KR100799592B1 - Apparatus and method of hierarachical modulation for scalable video bit stream - Google Patents

Abstract

An apparatus and a method for transmitting and receiving hierarchical modulation of scalable video bit stream are provided to solve a problem that a video compression standard H.264 used in the existing terrestrial DMB(Digital Multimedia Broadcasting) does not provide a scalability function that provides various screen resolutions/time resolutions/picture qualities, failing to provide a one-source multi-use service. An HP(High Priority) channel generating unit(812) generates an HP bit stream having an HP based on a base layer among a plurality of scalable layers included in a single scalable video bit stream. An LP(Low Priority) channel generating unit(813) generates an LP bit stream having an LP based on an enhancement layer among the scalable layers included in the single scalable video bit stream. A splitter(810). A splitter header parcing unit(812) parses an NAL(Network Layer Access) header included in an NAL unit of the received scalable video bit stream and discriminates the received scalable video bit stream as the base layer and the enhancement layer.

Description

Apparatus and Method of Hierarachical Modulation for Scalable Video Bit Stream

FIG. 1 is a diagram illustrating the concept of hierarchical modulation used in a terrestrial DMB advanced network.

2 is a diagram illustrating the concept of scalable video coding (SVC).

3 is a diagram illustrating a configuration of a conventional terrestrial DMB service.

4 is a diagram illustrating available channel capacity in a terrestrial DMB advanced network.

5 is a diagram illustrating a configuration in which scalable video is applied to a terrestrial DMB advanced network according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of a transmitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB advanced network according to an embodiment of the present invention.

7 illustrates a configuration of a scalable video bitstream for applying a hierarchical modulation scheme according to an embodiment of the present invention.

8A illustrates a configuration of a splitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB advanced network according to an embodiment of the present invention.

8B illustrates an operation of a splitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

FIG. 8C is a diagram illustrating a splitter algorithm for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

9 is a diagram illustrating a configuration of a receiver for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB advanced network according to an embodiment of the present invention.

FIG. 10A illustrates a configuration of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

FIG. 10B illustrates an operation of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

FIG. 10C is a diagram illustrating an algorithm of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

The present invention relates to an apparatus and a method for hierarchical modulation transmission and reception of a scalable video bitstream, and more particularly, to an apparatus and a method for hierarchical modulation and transmission of a scalable video bitstream for high quality video service in a terrestrial DMB advanced network. It is about a method.

Since the realization of digital broadcasting technology, various convergences of broadcasting and communication have been attempting to develop various next generation digital multimedia transmission methods that can provide additional data services including high quality digital TV service and high quality audio and video anywhere and anytime in the world.

In addition, social-technical changes in digital broadcasting services are rapidly occurring in accordance with diversification of broadcasting media, expansion of programs, and user preferences, and different types of information from independent / fixed environment to integrated / mobile use environment. The broadcasting environment is changing from providing audio / text services to providing integrated information services.

As part of this change in the broadcasting environment, Digital Multimedia Broadcasting (DMB) technology can provide a variety of value-added data services such as CD-quality audio services, traffic and advertisement, as well as clear image quality services anytime, anywhere in a mobile environment. Is being developed rapidly around the world.

Digital Multimedia Broadcasting (DMB) is the next generation of digital broadcasting that provides high-quality CD-quality sound, various data services, two-way interactivity, and excellent mobile reception quality beyond the conventional AM and FM radio types according to the digitization of voice broadcasting. It is a service.

Moreover, DMB has expanded the concept of 'listening broadcasts' of existing radio broadcasts into' viewing and listening broadcasts'.In addition to music broadcasting, DMB can also display various multimedia information such as news, traffic information, weather information, geographic location information, and video information. And may be transmitted as an image.

As a result, the concept of digital radio broadcasting (DAB) in Korea has been expanded from the initial voice and data services to video multimedia services.In early 2003, digital audio broadcasting (DMB) was renamed from 'Digital Audio Broadcasting'. Changed to.

However, it has led the global standardization through research and development of technology that can service mobile multimedia services of large-capacity, high-quality and practical communication broadcasting convergence type that greatly surpasses the quality and functions that existing terrestrial DMB can provide through various terminals. Only then can we maintain the competitiveness of continuous terrestrial DMB technology.

