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IEEE International Symposium on Broadband Multimedia Systems and Broadcasting

作者： Tripathi, Subarna Piccinelli, Emiliano Mario STMicroelect Adv Syst Technol Gnoida 201308 UP India STMicroelect Adv Syst Technol I-20041 Agrate Brianza Italy

ISBN: (纸本)9781424416486

Video transcoding is becoming nowadays more and more popular, due to the necessity to cope with several different encoding standards, available bandwidth and decoder capabilities. In this paper we are going to discuss the strategy for implementation of a buffer-based rate control algorithm (constant bit rate) in a MPEG2 to MPEG4 Simple profile transcoder which is over performing during scene changes, always preserving the so called VBV compliancy. This technique is extendable to the transcoding to any video standard having only predicted (P) frames.

关键词： rate control content adaptation quantization parameter video buffering verifier (VBV)

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An ROI-codec-supported rate control algorithm in video compression

An ROI-codec-supported rate control algorithm in video compr...

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Conference on Electronic Imaging and Multimedia Technology V

作者： Li Zi-yin Jin Shang-Zhong China Jiliang Univ Hangzhou 310018 Zhejiang Peoples R China

ISBN: (纸本)9780819470089

For low bit rate video compression, the quality of reconstructed video is usually poor. The high codec priority of region of interest (ROI) can improve image quality obviously. Nowadays, video segmentation methods are often used for extracting ROI, but these methods have high computational complexity and are not satisfied to real time communication. On the other hand, in most existing rate control algorithms, ROI can't select the low and high bit rate R-Q model adaptively. Aiming at these problems, in this paper, a simple and efficient approach of extracting ROI is proposed which can decrease the computational complexity of existing ROI extracting algorithms. Bits are distributed to ROI and non-ROI (NROI) respectively according to the image complexity and motion information. Moreover, the judgment criterion of distinguishing between low and high bit rate coding category is derived, which makes the algorithm select the R-Q model adaptively and decrease the rate control errors. In addition, the scheme of modifying the coding order of macro blocks (MBs) can enhance the objective image quality. Experiment results demonstrate that the proposed algorithm achieves a bit rate closer to the target, provides fewer skipped frames, and gets better objective and subjective image quality significantly compared with TMN7 and TMN8 algorithms.

关键词： video compression rate control ROI quantization parameter

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Performance Comparison of Jpeg, Jpeg XT, Jpeg LS, Jpeg 2000, Jpeg XR, HEVC, EVC and VVC for Images 6

Performance Comparison of Jpeg, Jpeg XT, Jpeg LS, Jpeg 2000,...

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6th International Conference for Convergence in Technology (I2CT)

作者： Kumar, Naveen S. Bharadwaj, Vamshi M. V. Subbarayappa, Shreyanka MS Ramaiah Univ Appl Sci Dept Elect & Commun Engn Bengaluru India MS Ramaiah Univ Appl Sci Fac Engn & Technol Dept Elect & Commun Engn Bengaluru India

ISBN: (纸本)9781728188768

Online videos and image blogging are some of the major sources for internet traffic and are estimated to have exponential growth in the future. Efforts are made to introduce advanced compression formats for images and included in the future codecs. This paper focuses on analyzing and comparing the existing codecs with the potential codecs to obtain very good quality images with substantially high compression rate. Using the same test conditions and same test content-set for both image and video codecs, like JPEG, JPEG LS, JPEG XR, JPEG 2000, JPEG XT, HEVC, VVC and EVC, the output quality of the image is analyzed using quality metrics like PSNR (Peak Signal-to-Noise Ratio) and SSIM (Structural Similarity Index Metric). Fitting properties of each codec, conditions of testing and performance comparison between the codecs are analyzed. The test results indicate that JPEG XR is best suited for low resolution and HD image compressions while JPEG 2000 and JPEG XT are best suited for grey-scale and 4K image compressions respectively. The paper concludes with detailed analysis of codec performance including suggestion over its applications and scope for future work.

