KR102087585B1 - Method configuring and transmitting m-unit - Google Patents

Abstract

The present specification discloses a method for setting up and transmitting an M-unit in a system. In the present specification, an MFU (Media Fragment Unit) is received from a media encoder, and a payload is configured to configure an M-unit including the MFU, wherein the M-unit includes information that needs to be distinguished for every M-unit. And a reference header comprising a unit header and information independent of the M-unit.

Description

Setting method and transmission method of M-unit {METHOD CONFIGURING AND TRANSMITTING M-UNIT}

The present invention relates to an M unit of MPEG Media Transport (MMT), and more particularly, to a method and apparatus for setting or transmitting an M unit.

Recently, ISO / IEC JTC1 / SC29 / WG11 (hereinafter referred to as MPEG) is standardizing MPEG-H, which is a multimedia encoding representation and multiplexing transmission standard to be used in the future of ultra-high-definition TV (UHDTV). MPEG-H will be published as a set of standards, consisting of a part 1 system, a part 2 video, and a part 3 audio, similar to the existing MPEG-1, MPEG-2, MPEG-4, and the like. Part 1 of MPEG-H is MPEG Media Transport (MMT), part 2 is High-Efficiency Video Coding (HEVC), and part 3 is not yet finalized. It is expected to be the next generation audio compression coding standard to standardize. MMT is the next generation multimedia multiplexing delivery standard being standardized in MPEG following the MPEG-2 Transport Stream (TS) standard, and HEVC is the next generation video compression coding standard considering application to UHDTV which is jointly standardized by ISO and ITU-T.

MMT is IP-friendly and aims to deliver multimedia with several different types of channels. MMT consists of three functions: Encapsulation (E), Delivery (D), and Control (C). In the E function, the multimedia content is packaged as an entity. In the D function, the packaged content is packetized and transmitted according to the IP protocol, and the C function delivers such multimedia service search information and various control information.

At present, many companies and schools are participating in the standardization of MMT, and technology has been proposed in all areas of MMT. In particular, a method of transmitting and receiving a new structure of M-UNIT in MMT is required.

An object of the present invention is to provide a method and apparatus for setting an M unit of a new structure.

Another technical problem of the present invention is to provide a method and apparatus for transmitting an M unit of a new structure.

According to an aspect of the present invention, a method for setting an M-unit in a system includes receiving a Media Fragment Unit (MFU) from a media encoder; And configuring an M-unit including the MFU in a payload, wherein the M-unit is independent of the M-unit header and the M-unit including information that needs to be distinguished for every M-unit. It is configured to include a reference header containing the information.

According to another aspect of the present invention, a method for transmitting an M-unit in a system includes receiving a Media Fragment Unit (MFU) from a media encoder; And configuring an M-unit including the MFU in a payload to include an M-unit header including information that needs to be distinguished for every M-unit, and a reference header including non-dependent information on the M-unit. ; And transmitting the M-unit.

According to the present invention, an M-unit including a reference header may perform compression and transporting through header division. In addition, an M-unit including a reference header does not need to attach a field that is repeated many times for each unit, and if it is delivered before the unit, it can be sent to an arbitrary position, and a retransmission policy for packet errors can be applied. It can be taken independently, and out-of-band transmission is possible as well.

1 shows an example of the structure of a reference header according to the present invention.
2 shows an example of a plurality of MFU aggregation method according to the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In addition, in order to clearly describe the present invention, parts not related to the present invention are omitted, and the same or similar reference numerals in the drawings represent the same or similar components.

M-Unit (M-Unit) is a basic unit that proceeds to the next process after the system (eg, multimedia system) takes over the MFU (Media Fragment Unit).

MFU is the output of a media encoder (eg, a video encoder or an audio encoder). At this time, the header of the MFU is generated from the media encoder and transferred to the system. The header of the MFU is used as a channel to convey information to the system that is useful for system operation (for example, transmission or storage of information or signals) among the media encoder's known or known information. The MFU is the output of a media encoder consisting of encoded data (eg audio data or video data) and an MFU header.

