Survey of Error Correction Mechanisms for Video Streaming over the Internet <s> A. Optimal Mode Selection <s> This paper addresses the problem of encoder optimization in a macroblock-based multimode video compression system. An efficient solution is proposed in which, for a given image region, the optimum combination of macroblock modes and the associated mode parameters are jointly selected so as to minimize the overall distortion for a given bit-rate budget. Conditions for optimizing the encoder operation are derived within a rate-constrained product code framework using a Lagrangian formulation. The instantaneous rate of the encoder is controlled by a single Lagrange multiplier that makes the method amenable to mobile wireless networks with time-varying capacity. When rate and distortion dependencies are introduced between adjacent blocks (as is the case when the motion vectors are differentially encoded and/or overlapped block motion compensation is employed), the ensuing encoder complexity is surmounted using dynamic programming. Due to the generic nature of the algorithm, it can be successfully applied to the problem of encoder control in numerous video coding standards, including H.261, MPEG-1, and MPEG-2. Moreover, the strategy is especially relevant for very low bit rate coding over wireless communication channels where the low dimensionality of the images associated with these bit rates makes real-time implementation very feasible. Accordingly, in this paper, the method is successfully applied to the emerging H.263 video coding standard with excellent results at rates as low as 8.0 Kb per second. Direct comparisons with the H.263 test model, TMN5, demonstrate that gains in peak signal-to-noise ratios (PSNR) are achievable over a wide range of rates. <s> BIB001 </s> Survey of Error Correction Mechanisms for Video Streaming over the Internet <s> A. Optimal Mode Selection <s> In this article we provide an overview of rate-distortion (R-D) based optimization techniques and their practical application to image and video coding. We begin with a short discussion of classical rate-distortion theory and then we show how in many practical coding scenarios, such as in standards-compliant coding environments, resource allocation can be put in an R-D framework. We then introduce two popular techniques for resource allocation, namely, Lagrangian optimization and dynamic programming. After a discussion of these techniques as well as some of their extensions, we conclude with a quick review of literature in these areas citing a number of applications related to image and video compression and transmission. <s> BIB002 </s> Survey of Error Correction Mechanisms for Video Streaming over the Internet <s> A. Optimal Mode Selection <s> We describe an effective method for increasing error resilience of video transmission over bit error prone networks. Rate-distortion optimized mode selection and synchronization marker insertion algorithms are introduced. The resulting video communication system takes into account the channel condition and the error concealment method used by the decoder, to optimize video coding mode selection and placement of synchronization markers in the compressed bit stream. The effects of mismatch between the parameters used by the encoder and the parameters associated with the actual channel condition and the decoder error concealment method are evaluated. Results for the binary symmetric channel and wideband code division multiple access mobile network models are presented in order to illustrate the advantages of the proposed method. <s> BIB003 </s> Survey of Error Correction Mechanisms for Video Streaming over the Internet <s> A. Optimal Mode Selection <s> Resilience to packet loss is a critical requirement in predictive video coding for transmission over packet-switched networks, since the prediction loop propagates errors and causes substantial degradation in video quality. This work proposes an algorithm to optimally estimate the overall distortion of decoder frame reconstruction due to quantization, error propagation, and error concealment. The method recursively computes the total decoder distortion at pixel level precision to accurately account for spatial and temporal error propagation. The accuracy of the estimate is demonstrated via simulation results. The estimate is integrated into a rate-distortion (RD)-based framework for optimal switching between intra-coding and inter-coding modes per macroblock. The cost in computational complexity is modest. The framework is further extended to optimally exploit feedback/acknowledgment information from the receiver/network. Simulation results both with and without a feedback channel demonstrate that precise distortion estimation enables the coder to achieve substantial and consistent gains in PSNR over known state-of-the-art RD- and non-RD-based mode switching methods. <s> BIB004
There are two coding modes for black, Inter-mode. With this mode, loss of packet may degrade video quality over a large number of frames. Intra-mode can effectively stop error propagation at the cast of compression efficiency. Inter-mode can achieve compression efficiency at the risk of error propagation. Therefore, the aim of optimal mode selection method is to find the trade-off between coding efficiency and error robustness, since different prediction modes typically result in different levels of coding efficiency and robustness. Many research have been done about the optimal mode selection BIB003 BIB004 22] . www.ijacsa.thesai.org Optimal mode selection based on rate distortion (R-D) aim to minimize the quantization distortion between the original block and reconstructed block according to bit budget BIB002 BIB001 . The R-D optimized mode selection consider as a classical approach. The classical R-D optimized mode selection cannot achieve global optimality under the error-prone environment since it does not consider the network congestion status and the receiver behavior. To overcome this problem the end-toend approach has been proposed [22] , which consider the source behavior , path characteristic and receiver behavior.