Proxy caching for robust video delivery over lossy networks

Video delivery is anticipated to become among the most popular services in networking. The rapid advances in communication technologies, combined with the increasing efficiency of video compression techniques have paved the way for innovative and exciting video communication applications. However, the acceptance of video communication services can suffer severely from variations and deterioration of the video quality. In the absence of Quality-of-Service aware networks, the communicating applications cannot control the service parameters offered to them by the underlying protocol layers. By consequence, the applications may experience varying packet delivery delays and often also packet loss. This results in severe degradation in the video quality as perceived by the user.In this dissertation, we develop a framework for prioritized video delivery. We introduce models for the estimation of distortion resulting from loss of video packets. Based on these models, we propose a video packet prioritization mechanism, which reflects accurately the importance of the video data carried in one packet for the video quality at the end user. Using this prioritization scheme, we design error control and avoidance techniques, which achieve near-to-optimal video quality.Given the trend towards wireless and mobile access to video services, we advocate the deployment of proxy caches in proximity to end users. Proxy caches should adapt the video stream to the needs of each video receiver, hence, ameliorating the perceived video quality, while still meeting tight delay constraints and low device capabilities. We introduce the idea of proxy caching for adaptive retransmission and show how appropriate retransmission schemes, based on size-distortion optimization, leads to significant quality improvements, even under strong delay and buffer constraints. We then construct a forward error correction code, which protects the different video packets at different levels based on their distortion-based priority. We show that our code achieves near-optimal quality at low code rates and end-to-end delays. Finally, we develop a rate estimation and shaping algorithm, which drops low priority video packets to meet rate constraints.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2004

Author dc:creator

• Bouazizi, Imed

Contributors dc:contributor

• Spaniol, Otto

• info:eu-repo/classification/ddc/004
• Videoübertragung
• Paketvermittlung
• Bildqualität
• Datenkompression
• Pufferspeicher
• Verzerrung <Elektrotechnik>
• Verzögerungszeit
• Übertragungsfehler
• Informatik
• proxy caching
• video streaming
• video delivery
• robustness
• distortion estimation

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-120757%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:58931