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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Victor Sanchez Dept. of Computer Science University of Warwick Coventry UK

ISBN: (纸本)9781538646595

This paper proposes a rate control (RC) algorithm for intra-coded sequences (I-frames) within the context of block-based predictive transform coding (PTC) that employs piecewise linear approximations of the rate-distortion (RD) curve of each frame. Specifically, it employs information about the rate (R) and distortion (D) of already compressed blocks within the current frame to linearly approximate the slope of the corresponding RD curve. The proposed algorithm is implemented in the High-Efficiency Video coding (HEVC) standard and compared with the current HEVC RC algorithm, which is based on a trained rate-lambda (R-λ) model. Evaluations on a variety of intra-coded sequences show that the proposed RC algorithm not only attains the overall target bit rate more accurately than the current RC algorithm but is also capable of encoding each I-frame at a more constant bit rate according to the overall bit budget, thus avoiding high bit rate fluctuations across the sequence.

关键词： HEVC rate control intra-coding R-λ model rate control High efficiency video coding Ritchey-Chretien telescope target bit rate approximation Standing Orders I-Frame REMEDIAL DESIGN

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Low-Complexity intra-coding Scheme for HEVC

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2016年第12期35卷 4331-4349页

作者： Shang, Xiwu Wang, Guozhong Fan, Tao Li, Yan Zuo, Yifan Shanghai Univ Shanghai 200444 Peoples R China

Compared with H.264/AVC, the latest video standard High Efficiency Video coding (HEVC) known as H.265 improves the coding efficiency by adopting the quadtree splitting structure which is flexible in representing various textural and structural information in images. However, the computational complexity is dramatically increased, especially in the intra-mode decision process owing to supporting more partitions and modes. In this paper, we propose a low-complexity algorithm for HEVC intra-coding, which consists of a fast coding unit (CU) size decision (FCUSD) method and a fast prediction unit (PU) mode decision (FPUMD) method. In FCUSD, unnecessary CU sizes are skipped early according to the depth level of neighboring CUs and the rate distortion (RD) cost threshold derived from the former coded frame. In FPUMD, the PU mode and RD cost correlations between different depth levels are utilized to terminate unnecessary candidate modes. Experimental results demonstrate that the proposed algorithm can achieve about 50.99 % computational complexity reduction on average with 1.18 % BD-rate increase and 0.08 dB BD-psnr loss.

关键词： Low complexity intra-coding HEVC CU size PU mode

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A Fast Texture-Based 8K intra-Partitioning Algorithm for Versatile Video coding (VVC)

A Fast Texture-Based 8K Intra-Partitioning Algorithm for Ver...

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2024 Conference on Visual Communications and Image Processing

作者： Simsek, Altug Dundar, Gunhan Bogazici Univ Elect & Elect Engn Dept Istanbul Turkiye

ISBN: (纸本)9798331529543;9798331529550

Versatile Video coding (VVC), standardized in 2022 as ITU-T Recommendation H.266, ISO/IEC 23090-3 and MPEG-I Part3, is the latest block-based hybrid video coding standard. It defines many tools to increase compression efficiency while maintaining the same quality level. The tradeoff is the computational complexity. The intra-coding loop of VVC is computationally very complex due to its nature of iteratively trying all possible Quad-Tree Multitype-Tree (QTMT) partitioning alternatives starting from 128x128 coding Tree Unit (CTU) size and going down to 4x4 min coding Unit (CU) size. For camera-taken real-world broadcast video, compared to smaller resolutions, the objects in 8K are larger with respect to the fixed CTU size of VVC. As a result, for such 8K video, less detailed coding in the VVC QTMT may be enough for practical purposes. In this paper, we define a new fast intra-partitioning algorithm for 8K video and compare its performance with Common Test Conditions (CTC) All-intra (AI) configuration based on the compression efficiency (bits), quality (Y-PSNR, SSIM and MS-SSIM metrics), and computational complexity (runtime). We observe 81.61% runtime gain with only 2.99% increase in bitrate, 0.1339 dB decrease in Y-PSNR, 0.0022 decrease in SSIM and 0.0007 decrease in MS-SSIM on average. This is a remarkable gain in complexity with a limited effect on efficiency and quality.

关键词： VVC H.266 versatile video coding intra-coding CU partitioning texture-based partitioning 8K

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Reference picture selection scheme for robust HEVC video transmission using compressed domain saliency map

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JOURNAL OF REAL-TIME IMAGE PROCESSING 2023年第4期20卷 70页

作者： Xu, Jiajun Wang, Bing Peng, Qiang Southwest Jiaotong Univ Sch Comp & Artificial Intelligence Chengdu 611756 Peoples R China Chongqing Jiaotong Univ Sch Informat Sci & Engn Chongqing 40074 Peoples R China