As such, there is a need to develop a high quality mobile multimedia service technology that maintains compatibility with existing terrestrial DMB and satisfies the demands of consumers due to the wider quality of digital broadcasting services and broadband networks.

In conventional terrestrial DMB, due to the limited channel capacity, the maximum screen resolution is limited to CIF (352X288), so users cannot receive high resolution video service.

H.264 (ITU-T Rec. H.264 | ISO / IEC 14496-10 Annex A.2.1), the video compression standard used in existing terrestrial DMB, is H.-263 or MPEG-4 Part in most bit-rates. 2 The compression rate of more than 50% has been improved in Visual's Simple Profile.

H.264 provides high quality video service by using Deblocking filter and 1/4 Pixel Motion vector, and improved error robustness by using Motion compensation using Multiple reference frame and Switching P / SI (Switching I) frame. It has

In addition, H.264 adopts Network Abstraction Layer (NAL), so H.264 bitstream can be easily transmitted through various networks.

However, H.264 does not provide a scalability function that can provide various screen resolutions, time resolutions, and picture quality, which is why One-Source Multi-Use for high-quality video service in terrestrial DMB advanced network (Advanced T-DMB) You cannot provide services.

An object of the present invention is to provide a hierarchical modulation transmission / reception apparatus and method for scalable video bitstream for providing high quality service in a terrestrial DMB advanced network while maintaining backward compatibility with existing terrestrial DMB.

In order to achieve the above technical problem, a transmitter for a scalable video bitstream according to the present invention has a high transmission priority based on a base layer among a plurality of scalable layers included in one scalable video bitstream. A low transmission priority based on an HP channel generator for generating an HP bitstream having a high priority (HP) and an enhancement layer among the scalable layers included in one scalable video bitstream And a splitter for hierarchical modulation transmission of a scalable video bitstream having an LP channel generator for generating an LP bitstream having (Low Priority: LP).

More preferably, the splitter of the transmitter for the scalable video bitstream according to the present invention for analyzing the technical problem analyzes a NAL header included in a received network layer access (NAL) unit of the scalable video bitstream. The apparatus may further include a splitter header parser configured to divide the received scalable video bitstream into the base layer and the extension layer.

According to an aspect of the present invention, a receiver for a scalable video bitstream includes an HP bitstream having a high transmission priority and an LP bitstream having a low transmission priority generated by dividing the scalable video bitstream. And a compositor for the hierarchical modulated scalable video bitstream that receives and reconstructs the scalable video bitstream.

More preferably, a compositor of a receiver for a scalable video bitstream according to the present invention for achieving the technical problem is a bitstream receiver for receiving the HP bitstream and the LP bitstream, the received HP bitstream and the Reconstructing the scalable video bitstream for each AU (Access Unit) which is a combination of a header parser for a compositor for analyzing a NAL header and a slice header included in an NAL unit of an LP bitstream and a NAL unit corresponding to the same time axis, And an output bitstream reconstruction unit.

The transceiver for a scalable video bitstream according to the present invention for achieving the technical problem has a different transmission priority generated based on a specific layer of a plurality of the scalable layer by dividing the scalable video bitstream. A transmitter having a splitter for hierarchical modulation transmission of a scalable video bitstream generating a plurality of bitstreams, and a plurality of bitstreams having different transmission priorities generated based on a specific layer among the plurality of scalable layers. And a receiver having a compositor for receiving a hierarchical modulated scalable video bitstream to reconstruct the scalable video bitstream.

More preferably, the splitter of the transmitter of the transceiver for the scalable video bitstream according to the present invention for achieving the above technical problem is a HP bitstream having a high transmission priority based on a base layer of the plurality of scalable layers. HP channel generation unit for generating, LP channel generation unit for generating an LP bitstream having a low transmission priority based on an extension layer of the plurality of scalable layers and included in the NAL unit of the scalable video bitstream And a header parsing unit for splitting the NAL header, which divides the received scalable video bitstream into the base layer and the extension layer.

