• Journal of KIISE:Computing Practices and Letters
• /
• v.13 no.5
• /
• pp.260-270
• /
• 2007

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. However, since mobile clients use wireless network and the wireless network have less stable bandwidth according to distance from AP and environments, it is hard to support stable QoS to mobile clients. In this paper, we propose a dynamic bit rate control method for transcoding in order to supprot stable QoS of streaming media service to mobile clients via wireless network. The proposed method is shown to serve seamless streaming media service with adaptive bit rate control according to state of wireless network in real time and to reduce transmission failure from experiment.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.513-516
• /
• 2005

SVC(Scalable Video coding) is the standardization of MPEG that aims to support multi spatial, temporal, and quality layers. We can support the video service guaranteeing the QoS in varied network circumstance by using SVC bitstream. In this paper, we propose the real-time SVC bitstream extractor that is able to extract the bitstream with varied frame rate and SNR quality in real-time. To do, extraction processing needs to be performed by GOP unit. As well , essential bitstream information for real-time extraction is aquired before doing extraction process. The proposed method is implemented by using JSVM 2.0. Experimental results show that the proposed method is valid.

• Journal of Broadcast Engineering
• /
• v.24 no.2
• /
• pp.251-263
• /
• 2019

Recently the huge demand for Internet media streaming has dramatically increased the cost of the CDN (Content Delivery Network) and the need for a means to reduce it is increasing day by day. In this situation, a P2P-assisted DASH technology has recently emerged, which uses P2P (Peer-to-Peer) communications based on WebRTC (Web Real-Time Communication) standards to reduce the CDN cost. This paper proposes an algorithm that can significantly improve CDN cost savings in this technology by selecting peers based on the transport history. Also we implemented this algorithm in an experimental system and, after setting experimental conditions that emulate the actual mobile network environment, we measured the performance of the experimental system. As a result, we demonstrated that the proposed algorithm can achieve higher CDN cost savings compared to the conventional algorithm where peers are selected at random.

• The KIPS Transactions:PartA
• /
• v.11A no.7 s.91
• /
• pp.547-554
• /
• 2004

To play back CM (Continuous Media) in online mode, the multimedia system Is required to have a real-time disk scheduling scheme that can efficiently fulfill the strict temporal constraints of serviced CM streams to prevent hiccups. In general, such disk scheduling is performed based on the concept of periodic prefetching since a CM stream has a rather long Playback time. In this paper, we also propose a periodic prefetching scheme that runs by using real-time disk channels, called on-time delivery channels. Since the channels are generated from the bulk-SCAN algorithm and they can be allocated in a very flexible manner based on the EDF (earliest-deadline-first) algorithm, the proposed scheme provides a better Performance in terms of I/O throughput and the average response time, as well as hiccup-free playback of concurrent CM streams. To show that the proposed scheme outperforms other methods, we give some simulation results.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.441-450
• /
• 2008

The scalable extension of H.264, known as scalable video coding (SVC) has been the main focus of the Joint Video Team's work and was finalized at the end of 2007. Synchronization between media is an important aspect in the design of a scalable video streaming system. This paper proposes an efficient media synchronization mechanism for SVC video transport over IP networks. To support synchronization between video and audio bitstreams transported over IP networks, a real-time transport protocol/RTP control protocol (RTP/RTCP) suite is usually employed. To provide an efficient mechanism for media synchronization between SVC video and audio, we suggest an efficient RTP packetization mode for inter-layer synchronization within SVC video and propose a computationally efficient RTCP packet processing method for inter-media synchronization. By adopting the computationally simple RTCP packet processing, we do not need to process every RTCP sender report packet for inter-media synchronization. We demonstrate the effectiveness of the proposed mechanism by comparing its performance with that of the conventional method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2017.11a
• /
• pp.149-150
• /
• 2017

현재, 페이스북, 인스타그램 등 다양한 형태로 실시간 스트리밍 서비스를 제공되고 있다. 이로 인해 특정 소수가 아닌 일반인들도 손쉽게 실시간으로 인터넷 스트리밍이 가능하게 되었다. 과거, 스튜디오가 아닌 중계차가 갈 수 없는 곳에서는 실시간 스트리밍 서비스에 제약이 있었던 반면에 지금은 다양한 이동형 장비의 개발을 통해 공간적 제약이 현저히 줄어들었다. 따라서 본 논문에서는 촬영부터 송출까지 이동형 장비를 이용해 언제 어디에서나 실시간 스트리밍 서비스를 제공할 수 있는 시스템을 제안하였다.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.3
• /
• pp.1-7
• /
• 2021