关键词： Encoding decoding intra-prediction interprediction quantization parameter JPEG HEVC EVC VVC

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An adaptive preprocessing algorithm for low bitrate video coding

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第12期7卷 2057-2062页

作者： LI Mao-quan XU Zheng-quan School of Electronic Information Wuhan University Wuhan 430079 China Multimedia Communication Engineering Center State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan 430079. China

At low bitrate, all block discrete cosine transform (BDCT) based video coding algorithms suffer from visible blocking and ringing artifacts in the reconstructed images because the quantization is too coarse and high frequency DCT coefficients are inclined to be quantized to zeros. Preprocessing algorithms can enhance coding efficiency and thus reduce the likelihood of blocking artifacts and ringing artifacts generated in the video coding process by applying a low-pass filter before video encoding to remove some relatively insignificant high frequent components. In this paper, we introduce a new adaptive preprocessing algo- rithm, which employs an improved bilateral filter to provide adaptive edge-preserving low-pass filtering which is adjusted ac- cording to the quantization parameters. Whether at low or high bit rate, the preprocessing can provide proper filtering to make the video encoder more efficient and have better reconstructed image quality. Experimental results demonstrate that our proposed preprocessing algorithm can significantly improve both subjective and objective quality.

关键词： Blocking artifact quantization parameter Video preprocessing Bilateral filtering

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Feedback Channel Suppression in Distributed Video Coding with Adaptive Rate Allocation and quantization for Multiuser Applications

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2008年第unknown期2008卷 427247-427247页

作者： Yaacoub, Charles Farah, Joumana Pesquet-Popescu, Beatrice Holy Spirit Univ Kaslik Fac Sci & Comp Engn Dept Engn Jounieh Lebanon TELECOM ParisTech Signal & Image Proc Dept F-75634 Paris 13 France

We present a novel rate allocation technique for distributed multiuser video coding systems without the need for a permanent feedback channel. Based on analytical calculations, the system unequally distributes the available bandwidth among the different users, taking into account the actual amount of movement in the transmitted video as well as the transmission conditions of each user. On one hand, the quantization parameters are dynamically tuned in order to optimize the decoding quality. On the other hand, a frame dropping mechanism allows the system to avoid unnecessary channel use, when the analytical estimations show that the successful decoding of a given frame is not possible because of very high motion or bad channel conditions. A significant gain in the system performance is noticed compared with the case of equal allocation of channel resources and constant quantization parameters. Copyright (C) 2008 Charles Yaacoub et al.

关键词： Video Code quantization parameter Transmission Condition Channel Suppression Transmitted Video

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Zero-Block Mode Decision Algorithm for H.264/AVC

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2009年第3期18卷 524-533页

作者： Lee, Yu-Ming Lin, Yinyi Natl Cent Univ Dept Commun Engn Chungli 32054 Taiwan

In the previous paper [14], we proposed a zero-block intermode decision algorithm for H.264 video coding based upon the number of zero-blocks of 4 x 4 DCT coefficients between the current macroblock and the co-located macroblock. The proposed algorithm can achieve significant improvement in computation, but the computation performance is limited for high bit-rate coding. To improve computation efficiency, in this paper, we suggest an enhanced zero-block decision algorithm, which uses an early zero-block detection method to compute the number of zero-blocks instead of direct DCT and quantization (DCT/Q) calculation and incorporates two adequate decision methods into semi-stationary and nonstationary regions of a video sequence. In addition, the zero-block decision algorithm is also applied to the intramode prediction in the P frame. The enhanced zero-block decision algorithm brings out a reduction of average 27% of total encoding time compared to the zero-block decision algorithm.

关键词： Discrete cosine transform (DCT) early zero-block detection fast mode decision H.264/AVC quantization parameter variable block-size zero-block decision

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Perceptual VVC quantization refinement with ensemble learning

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DISPLAYS 2021年 70卷

作者： Wu, Yuxuan Wang, Zheng Chen, Weiling Lin, Liqun Wei, Hongan Zhao, Tiesong Fuzhou Univ Coll Phys & Informat Engn Fujian Key Lab Intelligent Proc & Wireless Transm Fuzhou 350108 Peoples R China

Compressing videos while maintaining an acceptable level of Quality of Experience (QoE) is indispensable. To this aim, a feasible method is to further increase the quantization parameter (QP) of video stream to eliminate visual redundancy, simultaneously utilizing perceptual characteristics of Human Visual System (HVS) to impose a threshold constraint on the maximum QP. In this paper, we employ Just Noticeable Distortion (JND) to characterize the aforementioned threshold constraint, thereby avoiding perceptual loss during QP refinement process. We propose an effective JND-based algorithm for QP optimization, in which a video saliency detection is introduced to extract regions of interest, a refinement model based on a lightweight network is designed to predict QP value and an ensemble learning method to improve generalization performance. Theoretical analysis and experimental results demonstrate that the proposed algorithm has been successfully applied to Versatile Video Coding (VVC) to achieve significant bitrate reduction without sacrificing perceived quality.

