Modeling Of Video Sources Research Articles

Simple model for VBR MPEG digital video sources with gamma functions

This article presents a very simple model based on gamma functions for MPEG1 and MPEG2 VBR digital video. This model is a simplification of Frey's et al model.It captures first grade statistics and the cyclicity of the autocorrelation function. Buffer overflow losses with the proposed model are of the same magnitude that buffer overflow losses of the original video clips. We have found three zones in the buffer overflow losses under certain conditions. Zone number two is of special interest because identified losses are produced by extraordinary large frames.

Power Optimization of Wireless Media Systems With Space-Time Block Codes

We present analytical and numerical solutions to the problem of power control in wireless media systems with multiple antennas. We formulate a set of optimization problems aimed at minimizing total power consumption of wireless media systems subject to a given level of QoS and an available bit rate. Our formulation takes into consideration the power consumption related to source coding, channel coding, and transmission of multiple-transmit antennas. In our study, we consider Gauss-Markov and video source models, Rayleigh fading channels along with the Bernoulli/Gilbert-Elliott loss models, and space-time block codes.

An adaptable neural-network model for recursive nonlinear traffic prediction and modeling of MPEG video sources

Multimedia services and especially digital video is expected to be the major traffic component transmitted over communication networks [such as internet protocol (IP)-based networks]. For this reason, traffic characterization and modeling of such services are required for an efficient network operation. The generated models can be used as traffic rate predictors, during the network operation phase (online traffic modeling), or as video generators for estimating the network resources, during the network design phase (offline traffic modeling). In this paper, an adaptable neural-network architecture is proposed covering both cases. The scheme is based on an efficient recursive weight estimation algorithm, which adapts the network response to current conditions. In particular, the algorithm updates the network weights so that 1) the network output, after the adaptation, is approximately equal to current bit rates (current traffic statistics) and 2) a minimal degradation over the obtained network knowledge is provided. It can be shown that the proposed adaptable neural-network architecture simulates a recursive nonlinear autoregressive model (RNAR) similar to the notation used in the linear case. The algorithm presents low computational complexity and high efficiency in tracking traffic rates in contrast to conventional retraining schemes. Furthermore, for the problem of offline traffic modeling, a novel correlation mechanism is proposed for capturing the burstness of the actual MPEG video traffic. The performance of the model is evaluated using several real-life MPEG coded video sources of long duration and compared with other linear/nonlinear techniques used for both cases. The results indicate that the proposed adaptable neural-network architecture presents better performance than other examined techniques.

Modeling and prediction of hybrid-coded variable bit rate video sources in fuzzy logic perspectives

This paper presents the modeling and prediction of variable bit rate video sources using fuzzy set and fuzzy logic theory. The sources are coded with the hybrid motion compensation/differential pulse code modulation/discrete cosine transform algorithm. The fuzzy logic prediction scheme discussed here is in the category of computational intelligence algorithms. It has the capability to handle statistically difficult to describe or unknown series. The proposed fuzzy logic prediction method is aimed at fast computation for online operation. It can be applied to the development of connection admission control, usage parameter control, and congestion control algorithms in multimedia communication networks.

Content-based MPEG video traffic modeling

In this paper, we propose a video model to generate VBR MPEG video traffic based on the scene content description. Long sessions of nonhomogeneous video clips are decomposed into homogeneous video shots. The shots are then classified into different classes in terms of their texture and motion complexity. Each shot class was uniquely described with an autoregressive model. Transitions between the shots and their durations have been analyzed. Unlike many classical video source models, this model may be used to generate traffic of any type of video scenes ranging from a low complexity video conferencing to a highly active sport program. The performance of the model is evaluated by measuring the mean cell delay when the generated video traffic is fed to an ATM multiplex buffer.

An effective model for VBR video with application to an ATM multiplexer

The effective design and engineering of communication networks require accurate mathematical models that should capture the important statistical properties of traffic sources. The ATM Forum has specified some QoS requirements for video traffic, which are essential for the effective management and operation of ATM networks. In this paper, a model for VBR video sources using a modified first-order autoregressive model is presented. Two levels of states with arbitrary average duration are used to represent the source bit-rate. The corresponding ratio of the statistical duration averages in the two levels is used as a new parameter to quantify the activity behaviour of the pertinent sources. A derivation for the resulting model statistical equations is presented and matched to some experimental data. Then, the obtained matched parameters are plugged into the simulation model. The major results are presented for various parameter values, along with an assessment of their effects on the performance of an ATM multiplexer.

