Network support for mobile multimedia using a self-adaptive distributed proxy

Abstract

Recent advancements in video and audio codec technologies (e.g., RealVideo [18]) make multimedia streaming possible across a wide range of network conditions. With an increasing trend of ubiquitous connectivity, more and more areas have overlapping coverage of multiple wired and wireless networks. Because the best network service changes as the user moves, to provide good multimedia application performance, the service needs to adapt to user movement as well as network and computational resource variations. For wireless multimedia applications, one must ensure smooth transitions when network connectivity changes. We argue that network adaptations for multimedia applications should be provided at the application layer with help from proxies in the network. The reasons are ease of programming, ease of deployment, better faulttolerance, and greater scalability.We propose a self-adaptive distributed proxy system that provides streaming multimedia service to mobile wireless clients. Our system intelligently adapts to the real-time network variations and hides handoff artifacts using application protocol specific knowledge whenever possible. It also uses application-independent techniques such as dynamic relocation of transcoders and automatic insertion of forward error correction and compression into the data transcoding path. We advocate a composable, relocatable transcoding data path consisting of a directed acyclic graph of stronglytyped operators to bridge any data format mismatch between the client and the data source. In this paper, we present the design, implementation, and evaluation of our system in the context of streaming video playback involving a series of transcoding proxies and a mobile client.

Proxy-Based Visual Content Repurposing Using Selection Algorithm

“…For the measurement, we used a widely accepted objective measure of visual quality metric called the Peak Signal to-Noise-Ratio (PSNR) defined in Eq. (2). Where, MSE is the mean square error between the original content and the reconstructed visual content.…”

“…One of the benefits of our approach compared to other works e.g. [2] is that it enables for heterogeneous (between different coding standards) repurposing as well as homogeneous (within standard) repurposing. Additional proxies and/or services can also be easily added to the existing services to support any new media formats that need to be repurposed.…”

An approach to the identification of network elements composing heterogeneous end-to-end paths

“…Our approach may help end-hosts (or intermediate systems) to identify pieces of networks, opening the way to a wide variety of research studies that aim to provide greater control over the entire end-to-end network paths. Some scenarios could be the following: adaptive and network-aware applications [41][42][43][44], reactive and intelligent routing [45,46], overlay networks [47][48][49][50], source-routing [51].…”

Adaptive video streaming for embedded devices

“…This is performed by reconfiguring the encoder properties appropriately (quality factor, frame rate, etc.). In [16], a self-adaptive proxy is proposed to manage QoS for multimedia applications. The limitation of these proposals is that reconfiguration policies are embedded in the application code and cannot be modified without additional development efforts.…”