ITU-T standardization of audiovisual communication systems in ATM and LAN environments

Okubo, Sakae; Dunstan, S.; Morrison, G.; Nilsson, Mike; Radha, Hayder; Skran, D.L.; Thom, Gary A.

doi:10.1109/49.611153

Cited by 23 publications

(6 citation statements)

References 13 publications

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“…We assume that (13) is also true for . In other words, the following equations are true: (15) where for (16)…”

Section: Solution Of Optimization Problemmentioning

confidence: 99%

“…On the other hand, video requires a relatively large bandwidth and hence it should be compressed before transmission. Many variable-bit-rate (VBR) video compression algorithms have been proposed and standardized [13]- [15]. These algorithms can provide a Manuscript received February 13, 1998 constant image quality [16], [17], and multiple VBR video streams can effectively share the communication bandwidth via statistical multiplexing [18].…”

Section: Introductionmentioning

confidence: 99%

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Congestion control for multipoint videoconferencing

Leung

2000

IEEE Trans. Circuits Syst. Video Technol.

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Multipoint videoconference service allows multiple and far-away conferees to conduct a meeting without leaving their offices. Variable-bit-rate video compression is attractive for videoconferencing, because it can provide a constant image quality and it can effectively utilize the communication bandwidth via statistical multiplexing. When some conferences temporarily generate heavy traffic to a link, congestion occurs and some video packets have to be discarded. Since the packets of different conferences are multicast to different number of conferees, the loss of different packet will affect different number of people. If we discard the packets sent to the smallest number of conferees, we can minimize the number of affected conferees to give the best mean quality of service, but the conference having a smaller number of conferees will suffer from a poorer quality of service. Therefore, we must consider both the mean quality of service and fairness in congestion control. In this paper, we propose a congestion-control strategy for multipoint videoconferencing. This strategy has a control parameter which we can tune to make a tradeoff between the mean quality of service and fairness. In addition, the strategy only involves some simple arithmetic and logic operations, and hence, it can be executed quickly for real-time congestion control.Index Terms-Congestion control, variable bit rate video, videoconferencing.

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“…We assume that (13) is also true for . In other words, the following equations are true: (15) where for (16)…”

Section: Solution Of Optimization Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Congestion control for multipoint videoconferencing

Leung

2000

IEEE Trans. Circuits Syst. Video Technol.

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“…N-ISDN delivers H.26x video, while B-ISDN delivers MPEG and H.26x. I.580 is the ITU-T recommendation that covers the general arrangements for internetworking between B-ISDN and 64 Kbit/s-based N-ISDN [13], [14].…”

Section: Overview Of the Real-time Video Systemmentioning

confidence: 99%

Error-propagation prevention technique for real-time video transmission over ATM networks

Wang

Chang

1999

IEEE Trans. Circuits Syst. Video Technol.

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Video sequences compressed by the current videocompression standards-such as MPEG-1/2 and H.261/H.263, which include motion compensation and variable-length coding-are very sensitive to channel disturbances. There exist many error-concealment techniques that can improve the video quality substantially. However, they generally do not prevent or terminate the error propagation. The forced intraupdate technique was proposed for H.245 recently. In this paper, we present an efficient temporal error-propagation prevention method that implements the forced intraupdate concept implicitly. Once an error is detected at the decoder, the starting address of the erroneous macroblocks is sent back to the encoder. The encoder marks the possible damaged area, and the encoding process continues as normal except that the motion estimation will probably not refer to the erroneous part. Thus, the impact of the cell loss is limited to the erroneous slice only, and the damage from the error propagation is greatly reduced. Simulation results of MPEG-2 coding over asynchronous transfer mode (ATM) networks show that the error concealment with feedback can effectively isolate the error and reduce the damage to give satisfactory performance even when the cell-loss rate is higher than 1%. With the delay analysis of ATM networks, we also show that in most cases, the encoder has adequate time to get the feedback information before processing the next I-or P-frames. Index Terms-Asynchronous transfer mode (ATM), error concealment, error prevention, error propagation, quality of service, video coding. I. INTRODUCTION T HE MOST commonly used video-compression techniques are based on MPEG-1/2 [1]-[3] or H.26x-i.e., H.261 or H.263 [4], [5]-where motion compensation, discrete cosine transform (DCT)-based coding, variable-length coding (VLC), and adaptive quantization are performed. These coding techniques are very sensitive to channel disturbances. A single error may cause error propagation in both spatial and temporal domains. Both MPEG and H.26x streams are constructed by layered structures. In MPEG, a groupof-pictures (GOP) layer generally includes one intrapicture (I-frame), several predicted pictures (P-frames), and several bidirectional predictive pictures (B-frames). The H.26x coding streams may consist of one I-frame and many P-frames or PB-frames. Each picture is further divided into a number of slices, or group of blocks (GOB) in H.26x, of contiguous macroblocks (MB's). A slice is the minimum element that Manuscript

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“…However, variable bit rate (VBR) traffic such as video applications based on MPEG or H-series [14], [15] coding has high variation in the number of packets generated. Those algorithms analyzed by simplified video models fail to capture the features in real applications.…”

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confidence: 99%

Scheduling multimedia services in a low-power MAC for wireless and mobile ATM networks

Chen¹,

Sivalingam

Agrawal³

et al. 1999

IEEE Trans. Multimedia

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This paper describes the design and analysis of the scheduling algorithm for energy conserving medium access control (EC-MAC), which is a low-power medium access control (MAC) protocol for wireless and mobile ATM networks. We evaluate the scheduling algorithms that have been proposed for traditional ATM networks. Based on the structure of EC-MAC and the characteristics of wireless channel, we propose a new algorithm that can deal with the burst errors and the locationdependent errors. Most scheduling algorithms proposed for either wired or wireless networks were analyzed with homogeneous traffic or multimedia services with simplified traffic models. We analyze our scheduling algorithm with more realistic multimedia traffic models based on H.263 video traces and self-similar data traffic. One of the key goals of the scheduling algorithms is simplicity and fast implementation. Unlike the time-stamped based algorithms, our algorithm does not need to sort the virtual time, and thus, the complexity of the algorithm is reduced significantly.Index Terms-Low-power operation, multiple access methods, queuing and scheduling algorithms, wireless and mobile ATM, wireless multimedia communications.

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ITU-T standardization of audiovisual communication systems in ATM and LAN environments

Cited by 23 publications

References 13 publications

Congestion control for multipoint videoconferencing

Congestion control for multipoint videoconferencing

Error-propagation prevention technique for real-time video transmission over ATM networks

Scheduling multimedia services in a low-power MAC for wireless and mobile ATM networks

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