• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.12
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• pp.67-72
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• 1993

An adaptive block truncation coding(BTC) using human visual system(HVS) is proposed. To reduce visible blocking effect at sensitive area in HVS. a new category classification coefficient is proposed. The categroy classification coefficient was derived by combining the modified HVS and standard deviation. By computer simulations, we showed that the proposed method reduced blocking effect at low bit rate coding more than the conventional Hui's method.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.49-52
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• 2008

This paper briefly introduces the current status of MPEG Audio Subgroup activities for standardizing a new audio coding technologies. Currently MPEG Audio Subgroup focused on spatial audio coding tools for compressing multiple audio objects and unified coding tools for presenting the consistence performance on speech and audio signal at the same time. Also a new MAF (MPEG Application Format) for interactive music was introduced at the 84th MPEG meeting.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.538-541
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• 1999

MPEG-2 AAC(Advanced Audio Coding) is the most advanced coding scheme available for high quality audio coding. This MPEG-2 AAC audio Standard allows for ITU-R ‘indistinguishable’ quality according to at data rates of 320 kb/s for five full-bandwidth channel audio signals. The compression ratio is around a factor of 1.4 better compared to MPEG Layer 3, you get the same quality at 70% of the bitrate. This paper suggest optimization method for MDCT/IMDCT (Modified Discrete Cosine Transform/Inverse Modified Discrete Cosine Transform) in Encoder and Decoder for AAC.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2021.06a
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• pp.78-80
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• 2021

In this paper, we proposed an improved method on the picture order of coding (POC) of MPEG-5 Essential video Coding (EVC) encoder to support a short intra period for Video-based Point Cloud Compression (V-PCC). As a codec-agnostically designed standard, V-PCC claimed to be able to work with a lot of codecs. Current EVC test model software shows that the baseline profile could not provide appropriate POC calculation. The proposed method offers a solution to this POC-related problem and provides up to 44.6% coding grains for EVC based V-PCC.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3672-3684
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• 2015

Recently, the standardization of backward compatible JPEG image coding for high dynamic range (HDR) image has been undertaken to establish an international standard called "JPEG XT." The JPEG XT consists of two layers: the base layer and the residual layer. The base layer contains tone mapped low dynamic range (LDR) image data and the residual layer contains the error signal used to reconstruct the HDR image. This paper gives the result of a study to evaluate the overall performance of tone mapping operators (TMOs) for this standard. The evaluation is performed using five HDR image datasets and six TMOs for profiles A, B, and C of the proposed JPEG XT standard. The Tone Mapped image Quality Index (TMQI) and no reference image quality assessment (NR IQA) are used for measuring the LDR image quality. The peak signal to noise ratio (PSNR) is used to evaluate the overall compression performance of JPEG XT profiles A, B, and C. In TMQI and NR IQA measurements, TMOs using display adaptive tone mapping and adaptive logarithmic mapping each gave good results. A TMO using adaptive logarithmic mapping gave good PSNRs.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.79-86
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• 2008

H.264/AVC is the newest international video coding standard developed by the joint ITU-T and ISO/IEC standards organizations. This newest video coding standard offers much higher coding efficiency than the H.261, H.263 and MPEG-4. But it has high computing complexity and high H/W resources wasting problem. This paper described the two unit parallel pipeline structure. This new structure comparing with standard model decreased the computing complexity of 67% and the H/W resources waste of 3%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.973-983
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• 2019

The importance of information security has been increasingly emphasized at the national, organizational, and individual levels due to the widespread adoption of software applications. High-safety software, which includes embedded software, should run without errors, similar to software used in the airline and nuclear energy sectors. Software development techniques in the above sectors are now being used to improve software security in other fields. Secure coding, in particular, is a concept encompassing defensive programming and is capable of improving software security. In this paper, we propose a software security vulnerability detection method using an improved coding standard searching technique. Public static analysis tools were used to assess software security and to classify the commands that induce vulnerability. Software security can be enhanced by detecting Application Programming Interfaces (APIs) and patterns that can induce vulnerability.

• Journal of the Korea Computer Industry Society
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• v.6 no.5
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• pp.801-812
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• 2005

H.264/AVC is the international video coding standard which has significant improvements of coding efficiency. ITU-T(International Telecommunication Union-Telecommunication standardization sector) and MPEG(Moving Picture Experts Group) adopts various complex coding tool such as variable block size motion, multiple reference frames, quarter-pel motion estimation/compensation (ME/MC) and rate-distortion(RD) optimization, etc. H.264 reference model employs complex mode decision technique based on RD optimization which requires high computational complexity. In this paper, we propose an efficient coding mode decision based on the cost distribution of RD in the macroblock coding mode sequence. Simulation results show that the proposed method reduces encoding time by 34% on average and save the number of computing RD cost by 82%.

• ETRI Journal
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• v.43 no.2
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• pp.313-323
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• 2021

The Joint Video Exploration Team (JVET) has studied future video coding (FVC) technologies with a potential compression capacity that significantly exceeds that of the high-efficiency video coding (HEVC) standard. The joint exploration test model (JEM), a common platform for the exploration of FVC technologies in the JVET, employs quadtree plus binary tree block partitioning, which enhances the flexibility of coding unit partitioning. Despite significant improvement in coding efficiency for chrominance achieved by separating luminance and chrominance tree structures in I slices, this approach has intrinsic drawbacks that result in the redundancy of block partitioning data. In this paper, an adaptive tree structure correlating luminance and chrominance of single and dual trees is presented. Our proposed method resulted in an average reduction of -0.24% in the Y Bjontegaard Delta rate relative to the intracoding of JEM 6.0 common test conditions.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.39-42
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• 2005

H.264, a recently proposed international video coding standard, has adopted context-based adaptive variable length coding (CAVLC) as the entropy coding tool in the baseline profile. By combining an adaptive variable length coding technique with context modeling, we can achieve a high degree of redundancy reduction. However, CAVLC in H.264 has weakness that the correct prediction rate of the variable length coding (VLC) table is low in a complex area, such as the boundary of an object. In this paper, we propose a VLC table prediction scheme considering multiple reference blocks; the same position block of the previous frame and the neighboring blocks of the current frame. The proposed algorithm obtains the new weighting values considering correctness of the VLC table for each reference block. Using this method, we can enhance the prediction rate of the VLC table and reduce the bit-rate.