A novel unbalanced multiple description coder for robust video transmission over ad hoc wireless networks

22nd International Conference on Advanced Information Networking and Applications (Aina 2008)

et al. 2008

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Robust transmission of live video over ad hoc wireless networks presents new challenges: high bandwidth requirements are coupled with delay constraints; nodes are constrained in processing power and storage capacity; ad hoc wireless networks suffer from bursty packet losses that drastically degrade the viewing experience. Accordingly, we propose a simple, but practical unbalanced multiple description (UMD) codec that uses single path transport only. At the UMD decoder, the lost LowResolution (LR) frames can be recoded from the corresponding ones of the correctly received HighResolution (HR) stream. This makes LR more robust to packet losses and ensures continuous video playback. The simulation results show that the proposed UMD codec has higher decoded quality, smaller quality fluctuation and lower probability of pause than other error resilience techniques, especially when channel burstiness becomes large. We also propose a novel sequence-based error concealment (EC) algorithm for our UMD decoder. It recursively uses multi-frame recovery principle to frame-by-frame reduce error drift in the HR description with respect to the LR description. In fact, the algorithm can be applied to most UMD schemes. It has the advantage of working on integer-, half-or quarter-pixel precision and looking backward without buffering future frames. Experimental results show that error decreases the fastest if the UMD decoder uses our EC algorithm. It can provide satisfactory performance on both objective and subjective evaluation. 1

Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

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Supporting Live Video on Ad Hoc Wireless Networks: Unbalanced Multiple Description Coding, Single Path Transport and Recursive Error Concealment

22nd International Conference on Advanced Information Networking and Applications (Aina 2008)

et al. 2008

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“…Previously we have committed many research efforts towards transmitting UMDC over multiple paths and observed encouraging results [6]. However, although exploiting path diversity indeed decreases the correlation among the descriptions [7][8], it complicates existing underlay network topology and requires additional link resource in reality.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the simple LR-HR replacement policy adopted in [9] introduces the error-drift effect when any description encounters packet loss. Towards this end, we further improve our UMDC approach [6] to adapt to single path transmission (SPT).…”

Section: Introductionmentioning

confidence: 99%

An Unbalanced Multiple Description Coding Scheme for Video Transmission Over Wireless Ad Hoc Networks

2006 IEEE International Conference on Multimedia and Expo

2006

Video transmission over wireless ad hoc networks is hampered by packet losses. Even a single packet loss may cause error propagation until an intra-coded frame is received. Indeed, packet losses greatly degrade the video quality. In this paper, we propose an Unbalanced Multiple Description Coding (UMDC) scheme over a single path which requires only one single path as additional links are difficult to be guaranteed in reality and is capable of quickly recovering from packet losses and ensuring continuous playback. The proposed scheme uses two descriptions, the High-Resolution (HR) description and the Low-Resolution (LR) one. It uses the 'peg frames' to limit error propagation in the HR description. The two descriptions can help each other recover from packet losses. The simulation results show that the proposed UMDC scheme over a single path has a comparable performance with our UMDC scheme with multiple path transmission (MPT) and has a better viewing experience than the state-of-the-art FEC-based scheme.

Joint Error Concealment and Error Recovery for Consecutive Frame Losses under the Unbalanced Multiple Description Coding Architecture

Proceedings of the 3rd International ICST Conference on Mobile Multimedia Communications

et al. 2007

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Real-time video transmission over error-prone wireless networks often experiences consecutive frame losses due to either temporary link outages or traffic congestion. Although error concealment (EC) techniques have been extensively studied, they usually cannot handle the problem. Thus, we envision using EC under the unbalanced multiple description coding (UMDC) architecture. UMDC has almost no coding delay and can produce two descriptions at any bit-rates adaptive to different path bandwidths. In this paper, we propose an iterative EC algorithm able to adaptively exploit both the high-resolution (HR) and lowresolution (LR) information via multi-hypothesis weights. It is applied to both lost HR frames and following undecoded ones. Considering error propagation, we design an interframe error recovery (ER) algorithm for the undecoded HR frames. It iteratively uses multi-frame recovery principle to frame-by-frame reduce error drift in the HR stream with respect to the intermediate information from EC. The joint design of EC and ER can be applied to most UMD approaches. Extensive experiments have been carried out under different conditions. The proposed EC technique exhibits high PSNR gains versus the usual ones under the UMDC architecture and the classical ones without the support of UMDC. The proposed ER technique is efficient in reducing error drift. In conclusion, joint EC and ER can provide satisfactory performance on both PSNR and visual quality.