Optimal Frame Selection with Adaptive Playout for Delivering Stored Video under Constrained Resources
ABSTRACT In this paper, we propose a server-client coordinated joint optimal frame selection with adaptive playout for delivering stored video under both limited channel bandwidth and finite client buffer condition. In particular, the client will reduce the frame playout rate whenever its buffer fullness level falls below a given threshold in an attempt to prevent buffer underflow. And when the buffer fullness exceeds the threshold, the client will switch back to the normal frame playout rate. The server is aware of the adaptive playout decision made by the client and incorporates the decision into its optimal frame selection framework for joint optimization. The objective is to minimize the number of frames that must be discarded in order to prevent client buffer underflow or overflow and make full use of the limited bandwidth resource.
- SourceAvailable from: Chun Tung Chou[Show abstract] [Hide abstract]
ABSTRACT: This paper aims to reduce the prebuffering requirements, while maintaining continuity, for video streaming. Current approaches do this by making use of adaptive media playout (AMP) to reduce the playout rate. However, this introduces playout distortion to the viewers and increases the viewing latency. We approach this by proposing a frame rate optimization framework that adjusts both the encoder frame generation rate and the decoder playout frame rate. Firstly, we model this problem as the joint adjustment of the encoder frame generation interval and the decoder playout frame interval. This model is used with a discontinuity penalty virtual buffer to track the accumulated difference between the receiving frame interval and the playout frame interval. We then apply Lyapunov optimization to the model to systematically derive a pair of decoupled optimization policies. We show that the occupancy of the discontinuity penalty virtual buffer is correlated to the video discontinuity and that this framework produces a very low playout distortion in addition to a significant reduction in the prebuffering requirements compared to existing approaches. Secondly, we introduced a delay constraint into the framework by using a delay accumulator virtual buffer. Simulation results show that the the delay constrained framework provides a superior tradeoff between the video quality and the delay introduced compared to the existing approach. Finally, we analyzed the impact of delayed feedback between the receiver and the sender on the optimization policies. We show that the delayed feedbacks have a minimal impact on the optimization policies.IEEE Transactions on Multimedia 11/2011; 14(3). DOI:10.1109/TMM.2011.2180706 · 1.78 Impact Factor
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ABSTRACT: Client-side data buffering is a common technique to deal with media playout interruptions of streaming video caused by network jitters and packet losses of best-effort networks. However, stronger playout interruption protection inevitably amounts to larger data buffering and results in more memory requirements and longer playout delay. Adaptive media playout (AMP), also a client-side technique, can reduce the buffer requirement and avoid buffer outage but at the expense of visual quality degradation because of the fluctuation of playout speed. In this paper, we propose a novel AMP scheme to keep the video playout as smooth as possible while adapting to the channel condition. The triggering of the playout control is based on buffer variation rather than buffer fullness. Experimental results show that our AMP scheme surpasses conventional schemes in unfriendly network conditions. Unlike previous schemes that are tuned for a specific range of packet loss and network instability, the proposed AMP scheme maintains consistent performance across a wide range of network conditions.IEEE Transactions on Multimedia 12/2009; DOI:10.1109/TMM.2009.2030543 · 1.78 Impact Factor
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ABSTRACT: 350 words maximum: (PLEASE TYPE) In this research, we focus on two areas of video adaptation: video rate control and frame rate control. The first part is on video rate control, which aims to adjust video bitrate to meet the network constraint. To that end, we propose a joint source rate and congestion control scheme called video TCP·frlendly rate control (VTFRC) that incorporates the video bit rate characteristic into the TFRC rate. VTFRC uses a frame complexity measure and the rate gap between the TCP and TFRC rates to opportunistically encode the video at a higher rate. Experiments show that VTFRC Improves video quality over existing scheme while maintaining TCP-friendliness. However, VTFRC needs the encoder meet a target bitrate and provide a frame complexity measure. To do this, we propose a complexity· based rate control scheme using edge energy. We show that this scheme can describe the individual complexities of the frames without needing any information on the whole video. Experiments show that the scheme produces a video stream that is closer to the target bitrate while improving on its video quality over existing schemes.