More preferably, the compositor of the receiver of the transceiver for the scalable video bitstream according to the present invention for achieving the technical problem is an HP bitstream having a high transmission priority generated based on a base layer among the scalable layers. And a bitstream receiver configured to receive an LP bitstream having a low transmission priority generated based on an extension layer, and analyze the NAL header and the slice header included in the received HP bitstream and the NAL unit of the LP bitstream. And a bitstream reconstruction unit configured to reconstruct and output the scalable video bitstream for each AU that is a combination of a compositor header parser and a NAL unit corresponding to the same time axis.

According to an aspect of the present invention, there is provided a method of transmitting a scalable video bitstream, wherein the HP bit has a high transmission priority based on a base layer among a plurality of scalable layers included in one scalable video bitstream. HP channel generation step of generating a stream and LP channel generation step of generating an LP bitstream having a low transmission priority based on an extension layer among a plurality of scalable layers included in one scalable video bitstream. One split step is included.

More preferably, in the splitting step of the scalable video bitstream transmission method according to the present invention, the NAL header included in the received NAL unit of the scalable video bitstream is received. The method further includes splitting a header for splitting the scalable video bitstream into the base layer and the extension layer.

According to an aspect of the present invention, there is provided a method of receiving a scalable video bitstream, wherein the scalable video bitstream is divided into an HP bitstream having a high transmission priority and an LP bitstream having a low transmission priority. And receiving a composite, for the hierarchical modulated scalable video bitstream reconstructing the scalable video bitstream.

More preferably, the composite step of the scalable video bitstream receiving method according to the present invention for achieving the technical problem is a bitstream receiving step for receiving the HP bitstream and the LP bitstream, the received HP bitstream And a bitstream for reconstructing and outputting the scalable video bitstream for each AU that is a combination parsing step of analyzing a NAL header and a slice header included in the NAL unit of the LP bitstream and a NAL unit corresponding to the same time axis. Reconstruction step is included.

According to an aspect of the present invention, there is provided a method for transmitting and receiving a scalable video bitstream in which a scalable video bitstream generates a plurality of bitstreams having different transmission priorities according to a specific layer among a plurality of scalable layers. A hierarchical modulated scalable video bit for reconstructing the scalable video bitstream by receiving a plurality of bitstreams having different transmission priorities according to a specific layer among a plurality of the scalable layers and a transmission step for hierarchical modulation transmission Receiving step for the stream.

More preferably, the transmitting of the scalable video bitstream transmission and reception method according to the present invention for achieving the technical problem generates an HP bitstream having a high transmission priority based on a base layer among the plurality of scalable layers. An HP channel generation step, an LP channel generation step of generating an LP bitstream having a low transmission priority based on an extension layer among a plurality of scalable layers, and an NAL unit of the received scalable video bitstream And a header parsing step for splitting the received scalable video bitstream into the base layer and the extension layer by analyzing a NAL header.

More preferably, the receiving step of the method for transmitting and receiving a scalable video bitstream according to the present invention for achieving the technical problem is an HP bitstream having a high transmission priority generated based on a base layer of the scalable layer and Receiving a bitstream receiving the LP bitstream having a low transmission priority generated based on the enhancement layer, analyzing the NAL header and slice header included in the received HP bitstream and the NAL unit of the LP bitstream And a bitstream reconstruction step of reconstructing and outputting the scalable video bitstream for each access unit (AU), which is a combination of a composite parsing step and a NAL unit corresponding to the same time axis.

As such, the present invention splits the scalable video bitstream at the transmitting end and generates the scalable video bitstream at the receiving end to generate and reconstruct two sub bitstreams (HP bitstream, LP bitstream) in the terrestrial DMB advanced network. An apparatus and method for hierarchical modulation transmission and reception of a scalable video bitstream are described.

Hereinafter, an apparatus and method for hierarchical modulation transmission and reception of a scalable video bitstream according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating the concept of hierarchical modulation used in a terrestrial DMB advanced network.

As the existing wireless LAN is evolving to Wibro (Wireless Broadband Internet) and the existing mobile communication network is evolving to HSDPA (High Speed Downlink Packet Access), the terrestrial DMB also provides high transmission efficiency / high quality service in the future. Must be able to provide

The terrestrial DMB advancement network, which can provide such high transmission efficiency / high quality service, uses a hierarchical modulation method that can extend about twice the available channel capacity provided by the existing terrestrial DMB.

