• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.99-101
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• 2011

MPEG-DASH(Dynamic Adaptive Streaming over HTTP)는 MPEG(Moving Picture Experts Group)에서 표준화 중인 HTTP를 이용한 적응형 비디오 스트리밍 기술이다. MPEG-DASH는 인터넷 방화벽에 의해 차단되는 RTP/UDP를 이용한 AV 스트리밍 대신 현재 HTTP/TCP를 이용하여 AV 스트리밍을 하는 추세에 맞춰 유무선 인터넷에서 망 환경 및 단말 환경에 동적 적응적으로 AV 스트리밍을 달성하기 위한 기술에 대한 표준이다. HTTP를 이용한 AV 스트리밍은 서버의 부담을 최소화하고 클라이언트의 지능적 처리에 전적으로 의존하는 스트리밍 방식이다. MPEG-DASH 클라이언트는 HTTP의 파일 전송 요청 또는 파일 일부 전송 요청만을 사용하여 스트리밍을 달성한다. 2011년 7월 제97차 MPEG 회의에서 MPEG-DASH DIS(Draft International Standard) 2차 버전이 승인되었다. 본 논문에서는 이 DIS 2차 버전에 따라 MP4 파일 포맷 기반의 MPEG-DASH 클라이언트를 구현하고 그 동작을 실험을 통해 검증하였다.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.283-299
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• 2015

In this paper, we propose new broadcasting services that combine MMT (MPEG Media Transport) standard with MPEG-DASH (Dynamic Adaptive Streaming over HTTP) standard. MMT is a next-generation multimedia transport standard that is IP-friendly and provides functionalities appropriate for hybrid broadcasting that uses broadcast physical channels and the Internet simultaneously. MPEG-DASH enables media streaming services that can be dynamically adaptive both to the network traffic conditions of wired and/or wireless Internet and the receiving entity environment. We explain the scenarios of the proposed broadcasting services and demonstrate that various hybrid broadcasting services can be easily realized through the combined usage of MMT and MPEG-DASH. By making the test bitstreams containing contents for the new services and developing the receiver back-end software that performs the function of the receiving entity for the new services on personal computers, we verified that the proposed scenarios can be realized.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.18-21
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• 2018

최근 시청자에게 실재적인 몰입감을 제공하는 실감미디어가 발전하고 있다. 이러한 실감미디어 중 가장 접근성이 뛰어난 것은 VR으로, 현재 다양한 서비스에 응용되고 있는 상황이다. 하지만 360VR은 높은 비트 전송률과 고해상도의 특성을 지니고 있기 때문에 대역폭 비용 및 시청자의 QoE 보장의 불확실성 등의 다양한 문제가 있다. 이러한 문제를 개선시키기 위해 HTTP 기반의 적응적 스트리밍 기법이 발전해나가고 있으며 이 기술의 표준으로 MPEG-DASH가 채택되었다. MPEG-DASH는 TCP 기반의 전송 프로토콜을 사용하고 있지만 현재 TCP는 고용량의 데이터가 전송되는 웹 기반에서 HTTP의 병목현상을 일으켜 대역폭 효율성을 떨어뜨리는 하나의 원인으로 나타나고 있다. 이러한 문제를 해결하기 위해 본 논문에서는 UDP 기반의 QUIC 프로토콜을 MPEG-DASH에 적용하는 시스템을 고안하고 이를 QUIC-DASH라 칭한다. 고해상도의 360VR 송출 실험으로 QUIC-DASH 시스템과 기존의 MPEG-DASH 시스템을 비교 분석한 결과로 대역폭의 절감이 이루어진 것을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.203-206
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• 2012

본 논문은 HTTP protocol을 이용한 미디어 Streaming 서비스 표준인 MPEG-DASH(Dynamic Adaptive Streaming over HTTP)를 기반으로 한 N-Screen 서비스 동기화 방안을 제시한다. N-Screen 서비스란 다수의 미디어 Device를 이용하여 하나의 콘텐츠들을 공유 및 전송하는 서비스를 뜻한다. 이는 MPEG-DASH 표준 기술을 활용함으로써 보다 효율적인 서비스 이용이 가능하다. DASH는 다수의 품질의 같은 영상들을 시간별로 분할하여 Server에서 보유하여 한 Device에게 네트워크 환경에 맞춰 가장 적합한 Segment들을 전달 및 전환함으로써 끊기지않는 Streaming 서비스가 가능하다. 하지만 현재 MPEG-DASH 표준기술에서는 N-Screen 서비스에 대한 활용방안 시나리오가 재정되어 있지 않아 다수의 Device에서 Segment를 끊김없는 Media Streaming 서비스를 지원하기 위한 방안이 필요하다. 이를 위해 본 논문에서는 한 Device가 다른 Device에게 N-screen을 위한 동기화 정보를 전송함으로써 특정 콘텐츠가 끊기지 않고 연이어 볼 수 있는 동기화를 이룰 수 있는 방안을 대한 서비스 시나리오를 제시한다.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.942-951
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• 2018

