• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.632-634
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• 1999

기존의 화상전화 시스템 및 화상회의 시스템은 H/W로 구현된 H.263 CODEC을 사용한 경우는 있었지만, 컴퓨터의 성능변수와 직접적인 관계가 있는 S/W CODEC을 사용한 경우는 드물었다. 여기에 착안하여 본 연구는 PSTN 망에서의 화상회의 및 화상전화에 응용할 수 있는 실시간 H.263 S/W CODEC을 구현하였다. H.263 S/W CODEC을 MuX(Multimedia I/O Server)의 DLM으로 구현함으로써 현재 LAN 기반으로 동작하는 MuX를 PSTN망으로 확장하는데 있어 기반 기술로 사용할 수 있으며, 대역폭이 낮은 LAN 환경에서도 안정적인 화상회의가 가능하도록 하였다.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.947-950
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• 2001

This paper implements H.263 codec using SIMD(single instruction multiple data) method in real time based on PC. This system uses INS algorithm previously proposed by the authors as motion estimation module. SIMD method is used in DCT, IDCT, quantization, motion estimation, and display module. The developed algorithms are implemented using TMN5. Using the above algorithm, H.263 Codec can communicate more than 15 frames/sec in CIF resolution on a Pentium-IV 1.7GHz computer.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.477-485
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• 2002

In this paper, we present an efficient hardware architecture for the H.263 video codec and its VLSI implementation. This architecture is based on the unified interface by which internal hardware engines and an internal RISC processor are connected one another. The unified interface enables the modular design of internal blocks, efficient hardware/software partitioning, and pipelined paralled operations. The developed VLSI supports the H.263 version 2 profile 3 @ level 10, and moreover, both the control protocol H.245 and the multiplexing protocol H.223. Therefore, it can be used for the complete ITU-T H.324 or 3GPP 3G 324M multimedia processor with the help of an external audio codec. Simultaneous encoding and decoding of QCIF format images at a rate greater than 15 frames per second is achieved at 40 MHz clock frequency.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.4
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• pp.214-221
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• 2003

This paper shows an implementation of video codec (coder/decoder) on an embedded system. The video codec supports both H.261 and H.263 standards. For efficient real-time processing, the video codec is partitioned into a software module and a hardware module. Both modules are codesigned on an embedded system. The software module is processed on a real-time operating system and a RISC processor. It cooperates with the hardware module to compress and decompress images in real time. AMBA (Advanced Microcontroller Bus Architecture) AHB (Advanced High-performance Bus) is used as the system bus. The hardware module works both as AHB masters and as AHB slaves. The encoder part of the hardware module operates in a pipelines mode to compress images in real time. The video codec compresses 15 CIF frames and simultaneously decompresses 15 CIF frames in a second according to H.261 or H.263 standard at 33 MHz frequency.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.12-14
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• 1999

H.263+[1]는 1996년에 비디오압축 표준안으로 확정된 H.263의 확장으로 현재 널리 퍼져 있는 저 전송률의 가정용 전화선을 위한 비디오 압축에 관한 표준안으로 1988년에 확정되었다. H.263+의 기본 알고리즘은 H.263과 같으나 사용상의 편의를 위한 여러 선택모드와 이종의 네트워크환경에서 발생하는 대역폭의 변화나 에러를 위한 scalability(계층부호화)와 같은 새로운 기능이 추가되었다. 새로운 표준안에 따른 실시간 비디오 전송을 처리하기 위해서 필연적으로 하드웨어 코덱의 개발 필요성이 대두되고 있으며 실시간 비디오 코덱은 영상회의 전화기나 멀티미디어 전송시스템의 핵심기술로써 적용될 수 있다. 본 논문에서는 ITU-T H.263+의 기본모드와 새로이 추가된 선택모드 일부를 지원하는 코덱을 하드웨어 기술 언어인 VHDL(VHSIC Hardware Description Language)을 사용하여 기술하고 각 모듈과 최상의 모듈을 시뮬레이션하여 동작을 검증했다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.771-782
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• 2000

In this paper, an H.263 video codec is implemented by adopting the concept of hardware and software co-design. Each module of the codec is investigated to find which approach between hardware and software is better to achieve real-time processing speed as well as flexibility. The hardware portion includes motion-related engines, such as motion estimation and compensation, and a memory control part. The remaining portion of theH.263 video codec is implemented in software using a RISC processor. This paper also introduces efficient design methods for hardware and software modules. In hardware, an area-efficient architecture for the motion estimator of a multi-resolution block matching algorithm using multiple candidates and spatial correlation in motion vector fields (MRMCS), is suggested to reduce the chip size. Software optimization techniques are also explored by using the statistics of transformed coefficients and the minimum sum of absolute difference (SAD)obtained from the motion estimator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1755-1766
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• 1999

A region-based video codec based on the H.263+ standard is examined and its associated novel rate control scheme is proposed in this work. The region-based coding scheme is a hybrid method that consists of the traditional block DCT coding and the object-based coding. Basically, we adopt H.263+ as the platform, and develop a fast macroblock-based segmentation method to implement the region-based video codec. The proposed rate control solution includes rate control in three levels: encoding frame selection, frame-layer rate control and macroblock-layer rate control. The goal is to enhance the visual quality of decoded frames at low bit rates. The efficiency of proposed rate control scheme applied to the region-based video codes is demonstrated via several typical test sequences.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2577-2580
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• 2003

In this paper we present a teleoperation system of an internet-based mobile robot based on H.263 image compression algorithm. We control remotely the networked mobile robot with vision over the internet under unknown environments in the real time. The main feature of this system is that local operators need to download and install a client program and so they can command the robot in a remote location. Image information of remote location is compressed by H.263 video codec algorithm and then transmitted to a local operator. We constructed and tested a networked autonomous mobile robot in the real field. The experimental results show the usefulness of the robot under test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1914-1919
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• 2006

Video transfer problem on mobile is transfer speed and controls. Compression technique is needed to transfer videos and H.263 codec is used for compression, effectively controls camera on remote places, increased the real time connecting users. In this paper, we could solve the problem that use existent RF, and could transfer the most suitable image and audio.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.29-32
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• 2000

Layered video coding schemes allow the video information to be transmitted in multiple video bitstreams to achieve scalability. they are attractive in theory for two reasons. First, they naturally allow for heterogeneity in networks and receivers in terms of client processing capability and network bandwidth. Second, they correspond to optimal utilization of available bandwidth when several video qualify levels are desired. In this paper we propose a scalable video codec architectures with motion estimation, which is suitable for real-time audio and video communication over packet networks. The coding algorithm is compatible with ITU-T recommendation H.263+ and includes various techniques to reduce complexity. Fast motion estimation is Performed at the H.263-compatible base layer and used at higher layers, and perceptual macroblock skipping is performed at all layers before motion estimation. Error propagation from packet loss is avoided by Periodically rebuilding a valid Predictor in Intra mode at each layer.