Referring to FIG. 1, a hierarchical modulation scheme generates two sub bitstreams (HP bitstream and LP bitstream) by separating one bitstream through a high priority (HP) and a low priority (LP) channel. Can be.

As such, according to the hierarchical modulation scheme, two generated sub bitstreams (HP bitstream and LP bitstream) may be transmitted through one transmitter.

The terrestrial DMB advanced network, the next generation terrestrial DMB, can transmit data about 2 Mbps compared to the available data rate of 1.062 Mbps, which was available in the existing terrestrial DMB, and based on the increased available channel capacity, Service is available.

In the terrestrial DMB advanced network using the hierarchical modulation method, the conventional terrestrial DMB service of up to CIF (352X288) level resolution is provided through the HP (High Priority) channel and the high quality (high resolution) SD is provided through the Low Priority (LP) channel. A terrestrial DMB service having a (720X480) screen resolution can be simultaneously provided.

2 is a diagram illustrating the concept of scalable video coding (SVC).

The present invention applied SVC, which is being standardized in JVT (MPEG & VCEG), to the terrestrial DMB advancement network to maintain compatibility with existing terrestrial DMB while serving multimedia content of high quality (high resolution).

SVC, a scalable coding technology of H.264, simultaneously solves problems of low compression efficiency, complex scalability support, and high implementation complexity, which are problems of scalability based on hierarchical coding attempted by MPEG-2 and MPEG-4. A new scalable coding technique developed to solve this problem.

Referring to FIG. 2, the SVC encodes a plurality of video layers into one bit string. The SVC layer consists of one base layer and one or more enhancement layers that can be stacked on top of each other.

Each enhancement layer can express a maximum bit rate, frame rate, and resolution given to each other based on lower layer information. In SVC, as more layers are continuously stacked, various bit rates, screen rates, and resolutions can be supported.

As such, SVC is a multimedia solution of UMA (Universal Multimedia Access) environment that can solve various problems of bandwidth diversity, heterogeneity of receiving terminal performance and resolution, and various preference problems of content consumers in heterogeneous network environment. Coding technology suitable for content services.

The present invention proposes a hierarchical modulation transmission / reception apparatus and method for scalable video bitstream for providing high quality service in terrestrial DMB advanced network while maintaining backward compatibility with existing terrestrial DMB.

More specifically, the present invention splits the scalable video bitstream at the transmitter and scalable at the receiver to generate and reconstruct two sub bitstreams (HP bitstream, LP bitstream) in the terrestrial DMB advanced network. An apparatus and method are provided for transmitting and receiving hierarchical modulation of a scalable video bitstream that recomposes a video bitstream.

3 is a diagram illustrating a configuration of a conventional terrestrial DMB service. Referring to FIG. 3, in the conventional terrestrial DMB, one operator may have a data transmission capacity of 1.536 Mbps which avoids interference between channel frequencies at a total transmission data capacity of 2 Mbps.

The data transfer capacity of 1.536 Mbps can use about 1.062 Mbps of available channel capacity, except for external coding such as channel coding.

Therefore, one operator in the existing terrestrial DMB is capable of two AV programs, one audio service and one data service of CD quality level corresponding to the maximum CIF (352X288) level at a given available channel capacity.

In this case, the serviced AV program uses the H.264 video compression standard and encodes the AV program up to 512 Kbps ~ 548 Kbps for each operator.

4 is a diagram illustrating available channel capacity in a terrestrial DMB advanced network. Referring to FIG. 4, the terrestrial DMB advanced network, which is the next generation of the conventional terrestrial DMB, may have an available channel capacity that is approximately twice that of the existing layer by using a hierarchical modulation scheme.

In terrestrial DMB advancement network, existing terrestrial DMB service is available through HP (High Priority) channel and high transmission efficiency / high quality service through LP (Low Priority) channel.

In the case of a high transmission efficiency service, about 4 AV programs can be transmitted for CIF (352x288) class AV programs.

In the case of a high quality service, a video service having one CIF (352x288) level AV program and one SD (720X480) level resolution can be provided.

