410. That is, if the mode determination unit 410 determines to encapsulate in a certain CTS mode, the mode encapsulation unit 420 only encapsulates the CTS start value and the CTS increment value (or CTS time interval value) of the media processing unit, Excludes dedicated CTS values. In addition, if the mode determining unit 410 determines to encapsulate all the display modes, it encapsulates all the dedicated CTS values of all the access units.

According to another embodiment of the present invention, the mode encapsulation unit 420 mediates the DTS values of all of the access units in the media processing unit based on whether the CTS value and the DTS value are provided by the mode determination unit 410. Encapsulate all in the header of the fragment unit or exclude the DTS value of each of all access units in the media processing unit. That is, if the CTS value and the DTS value are the same, a field related to the DTS value may be selectively determined. In particular, in an application, since the DTS value and the CTS value have the same value in many cases, the DTS value may be substituted with the provided CTS value. If the CTS value and the DTS value are not the same, as in the conventional method, all the DTS values of all access units or media fragment units are displayed.

5A is a diagram illustrating a CTS and a DTS providing structure in the presence of a plurality of MFUs in all display modes of an MMT packet transmission apparatus according to an embodiment of the present invention. As shown in FIG. 5A, in the all display mode, the media fragment unit 520 (or access in the presence of a plurality of media fragment units 520 (or MFUs) (or a plurality of access units) in one media processing unit 510. Encapsulate a dedicated CTS 526 of a unit).

Referring to FIG. 5A, when the mode encapsulation unit 420 receives the information to encapsulate all the display modes from the mode determination unit 410, more specifically, all media fragment units belonging to the media processing unit ( Encapsulate a dedicated CTS 526 value for 520 (or access unit). If the encapsulation mode is determined as the full display mode, the media fragment unit 520 (or access unit) belonging to the media processing unit 510 does not have a CTS 526 value with a constant increment, and each dedicated CTS in an unstable state. It is difficult to simplify the CTS value because it has a value of (526). Thus, in this case, the CTS 526 value of each media fragment unit 520 (or access unit) is encapsulated to be displayed in full.

As shown in the upper figure of FIG. 5A, according to one embodiment of the present invention, the media processing unit 510 includes a media processing unit header 512 (Media Processing Unit Header) and a media processing unit payload 514. MPU-payload). The media processing unit header 512 includes encapsulation mode information, as described above. The media processing unit payload 514 may include each media processing unit 520 (or access unit). Media processing unit 520 (or access unit) may include coded data 522, DTS 524 value, CTS 526 value, and media fragment unit header 528 (Media Fragment Unit Header (MFUH)). have. In the all display mode, the time intervals of the CTS 526 values of the media processing unit 520 (or the access unit) are not constant, which makes it difficult to simplify the CTS 526 values and thus the media processing unit 520 as in the conventional manner. Encapsulate so that both dedicated CTS 526 values and dedicated DTS values 528 are displayed per (or access unit).

As shown in the lower figure of FIG. 5A, according to another embodiment of the present invention, if the DTS value is the same as the CTS 544, all of the display modes may be encapsulated such that only the CTS 544 value is displayed except the DTS value. Can be. When the mode encapsulation unit 420 receives information from the mode determination unit 410 that the DTS value is the same as the CTS 544 value, the mode encapsulation unit 420 is dedicated to all the media fragment units 540 (or access units) belonging to the media processing unit. Encapsulates only the CTS 544 value and excludes the DTS value. In this case, the mode determiner 410 may insert information regarding whether the CTS 544 value and the DTS value are equal to the header of the media processing unit. Encapsulation except for the DTS value may generate a media processing unit 530 of a shorter length than the media processing unit 510 including the DTS 524 value, and may improve transmission efficiency.

FIG. 5B is a diagram illustrating a CTS and DTS providing structure in the presence of a single MFU in all display modes of an MMT packet transmission apparatus according to an embodiment of the present invention. As shown in FIG. 5B, in the all-display mode, when there is a single media fragment unit 560 (MFU) (or a single access unit) in one media processing unit 550, the mode encapsulation unit 420 is a media fragment unit. 560 (or access unit) may be encapsulated so that all dedicated CTS 566 is displayed.

