Copyright © 2005 Published by Elsevier B.V.
Optimizing multimedia transcoding multicast trees
Received 28 March 2003;
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Abstract
In this paper, network hosted transcoding is studied for the optimization of resources in multicast applications. The configuration is as follows: one source node is sending a signal (e.g. a video stream) and several destinations request that signal but at a bit rate adjusted to their access link. Instead of transcoding at the source node, the nodes inside the network will take care of the reduction in bit rate. The advantages are that the source load and overall bandwidth usage are reduced while end-users get the service at a customized quality. The focus of this paper is on the calculation of the optimal multicast tree, including transcoding location optimization and estimation of the resource usage gain.
Keywords: Multicast trees; Transcoding; Active networks; Optimization
Article Outline
- 1. Introduction
- 2. ILP-formulation of the problem
- 2.1. Model description
- 2.1.1. The network
- 2.1.2. The types
- 2.1.3. Source and destination nodes
- 2.2. Variables
- 2.3. Formulation
- 2.3.1. Objective function
- 2.3.2. Constraints
- 3. Heuristics
- 3.1. Skinned Steiner Tree heuristic
- 3.1.1. Calculating the tree
- 3.1.2. Skinning the tree
- 3.2. Branch attach heuristic
- 3.2.1. Initialization
- 3.2.2. Attaching the branches
- 3.2.3. Distributed implementation
- 3.3. Post optimization
- 3.3.1. Upstream method
- 3.3.2. Downstream method
- 3.3.3. Active neighbor method
- 3.4. Favoring active nodes
- 4. Simulations
- 4.1. Video multicast
- 4.1.1. Video transcoding
- 4.1.2. Configuration
- 4.1.3. Results
- 4.2. Speech multicast
- 4.2.1. Configuration
- 4.2.2. Results
- 5. Conclusions
- Acknowledgements
- References
- Vitae







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