• The KIPS Transactions:PartD
• /
• v.10D no.7
• /
• pp.1177-1188
• /
• 2003

In this paper, a cyber space for multimedia conference is designed and implemented using gatekeeper and web service which satisfies H.323 standards. The implemented gatekeeper manages a registration and a call control for H.323 video conference terminals. The implemented gate-keeper can manage registered users efficiently with directory services using web service. Also, software maintenance of video conference system is established by service provider instead of users using control download on web. finally, we present the practical use of video conference through various applications of directory services.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.1B
• /
• pp.26-38
• /
• 2006

To construct seamless collaborative environments, what all participants intent should be delivered, and visual elements such gesture, facial expression, and ambiance should be shared with all participants. In this paper, we propose high-quality video service to support DV(digital video) and HDV(high-definition DV) based on Access Grid(AG) which is a prevalent collaborative system. The proposed service is designed for employing versatile media tools and codecs with SDP(session description protocol) and SAP(session announcement protocol). We also design network-adaptive video transmission module to mitigate the impact of network fluctuation. This periodically monitors multicast performance and controls frame rate on sender side considering network condition. The experimental results over the test bed show that proposed service enhances quality of AG video service and provides seamless high-quality video transport by mitigating the impact of network fluctuation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.595-598
• /
• 2005

MPEG-4 Visual is, and international standard for the object-based video compression, designed for supporting a wide range of applications from multimedia communication to HDTV. To control the minimum decoding complexity required at the decoder, the MPEG-4 Visual standard defines the co-called video buffering mechanism, which includes three video buffer models. Among them, the VCV(Video Complexity Verifier) defines the control of the processing speed for decoding of a macroblock, there are two models: VCV and B-VCV distinguishing the boundary and non-boundary MB. This paper presents the evaluation results of decoding complexity by measuring decoding time of a MB for rectangular, arbitrarily shaped video objects and the various types of objects supporting the resolution of HDTV using the optimized MPEG-4 Reference Software. The experimental results shows that decoding complexity varies depending on the coding type and more effective usage of decoding resources may be possible.

• Journal of Platform Technology
• /
• v.11 no.1
• /
• pp.11-22
• /
• 2023

Various video conferencing and collaboration applications have emerged due to the global epidemic of new viral infections. In addition to real-time video conferencing, video conferencing applications provide features such as chat and file sharing on various platforms. Because various personal information is stored through functions such as chatting, file and screen sharing, these video conferencing applications are the major target of analysis from a digital forensic investigation. In the case of applications that provide cross-platform, the form of stored data is different depending on the platform. Therefore, to utilize data of video conferencing application for forensic investigation, preliminary research on artifacts stored by platform is required. In this paper, we used the video conferencing applications GoToWebinar and GoToMeeting and analyzed the artifacts generated. As a result, we list the main data from a digital forensic investigation. We identify data stored for each platform provided by GoToWebinar and GoToMeeting and organize artifacts that can estimate user behavior. Also, we classify the data that can be acquired according to the role and environment within the video conference.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.05a
• /
• pp.650-652
• /
• 2022

Frame rate up-conversion (FRUC) algorithm is an image interpolation technology that improves the frame rate of moving pictures. This solves problems such as screen shake or blurry motion caused by low frame rate video in high-definition digital video systems, and provides viewers with a more free and smooth visual experience. In this paper, we propose a video compression technique using deep learning-based FRUC algorithm. The proposed method compresses and transmits after excluding some images from the original video, and uses a deep learning-based interpolation method in the decoding process to restore the excluded images, thereby compressing them with high efficiency. In the experiment, the compression performance was evaluated using the decoded image and the image restored by the FRUC algorithm after encoding the video by skipping 1 or 3 pages. When 1 and 3 sheets were excluded, the average BD-rate decreased by 81.22% and 27.80%. The reason that excluding three images has lower encoding efficiency than excluding one is because the PSNR of the image reconstructed by the FRUC method is low.

• 한국HCI학회:학술대회논문집
• /
• 2007.02a
• /
• pp.334-339
• /
• 2007

유비쿼터스 환경이 도래하면서 모바일 화상회의 시스템의 사용욕구가 증대되고 있다. 모바일 화상회의 시스템은 사용자가 가지고 있는 다양한 모바일 장치에의 적용과 무선 환경에서의 고용량 데이터의 전송을 요구한다. 본 논문에서는 다양한 플랫폼에서 구동할 수 있고 고용량 데이터의 무선 환경에서의 안정적인 전송을 위한 시스템 구조를 제안한다.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.168-171
• /
• 1988

This paper describes CODEC based on hybrid interframe and BTVQ including CRC(Conditional Replenishment Coding) system and RLC(Run Length Coding) method. Based upon the algorithm described in this paper, a practical CODEC has been designed for video conference and video phone use at 54Kbps using an ADSP-2100 as a CPU.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.1101-1104
• /
• 1998

The modern multimedia applications which are video processor, video conference or video phone and so forth require real time processing. Because of a large amount of image data, those require high compression performance. In this paper, the prosposed image processing encoder was designed by using wavelet transform encoding. The proposed filter block can process imae data on the high speed because of composing individual function blocks by parallel and compute both highpass and lowpass coefficient in the same clock cycle. When image data is decomposed into multiresolution, the proposed scheme needs external memory and controller to save intermediate results and it can operate within 33MHz.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11a
• /
• pp.280-282
• /
• 2005

In this paper we propose several mapping schemes for streaming video generated by state-of-the-art H.264 codec over IEEE 802.11e enabled wireless LANs. The schemes take advantage of both 802.11e's QoS mechanism and some novel features of the H.264 codec, so as to protect the most important information in terms of visual quality and reduce distortion under network congestion. The proposed methods are evaluated by means of the H.264 reference software codec, network simulation, and objective video quality measurements. Results show that the proposed methods achieve a robust and error resilient H.264 video streaming over wireless LANs than traditional best-effort streaming.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10a
• /
• pp.465-467
• /
• 1998

MPEG-2 는 Layered Coding방식을 채택하여 하나의 base layer와 4개의 enhancement layer로 이루어져 있으나 동영상 재생을 위해 필요한 최소한의 layer인 base layer 만으로도 데이터 양이 많기 때문에 인터넷 환경에 적용하기가 어렵다. 이에 base layer를 다시 세분화된 layer로 나누기 위해 인코딩 중에는 또는 인코딩 결과로 만들어지는 MPEG-2 Video steam 의 하부 구조인 블록층에 존재하는 8$\times$8블록의 AC 계수들을 layering한다. Layered된 base layer의 데이터는 통신망 및 단말기의 QoS에 따라 서로 다른 전송 채널을 통해 서버에서 클라이언트 디코더로 전송된 후 디코더에 실시간적으로 병합한 후 재생된다. 본 논문에서 제안하는 기법을 이용하여 기존에 encoding MPEG-2 Video steam의 AC계수를 layering할 경우에 QoS에 따라 가변적으로 데이터 양을 서버 쪽에서 조절할 수 있었고, 통신 선로 상에서 이동하는 데이터 양의 원래의 MPEG-2 Video steam 을 이용했을 때보다 인코딩 중에 블록을 변환하면 51% 정도 감소하고 인코딩 되어진 데이터를 이용했을 경우에는25%정도 감소하는 것을 알 수 있었다.