• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.194-195
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• 2019

In this paper, we propose a frequency location adaptive hard-decision quantization (HDQ) scheme for video coding. A threshold for zero quantized level is adaptively applied to unquantized transform coefficients based on its frequency location in the transform domain. The proposed method achieves an average of 1.13%, 1.57%, and 1.53% of bit-rate reduction in BDBR sense compared to the conventional HDQ scheme respectively in Y, Cb, and Cr under the all intra encoding configuration.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.151-154
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• 1997

In this paper, we propose a new watermarking algorithm for copyright protection of video data. The proposed algorithm inserts a watermark directly on the MPEG-2 bitstream. Since more and more video data are stored and transmitted in a compressed form, it is desirable to insert a watermark on the compressed bit stream to avoid the expensive full-decoding and re-encoding process. Embedding a watermark in the compressed domain, we can also avoid the effect of the compression error which may erase the watermark.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.114-115
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• 2019

This paper introduces an adaptive scalar quantization scheme for video coding technology. The method utilizes the property of the coefficient groups (CG) inside each transform block so that the dead-zone interval of the scalar quantizer is adaptively set up for different CGs. Its experimental results show that our proposed quantization scheme can achieve BDBR reduction of 4.75%, 5.93, and 5.16% for Y, Cb, and Cr channel respectively when encoding with HEVC.

• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.484-495
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• 2017

The development of display devices and the increase of network transmission bandwidth bring demands for over 2K high resolution video such as panorama video, 4K ultra-high definition commercial broadcasting, and ultra-wide viewing video. To compress these image sequences with significant amount of data, High Efficiency Video Coding (HEVC) standard with the highest coding efficiency is a promising solution. HEVC, the latest video coding standard, provides high encoding efficiency using various advanced encoding tools, but it also requires significant amounts of computation complexity compared to previous coding standards. In particular, the complexity of HEVC decoding process is a imposing challenges on real-time playback of ultra-high resolution video. To accelerate the HEVC decoding process for ultra high resolution video, this paper introduces a data-level parallel video decoding method using slice and/or tile supported by HEVC. Moreover, deblocking filter process is further parallelized. The proposed method distributes independent decoding operations of each tile and/or each slice to multiple threads as well as deblocking filter operations. The experimental results show that the proposed method facilitates executions up to 2.0 times faster than the HEVC reference software for 4K videos.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.75-76
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• 2008

A low complexity encoding scheme for coarse grain scalability is proposed. The proposed method exploits the statistics of residuals between current and reference blocks using the macroblock mode predicted from the previous quality layer. To test how the mode is optimal in the current layer, the statistical hypothesis testing for the variances of the residual sub-blocks is performed. The proposed method reduces the total encoding time up to 51% when three CGS scalability layers are encoded. However, the quality degradation and bit-rate increment of the each layer are negligible.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.260-264
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• 2013

This paper proposes a fast enhancement layer coding method to reduce computational complexity for Scalable HEVC (SHVC) which is based on High Efficiency Video Coding (HEVC). The proposed method decreases encoding time by simplifying Rate Distortion Optimization (RDO)for enhancement layers (EL). The simplification is achieved by restricting CU depths based on the correlation of coding unit (CU) depths between adjacent layers and scalability (spatial or quality) of EL. Comparing with the performance of SHM 1.0 software encoder, the proposed method reduces the encoding time by up to 31.5%.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.10
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• pp.130-139
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• 1994

Video compression algorithms are based on removing spatial and/or temproal redundancy inherent in image sequences by predictive(DPCM) encoding, transform encoding, or a combination of predictive and transform encoding. In this paper, each 8$\times$8 DCT coefficient of DFD(displaced frame difference) is adaptively quantized by one of the four quantizers depending on total distortion level, which is determined by characteristics of HVS(human visual system) and buffer status. Therefore, the number of possible quantizer selection vectors(patterns) is 4$^{64}$. If this vectors are coded, toomany bits are required. Thus, the quantizer selection vectors are limited to 2048 for Y and 512 for each U, V by the proposed method using SWAD(sum of weighted absolute difference) for discriminating vectors. The computer simulation results, using the codebook vectors which are made by the proposed method, show that the subjective and objective image quality (PSNR) are goor with the limited bit allocation. (17Mbps)

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.388-392
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• 2014

This paper proposes an early termination method of a block vector search for fast encoding of high efficiency video coding (HEVC) screen content coding (SCC). In the proposed algorithm, two blocks indicated by two block vector predictors (BVPs) were first employed as an intra block copy (IBC) search. If the sum of absolute difference (SAD) value of the block is less than a threshold defined empirically, an IBC BV search is terminated early. The initial threshold for early termination is derived by statistical analysis and it can be modified adaptively based on a quantization parameter (QP). The proposed algorithm is evaluated on SCM-2.0 under all intra (AI) coding configurations. Experimental results show that the proposed algorithm reduces IBC BV search time by 29.23% on average while the average BD-rate loss is 0.41% under the HEVC SCC common test conditions (CTC).

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.178-184
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• 2013

In this paper, we propose an efficient parallelization technique of PU-level motion estimation (ME) in the next generation video coding standard, high efficiency video coding (HEVC) to reduce the time complexity of video encoding. It is difficult to encode video in real-time because ME has significant complexity (i.e., 80 percent at the encoder). In order to solve this problem, various techniques have been studied, and among them is the parallelization, which is carefully concerned in algorithm-level ME design. In this regard, merge estimation method using merge estimation region (MER) that enables ME to be designed in parallel has been proposed; but, parallel ME based on MER has still unconsidered problems to be implemented ideally in HEVC test model (HM). Therefore, we propose two strategies to implement stable parallel ME using MER in HM. Through experimental results, the excellence of our proposed methods is shown; the encoding time using the proposed method is reduced by 25.64 percent on average of that of HM which uses sequential ME.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.698-708
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• 2020

VVC (Versatile Video Coding), which has been developing as a next generation video coding standard. Compared to HEVC (High Efficiency Video Coding), VVC is improved by about 34% in RA (Random Access) configuration and about 30% in LDB (Low-Delay B) configuration by adopting various techniques such as recursive block partitioning structure and GPM (Geometric Partitioning Mode). But the encoding complexity is increased by about 10x and 7x, respectively. In this paper, we propose a fast decision method of GPM mode and block partitioning using directionality of block to reduce encoding complexity of VVC. The proposed method is to apply the Hough transform to the current block to identify the directionality of the block, thereby determining the GPM mode and the specific block partitioning method to be skipped in the rate-distortion cost search process. As a result, compared to VTM8.0, the proposed method reduces about 31.01% and 29.84% encoding complexity for RA and LDB configuration with 2.48% and 2.69% BD-rate loss, respectively.