As shown in the upper figure of FIG. 5B, according to one embodiment of the present invention, when only one media fragment unit 560 (MFU) (or a single access unit) exists in one media processing unit 550, Simplification of the CTS 566 value will be difficult, and thus, encapsulation is all performed through the display mode. In this case, one media processing unit 550 includes a media processing unit header 552 and a payload 554, and the payload 554 includes only one media fragment unit 560 (or access unit). Doing. The media fragment unit 560 can include coded data 562, a DTS 564 value, a CTS 566 value, and a media fragment unit header 568.

As shown in the lower figure of FIG. 5B, according to another embodiment of the present invention, if the DTS value is the same as the CTS 584, the CTS is excluded except for the DTS value even in the full display mode for the single media fragment unit 580. Only the value 584 can be encapsulated. When the mode encapsulation unit 420 receives information from the mode determination unit 410 that the DTS value is the same as the CTS 584 value, the mode encapsulation unit 420 may be configured for one media fragment unit 580 (or access unit) belonging to the media processing unit. Encapsulate the dedicated CTS 584 value and exclude the DTS value. In this case, the mode determiner 410 may insert information regarding whether the CTS 584 value and the DTS value are equal to the header of the media processing unit. Encapsulation except for the DTS value may produce a media processing unit 570 of a shorter length than the media processing unit 550 including the DTS 564 value, and may improve transmission efficiency.

6 is a diagram illustrating a CTS and a DTS providing structure in a certain CTS mode of an MMT packet transmission apparatus according to an embodiment of the present invention. As shown in FIG. 6, in certain CTS modes in accordance with one embodiment of the present invention, all media fragment units 620, 650 (or access units) within media processing units 610, 640 have respective dedicated CTS values. Do not encapsulate.

Referring to FIG. 6, when the mode encapsulation unit 420 receives information that the encapsulation unit 410 performs encapsulation in a certain CTS mode, the mode encapsulation unit 420 is configured in the media processing units 610 and 640. Instead of encapsulating the CTS values of the media fragment units 620 and 650 (or access units) of the respective devices, only the starting CTS values 632 and 662 and the CTS value increments 634 and 664 (or CTS time interval values) are encapsulated. Encapsulation is performed while simplifying the data amount of timing information. If the CTS values of successive media fragment units 620, 650 (or access units) are constantly increasing, then only the starting CTS values 632, 662 and the CTS value increments 634, 664 (or CTS time interval values) are used. Since the CTS values of the media fragment units 620, 650 (or access units) can be calculated, encapsulation is performed except for the dedicated CTS values of each media fragment unit 620, 650 (or access units). According to an embodiment of the present invention, the starting CTS values 632 and 662 and the CTS value increments 634 and 664 (or CTS time interval values) may be encapsulated through separate reference headers 630 and 660. However, although not shown in the drawings, it is not necessarily encapsulated in separate reference headers 630 and 660, but may be encapsulated in the media processing unit header 612.

As shown in the upper figure of FIG. 6, according to one embodiment of the present invention, the media processing unit 610 may include one or more media fragment units 620 (or access units) that do not indicate dedicated CTS values. Can be. The media processing unit 610 includes a media processing unit header 612 and a payload 614, and includes a media fragment unit 620 (or access unit) including data 622 coded in the payload 614. This includes. The media processing unit header 612 includes sequence information of all the media fragment units 620 (or access units) included in the media processing unit 610. That is, the dedicated CTS value of the nth media fragment unit 620 (or access unit) in the media processing unit 610 is to be calculated via the starting CTS value 632 + (n-1) * CTS value increment 634. Can be. Media fragment unit 620 (or access unit) may include coded data 622, DTS value 624, and media fragment unit header 628.

