RD Optimized, Adaptive, Error-Resilient Transmission of MJPEG2000-Coded Video over Multiple Time-Varying Channels
- PDF / 4,556,622 Bytes
- 13 Pages / 600.03 x 792 pts Page_size
- 3 Downloads / 228 Views
RD Optimized, Adaptive, Error-Resilient Transmission of MJPEG2000-Coded Video over Multiple Time-Varying Channels Scott Bezan and Shahram Shirani Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON, Canada L8S 4K1 Received 25 February 2005; Revised 22 August 2005; Accepted 1 September 2005 To reliably transmit video over error-prone channels, the data should be both source and channel coded. When multiple channels are available for transmission, the problem extends to that of partitioning the data across these channels. The condition of transmission channels, however, varies with time. Therefore, the error protection added to the data at one instant of time may not be optimal at the next. In this paper, we propose a method for adaptively adding error correction code in a rate-distortion (RD) optimized manner using rate-compatible punctured convolutional codes to an MJPEG2000 constant rate-coded frame of video. We perform an analysis on the rate-distortion tradeoff of each of the coding units (tiles and packets) in each frame and adapt the error correction code assigned to the unit taking into account the bandwidth and error characteristics of the channels. This method is applied to both single and multiple time-varying channel environments. We compare our method with a basic protection method in which data is either not transmitted, transmitted with no protection, or transmitted with a fixed amount of protection. Simulation results show promising performance for our proposed method. Copyright © 2006 Hindawi Publishing Corporation. All rights reserved.
1.
INTRODUCTION
Video data is very large in its raw form and as such requires some level of source coding (compression) in order to be effectively transmitted. Unfortunately, many compression methods (usually of the lossy variety) introduce distortion in the reconstructed frame. In addition to the quantization distortion, source coding can leave the coded data vulnerable to bit errors that frequently occur in transmission over error-prone channels. If a constant source rate is assumed, any further distortion seen in the reconstructed frame will be due to channel-introduced errors. To this end, error protection (channel coding) is introduced to the source-coded data in order to enable correction of some erroneous bits at the receiver. Ideally, the channel coder could add as much channel code as necessary to correct all bit errors in transmission. In reality, transmission channels are bandlimited, so this solution is infeasible. Therefore, a rate-distortion (RD) tradeoff exists between the amount of error correction added, while considering a channel bandwidth constraint and the reconstructed distortion influenced by channel errors. Finding the optimum balance between rate and distortion is challenging, but more complication arises when channels are time-varying. In this case, when the condition of a channel changes with time, past optimized channel codes may no
longer be relevant, therefore some manner of adaptation to the channel condit
Data Loading...
