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The training of Karhunen-LoSve transform matrix and its application for H.264 intra coding

MULTIMEDIA TOOLS AND APPLICATIONS 2009年第1期41卷 111-123页

作者： Gao, Yi Chen, Jiazhong Yu, Shengsheng Zhou, Jingli Po, Lai-Man Huazhong Univ Sci & Technol Dept Comp Sci Wuhan 430074 Peoples R China City Univ Hong Kong Dept Elect Engn Kowloon 999077 Hong Kong Peoples R China

In H.264/AVC, 4 x 4 discrete cosine transform (DCT) is performed on the residual signals after intra prediction for decorrelation. Actually, residual blocks with different prediction modes exhibit different frequency characteristics. Therefore, the fixed transform matrix cannot match the energetic distribution of residual signals very well, which degrades the decorrelation performance. Fortunately, the energetic distributions of residual blocks with the same mode are relatively coincident, which makes it possible to train a universally good Karhunen-LoSve transform (KLT) matrix for each mode. In this paper, an optimal frequency matching (OFM) algorithm is proposed to train KLT matrices for residual blocks and nine KLT matrices corresponding to nine prediction modes of 4 x 4 intra blocks are trained. Experimental results show that KLT with trained matrices yields a persistent gain over H.264 using 4 x 4 DCT with an average peak signal-to-noise ratio (PSNR) enhancement of 0.22dB and a maximum enhancement of 0.33dB.

关键词： Karhunen-Loeve transform Discrete cosine transform intra coding H.264/AVC

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Statistical Early Termination and Early Skip Models for Fast Mode Decision in HEVC intra coding

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ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 2019年第3期15卷 70-70页

作者： Zhang, Yun Li, Na Kwong, Sam Jiang, Gangyi Zeng, Huanqiang Chinese Acad Sci Shenzhen Inst Adv Technol Shenzhen 518055 Peoples R China City Univ Hong Kong Dept Comp Sci Kowloon Hong Kong Peoples R China Ningbo Univ Fac Informat Sci & Engn Ningbo 315211 Zhejiang Peoples R China Huaqiao Univ Sch Informat Sci & Engn Xiamen 361021 Fujian Peoples R China

In this article, statistical Early Termination (ET) and Early Skip (ES) models are proposed for fast coding Unit (CU) and prediction mode decision in HEVC intra coding, in which three categories of ET and ES sub-algorithms are included. First, the CU ranges of the current CU are recursively predicted based on the texture and CU depth of the spatial neighboring CUs. Second, the statistical model based ET and ES schemes are proposed and applied to optimize the CU and intra prediction mode decision, in which the coding complexities over different decision layers are jointly minimized subject to acceptable rate-distortion degradation. Third, the mode correlations among the intra prediction modes are exploited to early terminate the full rate-distortion optimization in each CU decision layer. Extensive experiments are performed to evaluate the coding performance of each sub-algorithm and the overall algorithm. Experimental results reveal that the overall proposed algorithm can achieve 45.47% to 74.77%, and 58.09% on average complexity reduction, while the overall Bjontegaard delta bit rate increase and Bjontegaard delta peak signal-to-noise ratio degradation are 2.29% and -0.11 dB, respectively.

关键词： HEVC mode decision intra coding coding unit intra angular prediction early skip early termination

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Fast intra coding Partition Decisions for Feature Video coding

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2023年第2期39卷 339-352页

作者： Fang, Jiunn-Tsair Tu, Yu-Liang Chang, Pao-Chi Ming Chuan Univ Dept Elect Engn Taoyuan City 333 Taiwan Natl Cent Univ Dept Commun Engn Taoyuan City 320 Taiwan

Future video coding (FVC) can support 4K high-resolution videos to replace the previous coding standard, high efficiency video coding (HEVC). In particular, FVC adopts quadtree with binary tree (QTBT) to improve coding efficiency;however, encoding time increases heavily. Thus, we propose fast partition algorithms for FVC intra coding. Fast partition algorithms include spatial correlation method and deep learning method. The spa-tial correlation method uses gradient variances of pixels to determine early skip and early termination for QT depths 0 and 1, respectively. The deep learning method uses convolu-tional neural networks (CNNs) to predict the QTBT coding structure at QT depth 2 with its corresponding coding trees. Experimental results show that the proposed method can reduce encoding time by 12.49% on average but increases Bjontegaard delta bit rate (BDBR) by about 0.54%.

