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Fast motion re-estimation for arbitrary downsizing video transcoding using H.264/AVC standard

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2004年第3期50卷 887-894页

作者： Tan, YP Sun, HW Nanyang Technol Univ Sch Elect & Elect Engn Singapore 2263 Singapore

Downsizing video transcoding is a technique for adapting the bit rate or frame size of a precoded video to suit better the constraints of transmission networks and target applications. To sustain good video quality at reduced bit rates, we halve previously-proposed H.263-based transcoding techniques for downsizing precoded videos by an arbitrary factor. To fully exploit the advantages of video transcoding, we investigate and propose in this paper an effective and fast motion re-estimation method for arbitrary downsizing video transcoding using the newly developed H.264/AVC standard. Specifically, as H.264/AVC allows more macroblock partitions and reference frames for inter-frame motion-compensated prediction, we propose an area-weighted vector median filter to estimate the new required motion vectors from the motion vectors existing in a precoded video. Experimental results show that the proposed method can achieve a notable improvement in both subjective and objective video quality for transcoding,precoded H.263 or H.264 videos at reduced bit rates and frame sizes.

关键词： arbitrary downsizing fast motion estimation H.264/AVC video transcoding weighted vector median filter

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Region-of-interest-based video transcoding from MPEG-2 to H.264 in the compressed domain

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OPTICAL ENGINEERING 2008年第9期47卷

作者： Xie, Rong Yu, Songyu Shanghai Jiao Tong Univ Dept Elect Engn Inst Image Commun & Informat Proc Shanghai 200240 Peoples R China Shanghai Key Lab Digital Media Proc & Transmiss Shanghai 200240 Peoples R China

A new MPEG-2-to-H. 264 video transcoding algorithm based on regions of interest (ROIs ) is proposed. The whole transcoding scheme, including the ROI detection, is applied in the compressed domain to alleviate the computational load. The ROI detection uses the motion information from the partially decoded MPEG-2 bitstream. Then the ROIs that are likely to attract the viewer's attention are transcoded with drift compensation to provide better quality, while other regions are transcoded without drift compensation to save computational complexity. Experimental results show that our algorithm provides a better trade-off between computational complexity and picture quality. It achieves a speedup of 2 times over the closed-loop transcoding algorithm in the compressed domain, while giving comparable visual quality. (C) 2008 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.2976797]

关键词： video transcoding region of interest H.264 MPEG-2

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Cluster-based optimized parallel video transcoding

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PARALLEL COMPUTING 2012年第4-5期38卷 226-244页

作者： Barlas, Gerassimos Amer Univ Sharjah Comp Sci & Engn Dept Coll Engn Sharjah U Arab Emirates

video transcoding is a popular technique for delivering video content of varying quality and size to diverse audiences. In this paper an analytical approach to the optimization of a large collection of parallel transcoding techniques based on temporal partitioning, is pursued. The key elements in the design of such techniques are identified, allowing them to be enumerated and classified. Closed-form solutions to the partitioning/scheduling problem (and optimum operation sequencing where necessary) are derived for the most important of these methods, under CBR input media conditions. Subsequently, appropriate heuristics allow the solution of the partitioning problem under VBR input media conditions. The paper is concluded by an extensive battery of tests for the most significant strategies, on several feature-length video streams. The tests reveal not only how one of the proposed strategies, namely NPWFVBR, strikes a nice balance between efficiency and distortion minimization on heterogeneous platforms, but also allow us to derive guidelines for transcoding solution deployment. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Parallel video encoding video transcoding Divisible Load Theory

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Analysis of video Quality Losses in Homogeneous HEVC video transcoding

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IEEE ACCESS 2019年 7卷 96764-96774页

作者： Grajek, Tomasz Stankowski, Jakub Karwowski, Damian Klimaszewski, Krzysztof Stankiewicz, Olgierd Wegner, Krzysztof Poznan Univ Tech Chair Multimedia Telecommun & Microelect PL-60965 Poznan Poland

This paper presents a detailed, quantitative analysis of video quality losses in a homogeneous HEVC video transcoder together with the analysis of the origin of those quality losses and the influence of quantization step alignment on transcoding. With the use of HM15.0 reference software and a set of test video sequences, the cascaded pixel domain video transcoder (CPDT) concept has been used to gather all the necessary data needed for the analysis. This experiment was performed for a wide range of source and target bitrates. The essential result of the work is an extensive evaluation of CPDT, commonly used as a reference in works on effective video transcoding. So far, no such extensively performed study has been made available. The quality degradation between a transcoded video and a video that would be the result of direct compression of the original video at the same bitrate as the transcoded one has been reported. The dependences between quality degradation caused by transcoding and bitrate changes of the transcoded data stream are clearly presented in graphs.

