• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.93-101
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• 2007

Small area and low power implementation are important requirements for various multimedia processing hardware, especially for mobile environment. This paper presents a hardware architecture of H.264/AVC Intra Prediction module aiming on small area and low power. A single arithmetic unit was shared and processed sequentially for all mode decisions and computations to predict an image frame. As a result, we could get smaller area and smaller memory size compared to other existing implementations. The proposed architecture was verified using the Altera Excalibur device, and the implemented hardware has been described in Verilog-HDL and synthesized on Samsung STD130 0.18um CMOS Standard Cell Library using Synopsys Design Compiler. The synthesis result was about 11.9K logic gates and 1078 byte internal SRAM and the maximum operating frequency was 107Mhz. It consumes 879,617 clocks to process one QCIF frame, which means it can process 121.5 QCIF$(176\times144)$ frames per second, therefore it shows that it can be used for real time H.264/AVC encoding of various multimedia applications.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.6
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• pp.37-42
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• 2008

In H.264/AVC decoder, intra predictor, motion compensator, and deblocking filter need to read reference images in external frame memory in decoding process. They read external frame memory very frequently, which lowers system operation speed and increases power consumption. This paper proposes a intra predictor integrated with motion compensator without external frame memory. It achieves power reduction and memory bandwidth minimization by exploiting data reuse of common and repetitive pixels. The proposed infra predictor achieves more than $45%\;{\sim}\;75%$ cycle time reduction compared with conventional intra predictors.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.836-846
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• 2014

To expedite UHD (Ultra High Definition) video service, the HEVC (High-Efficiency Video Coding) technology has recently been standardized and it achieves two times higher compression efficiency than the conventional H.264/AVC. To obtain the improved efficiency, however, it employs many complex methods which need complicated calculation, thereby resulting in a significantly increased computational complexity when compared to that of H.264/AVC. For example, to improve the coding efficiency of intra frame coding, up to 35 intra prediction modes are defined in HEVC, but this results in an increased encoding time than the H.264/AVC. In this paper, we propose a fast intra prediction mode decision scheme which reduces computational complexity by changing the number of intra prediction mode in accordance with the percentage of PU sizes for a given video resolution, and by classifying the 35 intra prediction modes into 4 categories considering video resolution and quantization parameter. The experimental results show that the total encoding time is reduced by about 7% on average at the cost of only 2% increase in BD-rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.790-800
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• 2009

For the improvement of coding efficiency, the H.264/AYC standard uses new coding tools such as 1/4-pel-accurate motion estimation, multiple references, intra prediction, loop filter, variable block size etc. Using these coding tools, H.264/AYC has achieved significant improvements from rate-distortion point of view compared to existing standards. However, the encoder complexity was greatly increased due to these coding tools. We focus on the complexity reduction method of intra macroblock mode selection. The proposed algorithm for fast intra mode selection calculates the edge activity in transform domain, and performs fast encoding of intra frame in H.264/AYC through the fast prediction mode selection of intra4x4 and chrominance blocks. Simulation results show that the proposed method saves about 59.76% for QCIF sequences and 65.03% for CIF sequences of total encoding time, while bitrate increase and PSNR decrease are very small.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.2
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• pp.48-56
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• 2009

We propose a fast intra mode skip decision algorithm for H.264/AVC video encoding. Although newly added MB encoding algorithms based on various prediction methods increase compression ratio, they require a significant increase in the computational complexity because we calculate rate-distortion(RD) cost for all possible MB coding modes and then choose the best one. In this paper, we propose a fast mode decision algorithm based on an adaptive motion vector map(AMVM) method for H.264/AVC video encoding to reduce the processing time for the inter frame. We verify that the proposed algorithm generates generally good performances in PSNR, bit rates, and processing time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7C
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• pp.681-686
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• 2009

In H.264/Ave, an intra prediction added to the P-frame coding slightly improves both of image quality and bit rate, but greatly increases an amount of computation. In order to reduce the increase in computation, this paper proposes an image contents based intra prediction coding using characteristics that the best intra block mode depends on the image content of a macro block. The proposed algorithm estimates the image content with image complexity and the best inter block mode, and then selects or excludes a intra block mode on the basis of it. The simulation results show that the proposed algorithm reduces average O.OldB in image quality, and increases average 0.38% in the bit rate, but reduces average 37.02% in computation time compared with the conventional algorithm.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.20-27
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• 2009

H.264/AVC video coding standard adapting a rate-distortion optimization technique to select the best coding mode with multi reference frames for each macroblock gets a higher coding efficiency than those of previous video coding standards but the computational complexity increases drastically. Therefore, many fast mode decision algorithms are proposed to reduce the computational complexity. Among them, we propose a fast intra mode decision algorithm based on directional information of I4MB. The proposed algorithm achieves consistent time saving about 15% in IPPP sequences and 44% in all I frame sequences with negligible loss in PSNR and small increment of bit rate compared with that of JM11.0.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.115-122
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• 2005

There are some problems in directly applying the conventional MPEG bit-stream based watermarking schemes to the bit-stream of a new compression standard, H.264/AVC. In this paper we analyze the effects of the conventional DCT-based watermarking scheme to H.264/AVC, especially in terms of image distortions and bit-rate changes. It turns out that the intra-frame prediction md CAVLC of H.264/AVC with the watermarking worsen the image distortions and bit-rate changes. The experiment results show on average 28.17dB decrease in PSNR and 56.71% increase in bit-rate over all QPs.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.498-512
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• 2010

Intra coding is an indispensable coding tool since it can provide random accessibility as well as error resiliency. However, it is the problem that intra coding has relatively low coding efficiency compared with inter coding in the area of video coding. Even though H.264/AVC has significantly improved the intra coding performance compared with previous video standards, H.264/AVC encoder complexity is significantly increased, which is not suitable for low bit rate interactive services. In this paper, a Voting-based Intra Mode Bit Skip (V-IMBS) scheme is proposed to improve coding efficiency as well as to reduce encoding time complexity using decoder-side prediction. In case that the decoder can determine the same prediction mode as what is chosen by the encoder, the encoder does not send that intra prediction mode; otherwise, the conventional H.264/AVC intra coding is performed. Simulation results reveal a performance increase up to 4.44% overall rate savings and 0.24 dB in peak signal-to-noise ratio while the frame encoding speed of proposed method is about 42.8% better than that of H.264/AVC.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.200-213
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• 2008

H.264| MPEG-4 AVC is a new video codingstandard defined by JVT (Joint Video Team) which consists of ITU-T and ISO/IEC. Many techniques are adopted fur the compression efficiency: Especially, an intra prediction in an inter frame is one example but it leads to excessive amount of encoding time due to the decision of a candidate mode and a RDcost calculation. For this reason, a fast determination of the best intra prediction mode is the main issue for saving the encoding time. In this paper, by using the result of statistical relation between intra $16{\times}16$ and $4{\times}4$ intra predictions, the number of candidate modes for $4{\times}4$ intra prediction is reduced. Firstly, utilizing motion vector obtained after inter prediction, prediction of a block mode for each macroblock is made. If an intra prediction is needed, the correlation table between $16{\times}16$ and $4{\times}4$ intra predicted modes is created using the probability during each I frame-coding process. Secondly, using this result, the candidate modes for a $4{\times}4$ intra prediction that reaches a predefined specific probability value are only considered in the same GOP For the experiments, JM11.0, the reference software of H.264|MPEG-4 AVC is used and the experimental results show that the encoding time could be reduced by 51.24% in maximum with negligible amounts of PSNR drop and bitrate increase.