关键词： future video coding intra coding quadtree with binary tree coding unit con-volutional neural networks

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Improved lossless intra coding for H.264/MPEG-4 AVC

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2006年第9期15卷 2610-2615页

作者： Lee, Yung-Lyul Han, Ki-Hun Sullivan, Gary J. Sejong Univ Dept Comp Engn Seoul 143747 South Korea Microsoft Corp Redmond WA 98052 USA

A new lossless intra coding method based on sample-by-sample differential pulse code modulation (DPCM) is presented as an enhancement of the H.264[MPEG-4 AVC standard. The H.264/AVC design includes a multidirectional spatial prediction method to reduce spatial redundancy by using neighboring samples as a prediction for the samples in a block of data to be encoded. In the new lossless;intra coding method, the spatial prediction is performed based on samplewise DPCM instead of in the block-based manner used in the current H.264/AVC standard, while the block structure is retained for the residual difference entropy coding process. We show that the new method, based on samplewise DPCM, does not have a major complexity penalty, despite its apparent pipeline dependencies. Experiments show that the new lossless intra coding method reduces the bit rate by approximately 12% in comparison with the lossless;intra coding method previously included in the H.264/AVC standard. As a result, the new method is currently being adopted into the H.264/AVC standard in a new enhancement project.

关键词： AVC differential pulse code modulation (DPCM) H.264 intra coding lossless image coding lossless video coding MPEG-4 spatial prediction

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Fast CU Partition Decision Algorithm for AVS3 intra coding

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IEEE ACCESS 2021年 9卷 7540-7549页

作者： Wu, Tong Liu, Shiyi Wang, Feng Wang, Zhenyu Wang, Rongjie Wang, Ronggang Peking Univ Shenzhen Grad Sch Sch Elect & Comp Engn Shenzhen 518055 Peoples R China Peng Cheng Lab Shenzhen 518055 Peoples R China City Univ Hong Kong Dept Comp Sci Hong Kong Peoples R China

The third generation of Audio Video coding Standard (AVS3) is an emerging video coding standard that surpasses High Efficiency Video coding (HEVC). AVS3 allows flexible block subdivision by applying Quad-Tree (QT), Binary-Tree (BT) plus Extend Quad-Tree (EQT) partition structure, while the increased flexibility comes at the cost of enormous coding complexity. In this paper, an ingenious early termination mechanism is proposed to skip unnecessary exhaustive searches of the whole tree branches. We carry out a series of restrictive measures based on coding Unit (CU) size and iteration status to make the sophisticated EQT split mode concentrate more on small CUs with complex texture structure. Historical QTBT partition information is also adopted as an important factor to skip EQT split mode in advance. Meanwhile, a fast CU partition algorithm based on the gradient is proposed to skip horizontal or vertical BT/EQT partition of CUs with prominent texture structure in another direction, in which early termination can be directly conducted in homogenous areas at the same time. Extensive experiments demonstrate that the proposed method can save 43% encoding time with only 0.53% BDBR increase on average under All intra(AI) configuration, which outperforms the preexisting fast algorithms.

关键词： AVS3 fast CU partition decision intra coding extend quad-tree gradient texture complexity analysis

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intra coding AND REFRESH BASED ON VIDEO EPITOMIC ANALYSIS

INTRA CODING AND REFRESH BASED ON VIDEO EPITOMIC ANALYSIS

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International Conference on Multimedia and Expo

作者： Wang, Qijun Hu, Ruimin Wang, Zhongyuan Hang, Bo Wuhan Univ Natl Engn Res Ctr Multimedia Software NERCMS Wuhan Peoples R China

ISBN: (纸本)9781424474936

In video coding, intra coding plays an important role in both coding efficiency and error resilience. In this paper, a new intra coding method based on video epitomic analysis is proposed. Image epitome suitable for coding is extracted through video epitomic analysis, and is used to generate the prediction for each block. The mapping between the original image and image epitome as well as image epitome should be coded and transmitted to the decoder side. Due to the independence of adjacent reconstructed blocks, the proposed intra coding method can also be applied to improve error resilience of intra refresh. Experimental results show that, the proposed intra coding method can significantly improve the performance of intra coding by 0.7dB in terms of PSNR. The simulation results under packet loss environment show that the proposed intra refresh can out-perform random intra refresh (RIR) by up to 1dB, and better subjective quality can also be obtained.

关键词： intra coding image epitome H.264\AVC intra refresh

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Low-Complexity intra coding in Versatile Video coding

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2022年第2期68卷 119-126页

作者： Choi, Kiho The Van Le Choi, Yongho Lee, Jin Young Gacheon Univ Sch Comp Seongnam 13120 South Korea Sejong Univ Dept Intelligent Mechatron Engn Seoul 05006 South Korea

Versatile Video coding (VVC) was finalized in 2020 and offered promising coding efficiency with a bitrate reduction of about 50% for same video quality as High Efficiency Video coding. However, its high encoding complexity is a heavy burden on real-time applications. In particular, the very high complexity in intra coding can be a big barrier into market entry. This paper presents an efficient low-complexity intra coding scheme, which employs downsampling and upsampling processes. The downsampling is simply performed by reducing the resolution of an original video in both horizontal and vertical directions. In the upsampling, convolutional neural network based super-resolution is used to increase the resolution of the reconstructed video. In addition, this paper thoroughly analyzes the performance and complexity of all intra coding tools in VVC. Experimental results demonstrate that the significantly high reduction of the encoding complexity can be achieved with acceptable video quality.

