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International Conference on Wireless Networks and Information Systems (WNIS)

作者： Xinchen Zhang Mei Huang Coll. of Phys. Sci. & Technol. Central China Normal Univ. Wuhan China Hubei Inst. of Forestry Exploration & Design Wuhan China

Video transmission through wireless channels is still a challenging problem on the limitations in bandwidth and the presence of channel errors. Video transcoding, due to its high practical values for a wide range of networked video applications, has become an active research topic. It is typically used to reduce the rate and change the format of the originally encoded video source to match network conditions and terminal capabilities. Error resilient video transcoding can insert error resilient tools in the compressed video to enhance error resilience of the video over wireless channels by increasing bit rate. In this paper, firstly we outline the technical issues and research results related to video transcoding, Then we discuss techniques for reducing the complexity and improving the video quality, such as intra marcoblock refresh, synchronization marker insertion, error concealment, joint optimization, redundant slices, unequal error protection, and so on. To achieve good resilient performance, a experimental video transcoding is designed and established. The results show its improved video quality at the reducing the complexity and the cost of bit rate.

关键词： transcoding Video compression Bit rate Resilience Code standards Standards development Streaming media Decoding Wireless networks Computer errors

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Effiecient WZ-to-H264 transcoding using motion vector information sharing

Effiecient WZ-to-H264 transcoding using motion vector inform...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： J.L. Martinez H. Kalva W.A.C Fernando P. Cuenca F.J. Quiles Instituto de Investigación en Informátical de Albacete Universidad de Castilla La Mancha Spain Department of Computer Science Florida Atlantic University USA Center of Communications Research University of Surrey UK

In mobile-to-mobile video communications, both the sender and the receiver devices should not have higher complexity requirements to perform complex video compression tasks. The traditional video coding solutions are not suitable to support this communications due to its extremely complex encoding algorithm. On the other hand, the new Wyner-Ziv video coding paradigm reduces the complexity of the encoder at the expenses of a more complex decoder. In this paper, we propose an improved WZ/H.264 video transcoder to support this mobile-to-mobile communications, using the low complexity Wyner-Ziv encoding and the traditional H.264 decoding to be implemented in the end-user devices. The improved transcoder converts the video from the Wyner-Ziv to H.264 and reuses the motion vectors generated in the Wyner-Ziv decoding, in order to reduce the computational complexity of the motion estimation process in the H.264 encoding. Simulations results show a complexity reduction up to 55% with negligible rate-distortion drop.

关键词： transcoding Mobile communication Encoding Decoding Video compression Video coding Video sharing Computational complexity Motion estimation Computational modeling

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Leveraging the quantization offset for improved requantization transcoding of H.264/AVC video

Leveraging the quantization offset for improved requantizati...

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Picture Coding Symposium, PCS

作者： Stijn Notebaert Jan De Cock Kenneth Vermeirsch Peter Lambert Rik Van de Walle Department of Electronics and Information Systems-Multimedia Laboratory Ghent University Ghent Belgium

Requantization transcoding is a method for reducing the bit rate of compressed video bitstreams. Most research on requantization is concerned with the architectural design, the selection of a suitable quantizer, or the reduction of requantization errors. In this paper, we propose to incorporate a new dimension in requantization transcoding: the quantization offset. We compare two requantization methods: increasing the quantization step size and decreasing the quantization offset. Furthermore, we propose a novel heuristic for requantization transcoding based on a theoretical rate-distortion analysis. The experimental results for H.264/AVC video show that requantization is improved in rate-distortion sense with gains up to 1 dB for open-loop requantization of B pictures compared to requantization with fixed quantization offset.

关键词： Quantization transcoding Automatic voltage control Rate-distortion Image reconstruction Video compression Transform coding Streaming media Image coding Laplace equations

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Efficient inter/intra mode decision for H.264/AVC inter frame transcoding

Efficient inter/intra mode decision for H.264/AVC inter fram...