As shown in the lower figure of FIG. 6, according to another embodiment of the present invention, even in a constant CTS mode, if the DTS value is the same as the CTS, the CTS value for the CTS value is excluded except for the DTS value for the media fragment unit 650. Only the information, i.e., the starting CTS value 662 and the CTS increment 664 included in the reference header 660 can be encapsulated. When the mode encapsulation unit 420 receives the information that the DTS value is the same as the CTS value from the mode determination unit 410, the CTSs for all the media fragment units 650 (or the access units) belonging to the media processing unit 640. 6 encapsulates the relevant information (start CTS value 662 and CTS increment 664 information included in reference header 660 in FIG. 6) and excludes the DTS value. In this case, the mode determiner 410 may insert information regarding whether the CTS value and the DTS value are the same to the header of the media processing unit. In the media processing unit 640 of the constant CTS mode excluding the DTS value, the header overhead included in the CTS mode is minimized to maximize the amount of data 652 that can be loaded in one media processing unit 640. The transmission efficiency can be maximized.

The syntax and semantics of the aforementioned CTS / DTS providing structure are as follows.

Table 1 is the syntax and semantics of the header of the media processing unit.

Table 1

Referring to Table 1, flag_constant_CTS information displayed in bold is information indicating whether a constant CTS mode is present. If the flag_constant_CTS information has a value of 1, the access unit belonging to the media processing unit is in a constant CTS mode. The constant CTS mode means that the time interval between access units of all the media processing units belonging to the mode is constant, and the start value and the time interval are indicated in the reference header. If the flag_constant_CTS information has a value of 0, all access units belonging to the corresponding media processing unit operate in the display mode. In all-display mode, every access unit of every media processing unit belonging to the mode explicitly writes a dedicated CTS value.

In addition, if the flag_DTS_by_CTS information indicated by bold has a value of 1, the DTS value of the access unit of the media processing unit has the same value as the CTS value. Therefore, it does not have a header field corresponding to the DTS. If the flag_DTS_by_CTS information has a value of zero, all access units of the corresponding media processing unit have a dedicated DTS value.

According to an embodiment of the present invention, the flag_constant_CTS information and the flag_DTS_by_CTS information may have a length value of 1 bit.

7 is a diagram illustrating the configuration of a separate MPU reference header in a certain CTS mode of the MMT packet transmission apparatus according to an embodiment of the present invention. Referring to FIG. 7, the media processing unit 700 may include base_CTS information 710 and CTS_increment information 720.

The base_CTS information 710 means a start CTS value, that is, a CTS value of a start access unit, for a media processing unit using a certain CTS mode.

The CTS_increment information 720 means an increment of the CTS for each media unit for a media processing unit using a certain CTS mode.

According to an embodiment of the present invention, the base_CTS information 710 and the CTS_increment information 720 may be used only in section_ID = 0x0001: Timestamp Description, the base_CTS information 710 is 32 bits, and the CTS_increment information 720 is 16. It may have a length value of a bit.

Table 2 is the syntax and semantics of the reference header of the media processing unit.

TABLE 2

Table 3 shows the syntax and semantics of the payload of the media processing unit.

TABLE 3

Referring to Table 3, flag_constant_CTS information is information indicating whether or not the constant CTS mode. If the value of the flag_constant_CTS information is 0, the CTS of the access unit (or media fragment unit) existing in the media processing unit is not constant, and the display mode is entirely displayed. Therefore, the CTS information should be encapsulated to be displayed one by one. According to an embodiment of the present invention, 32 bits may be allocated for the bit length associated with the CTS value. And, the flag_DTS_by_CTS information is information related to whether the DTS value and the CTS value are equal. If the value of the flag_DTS_by_CTS information is 0, it means that the DTS value and the CTS value are not the same, and thus, display all the DTS values separately from the CTS value. shall. According to an embodiment of the present invention, 32 bits may be allocated for the bit length associated with the DTS value.

8 is a block diagram schematically illustrating a configuration of an MMT packet receiving apparatus according to an embodiment of the present invention. As shown in FIG. 8, the MMT packet receiving apparatus may include a receiver 820, a depacketizer 830, a decapsulator 840, a decoder 850, and a display 860.

Referring to FIG. 8, the receiver 820 receives an MMT packet from a transmitting side through a network 810. The depacketizer 830 depackets the received MMT packet to generate a media processing unit. The depacketizer 830 may transmit information related to the network delay to the decapsulator 840 and the decoder 850 in consideration of the network delay.

