Efficient Delivery of Scalable Video Using a Streaming Class Model

Jason Quinlan,Ahmed Zahran,Cormac Sreenan

doi:10.3390/info9030059

Abstract

When we couple the rise in video streaming with the growing number of portable devices (smart phones, tablets, laptops), we see an ever-increasing demand for high-definition video online while on the move. Wireless networks are inherently characterised by restricted shared bandwidth and relatively high error loss rates, thus presenting a challenge for the efficient delivery of high quality video. Additionally, mobile devices can support/demand a range of video resolutions and qualities. This demand for mobile streaming highlights the need for adaptive video streaming schemes that can adjust to available bandwidth and heterogeneity, and can provide a graceful changes in video quality, all while respecting viewing satisfaction. In this context, the use of well-known scalable/layered media streaming techniques, commonly known as scalable video coding (SVC), is an attractive solution. SVC encodes a number of video quality levels within a single media stream. This has been shown to be an especially effective and efficient solution, but it fares badly in the presence of datagram losses. While multiple description coding (MDC) can reduce the effects of packet loss on scalable video delivery, the increased delivery cost is counterproductive for constrained networks. This situation is accentuated in cases where only the lower quality level is required. In this paper, we assess these issues and propose a new approach called Streaming Classes (SC) through which we can define a key set of quality levels, each of which can be delivered in a self-contained manner. This facilitates efficient delivery, yielding reduced transmission byte-cost for devices requiring lower quality, relative to MDC and Adaptive Layer Distribution (ALD) (42% and 76% respective reduction for layer 2), while also maintaining high levels of consistent quality. We also illustrate how selective packetisation technique can further reduce the effects of packet loss on viewable quality by leveraging the increase in the number of frames per group of pictures (GOP), while offering a means of reducing overall error correction and by providing equality of data in every packet transmitted per GOP.

Highlights

Recent years have featured a dramatic rise in the volume of video streaming traffic over the Internet and mobile networks
We investigate the transmission of well-known scalable video models over a lossy network and determine how the variation in viewable quality is affected by packet loss
The results provided in Appendix A for Scalable Video Coding (SVC)-Streaming Classes (SC) (SVC using a Streaming Class model) illustrate that, as we increase the group of pictures (GOP) value, different levels of allocated Forward Error Correction (FEC) can provide continuous levels of maximum stream quality for all packet byte-size allocation schemes illustrated above, illustrating both adaptation in FEC allocation and packet byte-size allocation by which viewable quality can be preserved during moments of packet loss

Summary

Introduction

Recent years have featured a dramatic rise in the volume of video streaming traffic over the Internet and mobile networks. Benefits of SVC include permitting devices to utilise pre-buffered lower layer data when requesting an increase in stream quality. The additional layer needs to be transmitted and not the base layer, minimising the bandwidth transmission cost, providing the benefit of cumulative stream transmission, where different layers can be combined to increase overall viewable quality. This allows devices with differing stream requirements to selectively choose between the layers on offer, in order to maximise their respective stream quality without requesting additional data to be transmitted. Looking to the near future, a scalable extension to High Efficiency Video Coding (HEVC) is posed for release and further development [14,15,16,17]

Methods

Results

Discussion

Conclusion