The high level of compression achieved by high efficiency video coding (HEVC) helps reduce network traffic loads and mitigate data rate requirements. However, HEVC is vulnerable to error-prone channels where transmission errors can result in severe degradation of video quality. In this paper, a saliency-aware encoding scheme is proposed to improve the error robustness of HEVC streaming, by reducing temporal error propagation in case of packet loss. The proposed scheme firstly introduces a saliency detection model in compressed domain, based on two HEVC features derived from the depth splitting of the coding unit and the residual. Incorporated with the saliency map, an improved reference frame selection strategy is then introduced to reduce the inter-prediction mismatch that occurs at the decoder after packet loss. Specifically, the reference frames are dynamically selected based on the saliency-weighted Lagrangian optimisation, which not only reduces the number of prediction units (PUs) that depend on a single reference in saliency regions but also chooses the optimal coding mode for non-saliency regions. Finally, the most salient PUs are required to select the reference block in which most of the pixels are coded with intra-mode, for providing more robust reference to saliency regions. The simulation results show that the proposed reference picture selection scheme outperforms other reference methods with higher error robustness and a smaller loss in coding efficiency. Compared to the HEVC reference software, the proposed scheme is able to improve the quality of recovered video after packet loss, achieving average PSNR gains of up to 1.92 dB.

关键词： Robust video coding Reference picture selection intra-coding Saliency map

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Data-Parallelism Based Hardware Architecture for the intra-coding Module Used in the H.264/AVC Encoder

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ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2014年第5期39卷 3781-3797页

作者： Messaoudi, Kamel Toumi, Salah Bourennane, El-Bay Touiza, Maamar Mentouri Univ Constantine Dept Elect Constantine Algeria Badji Mokhtar Univ Annaba LERICA Lab Annaba Algeria Burgundy Univ Lab LE21 F-21078 Dijon France

In this paper, we propose a hardware architecture for the intra-coding module used in the H.264 encoder. The proposed architecture is based on data-parallelism principles, with a 128-bit data input. This data input is retrieved from a DDR2 memory using an intelligent memory controller specially designed for the H.264 encoder. Unlike other architectures using different intra-prediction modes in parallel, we propose to implement the different modes in series to avoid an excessive use of FPGA resources. This also provides the ability to process data in parallel. In this manner, we can ensure a pipelined architecture to reduce the required number of clock cycles to process each macroblock. Data-Parallelism based hardware architectures are proposed for the intra-prediction, the integer transform, the quantization, the inverse integer transform, the inverse quantization, and the mode decision modules. Results and performance measurements of the intra-coding module were validated on the Xilinx Virtex5-ML501 platform. The proposed architecture occupies 18 % of the FPGA's resources and operates at a maximum frequency of 155MHz.

关键词： intra-coding H.264/AVC codec IP encoder Data-parallelism FPGA

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An Advanced LiDAR Point Cloud Sequence coding Scheme for Autonomous Driving 20

An Advanced LiDAR Point Cloud Sequence Coding Scheme for Aut...

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28th ACM International Conference on Multimedia (MM)

作者： Sun, Xuebin Wang, Sukai Wang, Miaohui Cheng, Shing Shin Liu, Ming Shenzhen Univ Coll Elect & Informat Engn Shenzhen Peoples R China Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Peoples R China Chinese Univ Hong Kong Stone Robot Inst Shatin Hong Kong Peoples R China Chinese Univ Hong Kong Dept Mech & Automat Engn Shatin Hong Kong Peoples R China Guangdong Key Lab Intelligent Informat Proc Shenzhen Peoples R China Shenzhen Inst Artificial Intelligence & Robot Soc Shenzhen Peoples R China

ISBN: (纸本)9781450379885

Due to the huge volume of point cloud data, storing or transmitting it is currently difficult and expensive in autonomous driving. Learning from the high efficiency video coding (HEVC) coding framework, we propose an advanced coding scheme for large-scale LiDAR point cloud sequences, in which several techniques have been developed to remove the spatial and temporal redundancy. The proposed strategy consists mainly of intra-coding and inter-coding. For intra-coding, we utilize a cluster-based prediction method to remove the spatial redundancy. For inter-coding, a predictive recurrent network is designed, which is capable of generating future frames according to the previously encoded frames. By calculating the residual error between the predicted and real point cloud data, the temporal redundancy can be removed. Finally, the residual data is quantized and encoded by lossless coding schemes. Experiments are conducted on the KITTI data set with four different scenes to verify the effectiveness and efficiency of the proposed method. Our approach can deal with multiple types of point cloud data from the simple to more complex, and yields better performance in terms of compression ratio compared with octree, Google Draco, MPEG TMC13 and other recently proposed methods.

关键词： LiDAR Point CLoud Sequence intra-coding Inter-coding Predictive Recurrent Network

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Cross residual transform for lossless intra-coding for HEVC

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2013年第10期28卷 1335-1341页

作者： Hong, Sung-Wook Kwak, Jae Hee Lee, Yung-Lyul Sejong Univ Dept Comp Engn Digital Media Syst Lab Seoul South Korea

A new lossless intra-coding method based on a cross residual transform is applied to the next generation video coding standard HEVC (High Efficiency Video coding). HEVC includes a multi-directional spatial prediction method to reduce spatial redundancy by using neighboring pixels as a prediction for the pixels in a block of data to be encoded. In the new lossless intra-coding method, the spatial prediction is performed as pixelwise DPCM but is implemented as block-based manner by using cross residual transform on the HEVC standard. The experimental results show that the new lossless intra-coding method reduces the bit rate of approximately 8.43% in comparison with the lossless-intra coding method in the HEVC standard and the proposed method results in slightly better compression ratio than the JPEG200 lossless coding. (C) 2013 Published by Elsevier B.V.