The decapsulation unit 840 decapsulates the media processing unit generated by the depacketizer 830 to generate an access unit. In some cases, the decapsulation unit 840 may generate a media fragment unit based on the media processing unit. According to an embodiment of the present invention, the decapsulation unit 840 may decode the media processing unit including information related to whether a time interval between composition time information (CTS) of all successive access units in the media processing unit is constant. Encapsulate.

The access unit generated through the decapsulation unit 840 is decoded through the decoder 850, and the decoded data is displayed through the display unit 860. At this time, the decoder 850 receives the CTS value and the DTS value for each access unit from the decapsulation unit 840 and decodes the CTS value and the DTS value accordingly.

9 is a detailed block diagram showing in detail the configuration of the decapsulation unit 840 of the MMT packet receiving apparatus according to an embodiment of the present invention. As shown in FIG. 9, the decapsulation unit 840 according to an embodiment of the present invention may include a mode determination unit 910 and a mode decapsulation unit 920.

Referring to FIG. 9, the mode determination unit 910 may determine a constant CTS mode in which a time interval between CTSs of all consecutive access units in the media processing unit is constant, based on information regarding whether a time interval is included in a header of the media processing unit. It is determined whether the display mode is all or not constant. The time interval schedule related information is included in the header of the media processing unit as information on whether the difference between the CTS values is the same by comparing the CTS values between all successive access units in the media processing unit. The time-interval schedule related information is flag_constant_CTS information, and if it is 1, it is a constant CTS mode, and if it is 0, it does not have a constant CTS time interval.

According to another embodiment of the present invention, the mode determination unit 910 is configured to completely determine the unique DTS values of all the access units in the media processing unit based on whether the CTS value and the DTS value included in the media processing unit header are the same. Determine whether to decapsulate or replace the DTS value with the CTS value.

The mode decapsulation unit 920 decapsulates the media processing unit based on the mode information determined by the mode determination unit 910. Specific operations of the mode decapsulation unit 920 will be described in detail with reference to FIGS. 10 to 12.

FIG. 10 is a diagram for describing a state in which the decapsulation unit 840 of the MMT packet receiving apparatus according to an embodiment decapsulates all of the media processing units in the display mode.

Referring to FIG. 10, when the mode determiner 910 parses flag_constant_CTS information, which is information about whether a time interval is fixed, and determines that the value has a value of 0, the mode determination unit 910 decapsulates the media processing unit in all display modes by considering all display modes. Send a command to the mode decapsulation unit 920. In the all display mode, the mode decapsulation unit 920 performs all decapsulation on the CTS value of each of all access units in the media processing unit. That is, decapsulation may be performed on the CTS value of the access unit 1, the CTS value of the access unit 2, and the CTS value of the access unit N, respectively, to obtain unique CTS values of all the access units belonging to the media processing unit. That is, the unique CTS values of all the access units belonging to the media processing unit are all decapsulated to obtain a CTS value matching each access unit and provide the access unit and the CTS value to the decoder 920.

FIG. 11 is a diagram for explaining a decapsulation unit 840 of an MMT packet receiving apparatus according to an embodiment of the present invention to decapsulate a media processing unit in a certain CTS mode.

If the mode determining unit 910 parses flag_constant_CTS information, which is information related to whether the time interval is fixed, and determines that the value has a value of 1, the mode determining unit 910 decodes the media processing unit of the predetermined CTS mode in a predetermined CTS mode. Transmission to the encapsulation unit 920. In the constant CTS mode, the mode decapsulation unit 920 does not fully decapsulate the CTS value of each of the access units in the media processing unit, but the CTS value (CTS bs) of the start access unit of the media processing unit. And decapsulate only the CTS time interval value (CTS inc) between successive access units and exclude the CTS value related information of the remaining access units other than the starting access unit. According to another embodiment of the present invention, in a constant CTS mode, a separate reference header of the media processing unit is parsed to determine the CTS value (CTS bs) of the starting access unit and the CTS time interval value (CTS) between the consecutive access units. inc) can be decapsulated.

