• Title, Summary, Keyword: Fast Intra Mode Decision

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Fast Intraframe Coding for High Efficiency Video Coding

  • Huang, Han;Zhao, Yao;Lin, Chunyu;Bai, Huihui
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.1093-1104
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    • 2014
  • The High Efficiency Video Coding (HEVC) is a new video coding standard that can provide much better compression efficiency than its predecessor H.264/AVC. However, it is computationally more intensive due to the use of flexible quadtree coding unit structure and more choices of prediction modes. In this paper, a fast intraframe coding scheme is proposed for HEVC. Firstly, a fast bottom-up pruning algorithm is designed to skip the mode decision process or reduce the candidate modes at larger block size coding unit. Then, a low complexity rough mode decision process is adopted to choose a small candidate set, followed by early DC and Planar mode decision and mode filtering to further reduce the number of candidate modes. The proposed method is evaluated by the HEVC reference software HM8.2. Averaging over 5 classes of HEVC test sequences, 41.39% encoding time saving is achieved with only 0.77% bitrate increase.

Fast Intra Coding using DCT Coefficients (DCT 계수를 이용한 고속 인트라 코딩)

  • Kim, Ga-Ram;Kim, Nam-Uk;Lee, Yung-Lyul
    • Journal of Broadcast Engineering
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    • v.20 no.6
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    • pp.862-870
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    • 2015
  • The RDO (Rate Distortion Optimization) process of HEVC results in good coding efficiency, but relatively requires much encoding time. In order to reduce the encoding time of RDO process, this paper proposes a method of fast intra prediction mode decision using DCT coefficients distributions and the existence of DCT coefficients. The proposed fast Intra coding sets the number of intra prediction mode candidates to three(3) from the RMD (Rough Mode Decision) process in HM16.0 reference SW and reduces the number of candidates one more time by investigating DCT coefficients distribution. After that, if there exists a quantized DCT block having all zero coefficient values for a specific candidate before the RDO process, the candidate is chosen without the RDO process. The proposed method reduces the encoder complexity on average 46%, while the coding efficiency is 2.1% decreased compared with the HEVC encoder.

Adaptive Coding Mode Decision Algorithm using Motion Vector Map in H.264/AVC Video Coding (H.264/AVC 부호기에서 움직임 벡터 맵을 이용한 적응적인 부호화 모드 결정 방법)

  • Kim, Tae-Jung;Ko, Man-Geun;Suh, Jae-Won
    • 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.

Fast Algorithm for 360-degree Videos Based on the Prediction of Cu Depth Range and Fast Mode Decision

  • Zhang, Mengmeng;Zhang, Jing;Liu, Zhi;Mao, Fuqi;Yue, Wen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.6
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    • pp.3165-3181
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    • 2019
  • Spherical videos, which are also called 360-degree videos, have become increasingly popular due to the rapid development of virtual reality technology. However, the large amount of data in such videos is a huge challenge for existing transmission system. To use the existing encode framework, it should be converted into a 2D image plane by using a specific projection format, e.g. the equi-rectangular projection (ERP) format. The existing high-efficiency video coding standard (HEVC) can effectively compress video content, but its enormous computational complexity makes the time spent on compressing high-frame-rate and high-resolution 360-degree videos disproportionate to the benefits of compression. Focusing on the ERP format characteristics of 360-degree videos, this work develops a fast decision algorithm for predicting the coding unit depth interval and adaptive mode decision for intra prediction mode. The algorithm makes full use of the video characteristics of the ERP format by dealing with pole and equatorial areas separately. It sets different reference blocks and determination conditions according to the degree of stretching, which can reduce the coding time while ensuring the quality. Compared with the original reference software HM-16.16, the proposed algorithm can reduce time consumption by 39.3% in the all-intra configuration, and the BD-rate increases by only 0.84%.

Fast Intra Prediction Mode Decision using Most Probable Mode for H.264/AVC (H.264/AVC에서의 최고 확률 모드를 이용한 고속 화면 내 예측 모드 결정)

  • Kim, Dae-Yeon;Kim, Jeong-Pil;Lee, Yung-Lyul
    • Journal of Broadcast Engineering
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    • v.15 no.3
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    • pp.380-390
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    • 2010
  • The most recent standard video codec, H.264/AVC achieves significant coding efficiency by using a rate-distortion optimization(RDO). The RDO is a measurement for selecting the best mode which minimizes the Lagrangian cost among several modes. As a result, the computational complexity is increased drastically in encoder. In this paper, a method for fast intra prediction mode decision is proposed to reduce the RDO complexity. To speed up Intra$4{\times}4$ and Chroma Intra encoding, the proposed method decides the case that MPM (Most Probable Mode) is the best prediction mode. In this case, the RDO process is skipped, and only MPM is used for encoding the block in Intra$4{\times}4$. And the proposed method is also applied to the chroma Intra prediction mode in a similar way to the Intra$4{\times}4$. The experimental results show that the proposed method achieves an average encoding time saving of about 63% with negligible loss of PSNR (Peak Signal-to-Noise Ratio).

