• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2015.11a
• /
• pp.141-142
• /
• 2015

본 논문에서는 HEVC(High Efficiency Video Coding)을 위한 고속 부호화 알고리즘을 제안한다. 제안 방법은 HEVC 의 화면내 부호화 과정에서 주변 부호화 모드 정보인 MPM(Most Probable Mode)과 RMD(Rough Mode Decision) 과정의 결과로 얻어지는 후보 모드들의 상관관계를 이용하여 높은 계산 복잡도를 가지는 RDO(Rate-Distortion Optimization) 과정이 고려하는 후보의 개수를 줄여 전체 부호화기의 부호화 복잡도를 낮춘다. 실험 결과에서는 제안 방법이 약 0.29% BD-rate 의 부호화 손실만으로 20.43%의 부호화 복잡도를 감소시켰음을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.11
• /
• pp.127-136
• /
• 2007

An abrupt scene-change frame is one that is hardly correlated with the previous frames. In that case, because an intra-coded frame has less distortion than an inter-coded one, almost all macroblocks are encoded in intra mode. This breaks up the rate control flow and increases the number of bits used. Since the reference software for H.264 takes no special action for a scene-change frame, several studies have been conducted to solve the problem using the quadratic R-D model. However, since this model is more suitable for inter frames, the existing schemes are unsuitable for computing the QP of the scene-change intra frame. In this paper, an improved rate control scheme accounting for the characteristics of intra coding is proposed for scene-change frames. The proposed scheme was validated using 16 test sequences. The results showed that the proposed scheme performed better than the existing H.264 rate control schemes. The PSNR was improved by an average of 0.4-0.6 dB and a maximum of 1.1-1.6 dB. The PSNR fluctuation was also in proved by an average of 18.6 %.

• Journal of the Semiconductor & Display Technology
• /
• v.12 no.1
• /
• pp.35-39
• /
• 2013

H.264/AVC is an authoritative international video coding standard which shows code and efficiency more improved than the existing video standards. Above all, the parameter block mode of H.264/AVC significantly contributes much to high compression efficiency. However, as the occasion demands, users tend to pass while overlooking the part that can produce a little higher compression efficiency. We, taking notice of this point, are designed to bring in much higher compression efficiency by gathering up the overlooked parts. This paper suggests the algorithm that produces efficient performance improvement by using the histogram of luminance in the pixel unit (Macroblock) of respective prediction block and applying specific thresholds. The experimental results proves that the technique proposed by this paper increases the compression efficiency of the existing H.264/AVC algorithm by 0.4% without any increase in the whole encoding time and PSNR complexity.

• Journal of Korea Multimedia Society
• /
• v.11 no.7
• /
• pp.956-965
• /
• 2008

H.264/AVC is the newest video coding standard of ITU-T VCEG and the ISO/IEC MPEG, offering a significant performance improvement over previous video coding standards. However, the computational complexity of H.264/AVC is drastically increased because of new technologies such as intra prediction, variable block size, quarter-pels motion estimation/compensation, etc. In this paper, we propose a fast intra prediction scheme which has two step processing. The first step is a fast block size decision which can be calculated only in one block without considering all cases of $4{\times}4$ block and $16{\times}16$ block. The complexity of the intra prediction can be reduced by using boundary difference values of macroblock. After selecting the block size, we can make mode decision using the neighbouring reference pixels and representative pixels of the block in the second step. The experimental results show that the proposed algorithm saved on the average 41.5% encoding time without any significant PSNR losses.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12C
• /
• pp.1046-1054
• /
• 2008

Since the high quality digital TV systems are broadly deployed in the market, the digital video contents will be edited and distributed in MPEG-2 MP@HL fonnat. Due to its impressive coding efficiency, the H.264/AVC codec has rapidly replaced the MPEG-4 SP codec for mobile digital video terminal with low quality. For the bro ad distribution of digitial video contents produced in MPEG-2 format, the MPEG-2 to H.264/AVC transcoding is highly necessary nowadays. In this paper, we propose a fast intra MB prediction mode decision method to reduce the computational complexity in the transcoding, which is the main bottleneck in the transcoders. The proposed method is based on the several relationships such as DCT coefficients and edge orientation, correlation between prediction directions in the $Intra16{\times}16$ and $Intra4{\times}4$ modes, correlation between edge-orientations of luminance an d chrominance components. The simulation results show that the proposed method can reduce the computational complexity upto 70% and 40%, compared with the cascaded transcoder and the well-known fast intraframe transc oder, respectively.

