Video quality

About: Video quality is a research topic. Over the lifetime, 13143 publications have been published within this topic receiving 178307 citations.

Complexity-based consistent-quality encoding in the cloud

Abstract: A cloud-based encoding pipeline which generates streams for video-on-demand distribution typically processes a wide diversity of content that exhibit varying signal characteristics. To produce the best quality video streams, the system needs to adapt the encoding to each piece of content, in an automated and scalable way. In this paper, we describe two algorithm optimizations for a distributed cloud-based encoding pipeline: (i) per-title complexity analysis for bitrate-resolution selection; and (ii) per-chunk bitrate control for consistent-quality encoding. These improvements result in a number of advantages over a simple “one-size-fits-all” encoding system, including more efficient bandwidth usage and more consistent video quality.

Content-Aware Playout and Packet Scheduling for Video Streaming Over Wireless Links

Abstract: Media streaming over wireless links is a challenging problem due to both the unreliable, time-varying nature of the wireless channel and the stringent delivery requirements of media traffic. In this paper, we use joint control of packet scheduling at the transmitter and content-aware playout at the receiver, so as to maximize the quality of media streaming over a wireless link. Our contributions are twofold. First, we formulate and study the problem of joint scheduling and playout control in the framework of Markov decision processes. Second, we propose a novel content-aware adaptive playout control, that takes into account the content of a video sequence, and in particular the motion characteristics of different scenes. We find that the joint scheduling and playout control can significantly improve the quality of the received video, at the expense of only a small amount of playout slowdown. Furthermore, the content-aware adaptive playout places the slowdown preferentially in the low-motion scenes, where its perceived effect is lower.

Developing a predictive model of quality of experience for internet video

Abstract: Improving users' quality of experience (QoE) is crucial for sustaining the advertisement and subscription based revenue models that enable the growth of Internet video. Despite the rich literature ...

Wireless Video Communications: Second to Third Generation and Beyond

Abstract: From the Publisher: "Bridging the gap between the video compression and communication communities, this unique volume provides an all-encompassing treatment of wireless video communications, compression, channel coding, and wireless transmission as a joint subject. WIRELESS VIDEO COMMUNICATIONS begins with relatively simple compression and information theoretical principles, continues through state-of-the-art and future concepts, and concludes with implementation-ready system solutions. This book's deductive presentation and broad scope make it essential for anyone interested in wireless communications. It systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems. It provides in a comprehensive manner "implementation-ready" overall system design and performance studies, giving cognizance to the contradictory design requirements of video quality, bit rate, delay, complexity error resilience, and other related system design aspects. Topics covered include*information theoretical foundations*block-based and convolutional channel coding*very-low-bit-rate video codecs and multimode videophone transceivers*high-resolution video coding using both proprietary and standard schemes*CDMA/OFDM systems, third-generation and beyond adaptive video systems. WIRELESS VIDEO COMMUNICATIONS is a valuable reference for postgraduate researchers, system engineers, industrialists, managers and visual communications practitioners. About the Authors Lajos Hanzo has enjoyed a prolific 24-year career during which he has held various research and academic positions in Hungary, Germany, and the United Kingdom. He has coauthored five bookson mobile radio communications and published over 300 research papers on a variety of topics. Dr. Hanzo's research interests cover the entire spectrum of mobile multimedia communications, including voice, audio, video and graphic source compression, channel coding, modulation, networking and the joint optimization of these system components. He holds a chair in communications in the Department of Electronics and Computer Science at the University of Southampton, England, and he is a consultant to Multiple Access Communications Ltd. Peter J. Cherriman graduated in 1994 with an M.Eng. In information engineering from the University of Southampton. Since 1994, he has been with the Department of Electronics and Computer Science at the University of Southampton, where he completed his Ph.D. in mobile video networking. Dr. Cherriman is working on projects for the Mobile Virtual Centre of Excellence, U.K. His current areas of research include robust video coding, microcellular radio systems, power control, dynamic channel allocation, and multiple access protocols. Jurgen Streit received his Dipl.-Ing. in electronic engineering from the Aachen University of Technology, Germany, in 1993. Since 1992 he has been with the Department of Electronics and Computer Science at the University of Southampton, working with the Mobile Multimedia Communications Research Group. Dr. Streit earned a Ph.D. in image coding, and he is currently working as a software consultant."

Temporal Trajectory Aware Video Quality Measure

Abstract: The measurement of video quality for lossy and low-bitrate network transmissions is a challenging topic. Especially, the temporal artifacts which are introduced by video transmission systems and their effects on the viewer's satisfaction have to be addressed. This paper focuses on a framework that adds a temporal distortion awareness to typical video quality measurement algorithms. A motion estimation is used to track image areas over time. Based on the motion vectors and the motion prediction error, the appearance of new image areas and the display time of objects is evaluated. Additionally, degradations which stick to moving objects can be judged more exactly. An implementation of this framework for multimedia sequences, e.g., QCIF, CIF, or VGA resolution, is presented in detail. It shows that the processing steps and the signal representations that are generated by the algorithm follow the reasoning of a human observer in a subjective experiment. The improvements that can be achieved with the newly proposed algorithm are demonstrated using the results of the Multimedia Phase I database of the Video Quality Experts Group.