5 is a diagram illustrating a configuration in which scalable video is applied to a terrestrial DMB advanced network according to an embodiment of the present invention.

Referring to FIG. 5, when hierarchically encoding an AV program with scalable video, the CIF (352X288) class corresponding to the base layer in the HP channel and the SD (720X480) class corresponding to the enhancement layer in the LP channel are used. Scalable video coding.

The existing terrestrial DMB terminal receives CIF (352X288) level service through the HP channel, while the terrestrial DMB advanced network dedicated terminal receives additional SD (720X480) level video service through the LP channel.

Thus, according to the present invention, it is possible to provide a high quality DMB service in the terrestrial DMB advanced network while maintaining backward compatibility with the existing terrestrial DMB.

FIG. 6 is a diagram illustrating a configuration of a transmitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB advanced network according to an embodiment of the present invention.

Referring to FIG. 6, the transmitter according to the present invention has a transmission protocol standard of MPEG-4 / MPEG-2 Systems, Reed Solomon, and Convolutional interleaver in the same manner as the conventional terrestrial DMB. The video encoder includes a splitter 600.

After splitting the scalable video having a hierarchical structure, the splitter 600 splits the scalable video bitstream encoded for each channel.

In detail, scalable video (SVC) encodes a plurality of video layers into one bitstream, and each layer has a bit rate, a frame rate, an image size, and an image quality. It is divided into sub-bitstreams for each channel for transmission.

7 illustrates a configuration of a scalable video bitstream for applying a hierarchical modulation scheme according to an embodiment of the present invention.

Referring to FIG. 7, the scalable video bitstream may include a base layer allocated to an HP channel and an extension layer allocated to an LP channel.

The base layer assigned to the HP channel has a 30 frame rate in CIF class and is encoded at 384 Kbps to maintain backward compatibility with existing terrestrial DMB.

The enhancement layer is assigned to the LP channel simultaneously with the base layer assigned to the HP channel.

The extended layer has 30 frame rates in SD class and is encoded at about 900 Kbps.

In order to match the target bit rate allocated to each channel, the rate control algorithm of H.264 is applied to SVC, and the base layer video encoding follows the H.264 standard.

In the terrestrial DMB advanced network, the target bit rate according to scalable video coding may be variable within a range not exceeding the total available channel capacity for each service provider.

In addition, the extended layer allocated to the LP channel can be encoded at 15 frame rates by using non-reference pictures when the bit rate is large according to the content type.

In this case, you will need to output only the reference pictures of the extension layer where the splitter is assigned to the LP channel.

In addition, in the next generation DMB advanced network, scalability of fine granular scalability (FGS) is not considered in consideration of the performance of the terminal compared to scalable video complexity.

8A illustrates a configuration of a splitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

Referring to FIG. 8A, the splitter 810 may include a splitter header parser 811, an HP channel generator 812, and an LP channel generator 813.

The splitter 810 divides one scalable video bitstream into bitstreams suitable for each channel for transmission of hierarchical modulation.

The scalable video bitstream includes a plurality of scalable layers having different bit rates, screen rates, and resolutions in one bitstream.

The splitter header parsing unit 811 parses the NAL header included in the NAL unit of the scalable video bitstream.

The splitter header parsing unit 811 parses the NAL header to divide the scalable video bitstream into a base layer and an extension layer.

The HP channel generator 812 generates an HP bitstream having a high transmission priority (HP) based on a base layer among a plurality of scalable layers included in one scalable video bitstream.

The LP channel generator 813 generates an LP bitstream having a low transmission priority (LP) based on an extension layer among a plurality of scalable layers included in one scalable video bitstream.

The terrestrial DMB advancement network employs a hierarchical modulation scheme that can extend about twice the available channel capacity provided by existing terrestrial DMB.

In order to apply the hierarchical modulation scheme, the present invention separates one scalable video bitstream through a splitter 810 through a high priority (HP) and a low priority (LP) channel to separate two sub bitstreams (HP stream and LP). Streams). In addition, according to the present invention, two generated bitstreams may be transmitted through one transmitter.