Through decapsulation in constant CTS mode, access unit 1 is the start CTS value (CTS bs), access unit 2 is the start CTS value (CTS bs) plus 1 x CTS time interval value (CTS inc), Access unit N is a CTS value (CTS bs) value plus (N-1) x CTS time interval value (CTS inc), all of which belong to the media processing unit without decapsulating each CTS value separately. The CTS value of the access unit can be obtained. That is, the CTS values of all the access units belonging to the media processing unit are calculated using only the CTS start value and the CTS time interval value, so as to obtain a CTS value matching each access unit and provide the access unit and the CTS value to the decoder 920. Can be.

12 is a diagram for describing a state in which the decapsulation unit 840 of the MMT packet receiving apparatus delivers DTS and CTS information to the decoder 850 according to timing information included in a media processing unit. Drawing.

As shown in the upper figure of FIG. 12, according to an embodiment of the present invention, the mode determining unit 910 of the decapsulation unit 840 is based on flag_DTS_by_CTS information, which is information on whether the CTS value is equal to the DTS value. As a result, it is determined whether the CTS value and the DTS value of the access unit included in the media processing unit are the same. As a result, when the flag_DTS_by_CTS information has a value of 0, the DTS value is not the same as the CTS value, and the mode decapsulation unit 920 decapsulates the DTS value displayed separately from the CTS value and transmits it to the decoder 850. The decoder 850 performs decoding based on the DTS value, stores the reordering buffer (not shown) until the time corresponding to the CTS value, and then expresses the access unit through the display unit 860 at the time corresponding to the CTS value. Can be. According to an embodiment of the present invention, the decoder 850 may perform decoding in consideration of the network delay calculated by the depacketizer 820.

As shown in the lower figure of FIG. 12, according to another embodiment of the present invention, the mode determination unit 910 of the decapsulation unit 840 may determine the CTS value of the access unit included in the media processing unit based on the flag_DTS_by_CTS information. It is determined whether DTS and DTS are the same. As a result of the determination, if the flag_DTS_by_CTS information has a value of 1, the mode determination unit 910 determines that the DTS value is the same as the CTS value. In this case, the mode decapsulation unit 920 may decapsulate the media processing unit in which the DTS value field does not exist to obtain only the CTS value. Since the obtained CTS value is the same as the DTS value, only the CTS value is transmitted to the decoder 850. Since the CTS value is the same as the DTS value, the decoder 850 performs decoding based on the CTS value, and at the same time as the decoding, the display unit 860 represents the decoded access unit.

Technical features related to the packet transmission apparatus and method, the reception apparatus and the method of the MMT system of the present invention may also be implemented as a computer-readable recording medium.

Although described above with reference to the drawings and embodiments, it does not mean that the scope of protection of the present invention is limited by the above drawings or embodiments, and those skilled in the art to the spirit of the present invention described in the claims It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the invention.

Claims (20)