In these days, 360 degree videos, which is provided via VR, have high resolution and quality of 8K. These kinds of videos inevitably require streaming technology which guarantees QoS. Therefore, we suggest MPEG DASH HTTP protocol which stably provides streaming services of high quality videos in 8K, which are 360 degree tile-encoded, on low-spec devices such as OTT and IPTV Settop and Tile Segment Cache management structure for servers operating streaming services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2544-2557
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• 2019

Adaptive bitrate streaming is a crucial element in the implementation of high-quality streaming of media content over the Internet. Dynamic adaptive streaming over HTTP (MPEG-DASH) has lately emerged as the de facto solution for over-the-top (OTT) video streaming services. In this paper, we perform macro-level analysis on a real-world MPEG-DASH-based Internet live broadcasting service to gain insight into its behavior throughout the end-to-end service-provision chain, from broadcasters to viewers. Based on this analysis, we propose methods to improve the quality-of-experience (QoE) of MPEG-DASH-based services, particularly with regard to reducing broadcasting delays between recording and viewing of videos, as well as synchronizing client terminals.

• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.115-121
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• 2013

Recently an extension to DMB AF (Digital Multimedia Broadcasting Application Format) standard has been proposed in such a way that the extended DMB AF can include stereoscopic video and stereoscopic images for interactive service data, i.e., MPEG-4 BIFS (Binary Format for Scene) data, in addition to the existing 2D video and 2D images for BIFS services. In this paper we developed a service that provides the streaming of 3D contents in DMB AF by using MPEG-DASH (Dynamic Adaptive Streaming over HTTP) standard and validated it by implementing the client software.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.47-53
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• 2012

In general, it is essential that contents are to be provided with proper bitrate according to network conditions in order to support higher quality of video streaming services over wired and wireless networks. Recently, DASH is adopted by the MPEG as the standard for HTTP based adaptive streaming technology and consists of the server and clients. The clients should parse XML files from the server and play contents after accessing the finely divided segments into various bitrates. In this paper, we designed a Smart AP(Access Point) which exists between DASH contents server and Non-DASH clients enables provide DASH services to Non-DASH clients. In addition, proposed Smart AP provides DASH service to various types of clients as maintaining the existing environment without additional development costs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5981-5997
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• 2017

Advanced Television Systems Committee (ATSC) produced ATSC 2.0 standard, which has been used for a HD/SD digital broadcasting service with MPEG-2 Transport Stream (TS) as a delivery protocol. Recently, users might want to consume multimedia services without being constrained by transport network. However, MPEG-2 TS is not suitable protocol for IP network. Thus, ATSC has enacted ATSC 3.0 standard, which is designed for a hybrid service through a conversion of both broadcasting and broadband channels. The ATSC 3.0 specifies delivery protocols as MPEG Media Transport (MMT) for a broadcasting environment and Dynamic Adaptive Streaming over HTTP (DASH) for a broadband. However, it seems difficult to combine broadcast and broadband for hybrid broadcasting, and it is difficult to synchronize media data between MMT and DASH. This paper suggests various new service scenarios to be brought up by a hybrid broadcasting, ATSC 3.0, and also proposes a stable mechanism for switching contents between different delivery protocols such as MMT and DASH.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.660-669
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• 2019

Recently, with the development of three-dimensional scanning devices and multi-dimensional array cameras, research is continuously conducted on techniques for handling three-dimensional data in application fields such as AR (Augmented Reality) / VR (Virtual Reality) and autonomous traveling. In particular, in the AR / VR field, content that expresses 3D video as point data has appeared, but this requires a larger amount of data than conventional 2D images. Therefore, in order to serve 3D point cloud content to users, various technological developments such as highly efficient encoding / decoding and storage, transfer, etc. are required. In this paper, V-PCC bit stream created using V-PCC encoder proposed in MPEG-I (MPEG-Immersive) V-PCC (Video based Point Cloud Compression) group, It is defined by the MPEG-DASH (Dynamic Adaptive Streaming over HTTP) standard, and provides to be composed of segments. Also, in order to provide the user with the information of the 3D coordinate system, the depth information parameter of the signaling message is additionally defined. Then, we design a verification platform to verify the technology proposed in this paper, and confirm it in terms of the algorithm of the proposed technology.