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Liujin Yu

Bio: Liujin Yu is an academic researcher from Oregon Health & Science University. The author has contributed to research in topics: The Internet & Internet video. The author has an hindex of 1, co-authored 1 publications receiving 121 citations.

Papers
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Proceedings ArticleDOI
01 Mar 1998
TL;DR: The player has a number of advanced features including dynamic adaptation to changes in available bandwidth, latency and latency variation; a multi-dimensional media scaling capability driven by user-specified quality of service (QoS) requirements; and support for complex content comprising multiple synchronized video and audio streams.
Abstract: This paper describes the design and implementation of a real-time, streaming, Internet video and audio player. The player has a number of advanced features including dynamic adaptation to changes in available bandwidth, latency and latency variation; a multi-dimensional media scaling capability driven by user-specified quality of service (QoS) requirements; and support for complex content comprising multiple synchronized video and audio streams. The player was developed as part of the QUASAR project at Oregon Graduate Institute, is freely available, and serves as a testbed for research in adaptive resource management and QoS control.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

121 citations


Cited by
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Proceedings ArticleDOI
01 Dec 2002
TL;DR: A new inter-client synchronization framework for one-to-many media streaming is proposed employing a server-client coordinated adaptive playout control, which can reduce the playout discontinuity without degrading the media quality, and thus mitigate the client heterogeneity.
Abstract: A new inter-client synchronization framework for one-to-many (i.e., multicast) media streaming is proposed employing a server-client coordinated adaptive playout control. The proposed adaptive player controls the playback speed of audio and video by adopting the time-scale modification of audio. Based on the overall synchronization status as well as the buffer occupancy level, the playout speed of each client is manipulated within a perceptually tolerable range. Additionally, the server implicitly helps increasing the time available for retransmission while the clients perform an interactive error recovery mechanism with the assistance of playout control. By coordinating the playout speed of each client, the inter-client synchronization with respect to the target presentation time is smoothly achieved. RTCP-compatible signalling between the server and group-clients is performed, where the exchange of controlling message is restricted. The network-simulator based simulations show that the proposed framework can reduce the playout discontinuity without degrading the media quality, and thus mitigate the client heterogeneity.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

481 citations

Proceedings ArticleDOI
21 Mar 1999
TL;DR: This work considers the use of an application-layer performance measure-the utility-in the context of bandwidth allocation for an available bit rate service, and concludes that the scheme is equivalent to bandwidth max-min allocation when the utility of all applications are equal.
Abstract: We consider the use of an application-layer performance measure-the utility-in the context of bandwidth allocation for an available bit rate service. This bandwidth allocation scheme can be viewed as a generalization of traditional available bit rate service; the scheme is equivalent to bandwidth max-min allocation when the utility of all applications are equal. The goal of the allocation scheme is to provide a good application-layer service to a wide diversity of applications sharing available bandwidth. We achieve this goal while also supporting changes in utility over time, tolerating some inaccuracy in utility function specification, and addressing the issue of circumvention through pricing.

220 citations

Patent
14 Mar 2001
TL;DR: In this article, a grid of display windows, each of which displays an image received from the camera associated with that window, is used to monitor received video and automatically start recording upon detecting motion within the video stream.
Abstract: A digital video system (20) including a computer (22) connected via a network (28) to a number of video servers (26) and cameras (24). The computer (22) includes a program that provides a grid of display windows, each of which displays an image received from the camera associated with that window. The program sequentially polls each camera, accessing and displaying an images from the camera in its associated window. The program can access the cameras (24) at different frame rates. The program stores image streams in a single file, concatenating each successive image onto the end of the file. The file is then indexed using SOI and EOI markers to permit fast access to individual images within the file. The program can monitor received video and automatically start recording upon detecting motion within the video stream. Motion detection is implemented by comparing color component values for pixels from different images.

208 citations

Patent
05 Jan 2007
TL;DR: In this paper, the authors propose a system that allows on-the-fly adaptation of a send rate for content sent to a client based on a detected read rate of the client system for data previously sent.
Abstract: Systems and methods provide for on-the-fly adaptation of a send rate for content sent to a client based on a detected read rate of the client system for data previously sent. The system and method work within the bounds of simple, existing, open protocols and the media files served are playable by standard media playback clients. The method is driven by a request for media content from a client, in response to which the server provides portions of the media content and monitors the reception rate of the content as it is sent to the client. This method allows for dynamic modification of the send rate of the content after the server has calculated an adjustment to correct for the difference between the reading rate and sending rate, thereby allowing for a send rate most compatible with the client.

106 citations

Patent
Naveen Thumpudi1, Wei-ge Chen1
18 Jul 2003
TL;DR: In this article, the trellis nodes are derived by quantizing buffer fullness values and a cost function that considers smoothness in quality as well as quality in absolute terms.
Abstract: CBR control strategies provide constant or relatively constant bitrate output with variable quality. The control strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder uses a trellis in two-pass or delayed-decision CBR encoding. The trellis nodes are states derived by quantizing buffer fullness values. The transitions between nodes of a previous stage and nodes of a current stage depend on encoding a current chunk of audio at different quality levels. When pruning the trellis, the encoder uses a cost function that considers smoothness in quality as well as quality in absolute terms. The encoder may store compressed data at different quality levels, then output the compressed data after simplification of the trellis to a suitable point. If the two-pass or delayed-decision CBR encoding fails, the encoder uses one-pass CBR encoding for the sequence or part of the sequence.

98 citations