• Journal of IKEEE
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• v.20 no.3
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• pp.326-329
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• 2016

HEVC CABAC encoder performs binary arithmetic encoding after syntax elements are converted into binary values. Therefore, in HEVC CABAC decoder, binarized syntax elements from binary arithmetic decoder should be de-binarized into original syntax elements in the de-binarizer. In this paper, a HEVC CABAC de-binarizer architecture was proposed and implemented. It consists of a controller that analyzes and merges binarized syntax elements and an engine that converts merged binarized syntax elements into original syntax elements. The designed de-binarizer was described in Verilog HDL and it was synthesized and verified in 0.18um process technology. Its gate count and maximum operating frequency are 3,114 gates and 220 MHz, respectively.

• Journal of Korea Multimedia Society
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• v.8 no.10
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• pp.1403-1410
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• 2005

The synchronization problem is directly related to the quality of service in multimedia communication and especially in real-time communication. In this study, we found the cause of clock fluctuation between encoder and decoder in MPEG-2 system layer was that the standard decoder design only considered a fixed time delay component. To solve it, we proposed Extended-SRTS algorithm, which uses STC as service clock by synchronizing transport stream. As the result, we can improve the effect of frequency-drift, time-varying-network-jitter and packing-jitter and so on And by virtue of this algorithm, we can make low the dependency of network clock, which makes easy to synchronize and connect transparently at the ends point, we expect the proposed algorithm can be widely applied to the field of real -time multimedia communications.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.10-17
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• 2009

Wyner-Ziv video coding is a new video compression paradigm based on distributed source coding theory of Slepian-Wolf and Wyner-Ziv. Wyner-Ziv coding enables light-encoder/heavy-decoder structure by shifting complex modules including motion estimation/compensation task to the decoder. Instead of performing the complicated motion estimation process in the encoder, the Wyner-Ziv decoder performs the motion estimation for the generation of side information in order to make the predicted signal of the Wyner-Ziv frame. The efficiency of side information generation deeply affects the overall coding performance, since the bit-rates of the Wyner-Ziv coding is directly dependent on side information. In this paper, an improved side information generation method using field coding is proposed. In the proposed method, top fields are coded with the existing SI generation method and bottom fields are coded with new SI generation method using the information of the top fields. Simulation results show that the proposed method improves the quality of the side information and rate-distortion performance compared to the conventional method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.6
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• pp.1516-1529
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• 2023

In this paper, a motor gearbox fault-detection system based on a hierarchical flow-based model is proposed. The proposed system is used for the anomaly detection of a motion sound-based actuator module. The proposed flow-based model, which is a generative model, learns by directly modeling a data distribution function. As the objective function is the maximum likelihood value of the input data, the training is stable and simple to use for anomaly detection. The operation sound of a car's side-view mirror motor is converted into a Mel-spectrogram image, consisting of a folding signal and an unfolding signal, and used as training data in this experiment. The proposed system is composed of an encoder and a decoder. The data extracted from the layer of the pretrained feature extractor are used as the decoder input data in the encoder. This information is used in the decoder by performing an interlayer cross-scale convolution operation. The experimental results indicate that the context information of various dimensions extracted from the interlayer hierarchical data improves the defect detection accuracy. This paper is notable because it uses acoustic data and a normalizing flow model to detect outliers based on the features of experimental data.

• Journal of KIISE:Software and Applications
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• v.33 no.10
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• pp.823-835
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• 2006

Multimedia is a very popular service in the Internet. But, we cannot provide multimedia service at a uniform content, because networks and devices are various. Thus, an adaptive service is needed for multimedia transmission. Video Transcoding is the good solution that can service multimedia adaptively. This paper proposes the streaming system that is composed of encoder, transcoder, decoder The encoder enhanced time complexity and PSNR in case of transcoding using PP(Prediction Period). The decoder is almost same as the traditional media player. Transcoder reduced time complexity through combination of prediction period in encoder and skipping period to control frame rate in transcoder. In simulation results, the performances of proposed scheme outperform the system with traditional transcoder in time complexity and PSNR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.439-446
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• 2011

In this paper, we proposed and implemented a dedicated hardware for Huffman coding which is a method of entropy coding to use compressing multimedia data with video coding. The proposed Huffman codec consists Huffman encoder and decoder. The Huffman encoder converts symbols to Huffman codes using look-up table. The Huffman code which has a variable length is packetized to a data format with 32 bits in data packeting block and then sequentially output in unit of a frame. The Huffman decoder converts serial bitstream to original symbols without buffering using FSM(finite state machine) which has a tree structure. The proposed hardware has a flexible operational property to program encoding and decoding hardware, so it can operate various Huffman coding. The implemented hardware was implemented in Cyclone III FPGA of Altera Inc., and it uses 3725 LUTs in the operational frequency of 365MHz

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.712-722
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• 2002

We have investigated a novel optical decoder for a fiber-optic code division multiple access(CDMA) communication systems. The conventional optical encoder and decoder have the advantage of simple structure. However the number of users in the system is limited by the auto- and cross-correlation properties generated in decoding process. In previous studies, to improve the system performance, although they used an optical code that minimize the sidelobe and cross-correlation, could not yet find a novel methods for performance improvement in fiber-optic CDMA system. Thus, it is necessary to investigate the novel optical decode in order to improve the performance of system. In this paper, we schematize the AND gate logic element(AGLE) composed with 1$\times$2 or 1$\times$3 coupler and the optical thyristor and propose the novel optical decoder using K(weight) AGLE. The optical thyristor only passes the overlapped signal and clips other signals. Such a novel concept means that the optical thyristor can operate as a hard-limiter. We analyze the fiber-optic CDMA system using the novel optical decoder with simulation and is found that the novel optical decoder using the AGLE and optical thyristor excludes the sidelobe and cross-correlation intensity between any two sequences.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.86-96
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• 2013

Unified Speech and Audio Coding (USAC) is the speech/audio codec with the best quality, approved on Final Draft International Standard (FDIS) at MPEG meeting in 2011. Since MPEG conventionally standardizes only the decoder, it is not easy to study on the encoder technologies. Furthermore, Reference Model(RM) shows extremely poor performance. To solve these problems, the open source project(JAME) proposes the methods to make the improved performance of main encoder technologies in USAC. Especially, this paper introduces the encoder modules: the signal classifier for selective operation between two coders, the psychoacoustic model in frequency domain, and window transition technology. Finally, the results of verification test for FDIS and the performance of Common Encoder are appended.

• ETRI Journal
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• v.27 no.1
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• pp.53-63
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• 2005

A compressed video bitstream is sensitive to errors that may severely degrade the reconstructed images even when the bit error rate is small. One approach to combat the impact of such errors is the use of error concealment at the decoder without increasing the bit rate or changing the encoder. For spatial-error concealment, we propose a method featuring edge continuity and texture preservation as well as low computation to reconstruct more visually acceptable images. Aiming at temporal error concealment, we propose a two-step algorithm based on block matching principles in which the assumption of smooth and uniform motion for some adjacent blocks is adopted. As simulation results show, the proposed spatial and temporal methods provide better reconstruction quality for damaged images than other methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.105-109
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• 2002

The main ideas of hybrid video coding methods are to reduce the spatial and temporal redundancy for efficient data compression. If compressed video stream is transmitted through the error-prone channel, bitstream can be critically damaged and the spatio-temporal error propagates through successive frames at the decoder because of drift noise in the references between encoder and decoder. In this paper, I propose the lagrangian multiplier selection method in the error-prone environment. Finally, it is shown that the performance comparisons of the R-D optimized mode decision are made against the conventional method and simulation results are given in the following.