• ETRI Journal
• /
• v.29 no.3
• /
• pp.390-392
• /
• 2007

In this paper, we propose a new error concealment (EC) method using inter-layer correlation for scalable video coding. In the proposed method, the auxiliary motion vector (MV) and the auxiliary mode number (MN) of intra prediction are interleaved into the bitstream to recover the corrupted frame. In order to reduce the bit rate, the proposed method encodes the difference between the original and the predicted values of the MV and MN instead of the original values. Experimental results show that the proposed EC outperforms the conventional EC by 2.8 dB to 6.7 dB.

• Journal of Broadcast Engineering
• /
• v.24 no.6
• /
• pp.1134-1142
• /
• 2019

Detection of double compression is one of the most efficient ways of remarking the validity of videos. Many methods have been introduced to detect HEVC double compression with different coding parameters. However, HEVC double compression detection under the same coding environments is still a challenging task in video forensic. In this paper, we introduce a novel method based on the frame partitioning information in intra prediction mode for detecting double compression in with the same coding environments. We propose to extract statistical feature and Deep Convolution Neural Network (DCNN) feature from the difference of partitioning picture including Coding Unit (CU) and Transform Unit (TU) information. Finally, a softmax layer is integrated to perform the classification of the videos into single and double compression by combing the statistical and the DCNN features. Experimental results show the effectiveness of the statistical and the DCNN features with an average accuracy of 87.5% for WVGA and 84.1% for HD dataset.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.1B
• /
• pp.77-88
• /
• 2000

This paper presents an approach for rate control by adaptively selecting macroblock modes in video coding.The problem of rate control has been investigated by many authors where quantizer level is adjustedbased on the buffer fullness. The proposed approach is different fron the previous ones [4] id that it finds the optimal decision curve rather than finding a set of the modes. Proposed algorithm extends the coding decision options for rate control to motion/no-motion compensation as well as inter/intra decisions. Instead of having a fixed motion/no-notion compensation or inter/intra decision curve, one can utilize an adaptive decision curvebased on the characteristics of input frames so that the PSNR at a given bit rate is maximized. Therefore, the proposed approach provides better rate control than simple quantizer feedback approach interns of visual quality. The curve is obtained by utilizing simulated annealing optimization technique. Thealgorithm is implemented and simulations are compared with other approaches within H.261 video codec.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2015.07a
• /
• pp.560-563
• /
• 2015

동영상 부호화 표준, HEVC(High Efficiency Video Coding)는 부호화 성능을 극대화하기 위해 총 35 개의 화면내 예측 모드를 사용한다. 화면내 예측 모드는 각도를 가진 모드와 각도가 없는 모드로 구성된다. 부호화 성능을 높이기 위해 사용한 다수의 화면내 예측 모드 방법은 HEVC 부호화기의 복잡도를 증대 시키는데 큰 역할을 하게 된다. 본 논문은 총 35 개의 화면내 예측 모드 중 현재 블록의 주변 블록 정보로부터 얻을 수 있는 예측 모드들 및 각도를 대표하는 예측 모드들을 선별적으로 추려서 후보 예측 모드를 결정하고, 평가 과정을 거쳐 해당 후보 모드 중에서 최종 화면내 예측 모드를 결정한다. 본 제안 방법은 35 개의 전체 화면내 예측 모드 중 소수의 후보 모드만을 평가함으로써 HEVC 표준의 화면내 예측 및 부호화 과정의 복잡도를 감소시키려 한다. 제안 방법을 다양한 테스트 시퀀스에 적용한 결과, 35 개 화면내 예측 모드를 전부 사용한 경우와 비교하여 1.1%의 BD-rates 이 증가하면서 18.7%의 부호화기 복잡도를 감소시킬 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.9
• /
• pp.1957-1964
• /
• 2010

In Video coding, the first frame is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the intial QP for the first frame of GOP affects the first frame as well as the following frames. Traditionally, the initial QP of a GOP is determined by the initial QP of the previous GOP and the average QP of the inter mode frames. In case of JM, the initial QP of a GOP is adjusted as the initial QP being less than the average QP of inter mode frames by two. However, this method is not suitable for the low bit rate video coding. In this paper, the linear relationship between the optimal QP and the ratio of the PSNR of the first frame and the average PSNR of the inter mode frames is first investigated and the linear model is proposed based on the results of the investigation. The proposed model calculate the optimal initial QP using the encoding results of the previous GOP. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JM algorithm.