关键词： Just noticeable distortion quantization parameter Human visual system Refinement model Ensemble learning

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Subjective Evaluation of Ultra-high Definition (UHD) Videos

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KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 2020年第6期14卷 2464-2479页

作者： Rahim, Tariq Shin, Soo Young Kumoh Natl Inst Technol Gumi South Korea

This paper presents a detailed subjective quality assessment for the ultra-high definition (UHD) videos having frame rates of 30fps and 60 fps. The subjective assessment is based on the ITU-R BT-500 recommendations, where double stimulus continuous quality scale (DSCQS-type II) test is performed for the evaluation of the perceived quality of the user's in terms of differential mean opinion score (DMOS). Encoding of the UHD videos by opting encoders i.e. H.264/AVC, H.265/HEVC, and VP9 at five different quantization parameter (QP) levels is done to investigate the perceived user's quality of experience (QoE) given as DMOS. Moreover, the encoding efficiency as the encoding time for each encoder and qualitative performance by employing full-reference (FR) quality metrics are presented in this work.

关键词： Encoders H.264/AVC H.265/HEVC quality of experience quantization parameter and VP9

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Rate distortion optimization with adaptive content modeling for random-access versatile video coding

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INFORMATION SCIENCES 2023年第1期645卷

作者： Chen, Yi Wang, Shiqi Ip, Horace Kwong, Sam City Univ Hong Kong Dept Comp Sci Kowloon Hong Kong Peoples R China

In this paper, we study the capability of improving the rate-distortion (RD) performance based on the adaptive content modeling in the Versatile Video Coding (VVC) standard. In particular, the frame-level dependent relationships and inherent RD relationship are explored. As such, the rate dependency, distortion dependency and inherent RD characteristics are fully utilized in the global rate distortion optimization (RDO) process, and the quantization parameter (QP) for each frame could be adaptively solved. To facilitate the adaptive QP calculation, a two-pass coding strategy is proposed. In the first-pass coding, the video statistics are sufficiently collected with the proposed Dual Motion Compensation and Residual Coding (DMCRC) method to generate the parameters for the content-aware models. During the second-pass coding, the optimal QP at the frame level is obtained by optimizing the global RD performance with the dependent and inherent models. The proposed algorithm is implemented on VVC test model (VTM-4.0) and achieves significant performance gain for test sequences with constant and varying scenes.

关键词： Versatile video coding Rate-distortion optimization quantization parameter Inter-frame dependency Adaptive QP selection

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Quality of experience enhancement of high efficiency video coding video streaming in wireless packet networks using multiple description coding

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JOURNAL OF ELECTRONIC IMAGING 2018年第1期27卷 013028-013028页

作者： Boumehrez, Farouk Brai, Radhia Doghmane, Noureddine Mansouri, Khaled Badji Mokhtar Annaba Univ Fac Engn Sci Dept Elect Sidi Amar Annaba Algeria Khenchela Univ Fac Sci & Technol Dept Elect Engn Khenchela Algeria 8 Mai 1945 Guelma Univ Fac Sci & Technol LT Guelma Algeria Badji Mokhtar Annaba Univ LASA Annaba Algeria

Recently, video streaming has attracted much attention and interest due to its capability to process and transmit large data. We propose a quality of experience (QoE) model relying on high efficiency video coding (HEVC) encoder adaptation scheme, in turn based on the multiple description coding (MDC) for video streaming. The main contributions of the paper are (1) a performance evaluation of the new and emerging video coding standard HEVC/H.265, which is based on the variation of quantization parameter (QP) values depending on different video contents to deduce their influence on the sequence to be transmitted, (2) QoE support multimedia applications in wireless networks are investigated, so we inspect the packet loss impact on the QoE of transmitted video sequences, (3) HEVC encoder parameter adaptation scheme based on MDC is modeled with the encoder parameter and objective QoE model. A comparative study revealed that the proposed MDC approach is effective for improving the transmission with a peak signal-to-noise ratio (PSNR) gain of about 2 to 3 dB. Results show that a good choice of QP value can compensate for transmission channel effects and improve received video quality, although HEVC/H.265 is also sensitive to packet loss. The obtained results show the efficiency of our proposed method in terms of PSNR and mean-opinion-score. (c) 2018 SPIE and IS&T

关键词： high efficiency video coding/H.265 multiple description coding quality of experience quantization parameter packet loss ratio wireless networks

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