关键词： Cascaded pixel domain video transcoder CPDT HEVC H.265 video compression video transcoding

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video transcoding for wireless mobile Internet access

Video transcoding for wireless mobile Internet access

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Asia-Pacific Optical and Wireless Communications Conference (APOC 2003)

作者： Li, XH Anhui Univ Dept Elect Engn & Informat Sci Hefei 230039 Peoples R China

ISBN: (纸本)0819451797

A method of improved motion vector based on quantization errors in transcoding for wireless mobile Internet is proposed in this paper. The computational complexity of this scheme can be reduced. The control strategy of transcoder buffer is also discussed, and the number of coding bits on the picture layer in the whole is allocated, then different types of picture respectively are processed on the basis of frondose picture characteristics when each frame is coded. Finally optimal quantization parameter for every macroblock in a frame is select. The simulation results shows that this method can effectively speed up the transcoding without significant lose in quality. The output bit rate of the transcoder and the buffer fullness tend to be stabilized, and the peak signal-noise-ratio (PSNR) of the reconstructed picture is raised.

关键词： video transcoding wireless mobile Internet access motion estimation rate control

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An efficient arbitrary downsizing algorithm for video transcoding\

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 2004年第6期14卷 887-891页

作者： Shu, HY Chau, LP Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

When delivering video over communication networks, it is required to transcode the precoded video content to meet the demands of a broad range of end users with different bandwidths and resource constraints. One solution to transmit video over bandwidth-constrained channels is to reduce the spatial resolution of video frames and transmit a low-resolution version of the video as a tradeoff for the bit rate. In this paper, an arbitrary downsizing algorithm is proposed. This arbitrary downsizing algorithm is processed directly in the discrete cosine transform domain. Experimental results show that the proposed method can achieve a satisfactory performance. Compared to the existing methods, this algorithm is not only applicable to an intracoding frame but also to an intercoding frame. This is one of the crucial features of this method.

关键词： arbitrary downsizing video transcoding

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The realization of arbitrary downsizing video transcoding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 2006年第4期16卷 540-546页

作者： Shu, HY Chau, LP Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

In order to transmit the precoded bit stream through bandwidth constrained network, transcoding technique has been introduced to reduce the overall bit rate generated. Downsizing transcoding is one of the commonly used methods since it can reach very low bit rate without losing any motion information. Many efforts have been devoted to this research area. With the proposal of arbitrary downsizing, fine gradual reduction of bit rate and video quality becomes feasible. However, there is little research focusing on frame size selection for arbitrary downsizing transcoding. In this letter, the realization of arbitrary downsizing transcoding is discussed. Rate estimation scheme is applied on video sequences to choose the suitable frame size for the target bit rate. An efficient method is proposed to estimate the number of bits allocated to residue in requantization process. Experimental results show that, it can provide an accurate estimation and make a reliable decision in frame size selection.

关键词： arbitrary downsizing frame size selection video transcoding

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MDVQM: A novel multidimensional no-reference video quality metric for video transcoding

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2014年第3期25卷 542-554页

作者： Zhang, Fan Steinbach, Eckehard Zhang, Peng Tech Univ Munich Inst Media Technol D-80333 Munich Germany Huawei Technol Co Ltd Beijing Peoples R China

In this paper, we study the impact of quantization, frame dropping and spatial down-sampling on the perceived quality of compressed video streams. Based on the analysis of quality ratings obtained from extensive subjective tests, we propose a no-reference metric (named MDVQM) for video quality estimation in the presence of both spatial and temporal quality impairments. The proposed metric is based on the per-pixel bitrate of the encoded stream and selected spatial and temporal activity measures extracted from the video content. All the values required to compute the proposed video quality metric can be obtained without using the original reference video which makes the metric for instance useful for making transcoding decisions in a wireless video transmission scenario. Different from comparable metrics in the literature, we have also considered the case when both frame rate and frame size are changed simultaneously. The validation results show that the proposed metric provides more accurate estimation of the video quality than the state of the art metrics. (C) 2013 Elsevier Inc. All rights reserved.