8B illustrates an operation of a splitter for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

H.264 generates one bitstream consisting of NAL units after video encoding, and each NAL unit has a NAL header of 1 byte.

Like H.264, scalable video has a header having 2 bytes of scalability information in addition to the 1-byte NAL header of the existing H.264.

Each field of the NAL header is determined by an international standard.

Table 1 below shows the major NAL headers.

One of the main fields of the NAL header, Dependency_id, is a syntax for distinguishing the base layer and the extension layer.

Therefore, the splitter algorithm performed in the splitter 820 first analyzes (NAL header parsing) each NAL header coming into the input.

Two sub bitstreams (HP bitstream and LP bitstream) allocated to each of the HP and LP channels may be output.

An HP channel (HP bitstream) having a high transmission priority is generated based on a base layer among scalable layers included in one scalable video bitstream.

An LP channel (LP bitstream) having a low transmission priority is generated based on an extension layer among scalable layers.

FIG. 8C is a diagram illustrating a splitter algorithm for hierarchical modulation transmission of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

A simple pseudo-code for the splitter algorithm is shown below.

Case A) Pseudo code in case of splitting bitstream at SD frame rate

Case B) Pseudo code in case of splitting bitstream at SD class 15 frame rate using non-reference pictures

SPS and PPS are parameter NAL units indicating a sequence parameter set and a picture parameter set containing decoding information for each layer.

SEI represents supplemental enhancement information and scalability information, and Lid represents Dependency_id .

SPS and PPS also indicate the NAL unit type, and the SPS / PPS corresponding to the layer is also output through the splitter.

Each nal_unit_type is defined as shown in Table 2.

In order to split the scalable video bitstream, a process of analyzing the syntax information of the SVC NAL header is required, and the required syntax elements are as follows.

(1) nal_unit_type: It means the type of packet including NAL unit and can distinguish SEI, SPS, PPS and Slice.

(2) dependency_id: Information in the NAL header extended in H.264, used in the decoding process, and indicates a lower layer used for inter-layer prediction.

Therefore, in the bitstream encoded by the two layers, the base layer is represented by dependency_id = 0 and the enhancement layer is represented by dependency_id = 1. In addition, in Figure 7, Lid represents dependency_id for distinguishing between layers.

A process of dividing the scalable bitstream using a splitter is illustrated in FIG. 8C.

First, nal_unit_type and dependency_id may be known through NAL header parsing on the received bitstream (S801 and S802).

Exceptionally, in case of Supplemental Enhancement Information (SEI) messages, SEI messages are not transmitted when splitter splits because they are used when extracting bitstreams from an extractor supported by SVC, not necessary for the actual decoding process (S803). ).

In a bitstream having two layers, dependency_id of the base layer having the CIF resolution may have 0 and dependency_id of the enhancement layer having the 4CIF resolution may have 1. Therefore, the bitstream may be split using dependency_id (S804).

For reference, two picture parameter sets (PPSs) for the enhancement layer are generated to separately apply Intra_BL MB mode to key-picture and non-key-picture in single-loop decoding.

As described above, the splitter algorithm obtains two bitstreams corresponding to the base layer base layer of the scalable video and transmits them through HP and LP channels (S805 and S806).

9 is a diagram illustrating a configuration of a receiver for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB advanced network according to an embodiment of the present invention.

Referring to FIG. 9, the receiver according to the present invention is a compositor for reconstructing two sub-bit streams (HP bitstream, LP bitstream) received on HP and LP channels in front of a receiving decoder in order to receive high quality / high resolution AV service. (Compositor) 900.

The compositor 900 receives two sub bitstreams as inputs at the receiving end and reconstructs one scalable video bitstream which can be decoded.

In the case of the existing terrestrial DMB terminal, only the HP channel can be received to receive the existing service. As such, the present invention provides backward compatibility with existing terrestrial DMB.

In case of a terrestrial DMB advanced dedicated terminal, a compositor for reconstructing two sub bitstreams (HP bitstream, LP bitstream) received from HP and LP channels in front of a receiving decoder in order to receive high quality / high resolution AV service. 900).

FIG. 10A illustrates a configuration of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

The scalable video bitstream includes a plurality of scalable layers having different bit rates, screen rates, and resolutions in one bitstream.