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IEEE International Conference on Image Processing

作者： Chien-Da Wu Yinyi Lin Department of Communication Engineering National Central University Taiwan

In this paper, we propose an efficient inter/intra mode decision for H.264/AVC inter frame transcoding. A zero-block decision scheme is first employed to select some candidate inter and intra modes for prediction. Soon afterward, we incorporate a fast multi-reference frame motion estimation with adaptive search window into inter mode decision. For intra mode decision we suggest a mode refinement scheme to eliminate improbable modes for RDO calculations to a greater extent. The experimental results reveal that average 93% of computation time can be saved for the proposed H.264 inter frame transcoding algorithm, when compared with fully decoding/encoding procedure. The degradation in the rate-distortion performance is fairly small.

关键词： Automatic voltage control transcoding Streaming media Motion estimation Decoding Rate-distortion Video sequences Degradation HDTV Computational complexity

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Giving users an edge: A flexible Cloud model and its application for multimedia

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FUTURE GENERATION COMPUTER SYSTEMS-THE INTERNATIONAL JOURNAL OF ESCIENCE 2012年第6期28卷 823-832页

作者： Islam, Salekul Gregoire, Jean-Charles North South Univ Elect Engn & Comp Sci Dept Dhaka Bangladesh Inst Natl Rech Sci Montreal PQ Canada

We present the Edge Cloud architecture and explore how the user's experience of the Internet is enhanced through its use, by moving desktop functionality within the network, in the Void environment. We explore how this model allows us to expand the range of benefits of using the Internet Cloud model, especially when it comes to media processing and user customization. A prototype that transcodes audio/video stream inside the Cloud has been implemented and presented. The prototype is deployed in two different environments: in a local lab and in the Amazon EC2 public Cloud. We also study the performance of the prototype by analyzing the inter-arrival jitter. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Cloud computing Edge Cloud Desktop virtualization Media processing transcoding Jitter analysis

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Fast Inter Mode Decision Algorithm Based on the MB Activity for MPEG-2 to H.264/AVC transcoding

Fast Inter Mode Decision Algorithm Based on the MB Activity ...

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IEEE International Conference on Computational Science and Engineering, CSE

作者： Xingang Liu Wei Zhu Kook-Yeol Yoo Department of Information and Communication Engineering Yeungnam University of South Korea South Korea Department of Solution Research and Development Samsung Electronics Company Limited South Korea

Recently H.264/AVC is widely used for the mobile and low bitrate video codec in the various multimedia terminals. On the other hand, the MPEG-2 MP@HL codec is becoming a center of digital video contents since it is the standard codec for the digital TV (DTV).To provide the bridge between the contents in MPEG-2 and mobile terminals, the transcoding of MPEG-2 contents into H.264/AVC format is inevitable technology in the digital video market. The main bottleneck in the process lies in the computational complexity. In H.264/AVC, the variable block size (VBS) mode decision (MD) is employed for the improved performance in the motion compensated prediction. In this paper, the residual DCT-domain macroblock (MB) energy obtained from MPEG-2 decoding process is used for the decision of the predicted block sizes in H.264/AVC encoder. By this early decision of block sizes, the original candidate modes can be reduced effectively, resulting in the reduction of the computational complexity. The simulation results show that the proposed algorithm can reduces 50% computational complexity, compared with the well-known cascaded transcoder while maintaining the video quality.

关键词： Automatic voltage control transcoding Computational complexity Digital TV Bit rate Video codecs Code standards Bridges Decoding Computational modeling

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A novel H.264 SVC encryption scheme for secure bit-rate transcoding

A novel H.264 SVC encryption scheme for secure bit-rate tran...

