• Journal of Broadcast Engineering
• /
• v.18 no.4
• /
• pp.631-642
• /
• 2013

For the emerging High Efficiency Video Coding (HEVC) standard, a fast transform unit (TU) decision method is proposed. HEVC defines the TU representing a region sharing the same transformation, and it allows a residual block to be split into multiple TUs recursively to form a quadtree. By using the quadtree of TUs, HEVC supports various transform sizes from $4{\times}4$ to $32{\times}32$. The various sizes of TUs can provide a good coding efficiency, whereas this may increase encoding complexity dramatically. In the assumption that a TU with highly compacted energy is unlikely to be split, the proposed method determines TU sizes according to the position of the last non-zero transform coefficient. In the experimental results, the proposed method reduced 18% encoding run time with the negligible coding loss of 0.7% BD-rate for the Random_access case.

• The Journal of the Korea Contents Association
• /
• v.10 no.4
• /
• pp.28-35
• /
• 2010

The variable block size motion estimation (ME) and compensation (MC) using multiple reference frames is adopted in H.264/AVC to improve coding efficiency. However, the computational complexity for ME/MC increases proportional to the number of reference frames and variable blocks. In this paper, we propose a new efficient reference frame selection algorithm to reduce the complexity while keeping the visual quality. First, a motion vector reference map is constructed by SAD of $4{\times}4$ block unit for multi reference frames. Next, the variable block size motion estimation and motion compensation is performed according to the motion vector reference map. The computer simulation results show that the average loss of BDPSNR is -0.01dB, the increment of BDBR is 0.27%, and the encoding time is reduced by 38% compared with the original method for H.264/AVC.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.2
• /
• pp.89-96
• /
• 2016

The High Efficiency Video Coding (MPEG-H HEVC/ITU-T H.265) is the newest video coding standard which has the quadtree-structured coding unit (CU). The quadtree-structure splits a CU adaptively, and its optimum CU depth can be determined by rate-distortion optimization. Such HEVC encoding requires very high computational complexity for CU depth decision. Motivated that the blob detection, which is a well-known algorithm in computer vision, detects keypoints in pictures and decision of CU depth needs to consider high frequency energy distribution, in this paper, we propose to utilize these keypoints for fast CU depth decision. Experimental results show that 20% encoding time can be saved with only slightly increasing BDBR by 0.45% on all intra case.

• Journal of Broadcast Engineering
• /
• v.23 no.5
• /
• pp.628-635
• /
• 2018

In this paper, we propose a fast motion estimation algorithm which is important in video encoding. So many fast motion estimation algorithms have been published for improving prediction quality and computational reduction. In the paper, we propose an algorithm that reduces unnecessary computation, while almost keeping prediction quality compared with the full search algorithm. The proposed algorithm calculates the sum of partial block matching error for each candidate, selects the candidates for the next step, compares the stability of optimal candidates with minimum error, and finds optimal motion vectors by determining the progress of the next step. By doing that, we can find the minimum error point as soon as possible and obtain fast computational speed by reducing unnecessary computations. Additionally, the proposed algorithm can be used with conventional fast motion estimation algorithms and prove it in the experimental results.

• Journal of Korea Multimedia Society
• /
• v.13 no.7
• /
• pp.991-999
• /
• 2010

In this paper, we propose a fast motion estimation algorithm for video encoding. Conventional fast motion estimation algorithms have a serious problem of low prediction quality in some frames. However, full search based fast algorithms have low computational reduction ratio. In the paper, we propose an algorithm that significantly reduces unnecessary computations, while keeping prediction quality almost similar to that of the full search. The proposed algorithm uses distribution probability of motion vectors and adaptive search patterns and block matching criteria. By taking different search patterns and error criteria of block matching according to distribution probability of motion vectors, we can reduces only unnecessary computations efficiently. Our algorithm takes only 20~30% in computational amount and has decreased prediction quality about 0~0.02dB compared with the fast full search of the H.264 reference software. Our algorithm will be useful to real-time video coding applications using MPEG-2 or MPEG-4 AVC standards.

• The Journal of the Korea Contents Association
• /
• v.14 no.9
• /
• pp.102-109
• /
• 2014

Intra prediction in HEVC is also significantly improved from H.264/AVC with the increased prediction modes up to 35 that results in increase of the complexity cost. Hence, a fast intra mode decision algorithm is required for real-time applications. A fast intra mode decision is proposed in this paper for further complexity reduction in addition to the RMD (Rough Mode Decision) that has been adopted into the HEVC reference software, referred to as HM, for fast intra prediction. The proposed method reduces the complexity of intra mode decision by limiting the number of search modes in both steps of RMD and the final mode decision. Experimental results show that the proposed method provide about 13.2% encoding time reduction with 1.0% BD-rate increase on average over test sequences in HM 12.0.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.4
• /
• pp.589-598
• /
• 2003

In the conventional fractal image compression in the DWT(discrete wavelet transform), the domain and range blocks were classified as B${\times}$B block size first before all domain block for each range block was searched. The conventional method has a disadvantages that the encoding time takes too long, since the domain block for entire image was searched. As an enhancement to such inefficiencies and image quality, this paper proposes wavelet-based fractal image compression with multiscale factors. Thus, this proposed method uses multiscale factor along each level and band to enhance an overall image quality. In encoding process of this method, the range blocks are not searched for all the domain blocks; however, using the self affine system the range blocks are selected from the blocks in the upper level. The image qualify of the conventional method is 32.30[dB], and the proposed method is 35.97[dB]. The image quality is increased by 3.67[dB].

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.324-329
• /
• 2005

Dynamic Encoding Algorithm for Searches (DEAS) which is known as a fast and reliable non-gradient optimization method, was proposed [1]. DEAS reaches local or global optimum with binary strings (or binary matrices for multi-dimensional problem) by iterating the two operations; bisectional search (BSS) and unidirectional search (UDS). BSS increases binary strings by one digit (i.e., 0 or 1), while UDS performs increment or decrement of binary strings in the BSS' result direction with no change of string length. Because the interval of UDS exponentially decreases with increment of bit string length (BSL), DEAS is difficult to escape from local optimum when DEAS falls into local optimum. Therefore, this paper proposes hopping UDS (HUDS) which performs UDS by hopping as many as BSL in the final point of UDS process. HUDS helps to escape from local optimum and enhances a probability searching global optimization. The excellent performance of HUDS will be validated through the well-known benchmark functions.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.7C
• /
• pp.696-704
• /
• 2003

In this paper, we propose an improved early detection of all-zero DCT coefficients for fast video encoding. From the experimental observation, it is shown that the performance of the conventional method is limited because of the imprecision sufficient condition. When the calculation of the SAD in motion estimation is simply modified, more precise sufficient condition is derived from the theoretical analysis. Based on this idea, DCT and the quantization stages are effectively skipped in the proposed algorithm with no image degradation. The simulation results show that the proposed algorithm achieves computational saving over 10% compared to the conventional method.

• The KIPS Transactions:PartC
• /
• v.18C no.4
• /
• pp.255-264
• /
• 2011

TV-Anytime is an XML-based standard for description of PVR and digital broadcast services. It is referenced by many standards of digital broadcast service for their schemas and delivery protocols of contents guide. Although its readability and extensibility, TV-Anytime has a big problem which generates massive documents due to its text-based description method. Therefore, various encoding algorithms have been proposed to reduce the size of XML documents. This paper proposes efficient metadata encapsulation architecture based on the optimization information generated at server-side to minimize XML documents. Advanced indexing method is also proposed to reduce resources needed to encapsulate indices and to receive metadata with fast and explicit mechanism.