In order to apply the hierarchical modulation scheme, the transmitter according to the present invention separates one scalable video bitstream through a splitter (see FIGS. 8A and 8B) through a high priority (LP) channel and a low priority (LP) channel. To generate two sub-bit streams (HP stream and LP stream).

The compositor 1010 receives two sub-bit streams as inputs from the receiver and reconstructs and outputs one scalable video bit stream.

The compositor 1010 includes a bitstream receiver 1011, a header parser 1012 for a compositor, and a bitstream reconstruction unit 1013.

The bitstream receiver 1011 receives the HP bitstream and the LP bitstream.

The compositor header parsing unit 1012 analyzes the NAL header and the slice header included in the NAL unit of the received HP bitstream and LP bitstream.

The bitstream reconstruction unit 1013 receives two sub bitstreams (HP bitstream and LP bitstream) as inputs, and scalable video for each AU (Access Unit) which is a combination of NAL units corresponding to one same time axis that can be decoded. The bitstream is reconstructed and output.

FIG. 10B illustrates an operation of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

Basically, the compositor 1020 parses NAL header information and slice headers for NAL units to determine a picture order count (POC) corresponding to a display order of a corresponding NAL unit.

In the case of the compositor 1020, not only the information of Dependency_id, nal_ref_idc, and nal_unit_type of the existing NAL header, but also frame_num information of the slice header is used.

The final output of the compositor 1020 is to generate one scalable bitstream.

Therefore, POC information is necessary to output a bitstream for each access unit (AU), which is a combination of NAL units corresponding to the same time axis. Computing this POC information can follow the pseudo code provided by the existing SVC.

In conclusion, the compositor 1020 may output a decodeable bitstream using header information of the corresponding frame used in the splitter.

FIG. 10C is a diagram illustrating an algorithm of a compositor for hierarchical modulation reception of a scalable video bitstream in a terrestrial DMB enhancement network according to an embodiment of the present invention.

The compositor provides a function of reconstructing two bitstreams transmitted through the HP channel and the LP channel into a single decodable scalable bitstream.

To reconstruct the scalable bitstream, the frame_num element information in the Slice header as well as the syntax element used in the splitter are used. Syntax elements used in the Compositor are as follows.

(1) nal_unit_type

(2) frame_num: Used as ID of each picture and used in Slice header.

The process of reconstructing the bitstream using a compositor is illustrated in FIG. 10C.

The compositor sequentially acquires NAL units from buffers temporarily stored through HP and LP channels (S1001).

Nal_unit_type may be known through NAL header parsing for two input bitstreams split by a splitter (S1002).

First, one NAL is read from two input bitstreams, and then, the first conditional statement (S1003) of FIG. 10C is used to view the nal_unit_type of the NAL header. Is selected (S1004) to reconstruct the bitstream (S1009).

However, in the case of the enhancement layer, since two PPSs are used, the bitstream may be reconstructed using the packets of the LP channel using the second conditional statement S1005 of FIG. 10C to obtain the second PPS (S1009).

In other cases, since it corresponds to NAL Units containing actual slice information, the slice header of each NAL unit may be parsed (S1007) to obtain frame_num and reconstruct the bitstream (S1008 and S1009).

frame_num represents a picture order count (POC) corresponding to a display time of an actual bitstream.

In this way, the NAL header Dependency_id and slice header frame_num of the NAL unit to be input are analyzed (NAL header and slice header parsing). Picture Order Count (POC) can be calculated.

The bitstream may be reconstructed according to Dependency_id by collecting NAL units corresponding to the same POC, and the bitstream may be reconstructed from a NAL unit having a small frame_num of Slice NAL Units obtained from HP and LP.

In this case, a NAL unit having a low Dependency_id for each AU may be located before the bitstream.

In the case of reconstruction into one bitstream, in case of SEI / SPS / PPS, after determining nal_unit_type, the reconstructed NAL units corresponding to actual data may be located after the nal_unit_type.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored.

Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

As described above, the hierarchical modulation transmission / reception apparatus and method thereof of a scalable video bitstream according to the present invention provide high quality services in a future generation of terrestrial DMB advanced networks while maintaining backward compatibility with existing terrestrial DMB.