Fast intra prediction mode decision based on rough mode decision and most probable mode in HEVC (HEVC에서 Rough mode decision과 Most probable mode에 기반을 둔 고속 인트라 예측 모드 결정 방법)

  • Lee, Seung-ho;Park, Sang-hyo;Jang, Euee Seon
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.71-74
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    • 2013
  • 차세대 동영상 표준 코덱인 High Efficiency Video Coding(HEVC)은 기존의 AVC/H.264 보다 동일 화질 대비 최대 약 2배의 압축 성능을 보여준다. 이러한 HEVC의 성능을 얻기 위하여 복잡한 연산이 많은 기법이 도입되었고 이로 인하여 HEVC의 시간 복잡도는 AVC/H.264보다 더욱 증가하였다. HEVC의 시간 복잡도를 줄이기 위해서 다양한 고속 알고리즘이 논의되고 있고 인트라 예측 모드에서의 고속 알고리즘 연구 또한 많은 연구가 이루어지고 있다. 본 논문에서는 인트라 예측 모드 결정과정에서 HEVC에 구현된 Rough mode decision(RMD)와 Most probable mode(MPM)의 결과를 활용하여 고속화된 최종예측 모드 결정 방법을 제안한다. 실험 결과, HM 10.0의 All Intra 환경을 기준으로 BD-rate에서 약 0.9%의 손실과 함께 평균 24%의 속도 향상을 얻을 수 있었다.

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H.264/AVC Fast Macroblock Mode Decision Algorithm (H.264/AVC 고속 매크로블록 모드 결정 알고리즘)

  • Kim, Ji-Woong;Kim, Yong-Kwan
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.4
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    • pp.8-16
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    • 2007
  • For the improvement of coding efficiency, the H.264/AVC video coding standard employs new coding tools compared with existing coding standards. However, due to these new coding tools, the complexity of K264/AVC standard encoder is greatly increased. Specifically, the inter/intra mode decision method using RDO(rate-distortion optimization) technique is one of the most complex parts in H.264/AVC. In this paper, we focus on the complexity reduction in macroblock mode decision. In the proposed method, we reduce the complexity of the $4{\times}4$ mode decision process using $4{\times}4$ simple square filters, and using spatial block correlation method. Additionally, exploiting the best mode of sub_macroblock in $Inter8{\times}8$ mode, we proposed an algorithm to eliminate some intra modes in current macroblock mode decision process. In addition, we employed a method to raise the probability to select SKIP, $Intra16{\times}16$, and $Intra16{\times}16$ modes which usually show low complexity and low bitrate compared with other modes. From the simulation results, the proposed algorithm reduce the encoding time by maximum 83% of total, and reduce the bitrate of the overall sequences by $8{\sim}10%$ on the average compared with existing coding methods.

Sub-Sampled Pixels based Fast Mode Selection Algorithm for Intra Prediction in H.264/AVC (H.264/AVC 화면 내 예측을 위한 서브 샘플링 된 화소 기반 고속 모드 선택 기법)

  • Kim, Young-Joon;Kim, Won-Kyun;Jung, Dong-Jin;Jeong, Je-Chang
    • Journal of Broadcast Engineering
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    • v.17 no.3
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    • pp.471-479
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    • 2012
  • Intra prediction is one of the significant techniques in H.264/AVC reference software; however, it has heavy computational complexity. In order to solve this problem, many fast algorithms have been proposed. In this paper, we propose a fast intra mode decision algorithm which predicts the edge direction of the current block using sub-sampled pixels to reduce high computational complexity of the H.264/AVC encoder. The proposed algorithm shows that it not only improves the coding performance but also reduces the computational complexity of the H.264/AVC encoder compared to previous algorithms. The experimental results show that the proposed algorithm achieves the encoding time reduction of 75.93% on an average with slight peak signal-to-noise ratio (PSNR) drop and bit-rate increment.

An Efficient Mode Decision and Search Region Restriction for Fast Encoding of H.264/AVC (H.264/AVC의 빠른 부호화를 위한 효율적인 모드 결정과 탐색영역 제한)

  • Chun, Sung-Hwan;Shin, Kwang-Mu;Kang, Jin-Mi;Chung, Ki-Dong
    • Journal of Korea Multimedia Society
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    • v.13 no.2
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    • pp.185-195
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    • 2010
  • In this paper, we propose an efficient inter and intra prediction algorithms for fast encoding of H.264/AVC. First, inter prediction mode decision method decides early using temporal/spatial correlation information and pixel direction information. Second, intra prediction mode decision method selects block size judging smoothness degree with inner/outer pixel value variation and decides prediction mode using representative pixel and reference pixel. Lastly, adaptive motion search region restriction sets search region using mode information of neighboring block and predicted motion vector. The experimental results show that proposed method can achieve about 18~53% reduction compared with the existing JM 14.1 in the encoding time. In RD performance, the proposed method does not cause significant PSNR value losses while increasing bitrates slightly.

A FAST INTRA PREDICTION MODE SELECTION METHOD IN H.264/AVC SCALABLE VIDEO CODING

  • Park, Sung-Jae;Lee, Yeo-Song;Sohn, Chae-Bong;Jeong, S.Y.;Chung, Kwang-Sue;Park, Ho-Chong;Ahn, Chang-Bum;Oh, Seoung-Jun
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • pp.170-173
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    • 2009
  • In this paper, we propose a fast intra prediction mode selection method in Scalable Video Coding(SVC) which is an emerging video coding standard as an extension of H.264/Advanced Video Coding(H.264/AVC). The proposed method decides a candidate intra prediction mode based on the characteristic of macroblock smoothness. Statistical analysis is applied to computing that smoothness in spatial enhancement layer. We also propose an early termination scheme for Intra_BL mode decision where the RD cost value of Intra_BL is utilized. Compared with JSVM software, our scheme can reduce about 55% of the computation complexity of intra prediction on average, while the performance degradation is negligible; For low QP values, the average PSNR loss is very negligible, equivalently the bit rate increases by 0.01%. For high QP values, the average PSNR loss is less than 0.01dB, which equals to 0.25% increase in bitrate on average.

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