P. Pancha

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.<<ETX>>

Bandwidth-allocation schemes for variable-bit-rate MPEG sources in ATM networks

The complex traffic characteristics of variable-bit-rate (VBR) video sources makes them difficult to accommodate in asynchronous-transfer-mode (ATM) networks. To efficiently transport these services will require both an understanding of the source traffic and novel network control schemes. The performance of variable-bandwidth-allocation schemes that estimate the required bandwidth for a VBR Motion Picture Experts Group (MPEG) video source is studied using a simple prediction algorithm. The advantages of using a layered MPEG coder over the standard MPEG coder are discussed. A method for controlling a layered MPEG coder to reduce the effect of cell losses when compared to a standard MPEG coder is demonstrated. >

Bandwidth requirements of variable bit rate MPEG sources in ATM networks

The performance of variable bandwidth allocation schemes that estimate the required bandwidth for a variable-bit-rate (VBR) MPEG video source using a simple prediction algorithm is studied. The advantages of using a layered MPEG coder over the standard MPEG coder are discussed. A method for controlling a layered MPEG coder in order to reduce the effect of cell losses when compared to a standard MPEG coder is demonstrated.<<ETX>>

A look at the MPEG video coding standard for variable bit rate video transmission

The MPEG video coding standard for the transmission of variable-bit-rate video on asynchronous transfer mode (ATM)-based broadband ISDN is examined. The focus is on its use for real-time transmission of broadcast-quality video. The impact of two key parameters, the intraframe to interframe picture ratio and the quantization index that are defined in the standard, on the bit rates per frame was studied. These parameters can be used to control video sources depending on the state of the network. Also, as opposed to previous work which looks only at bit rates per frame, the bits generated per macroblock are studied. This is the basic MPEG coding unit. By packetizing these bits, insight was obtained into the cell arrival process to a network for a MPEG video source.<<ETX>>

Prioritized transmission of variable bit rate MPEG video

The traffic characteristics of an MPEG coder which generates a high-priority and a low-priority bit stream are studied. The prioritization scheme for the coder assigns components of the data stream to each priority level based on the value of a parameter B. Statistics of both high- and low-priority cells for a pure intraframe and a mixed interframe/intraframe coder are presented. In particular, the probability mass functions on a cells per slice basis of the high-priority and low-priority component for various values of B are shown. Statistics gathered from this type of prioritization scheme can be applied in several ways for network design and operation.<<ETX>>

Comparison of priority partition methods for VBR MPEG

Successful exploitation of prioritized ATM networks requires matching the characteristics of the coded source with the unique properties of the network. This is particularly true for video which is very bandwidth intensive. The authors describe and investigate the performance of three prioritization schemes in terms of the traffic characteristics, SNR, and visual quality. These schemes are further designed such that the high priority data stream is MPEG-I compliant and only a single pass through the encoder is required. A technique for choosing parameter values which achieve a specified high priority traffic bandwidth is presented for two of these schemes. The technique is demonstrated to be remarkably accurate for different video sequences.<<ETX>>

MPEGTool: an X window based MPEG encoder and statistics tool

In this paper, we describe MPEGTool, an X window-based tool that can be used to generate a motion picture expert group (MPEG) encoded bit stream for video sequences and to study the statistical properties of the encoded data. The tool was designed to study the characteristics of variable bit rate video sources for transmission over asynchronous transfer mode (ATM) based broadband integrated services digital network (B-ISDN). The tool, which has a window-based graphic user interface, allows a user to specify several of the MPEG parameters such as the intraframe-to-interframe ratio and the quantizer scale. The tool also includes a statistical package that allows the user to plot graphs of various statistics including bit distributions, ATM cell distributions, time se ries, autocorrelation functions and cell interarrival times.