Basic operations related to M-units include 1) distinguishing a plurality of MFUs when the M-unit includes a plurality of MFUs, 2) distinguishing AUs (Access Units) within the M-units, and 3) When the M-Unit is a Timed M-Unit, transmitting or distinguishing time information such as Composition Time Stamp (CTS) / Decode Time Stamp (DTS) at the level of encapsulation layer for each AU. Etc. Here, the CTS means the time for which the corresponding MFU is displayed on the screen, and the DTS means the time for which the corresponding MFU is spent in the decoder.

Hereinafter, the structure of the M-unit according to the present invention will be described. Specifically, 1) structure and use of the reference header, 2) aggregation of a plurality of MFU, 3) classification of AUs, 4) time stamp information. The system (eg, multimedia system) may set up (or configure) the M-unit in the following structure. The system may also transmit the configured M-unit to another system or another device.

1 shows an example of the structure of a reference header according to the present invention.

Referring to FIG. 1, a header of an M-unit according to the present invention may have a two-staged header structure including a reference header (RH). For example, it may be a two-level structure of a reference header and an M-unit header.

Only the essential information that is repeated for each payload is left in the front part of the payload (this part is called a first stage header), and the remaining information can be separated into a separate header called a reference header. (This part is called a second stage header).

In this case, the reference header may exist as a separate unit from the payload unit. It is also possible to send a reference header at any point in time if it is earlier than the M-unit to be used (not necessarily located immediately before the M-unit). In addition, the reference header can freely select in-band transmission or out-of-band transmission.

In addition, the reference header may include information that is necessary information at the M-unit level but does not need to be distinguished for each M-unit, or may include information that does not need to be dependent on a specific M-unit, whereas the prefix MUH ( Unlike reference, Prefix MU-Header) can contain information that needs to be distinguished for each M-unit. And, it is optional for an M-unit to include a reference header and does not necessarily need to include a reference header.

For example, the M-unit may have a structure in which a reference header (RH) and an M-unit header (MHU) are serially arranged. This may be referred to as a serial position (110).

As another example, the M-unit may have a structure in which both the RH and the MHU are located in front of the payload. This may be referred to as an aggregated position 120.

As another example, the M-unit may be a structure for performing out-of-band transmission with the RH. This may be referred to as an out-of-band fetch (130). MUH makes an OOB request to RH, and RH makes an OOB fetch to MUH.

As another example, the M-unit may be a structure 140 that includes one RH for every M-unit (or payload of the M-unit). That is, RH and MUH may be in a one-to-one correspondence.

As another example, the M-unit may be a structure 150 that does not include RH.

The M-unit including the above-described reference header may perform compression and transporting through header division. In general, a file archiving application is preferred in which header information is placed in one place. In a transmission application, the header information is interleaved between packet strings of a required portion. position).

In addition, an M-unit including a reference header does not need to attach a field repeated several times for each unit. If it is delivered before that unit, it can be sent to any location.

In addition, the M-unit including the reference header may independently take the retransmission policy for packet errors (Packet Error).

In addition, the M-unit including the reference header is capable of out-of-band transmission as well as in-band transmission.

On the other hand, among the methods of extension to include various information in the header, the method of extending according to bit options such as M2TS cannot take a separate retransmission policy for the header and can be sent to an arbitrary location. There is no flexibility. In addition, the header may not be transmitted out-of-bound (OOB).

2 shows an example of a plurality of MFU aggregation method according to the present invention.

Referring to FIG. 2, the M-unit is a structure that can contain two or more MFUs in one MU.

The system can select whether to aggregate more than one MFU in one payload M-unit. Specific description for the aggregation of MFU is included in RH, not MHU. Because the size of the technology for multiple MFUs is large enough to be stored directly in the MUH, simple media (eg audio codecs) often have the same structure (or the same size of the MFUs in the MU). This is because not all M-units need to have a dedicated description.

Meanwhile, according to the present invention, the MFU included in the MU may be divided into AU units. Here, AU (eg, MPEG AU) is the smallest data entity to which timing information is transmitted and is the smallest unit sharing the same time information. AU identification is very important.

