Impact of video scheduling on bandwidth allocation for multiplexed MPEG streams

Abstract

We present efficient schemes for scheduling the delivery of variable-bit-rate MPEG-compressed video with stringent quality-of-service (QoS) requirements. Video scheduling is being used to improve bandwidth allocation at a video server that uses statistical multiplexing to aggregate video streams prior to transporting them over a network. A video stream is modeled using a traffic envelope that provides a deterministic time-varying bound on the bit rate. Because of the periodicity in which frame types in an MPEG stream are typically generated, a simple traffic envelope can be constructed using only five parameters. Using the traffic-envelope model, we show that video sources can be statistically multiplexed with an effective bandwidth that is often less than the source peak rate. Bandwidth gain is achieved without sacrificing the stringency of the requested QoS. The effective bandwidth depends on the arrangement of the multiplexed streams, which is a measure of the lag between the GOP periods of various streams. For homogeneous streams, we give an optimal scheduling scheme for video sources at a video-on-demand server that results in the minimum effective bandwidth. For heterogeneous sources, a sub-optimal scheduling scheme is given, which achieves acceptable bandwidth gain. Numerical examples based on traces of MPEG-coded movies are used to demonstrate the effectiveness of our schemes.

An Efficient Statistical Multiplexing Method for H.264 VBR Video Sources for Improved Traffic Smoothing

“…Single server queuing models D-MMDP/D/1/k for modeling the ATM multiplexer was used in [10], and later bandwidth was estimated. Krunz et.al., [4,6] have assumed that cell per frame sequence of a video stream is a stationary stochastic process. The trace is arranged as a circular list and uses a random multiplexing technique.…”

Real-time transport of MPEG video with a statistically guaranteed loss ratio in ATM networks

“…Numerous models have previously been proposed for VBR video under various compression schemes [26], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45]. Since the VBR behavior of a video stream strongly depends on the compression technique used, many of these models do not characterize MPEG-coded video which is now widely-accepted as a standard for transmission and storage of video data in many multimedia systems.…”

“…Since the VBR behavior of a video stream strongly depends on the compression technique used, many of these models do not characterize MPEG-coded video which is now widely-accepted as a standard for transmission and storage of video data in many multimedia systems. How to characterize MPEG-coded video streams has been investigated by several researchers [36], [37], [41], [43], [44], [45]. They addressed the modeling of MPEG streams using a model fitting or an analytic approach.…”

“…Compared to the analytic approach considered in this paper, their approach doesn't scale well, i.e., has a limitation in dealing with a large number of multiplexed video streams. In [45], Krunz and Tripathi solved the bandwidth-allocation problem for multiplexed video streams using a time-varying traffic envelope. To reduce the bandwidth requirement, they proposed to arrange the starting times of component video streams in such a way that s , , and f frames evenly coincide with one another.…”

Efficient support for interactive scanning operations in MPEG-based video-on-demand systems

“…This form of rate-controlled compression results in variable picture quality during FS. By making the envelopes of the scan versions identical or sufficiently close to the envelope of the normal version, FS can be integrated into a previously proposed framework for the distribution of archived, MPEGcoded video streams [21,22]. By generating scan versions that exhibit similar envelopes to the normal version, FS operations can be made transparent to the underlying network and can be supported with little or no extra bandwidth and at the same decoding rate of normal playback.…”