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Picture Coding Symposium, PCS

作者： Nithin Thomas David Bull David Redmill University of Bristol UK

This paper presents a novel architecture for the secure delivery of encrypted H.264 SVC bitstreams. It relies on a block cipher and stream cipher used in a novel way that would allow an intermediary transcoder to truncate the bitstream to the appropriate bit-rate without decrypting the data. The system, called SVC-sec, is compared to other architectures presented in the literature and it is shown that SVC-sec offers many benefits, particularly when used with FGS streams.

关键词： Static VAr compensators Cryptography transcoding Streaming media Video coding Automatic voltage control Codecs Security Computer architecture TV broadcasting

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Logo insertion transcoding for H.264/AVC compressed video

Logo insertion transcoding for H.264/AVC compressed video

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IEEE International Conference on Image Processing

作者： Di Xu Panos Nasiopoulos Department of Electrical and Computer Engineering University of British Columbia BC Canada

H.264/AVC quickly gains ground in many aspects of video applications, due to its superior coding performance. Inserting a company logo into H.264/AVC compressed video streams has been a highly desirable application in the TV telecasting industry. In this paper, we propose a novel and efficient logo-insertion scheme for H.264/AVC compressed videos. Our proposed scheme overcomes the numerous coding dependencies, and minimizes the changes to the original compressed videos. Experimental results show that our proposed transcoding scheme achieves extraordinary video quality and significantly reduces the bit rate and computational cost. Compared with the cascaded transcoding scheme, our proposed logo-insertion method achieves an average of 1.16 dB PSNR increase, or a 68.6% bit-rate reduction. Our scheme also dramatically reduces the total transcoding time and the motion-estimation time by at least 67.2% and 97.4%, respectively.

关键词： transcoding Automatic voltage control Video compression Streaming media Transform coding TV Decoding Application software Bit rate Computational efficiency

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ARe-quantization noise reduction method in MPEG-2 to H.264 intra transcoding

ARe-quantization noise reduction method in MPEG-2 to H.264 i...

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IEEE Symposium on Industrial Electronics & Applications (ISIEA)

作者： Takeshi Yoshitome Kazuto Kamikura Nobuhiko Kitawaki NTT Corporation Japan Graduate School of Systems and Information Engineering University of Tsukuba Japan

An MPEG-2 to H.264 intra transcoding method is proposed. This method uses the encoding information from an MPEG-2 stream and keeps as many DCT coefficients of the original MPEG-2 bitstream as possible. Experimental results show that the proposed method improves PSNR by about 0.76-1.27 dB compared with a typical conventional method.

关键词： Noise reduction transcoding Encoding Transform coding Discrete cosine transforms Quantization Video compression Streaming media Decoding Noise figure

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Spatial transcoding from Scalable Video Coding to H.264/AVC

Spatial transcoding from Scalable Video Coding to H.264/AVC

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IEEE International Conference on Multimedia and Expo (ICME)

作者： Hui Liu Ye-kui Wang Ying Chen Houqiang Li University of Science and Technology Hefei China Nokia Research Center Tampere Finland Tampere University of Technology Tampere Finland

Scalable Video Coding (SVC) is backwards compatible to H.264/AVC in the sense that the base layer sub-bitstream is decodable by an H.264/AVC decoder. However, there are applications wherein it is desirable for an H.264/AVC decoder to obtain a higher resolution video representation than the base layer within SVC. In order to fulfill the needs of such application scenarios, transcoding of SVC enhancement layers to H.264/AVC is required. This paper presents a transcoding scheme that is capable of transcoding a spatial scalable SVC bitstreams to H.264/AVC bitstreams that provide high resolution than the H.264/AVC compliant base layer. To reduce the complexity at the transcoder, a fast mode decision (MD) process is proposed, wherein the original SVC macroblock coding modes and motion information are reused as much as possible. Experimental results show that proposed scheme performs elegantly compared with full-decoding-and-encoding transcoding with low computational complexity.

关键词： transcoding Video coding Automatic voltage control Static VAr compensators Decoding Spatial resolution Scalability Videoconference Computer displays Computer networks

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