Differentiated Data Persistence with Priority Random Linear Codes

Signal Processing: Image Communication

2009

a b s t r a c tConventionally, linear block codes designed for packet erasure correction are targeted to recover all the lost source packets per block, when the fraction of lost data is smaller than the redundancy overhead. However, these codes fail to recover any lost packets, if the number of erasures just exceeds the limit for full recovery capability, while it can still be beneficial to recover part of the symbols. In addition, common linear block codes are not well suited for unequal error protection, since different block codes with different rates must be allocated for each priority class separately. These two problems motivate the design of more flexible forward error correction (FEC) codes for media streaming applications. We first review the performance of short and long linear block codes. Long block codes generally offer better error correction capabilities, but at the price of higher complexity and larger coding delay. Short block codes can be more appropriate in media streaming applications that require smooth performance degradation when the channel loss rate increases. We study a new class of linear block codes using sparse generator matrices that permit to optimize the performance of short block codes for partial recovery of the lost packets. In addition, the proposed codes are extended to the design of unequal erasure protection solutions. Simulations of practical video streaming scenarios demonstrate that the flexible sparse codes offer a promising solution with interesting error correction capabilities and small variance in the residual loss rate. They typically represent an effective trade-off between short block codes with limited flexibility, and long block codes with delay penalties.

Section: Fec For Short Blocksmentioning

confidence: 93%

Flexible forward error correction codes with application to partial media data recovery

Korhonen¹,

Signal Processing: Image Communication

2009

“…Furthermore, the proposed solutions are usually computationally complex and difficult to extend to distributed settings. For example, priority random linear codes [33] are proposed for data dissemination in peer-to-peer and sensor networks, where improved data persistence is achieved due to the fact that the most important video data represents a combination of fewer source packets. The global encoding kernel (GEK) approach is proposed in [34] for defining unequal amount of protection to scalable data.…”

Section: Related Workmentioning

confidence: 99%

Prioritized Distributed Video Delivery With Randomized Network Coding

Thomos

Chakareski

2011

IEEE Trans. Multimedia

Abstract-We address the problem of prioritized video streaming over lossy overlay networks. We propose to exploit network path diversity via a novel randomized network coding (RNC) approach that provides unequal error protection (UEP) to the packets conveying the video content. We design a distributed receiver-driven streaming solution, where a client requests packets from the different priority classes from its neighbors in the overlay. Based on the received requests, a node in turn forwards combinations of the selected packets to the requesting peers. Choosing a network coding strategy at every node can be cast as an optimization problem that determines the rate allocation between the different packet classes such that the average distortion at the requesting peer is minimized. As the optimization problem has log-concavity properties, it can be solved with low complexity by an iterative algorithm. Our simulation results demonstrate that the proposed scheme respects the relative priorities of the different packet classes and achieves a graceful quality adaptation to network resource constraints. Therefore, our scheme substantially outperforms reference schemes such as baseline network coding techniques as well as solutions that employ rateless codes with built-in UEP properties. The performance evaluation provides additional evidence of the substantial robustness of the proposed scheme in a variety of transmission scenarios.Index Terms-Network coding, overlay networks, peer-to-peer (P2P) systems, rate allocation, scalable video delivery, unequal error protection, video streaming.

“…For example, priority random linear codes [4] are proposed for data dissemination in peer-to-peer and sensor networks, where improved data persistence is achieved due to the fact that the most important video data represents a combination of fewer source packets. The global encoding kernel (GEK) approach is proposed in [5] for defining unequal amount of protection to scalable data.…”

Section: Introductionmentioning

confidence: 99%

Randomized Network Coding for UEP video delivery in overlay networks

Thomos

Chakareski

2009 IEEE International Conference on Multimedia and Expo

2009

This paper presents a receiver-driven video delivery algorithm that exploits a novel Randomized Network Coding (RNC) scheme for unequal error protection (UEP). The main idea of our approach is to account for the unequal importance of media packets in the network coding algorithm for efficient stream delivery in lossy overlay networks. Based on the requests from their neighbours, the network nodes properly combine packets and forward them to their children nodes. The network coding operations at every node are formulated as a log-concave optimization problem, which is solved with a greedy algorithm in only a few iterations. Our experimental results demonstrate that the proposed scheme permits to respect the priorities between the different packet classes. It further outperforms baseline network coding techniques for video streaming in overlay networks.