Claims (15)

A transmitter for a scalable video bitstream that includes a plurality of scalable layers, An HP channel generator configured to generate an HP bitstream having a high transmission priority (HP) based on a base layer among a plurality of scalable layers included in one scalable video bitstream; And An LP channel generator configured to generate an LP bitstream having a low transmission priority (LP) based on an enhancement layer among a plurality of scalable layers included in one scalable video bitstream; And a splitter for hierarchical modulation transmission of the scalable video bitstream. The method of claim 1, wherein the splitter Splitter header parsing unit for analyzing the NAL header included in the NAL unit of the scalable video bitstream, and divides the received scalable video bitstream into the base layer and extension layer And a transmitter further comprising. The method of claim 1, The video encoding of the base layer and the enhancement layer is encoded according to H.264, wherein the base layer is encoded at 30 frame rate and 384 Kbps in the CIF class, and the enhancement layer is encoded at 30 frame rate and 900 Kbps in the SD class. Transmitter. A receiver for a scalable video bitstream that includes a plurality of scalable layers, Hierarchical modulated scalable video bits for receiving the HP bitstream having the high transmission priority and the LP bitstream having the low transmission priority generated by dividing the scalable video bitstream and reconstructing the scalable video bitstream And a compositor for the stream. The method of claim 4, wherein the compositor A bitstream receiver configured to receive the HP bitstream and the LP bitstream; A compositor header parsing unit for analyzing a received NAL header and a slice header included in the NAL unit of the HP bitstream and the LP bitstream; And And a bitstream reconstruction unit configured to reconstruct and output the scalable video bitstream for each access unit (AU), which is a combination of NAL units corresponding to a same time axis. The method according to claim 4 or 5, The HP bitstream is generated based on a base layer of the scalable layer, and the LP bitstream is generated based on an extension layer of the scalable layer. The method of claim 6, The base layer and the extension layer is based on the standard of H.264, the base layer is a CIF-class 30 frame rate and 384Kbps, the extended layer is SD frame, characterized in that encoded at 30 frame rate and 900Kbps . In the method of transmitting a scalable video bitstream including a plurality of scalable layers, An HP channel generating step of generating an HP bitstream having a high transmission priority based on a base layer among a plurality of scalable layers included in one scalable video bitstream; And And an LP channel generation step of generating an LP bitstream having a low transmission priority based on an extension layer among a plurality of scalable layers included in one scalable video bitstream. A transmission method characterized by the above-mentioned. 9. The method of claim 8, wherein said splitting step A header parsing step for splitting the received scalable video bitstream into the base layer and the extended layer by analyzing a NAL header included in the NAL unit of the received scalable video bitstream; Transmission method characterized in that. The method of claim 8, The video encoding of the base layer and the enhancement layer is encoded according to H.264, wherein the base layer is encoded at 30 frame rate and 384 Kbps in the CIF class, and the enhancement layer is encoded at 30 frame rate and 900 Kbps in the SD class. Transmission method. In the receiving method for a scalable video bitstream including a plurality of scalable layers, A hierarchical modulated scalable video bit for reconstructing the scalable video bitstream by receiving an HP bitstream having a high transmission priority and an LP bitstream having a low transmission priority generated by dividing the scalable video bitstream. Composite step for the stream; receiving method comprising a. 12. The method of claim 11 wherein the composite step is A bitstream receiving step of receiving the HP bitstream and the LP bitstream; A composite parsing step of analyzing the received NAL header and slice header included in the NAL unit of the HP bitstream and the LP bitstream; And And reconstructing and outputting the scalable video bitstream for each AU that is a combination of NAL units corresponding to the same time axis. The method of claim 11 or 12, The HP bitstream is generated based on a base layer of the scalable layer, and the LP bitstream is generated based on an extension layer of the scalable layer. The method of claim 13, The base layer and the extension layer is based on the standard of H.264, the base layer is received at 30 frames rate and 384Kbps in CIF class, the extended layer is encoded in 30 frame rate and 900Kbps in SD class Way. A computer-readable recording medium having recorded thereon a program for executing the method according to any one of claims 8 to 14.

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