In the apparatus for transmitting a packet in a MPEG Media Transport (MMT) system, The media processing unit is generated by performing encapsulation including information related to whether a time interval between composition time stamps (CTSs) of all consecutive access units (AUs) belonging to the media processing unit (MPU) is constant. Packet transmission apparatus in the MMT system, characterized in that it comprises an encapsulation unit. The method of claim 1, wherein the encapsulation portion Comparing and determining whether the time interval between the CTS of all consecutive access units in the media processing unit is constant or not to generate the time interval schedule related information, and based on the generated time interval schedule related information, the constant CTS mode And a mode determination unit that determines to encapsulate in at least one of all display modes. And And a mode encapsulation unit configured to perform encapsulation based on the determined mode information. The method of claim 1, An MMT packetizer configured to generate an MMT packet by performing packetization based on the encapsulated media processing unit; And And a transmitter configured to transmit the packetized MMT packet to a receiver. The method of claim 2, wherein the mode determination unit And deciding to encapsulate all in the display mode when only one access unit belongs to the media processing unit. The method of claim 2, wherein the mode determination unit In an environment where packet loss occurs, including applications that dynamically change the frame rate, including at least one of frame rate adaptive conversion and frame skipping, all encapsulate in display mode, The packet transmission apparatus of the MMT system, characterized in that for determining in a stable environment does not occur packet loss encapsulated in a certain CTS mode. The method of claim 4, wherein the mode encapsulation unit In the constant CTS mode, only the CTS value of the starting access unit of the media processing unit and the CTS time interval value between the consecutive access units are encapsulated and the encapsulation is excluded except for the CTS value related information of the remaining access units other than the starting access unit. Performing, In the full display mode, the packet transmission apparatus in the MMT system, characterized in that to encapsulate the CTS value of each of all access units in the media processing unit in a media fragment header. The method of claim 6, wherein the mode encapsulation unit And in said constant CTS mode, encapsulate a CTS value of a starting access unit in said media processing unit and a CTS time interval value between said successive access units into separate media processing unit headers. The method of claim 6, wherein the mode encapsulation unit In the constant CTS mode, the CTS value of the start access unit of the media processing unit is encapsulated as a 32-bit length value, and the CTS time interval value between the access units of the media processing unit is encapsulated as a 16-bit length value. Packet transmission apparatus in MMT system. The method of claim 4, wherein the encapsulation portion And encapsulating the CTS value and the Decoding Time Stamp (DTS) value of all the access units in the media processing unit. The method of claim 9, wherein the encapsulation portion Encapsulate all DTS values of each access unit in the media processing unit in a header of a media fragment unit or exclude DTS values of each of all access units in the media processing unit based on the equality information of the CTS value and the DTS value. And determining whether to encapsulate to perform encapsulation. The method of claim 9, wherein the encapsulation portion And encapsulating the time interval schedule related information and information on whether the CTS value and the DTS value are equal to each other in a header of the media processing unit. The method of claim 1, And the access unit is a media fragment unit. In a method for transmitting a packet in an MPEG Media Transport (MMT) system, The media processing unit is generated by performing encapsulation including information related to whether a time interval between composition time stamps (CTSs) of all consecutive access units (AUs) belonging to the media processing unit (MPU) is constant. Packet transmission method in the MMT system, characterized in that it comprises an encapsulation step. An apparatus for receiving a packet in an MPEG Media Transport (MMT) system, A decapsulation unit for decapsulating a media processing unit (MPU) containing information relating to whether a time interval between composition time stamps (CTSs) of all consecutive access units (AUs) in the media processing unit is constant Packet receiving apparatus in the MMT system, characterized in that. The method of claim 14, wherein the decapsulation portion A mode determination unit determining whether a time interval between CTSs of all consecutive access units in the media processing unit is a constant constant CTS mode or a non-uniform all-display mode based on the time interval schedule related information; And And a mode decapsulation unit configured to perform decapsulation of a media processing unit based on the determined mode information. The method of claim 15, wherein the mode decapsulation unit In the constant CTS mode, decapsulates only the CTS value of the starting access unit of the media processing unit and the CTS time interval value between the successive access units and excludes the information related to the CTS value of the remaining access units other than the starting access unit. Perform encapsulation, And in the all display mode, decapsulate all CTS values of each of all access units in the media processing unit. The method of claim 15, wherein the mode decapsulation unit In the constant CTS mode, the packet receiving apparatus in the MMT system, characterized by parsing a separate header of the media processing unit to decapsulate the CTS value of the starting access unit and the CTS time interval value between the successive access units. . The method of claim 14, wherein the decapsulation portion An apparatus for receiving a packet in an MMT system, characterized by decapsulating a media processing unit including information indicating whether the CTS value and the decoding time stamp (DTS) value of all access units in the media processing unit are the same. The method of claim 18, Further comprising a decoder for decoding the decapsulated access unit, The decoder may perform decoding by determining a CTS value as a DTS value for the media processing unit in which the DTS values of all the access units in the media processing unit are excluded based on the same information on the CTS value and the DTS value. Packet receiving apparatus in the MMT system characterized in that. In the method for receiving a packet in an MPEG Media Transport (MMT) system, A decapsulating step of decapsulating a media processing unit (MPU) containing information relating to whether a time interval between composition time stamps (CTSs) of all consecutive access units (AUs) in the media processing unit is constant; Packet receiving method in the MMT system, characterized in that it comprises a.

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