关键词： video quality assessment video transcoding Perceived video quality metric No-reference Frame dropping Spatial down-sampling Quality of experience Subjective video quality

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Hardware-Assisted, Low-Cost video transcoding Solution in Wireless Networks

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IEEE TRANSACTIONS ON MOBILE COMPUTING 2020年第3期19卷 581-597页

作者： Yoon, Jongwon Banerjee, Suman Hanyang Univ Coll Comp Ansan 15588 South Korea Univ Wisconsin Dept Comp Sci 1210 W Dayton St Madison WI 53706 USA

Wireless video streaming has become an extremely popular application in recent years. Internet video streaming to mobile devices, however, faces several challenges, e.g., unstable wireless connections, long latency, high jitter and etc. Bitrate adaptive streaming and video transcoding solutions are widely used to address the above-mentioned issues, however, there are still several shortcomings of these approaches. Such challenges hinder providing satisfactory quality of video streaming service to the mobile users. We propose a hardware-assisted, real-time video transcoding solution implemented on a commercial off-the-shelf device, Raspberry Pi. We employ the software and hardware coupled architecture in order to improve the performance/quality of video streaming and enhance the user satisfactions in wireless network. Our video transcoding solution can be applied to both the downlink and uplink streaming: for downlink stream, it can provide agile bitrate adaptation to sudden network dynamics and enhance video quality by running our transcoding solution at the wireless edge. It can be used to uplink stream for broadcasting live streams in real-time. We present the design and implementation of our video transcoding system in both cases with practical scenarios. The evaluation results reveal that our transcoding solution enhances the performance of video streaming compared with other adaptive bitrate streamings and it provides higher video quality without causing rebuffering or video stall. We bridge the gap between the wireless channel capacity and the video quality while providing a better streaming experience to end user.

关键词： Streaming media transcoding Bit rate Media Servers Wireless communication Real-time systems Adaptive bitrate streaming video transcoding wireless networks

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Crowdtranscoding: Online video transcoding With Massive Viewers

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IEEE TRANSACTIONS ON MULTIMEDIA 2017年第6期19卷 1365-1375页

作者： He, Qiyun Zhang, Cong Liu, Jiangchuan Simon Fraser Univ Sch Comp Sci Burnaby BC V5A 1S6 Canada

Driven by the advances in personal computing devices and the prevalence of high-speed network accesses, crowdsourced livecast platforms have emerged in recent years, through which numerous broadcasters lively stream their video content to fellow viewers. Compared to professional video producers and broadcasters, these new generation broadcasters are highly heterogeneous in terms of the network/system configurations and, therefore, the generated video quality, which calls for massive encoding and transcoding in order to unify the video sources and serve multiple quality versions to viewers with different configurations. On the other hand, with the rapid evolution in the hardware industry, high-performance processors become mainstream in personal computer market. More end devices can easily transcode high-quality videos in realtime. We witness huge computational resource among the massive fellow viewers that could potentially be used for transcoding. In this paper, we propose Crowdtranscoding, a novel framework for crowdsourced livecast systems that offloads the transcoding assignment to the massive viewers. We identify that the key challenges in Crowdtranscoding are to detect qualified stable viewers and to properly assign them to the source channels. We put forward a viewer crowdsourcing transcode scheduler to smartly schedule the workload assignment. Our solution has been evaluated under diverse viewer/channel conditions as well as different parameter settings. The trace-driven simulation confirms the superiority of CrowdTranscoder, while our PlanetLab-based and real world end-viewer experiments show the practical performance of our approach, which also give hint to the further enhancement.

关键词： video transcoding livecast crowdsourcing

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