In addition, the MU may include an AU start / end indicator, which may indicate an AU at which the MFU starts, or may indicate an AU at which the MFU ends, the number of AUs or the number of AUs. You can also indicate the number.

Meanwhile, according to the present invention, the M-unit may further include timestamp information.

The system may provide CTS and DTS information for MFUs included in the M-unit to provide time information of their screen configuration. In this case, the CTS and the DTS information provide a constant mode, and the DTS field may be selectively used. In addition, the CTS and DTS values may be described in MFU units. If the constant mode is used, additional description may be included in the reference header. For example, a starting point or incremental gaps of the CTS may be included in the reference header.

Hereinafter, the syntax and semantics of the M-unit according to the present invention will be described.

As described above, the header of the M-unit has a reference header (RH) or payload type (MHU).

The following table shows an example of syntax and semantics of the M-unit according to the present invention.

The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

 Here, MU_type designates a reference header use mode of the M-unit, and may be configured as 2 bits as an example. The following table shows an example of a bit configuration of the MU_type. The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

The following table shows an example of syntax and semantics of the M-unit base header. The M-unit base header refers to a header that is not a reference header among the M-unit headers. In this case, the M-unit base header may be located in front of the payload type M-unit. The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

Here, flag_multiple_MFU indicates that the M-unit includes two or more MFUs if the value is "1" and that the M-unit has only one MFU if the value is "0". Preferably, aggregation of MFUs may be used in a lossless environment (eg, lossless transport channel such as TCP or local file manipulation).

In addition, the flag_random_access_point has a value of "1" to indicate that the MFU included in the MFU including the random access point of the media among the MFUs included in the M-unit.

In addition, flag_timed has a value of "1" to indicate that the M-unit includes timed media data. Here, the timed media refers to media data (eg, audio frames and video frames) in which a time for consumption is designated as a specific time. flag_timed has "0" to indicate that the M-unit includes non-timed media data. Here, non-timed media data means media data for which a time for consumption is not specified.

In addition, if the flag_constant_CTS has a value of "1", it indicates that the AU belonging to the M-unit operates in the "constant mode". Here, the constant mode is a mode in which time intervals between AUs of all M-units belonging to the mode are constant, and a start value and a time interval are reported in a reference header. If flag_constant_CTS has a value of "0", it indicates that the AU belonging to the corresponding M-unit operates in "Full Descriptive Mode". Here, the full description mode is a mode in which a dedicated CTS value is explicitly written for all AUs of all M-units included in the mode.

If flag_DTS_by_CTS has a value of "1", it indicates that the DTS value of the AU of the corresponding M-unit is the same as the CTS value of the same AU. The M-unit does not have a header field corresponding to the DTS. If flag_ DTS_by_CTS has a value of "0", it indicates that all AUs of the corresponding M-unit have a dedicated DTS value.

Regarding pl_seqno, when the reference header mode (ref_header_mode) has a value of "01" or "10", the M-unit uses a reference header, and the corresponding M-unit (or M for each section of the reference header). A sequence number is assigned to specify a group of units. pl_seqno has a value increasing by 1 for each M-unit for the M-unit stream. pl_seqno is incremented only for payload type M-units and does not count reference headers that may exist in between.

The following table shows an example of syntax and semantics of an M-unit of payload type. The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

Here, CTS (Composition Time Stamp) means the time that the corresponding MFU is displayed on the screen. Decode Time Stamp (DTS) means the time that the MFU spends in the decoder.

The reference header of the M-unit may include one or more sections, and each section may have a unique section ID.

The system may adjust the number of reference headers of the M-units as needed, and may arbitrarily select the type of sections included in each reference header.

Table 5 shows an example of a reference header of the M-unit. The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

Here, in relation to the section ID, the reference header of the M-unit may be divided into several sections according to information to be provided, and the section ID is an ID for distinguishing between sections. It can have an unsigned integer format. The operation may be previously assigned according to the number of the section IDs, and the user may freely assign and use the section ID number according to the needs of the application.

The following table shows an example of initial numbering of section IDs according to the present invention. The following components are not limited to the order, and all components are not necessarily included and may be configured as some components.