In this paper, optimized media data retrieval and transmission based on the Hybrid CDN/P2P architecture and selective storage through user's prediction of requestability enable seamless data transfer to users and reduction of unnecessary traffic. We also propose a new media management method to minimize the possibility of transmission delay and packet loss so that media can be utilized in real time. To this end, we construct each media into logical segments, continuously compute weights for each segment, and determine whether to store segment data based on the calculated weights. We also designate scattered computing nodes on the network as local groups by distance and ensure that storage space is efficiently shared and utilized within those groups. Experiments conducted to verify the efficiency of the proposed technique have shown that the proposed method yields a relatively good performance evaluation compared to the existing methods, which can enable both initial latency reduction and seamless transmission.

• Journal of the Korea Convergence Society
• /
• v.8 no.9
• /
• pp.231-236
• /
• 2017

This study analyzes the characteristics of mobile live streaming service, the illegal and harmful information characteristics of mobile live streaming service for the purpose of eradicating illegal and harmful broadcasting, and shows illegal and harmful broadcast on the mobile live streaming service and eradication plan. First, we reviewed the mobile live streaming service, illegal and harmful broadcasts through literature review, and secondly surveyed illegal and harmful broadcasts of mobile live streaming services and their awareness and countermeasures. As a result, it is confirmed that the mobile live streaming service is illegal, harmful broadcasting exposure frequency is high, illegal, and harmful broadcasting exposure is caused by characteristics of real time broadcasting rather than user's. In order to eradicate the illegal and mobile information about the mobile live streaming service, it is necessary to fix the illegal service and harmful broadcasting reporting system, but the government has confirmed the requirements for regulatory measures. From a microscopic point of view, it will be necessary to investigate the illegal use of mobile live streaming services and the eradication of harmful information.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.10e
• /
• pp.343-345
• /
• 2002

본 논문에서 구현한 MPEG-4 미디어 재생기는 네트워크를 통하여 스트리밍 서버에 메시지를 전송하고, 스트리밍 서버로부터 전송된 미디어 스트림을 처리하여 사용자의 화면에 보여주는 역할을 수행한다. 미디어 재생기는 서버에게 VCR(Play, Pause, Stop, Jump)이벤트를 전송하며, 리눅스 운영체제에서 동작한다. 본 논문에서 제안하는 미디어 재생기는 VCR 연산을 위한 RTSP(Real Time Streaming Protocol)를 지원하며 데이터의 실시간 전송을 위하여 RTP(Real-time Transport Protocol)／RTCP(real-time transport control protocol)를 지원한다. RTP/RTCP를 통하여 네트워크 QoS와 관련된 정보를 획득하며 그 정보에 따라서 데이터 전송율을 조절하고 RTCP를 이용하여 에러 패킷에 대한 재전송을 사용한다. 재전송시 미디어 재생기의 버퍼링 상태와 멀티미디어 데이터의 재생시간을 고려하여 멀티미디어 데이터의 끊김이 없도록 한다.

• Journal of Broadcast Engineering
• /
• v.24 no.2
• /
• pp.329-340
• /
• 2019

Recently, broadcasting technologies have evolved as high-quality AV services such as domestic terrestrial UHD(Ultra-High Definition) broadcasting have been increasing, and broadcasting standards have been newly defined. Also, as network technology develops, contents are consumed not only in the country but also the world. Accordingly, content insertion technology, which is a method of providing suitable contents in accordance with the national and local environments, will be needed. This paper proposes a content insertion service system model and synchronization scheme using ATSC(Advanced Television Systems Committee) 3.0 Event Signaling standard under heterogeneous network environment of broadcasting network and internet network based on transmission standard DASH(Dynamic Adaptive Streaming over HTTP)/ROUTE(Real time Object delivery Over Unidirectional Transport) and MMT(MPEG Media Transport) of terrestrial UHD broadcasting. It also verifies that the service operates in an environment that meets the broadcast standard.