Evaluation of reservation-arbitrated access schemes for statistical multiplexing of variable-bit-rate video traffic over dual-bus metropolitan area networks

To address the problem of video communications over 802.6 MANs, a reservation-arbitrated (RA) access protocol is proposed which allows a variable-bit-rate video source to reserve isochronous channels on a bandwidth-on-demand basis. The paper explains the general method of RA access, compares four different schemes of acquiring incremental bandwidth in response to a reservation request, and evaluates the performance of RA access by simulations using two video-source models. Results indicate that RA access provides fair service under a cyclic capturing mechanism, permits statistical multiplexing while providing nearly isochronous transport service, allows a video source to adapt to its reserved bandwidth during network congestion, and facilitates the implementation of layered video coding techniques.

End-to-end modeling and simulation of MPEG-2 transport streams over ATM networks with jitter

The operation of MPEG-2 systems is modeled and simulated when an MPEG-2 transport stream is delivered through an ATM network with jitter. End-to-end packet-based analysis is performed for delivery of MPEG-2 transport streams over ATM networks. A novel approach to analyzing the decoder buffer behaviour in the presence of network jitter is presented. The probability density function of the interarrival time of the ATM adaptation layer 5 (AAL5) protocol data unit (PDU) is derived from an MPEG-2 video source model and an ATM network jitter model. Based on a real-time decoding requirement of the MPEG-2 transport stream (TS) system target decoder (T-STD), the decoder buffer behaviour is simulated. In this simulation, the packets' arrivals follow the derived probability density function of the AAL5 PDU interarrival time. The modeling and simulation results show the interactions among packet loss ratio, decoder buffer size, and network jitter level. We found that jitter affects decoder buffer size and packet loss ratio in a significant way.

The importance of long-range dependence of VBR video traffic in ATM traffic engineering

There has been a growing concern about the potential impact of long-term correlations (second-order statistic) in variable-bit-rate (VBR) video traffic on ATM buffer dimensioning. Previous studies have shown that video traffic exhibits long-range dependence (LRD) (Hurst parameter large than 0.5). We investigate the practical implications of LRD in the context of realistic ATM traffic engineering by studying ATM multiplexers of VBR video sources over a range of desirable cell loss rates and buffer sizes (maximum delays). Using results based on large deviations theory, we introduce the notion of Critical Time Scale (CTS). For a given buffer size, link capacity, and the marginal distribution of frame size, the CTS of a VBR video source is defined as the number of frame correlations that contribute to the cell loss rate. In other words, second-order behavior at the time scale beyond the CTS does not significantly affect the network performance. We show that whether the video source model is Markov or has LRD, its CTS is finite, attains a small value for small buffer, and is a non-decreasing function of buffer size. Numerical results show that (i) even in the presence of LRD , long-term correlations do not have significant impact on the cell loss rate; and (ii) short-term correlations have dominant effect on cell loss rate, and therefore, well-designed Markov traffic models are effective for predicting Quality of Service (QOS) of LRD VBR video traffic. Therefore, we conclude that it is unnecessary to capture the long-term correlations of a real-time VBR video source under realistic ATM buffer dimensioning scenarios as far as the cell loss rates and maximum buffer delays are concerned.

Study of the impact of MPEG-1 correlations on video-sources statistical multiplexing

Variable bit-rate (VBR) video is expected to become increasingly important with the large scale deployment of broadband-integrated services networks (B-ISDNs). While the modeling of VBR video sources has received significant attention, there is no widely accepted model which lends itself to mathematical analysis. Furthermore, new video compression standards are emerging, such as the MPEG family. A detailed statistical analysis of a long sample of a movie encoded with an MPEG-1 algorithm highlights that traffic generated by an MPEG-1 encoder has both a high degree of burstiness (peak/average ratio greater than five) and a strong long-term correlation (positive correlation lasts for ten/twenty minutes). In this paper, we propose and analyze a Markov model which captures both the burstiness and the temporal dependencies of MPEG traffic. Furthermore, we show that our model is a flexible traffic generator which is suitable for studying statistical multiplexing issues. Specifically, we study both the multiplexing of a VBR video source with low priority traffic and the multiplexing of several VBR video sources. The results obtained show that the long-term correlation significantly affects the tail of the delay distribution even for lightly loaded networks. The presence of a long range dependence in the MPEG traffic significantly reduces the gain in terms of network utilization which can be achieved with statistical multiplexing of i.i.d. sources.

MPEG coding for variable bit rate video transmission

For real-time transmission of broadcast-quality video on ATM-based B-ISDN, the intraframe to interframe ratio and the quantizer scale are two key parameters that can be used to control a video source in a network environment. Their impact on the traffic characteristics of the coder provides insights into the cell arrival process for an MPEG source. The authors obtain video source models for coders that utilize a standard algorithm that can be applied to a multitude of video services. The output stream of a video coder, which complies with the Motion Pictures Expert Group (MPEG) coding standard, is studied with an National Television Systems Committee (NTSC) quality video sequence as the input. Because the MPEG video coding algorithm has been proposed for a variety of applications, they also investigate the effect of changing the coding parameters on the statistics of interest. >