The Experts below are selected from a list of 15441 Experts worldwide ranked by ideXlab platform
Amy R. Reibman - One of the best experts on this subject based on the ideXlab platform.
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Quality monitoring of video over a Packet network
IEEE Transactions on Multimedia, 2004Co-Authors: Amy R. Reibman, Vinay A. Vaishampayan, Y. SermadeviAbstract:We consider monitoring the quality of compressed video transmitted over a Packet network from the perspective of a network service provider. Our focus is on no-reference methods, which do not access the original signal, and on evaluating the impact of Packet losses on quality. We present three methods to estimate mean squared error (MSE) due to Packet losses directly from the video bitstream. NoParse uses only network-level measurements (like Packet loss rate), QuickParse extracts the spatio-temporal extent of the impact of the loss, and FullParse extracts sequence-specific information including spatio-temporal activity and the effects of error propagation. Our simulation results with MPEG-2 video subjected to Transport Packet losses illustrate the performance possible using the three methods.
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VBR video: tradeoffs and potentials
Proceedings of the IEEE, 1998Co-Authors: T. V. Lakshman, Antonio Ortega, Amy R. ReibmanAbstract:The authors examine the Transport and storage of video compressed with a variable bit rate (VBR). They focus primarily on networked video, although they also briefly consider other applications of VBR video, including satellite transmission (channel sharing), playback of stored video, and wireless Transport. Packet video research requires careful integration between the network and the video systems; however, a major stumbling block has resulted because commonly used terms are often interpreted differently by the video and networking communities. The paper then, has two main goals: (i) to clarify the definitions of terms that are often used with different meaning by networking and video-coding researchers and (ii) to explore the tradeoffs entailed by each of the various modalities of VBR transmission (unconstrained, shaped, constrained, and feedback). In particular, they evaluate the tradeoff among the advantages (better video quality, less delay, and more calls) that were identified by early proponents of VBR video transmission. An underlying theme of this paper is that increased interaction between the video and network design has potential for improving overall decoded video quality without changing the network capacity.
Antonios Argyriou - One of the best experts on this subject based on the ideXlab platform.
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Error-Resilient Video Encoding and Transmission in Multirate Wireless LANs
IEEE Transactions on Multimedia, 2008Co-Authors: Antonios ArgyriouAbstract:In this paper, we present a cross-layer approach for video transmission in wireless LANs that employs joint source and application-layer channel coding, together with rate adaptation at the wireless physical layer (PHY). While the purpose of adopting PHY rate adaptation in modern wireless LANs like the IEEE 802.11a/b is to maximize the throughput, in this paper we exploit this feature to increase the robustness of wireless video. More specifically, we investigate the impact of adapting the PHY transmission rate, thus changing the throughput and Packet loss channel characteristics, on the rate-distortion performance of a transmitted video sequence. To evaluate the video quality at the decoder, we develop a cross-layer modeling framework that considers jointly the effect of application-layer joint source-channel coding (JSCC), error concealment, and the PHY transmission rate. The resulting models are used by an optimization algorithm that calculates the optimal JSCC allocation for each video frame, and PHY transmission rate for each outgoing Transport Packet. The comprehensive simulation results obtained with the H.264/AVC codec demonstrate considerable increase in the PSNR of the decoded video when compared with a system that employs separately JSCC and PHY rate adaptation. Furthermore, our performance analysis indicates that the optimal PHY transmission rate calculated by the proposed algorithm, can be significantly different when compared with rate adaptation algorithms that target throughput improvement.
Shaw-min Lei - One of the best experts on this subject based on the ideXlab platform.
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Forward error correction codes for MPEG2 over ATM
IEEE Transactions on Circuits and Systems for Video Technology, 1994Co-Authors: Shaw-min LeiAbstract:Transport of MPEG2 video and associated audio and data over ATM (asynchronous transfer mode) networks has attracted much interest. A defined MPEG2 Transport Packet of 188 bytes can fit into 4 ATM cells with 32 bits left for forward error correction (FEC) codes and cell sequence numbers. The author discusses the design of FECs to correct the error patterns generated by different scrambler and line codes used by several ATM physical layers. By choosing generator polynomials carefully, a single-error-correcting Reed-Solomon code can correct not only the single-byte error patterns but also the double-byte error patterns processed by a scrambler. A method of distributing 16 bits of FEC into 4 ATM cells (thus, 4 bits of FEC each cell) to accommodate a cell sequence number in each cell is also given. >
Y. Sermadevi - One of the best experts on this subject based on the ideXlab platform.
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Quality monitoring of video over a Packet network
IEEE Transactions on Multimedia, 2004Co-Authors: Amy R. Reibman, Vinay A. Vaishampayan, Y. SermadeviAbstract:We consider monitoring the quality of compressed video transmitted over a Packet network from the perspective of a network service provider. Our focus is on no-reference methods, which do not access the original signal, and on evaluating the impact of Packet losses on quality. We present three methods to estimate mean squared error (MSE) due to Packet losses directly from the video bitstream. NoParse uses only network-level measurements (like Packet loss rate), QuickParse extracts the spatio-temporal extent of the impact of the loss, and FullParse extracts sequence-specific information including spatio-temporal activity and the effects of error propagation. Our simulation results with MPEG-2 video subjected to Transport Packet losses illustrate the performance possible using the three methods.
T. V. Lakshman - One of the best experts on this subject based on the ideXlab platform.
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VBR video: tradeoffs and potentials
Proceedings of the IEEE, 1998Co-Authors: T. V. Lakshman, Antonio Ortega, Amy R. ReibmanAbstract:The authors examine the Transport and storage of video compressed with a variable bit rate (VBR). They focus primarily on networked video, although they also briefly consider other applications of VBR video, including satellite transmission (channel sharing), playback of stored video, and wireless Transport. Packet video research requires careful integration between the network and the video systems; however, a major stumbling block has resulted because commonly used terms are often interpreted differently by the video and networking communities. The paper then, has two main goals: (i) to clarify the definitions of terms that are often used with different meaning by networking and video-coding researchers and (ii) to explore the tradeoffs entailed by each of the various modalities of VBR transmission (unconstrained, shaped, constrained, and feedback). In particular, they evaluate the tradeoff among the advantages (better video quality, less delay, and more calls) that were identified by early proponents of VBR video transmission. An underlying theme of this paper is that increased interaction between the video and network design has potential for improving overall decoded video quality without changing the network capacity.