关键词： Encoding Complexity theory Standards Streaming media Artificial intelligence High efficiency video coding Decoding intra coding low complexity super-resolution versatile video coding (VVC)

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Texture-based fast QTMT partition algorithm in VVC intra coding

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SIGNAL IMAGE AND VIDEO PROCESSING 2023年第4期17卷 1581-1589页

作者： Li, Qiang Meng, Hui Li, Ya Chongqing Univ Posts & Telecommun Sch Commun & Informat Engn Chongqing 400065 Peoples R China Chongqing Key Lab Signal & Informat Proc Chongqing 400065 Peoples R China

The latest video coding standard is the versatile video coding (VVC) which was developed by JVET in July 2020. In VVC, a quadtree nested with multi-type trees using the binary tree and ternary tree structure can support more flexible CU partitioning. The QTMT structure allows more flexible CU shapes to adopt various local characteristics yet also introduces unprecedentedly high coding complexity for VVC intra coding. To reduce the excessive complexity, in this paper, we use Scharr operator-based gradient to describe texture information and subblock edge difference to describe structure information and then propose a fast QTMT partition method based on them. The fast algorithm includes three parts: the early termination of CU partition, the early decision of CU partition direction, and the early skip of ternary tree split mode. Experimental results show that the proposed algorithm can save 49.05% encoding time than anchor VTM14.0 only with 1.37% increase in BDBR.

关键词： CU partition intra coding QTMT Scharr operator Subblock edge difference

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Configurable Fast Block Partitioning for VVC intra coding Using Light Gradient Boosting Machine

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2022年第6期32卷 3947-3960页

作者： Saldanha, Mario Sanchez, Gustavo Marcon, Cesar Agostini, Luciano Univ Fed Pelotas Grad Program Comp Sci PPGC BR-96010610 Pelotas RS Brazil Univ Fed Pelotas Video Technol Res Grp ViTech BR-96010610 Pelotas RS Brazil Farroupilha Dept Informat BR-97555000 Alegrete Brazil Pontificia Univ Catolica Rio Grande do Sul Grad Program Comp Sci PPGCC BR-90619900 Porto Alegre RS Brazil

This article presents a configurable fast block partitioning decision for Versatile Video coding (VVC) intra-frame prediction using Light Gradient Boosting Machine (LGBM). VVC further improves the coding efficiency by introducing a Quadtree with nested Multi-Type Tree (QTMT), enabling five split types allowing square and rectangular coding Unit (CU) sizes. However, this improvement in the coding efficiency comes at the cost of a high computational burden since several combinations of block sizes and prediction modes are evaluated through the costly Rate-Distortion Optimization (RDO) process. In this article, we propose a partitioning decision using LGBM classifiers to avoid the exhaustive RDO process and skip the evaluation of split types that are unlikely to be chosen as the best one. For this purpose, five classifiers (one for each split type) were offline trained with an efficient training process and using effective features of texture, coding, and context information. The proposed solution is highly configurable and can provide several operation points with different tradeoffs between timesaving and coding efficiency, according to the application requirements. Considering five operation points, the configurable solution can reduce the encoding time from 35.22% to 61.34%, with coding efficiency losses from 0.46% to 2.43%. Compared to the state-of-the-art, our solution is able to outperform the related works in terms of combined rate-distortion and timesaving.

关键词： Encoding Complexity theory Shape Streaming media Boosting Transforms Tools VVC intra coding timesaving machine learning light gradient boosting machine

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Selective VS-MRF-ME and intra coding in H.264 based on spatiotemporal continuity of motion field

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2009年第5期24卷 405-414页

作者： Shen, Liquan Liu, Zhi Zhang, Zhaoyang Shi, Xuli Shanghai Univ Key Lab Adv Display & Syst Applicat Minist Educ Shanghai 200072 Peoples R China

The new video coding standard, H.264 uses variable size motion estimation (VS-ME), multiple reference frame motion estimation (MRF-ME) and spatial-based intra prediction with selectable block size in inter frame coding. These tools have achieved significant coding efficiency compared to coding a macroblock (MB) only based on motion-compensation in regular size with single reference frame. However, these new features also give rise to an exhaustive computation in the coding procedure since there are so many combinations of coding modes and reference frames to be tried. In this paper, a fast motion estimation algorithm based on the selective VS-MRF-ME and intra prediction is proposed to reduce H.264 coding computational complexity. The basic idea of the method is to utilize the spatiotemporal property of motion field in predicting where VS-MRF-ME and intra prediction are needed, and only in these regions VS-MRF-ME and intra coding are enabled. The motion field is generated by motion vectors from 16 x 16 motion estimation oil the nearest reference frame. Simulation results show that the proposed algorithm can save 50% computational complexity on average, with negligible loss of coding efficiency. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Video coding H.264 Motion continuity Variable size motion estimation Multiple-frame motion estimation intra coding

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