Efficient delivery of scalable media streaming over lossy networks
Supervisor(s) and Committee member(s): Cormac Sreenan (main supervisor), Ahmed Zahran (supervisor), Gabriel-Miro Muntean (first opponent), Sabin Tabirca (second opponent)
Recent years have witnessed a rapid growth in the demand for streaming video over the Internet, exposing challenges in coping with heterogeneous device capabilities and varying network throughput. When we couple this rise in streaming with the growing number of portable devices (smart phones, tablets, laptops) we see an ever-increasing demand for high-definition videos 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 us with graceful changes in video quality, all while respecting our viewing satisfaction. In this context the use of well-known scalable media streaming techniques, commonly known as scalable coding, is an attractive solution and the focus of this thesis. In this thesis we investigate the transmission of existing scalable video models over a lossy network and determine how the variation in viewable quality is affected by packet loss. This work focuses on leveraging the benefits of scalable media, while reducing the effects of data loss on achievable video quality. The overall approach is focused on the strategic packetisation of the underlying scalable video and how to best utilise error resiliency to maximise viewable quality. In particular, we examine the manner in which scalable video is packetised for transmission over lossy networks and propose new techniques that reduce the impact of packet loss on scalable video by selectively choosing how to packetise the data and which data to transmit. We also exploit redundancy techniques, such as error resiliency, to enhance the stream quality by ensuring a smooth play-out with fewer changes in achievable video quality. The contributions of this thesis are in the creation of new segmentation and encapsulation techniques which increase the viewable quality of existing scalable models by fragmenting and re-allocating the video sub-streams based on user requirements, available bandwidth and variations in loss rates. We offer new packetisation techniques which reduce the effects of packet loss on viewable quality by leveraging the increase in the number of frames per group of pictures (GOP) and by providing equality of data in every packet transmitted per GOP. These provide novel mechanisms for packetizing and error resiliency, as well as providing new applications for existing techniques such as Interleaving and Priority Encoded Transmission. We also introduce three new scalable coding models, which offer a balance between transmission cost and the consistency of viewable quality.
Mobile and Internet Systems Laboratory
The Mobile & Internet Systems Laboratory is a research laboratory within the Department of Computer Science at University College Cork. The Laboratory conducts research in the areas of computer networking and systems, with a focus on applications in the mobile/wireless and multimedia domains.
MISL is led by Professor Cormac J. Sreenan. The Laboratory was founded in year 2000 after Prof. Sreenan joined UCC from AT&T (Bell) Labs in the USA. Currently, over 15 research students and staff are involved in various research projects as part of the Mobile and Internet Systems Laboratory.
The Laboratory currently has four major research areas of interest:
- Video Streaming and Content Delivery Optimisation
- Quality of Service/Experience in Wireless Networks
- Next-generation Telecoms Networks
- Wireless Sensor Networks