Section ID operation description 0x0000 Reference Header Root Description One M-unit stream can use multiple reference header sections as needed, and these sections can be placed in two or more different reference headers as needed. Advance section IDs used throughout the M-Unit stream
If the M-Unit stream uses a reference header, the system must read the section before starting from the beginning to the next step.
Sections that let you know which section the M-Unit stream is using 0x0001 Timestamp Description Section providing constant time stamp information when the M-Unit uses constant time stamp mode.
The information described in this section is valid for M-units corresponding to mu_seqno from start_mu_seqno in this timestamp description to start_mu_seqno-1 in the next timestamp description 0x0002 Multiple MFU Aggregation Description If an M-unit contains more than one multiple MFU, the section referenced by that M-unit
The section and the M-unit are coupled to start_mu_seqno and seq_no of the M-unit. 0x0003 Dependency description If there is a dependency relationship between an M-unit or a group of M-units, a section describing that dependency 0x0004 to 0x7fff (TBD / Reserved) - 0x8000 to 0xffff User Defined User-selected section according to the application

Here, section_byte_length indicates the size of the corresponding section and may be in byte units. Here, the size of the section may include the size of a section ID, section_byte_length, or start_mu_seqno field. In addition, start_mu_seqno indicates an M-unit position in an M-unit stream to which the section is applied as a sequence number of an M-unit. Therefore, M-units of an M-unit stream using a reference header have a sequence number.

no_of_section means the number of all sections used in the M-unit stream. In addition, section_ID_used refers to a section ID used in the M-unit stream. At this time, no_of_section and section_ID_used may be used when the section ID is "0x0000".

base_CTS means a starting CTS value of a starting M-unit for an M-unit using a constant timestamp mode. CTS_increment means an increment (but AU unit) of the CTS for the M-unit using the constant timestamp mode. base_CTS and CTS_increment may be used when section ID is "0x0001".

 no_of_media_fragment_unit means the number of MFUs when one M-unit consists of two or more MFUs. MFU_byte_offset means a byte offset value of the current MFU from the start of the M-unit in the order of the MFU constituting the M-unit. MFU_byte_size means the byte size of the current MFU in the order of MFUs constituting the M-unit. At this time, no_of_media_fragment_unit and MFU_byte_offset MFU_byte_size may be used when the section ID is "0x0002".

In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and any steps may occur in a different order or at the same time than the other steps described above. Can be. In addition, those skilled in the art will appreciate that the steps shown in the flowcharts are not exclusive and that other steps may be included or one or more steps in the flowcharts may be deleted without affecting the scope of the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited thereto. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (10)

In the packet generating apparatus,
An encapsulation unit encapsulating a media fragment unit (MFU) to generate a media unit; And
A packetizer configured to packetize the media unit to generate a packet;
The media fragment unit is characterized in that the packet generating apparatus characterized in that divided into the asset unit (AU: Asset Unit) (AU) which is the smallest data entity (Data Entity) to which the timing is transmitted. The method of claim 1,
The packetization unit,
Generating the packet by including a flag indicating whether the media unit includes timed media data or non-timed media data,
And the flag has a size of 1 bit and is included in a payload header of the packet. The method of claim 2,
A value of 1 indicates that the media unit includes timed media data, and a value of 0 indicates that non-timed media data is included. . The method of claim 1,
And the media unit includes an indicator indicating the start of the asset unit. delete In the packet generation method,
Encapsulating a media fragment unit (MFU) to generate a media unit; And
Packetizing the media unit to generate a packet;
The media fragment unit is a packet generation method, characterized in that divided into the asset unit (AU: Asset Unit) (AU) which is the smallest data entity (Data Entity) that the timing is transmitted. The method of claim 6,
The packet generation step,
Generating a packet by including a flag indicating whether the media unit includes timed media data or non-timed media data, and
The flag has a size of 1 bit and is included in a payload header of the packet. The method of claim 7, wherein
A value of 1 indicates that the media unit includes timed media data; and a value of 0 indicates that non-timed media data is included. . The method of claim 6,
And the media unit includes an indicator indicating the start of the asset unit.
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