Browsing by Author "Chuang, HC"

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A buffer-feedback rate control method for video streaming over mobile communication systems
(2005)
Tseng, LC
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Chuang, HC
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Huang, CY
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Chiang, T
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電子工程學系及電子研究所
In a wireless video streaming service system, the receiver reports its required rate in the reverse link for each transmission. A data buffer is often installed in the receiver to stabilize the multimedia play-out rate. This buffer may underflow if there is a shortage of content. Simply increasing the transmission rates may cause resource problems. A more delicate way is trying to control the transmission rate when necessary. In this paper, a transmission rate control method utilizing the receiver buffer fullness level and the frame error rate (FER) information is proposed. Simulation results demonstrate the proposed control provides better play-out quality with reasonable system resources consumption.
A fast audio bit allocation technique based on a linear R-D model
(2002-08-01)
Lee, CY
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Fang, YC
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Chuang, HC
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Wang, CN
;
Chiang, T
The MPEG-1 Layer III audio coding is most widespread digital audio format on the Internet. Its encoder is more complicated than the other layers., in the MPEG-I audio specification, where the bit allocation constitutes significant part of the total computational load. This paper describes a fast bit allocation technique using a novel linear model to compute the bitrate and the global gain of the inner loop (rate control loop) for the classic MP3 bit allocation problem. Estimated quantization noise is approximated with a binomial expansion for the adjustment of the scalefactors. This procedure reduces the outer loop iterations (distortion control loop) to one loop. Our bit allocation technique is about five times faster compared to the well-known LAME MP3 encoder. Based on the objective quality measure, total number of distorted bands, and average total noise-to-masking ratio (NMR), our experimental results show that there is significant improvement in speedup of the encoding process without noticeable audio quality degradation.
A fast audio bit allocation technique based on a linear R-D model
(2002-01-01)
Lee, CY
;
Fang, YC
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Chuang, HC
;
Wang, CN
;
Chiang, TH
This paper describes a fast bit allocation technique using a novel linear model for the bitrate and the global gain of the inner loop in the classic MP3 bit allocation. The outer loop is approximated with a binomial expansion. Our technique is five times faster compared to the LAME MP3 encoder.
A novel adaptive video playout control for video streaming over mobile cellular environment
(2005)
Chuang, HC
;
Huang, C
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Chiang, T
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Video streaming is becoming one of the potential killer applications in a mobile service network. MPEG-4 Fine-Granularity Scalabitity is proposed to significantly increase the flexibility for video transmission. However, the bottleneck of bandwidth often occurs in the last-mile transmission from the base station to the mobile device, which incurs quality degradation. Adaptive Media Playout (AMP) is a receiver-based technique that could eliminate the buffer outage and hence improve the associated visual quality. This paper addresses the issue of AMP control utilized in a mobile cellular environment. Specifically, we propose a novel AMP control that could further improve the visual quality compared to other conventional AMP controls. Experimental results demonstrate the proposed control provides better visual quality with a low complexity.
A robust MPEG-21 media delivery video streaming system
(2004)
Su, TL
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Huang, MY
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Chuang, HC
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Wang, CN
;
Chiang, TH
MPEG-21 provides a unified solution, Universal Multimedia Access (UMA), for constructing a multimedia content delivery and rights management framework. Based on the concepts of UMA, we build a simplified UMA model for Internet and over wireless LAN. In this framework, the source video material is encoded and archived as MPEG-4 bitstreams. Moreover, novel intra refresh and error resilience schemes are used to improve the coding efficiency and robustness of the delivered bitstreams. Consequently, the multimedia information can be streamed through the transmission channels with packet losses. The recovered images have insignificant quality degradations for similar streaming systems. To have a more strict evaluation methodology according to the specified common conditions for MPEG-21 media delivery, a unicast streaming system is built on MPEG-21 part-13 Multimedia Test Bed for Resource Delivery. The results show that we can retain significantly improved subjective quality for video streaming over the Internet and wireless channels.
On the buffer dynamics of scalable video streaming over wireless network
(2004)
Chuang, HC
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Huang, C
;
Chiang, TH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
3G mobile standard offers unprecedented high speed digital service that can carry multimedia traffics such as video streaming. The distributed system buffers in the conventional client-server architecture absorb the fluctuations of channel conditions such as bit rate variations, delays and jitters. To enable easy control for the 3G system, MPEG committee is developing scalable video coding technology that provides flexibility for transmission over wireless networks. This paper will address issues in controlling these buffers that can impact and benefit the end-to-end system performance using the novel scalable video technology. specifically, we will explore the effects of diverse channel characteristics on the buffers performance tolerance, and its impact on the quality of service. A novel model-based Adaptive Media Playout (AMP) buffer control is proposed to mitigate the risks of buffer outage.
Procedures for testing manufacturing precision C(p)based on ((X)over-bar, R) or ((X)over-bar, S) control chart samples
(2005)
Pearn, WL
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Wu, CW
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Chuang, HC
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工業工程與管理學系
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Department of Industrial Engineering and Management
Process precision index C-p has been widely used in the manufacturing industry for measuring process potential and precision. Estimating and testing process precision based on one single sample have been investigated extensively. In this paper, we consider the problem of estimating and testing process precision based on multiple samples taken from ((X) over bar, R)or ((X) over bar, S)control chart. We first investigate the statistical properties of the natural estimator of C-p and implement the hypothesis testing procedure. We then develop efficient MAPLE programs to calculate the lower confidence bounds, critical values, and p-values based on m samples of size n. Based on the test, we develop a step-by-step procedure for practitioners to use in determining whether their manufacturing processes are capable of reproducing products satisfying the preset precision requirement.