关键词： HEVC intra-coding Loss less video coding Differential pulse code modulation (DPCM) Residual transform Cross residual transform

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Depth coding Based on Depth-Texture Motion and Structure Similarities

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2015年第2期25卷 275-286页

作者： Lei, Jianjun Li, Shuai Zhu, Ce Sun, Ming-Ting Hou, Chunping Tianjin Univ Sch Elect Informat Engn Tianjin 300072 Peoples R China Univ Washington Dept Elect Engn Seattle WA 98195 USA Univ Elect Sci & Technol China Sch Elect Engn Chengdu 611731 Peoples R China

This paper addresses high performance depth coding in 3D video by making good use of its coded texture video counterpart. The relationship between the depth and its associated texture video in terms of coding mode and motion vector is carefully examined. Our statistical study suggests that the skip-coding mode and its associated motion vectors in the coded texture can be shared for depth coding by saving bit rate at the cost of little increase of distortion, which subsequently results in a nonsequential coding of the depth map. In this sense, coding/prediction of a block can be performed using the skip-coded blocks below and right, which are not available in the conventional sequential coding, thus producing the so-called omnidirectional blocks predicted in the intra-coding by making the best use of (at most) four neighboring blocks. Moreover, in view of the depth-texture structure similarity, a depth-texture cooperative clustering-based prediction method is proposed for cluster-based depth prediction in the intra-coding, which exploits the structure similarity for the current coding block and its neighboring pixels around the block. On the other hand, some large prediction errors may be present for the depth-texture misaligned pixels, which may greatly compromise the coding performance. To deal with these large residuals induced by the depth-texture misalignment, a simple yet effective detection and rectification approach is incorporated in the proposed depth coding scheme. Experimental results show that our proposed depth coding scheme achieves superior rate-distortion performance compared with other relevant coding methods.

关键词： 3D video depth coding depth-texture misalignment intra-coding prediction

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Improved SAP based on adaptive directional prediction for HEVC lossless intra prediction

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2015年 33卷 78-84页

作者： Xia, Xiao-Peng Liu, En-Hai Qin, Jun-Ju Chinese Acad Sci Inst Opt & Elect Chengdu 610209 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Chengdu Normal Univ Chengdu 610072 Peoples R China

In HEVC (High Efficiency Video coding), linear interpolation of the boundary pixels is used as the predictor and pixels within the same PU (Prediction Unit) are in the same prediction direction. When the PU block is large and in high complexity, the prediction performance would worsen. Although many algorithms use the pixel-based weighted averaging or interpolation operations to perform the prediction which improves the performance of bitrate saving notably, there is still space for further improvement. This paper proposed an improved SAP (Sample-based Angular Prediction) algorithm based on adaptive directional prediction (ADSAP). The innovation of this paper lies in two aspects: it puts forward a new method to estimate the best prediction direction of current pixel and it introduces the concept of "frame-level pretreatment" which could greatly improve the encoding speed. Experimental results show that it could save the output bitrate by about 9.4158% when compared with the HEVC lossless intra prediction algorithm, which is better than other typical algorithms. Besides, the encoding and decoding time are reduced by about 11%. Moreover, when the minimum PU size gets larger, the increase of output bitrate of ADSAP is much less than that of HEVC and the conventional SAP algorithm, which makes the proposed algorithm quite suitable for the compression of high resolution videos. (C) 2015 Elsevier Inc. All rights reserved.

关键词： HEVC intra-coding Lossless video coding SAP Linear interpolation Prediction modes ADSAP Frame-level pretreatment

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Region Adaptive Measurements for Distributed Compressive Video Sensing

Region Adaptive Measurements for Distributed Compressive Vid...

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2016 2nd Workshop on Advanced Research and Technology in Industry Applications(WARTIA 2016)

作者： Hongyan Zhai Guangdong Industry Polytechnic

Due to limited resources,wireless video sensor networks(WVSN) needs low complexity methods to realize video capture and ***,distributed video coding(DVC) has emerged to reduce the video encoding complexity with a certain coding ***,compressive sensing(CS) has been proposed to directly capture the compressed data *** this paper,combining DVC and CS,a novel video coding framework has been designed for *** order to preserve low complexity at the encoder,odd frames of the original video can be compressed as key frames by standard intra-coding while even frames can be processed as CS frames by CS ***,flexible mode selection of the encoder is applied to improve coding ***,adaptive measurements are allocated for different blocks in view of the object and background regions in the video *** the decoder,the bi-directional dictionary is proposed as the sparse basis to improve the recovery quality of *** experimental results validate the effectiveness of the proposed scheme with better performance than other compared schemes.

关键词： Distributed Video coding Compressive Sensing Standard Video Codec intra-coding

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