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Tong Gan - One of the best experts on this subject based on the ideXlab platform.
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Reducing video-quality fluctuations for streaming scalable video using unequal error protection, retransmission, and interleaving
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, 2006Co-Authors: Tong Gan, Lu GanAbstract:Forward error correction based multiple description (MD-FEC) transcoding for transmitting Embedded Bitstream over the packet erasure networks has been extensively studied in the past. In the existing work, a single Embedded source Bitstream, e.g., the Bitstream of a group of pictures (GOP) encoded using three-dimensional set partitioning in hierarchical trees is optimally protected unequal error protection (UEP) in the rate-distortion sense. However, most of the previous work on transmitting Embedded video using MD-FEC assumed that one GOP is transmitted only once, and did not consider the chance of retransmission. This may lead to noticeable video quality variations due to varying channel conditions. In this paper, a novel window-based packetization scheme is proposed, which combats bursty packet loss by combining the following three techniques: UEP, retransmission, and GOP-level interleaving. In particular, two retransmission mechanisms, namely segment-wise retransmission and byte-wise retransmission, are proposed based on different types of receiver feedback. Moreover, two levels of rate allocations are introduced: intra-GOP rate allocation minimizes the distortion of individual GOP; while inter-GOP rate allocation intends to reduce video quality fluctuations by adaptively allocating bandwidth according to video signal characteristics and client buffer status. In this way, more consistent video quality can be achieved under various packet loss probabilities, as demonstrated by our experimental results.
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Weighted unequal error protection for transmitting scalable object-oriented images over packet-erasure networks
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, 2005Co-Authors: Tong GanAbstract:We investigate the problem of transmitting Embedded encoded object-oriented images over the packet-erasure networks. After giving a review of the existing combined unequal error protection (CUEP) and individual unequal error protection (IUEP) schemes, a novel weighted unequal error protection (WUEP) packetization scheme is proposed, which serves as an alternative to the existing methods. In our proposed framework, the Embedded Bitstreams of all concerned image objects are packetized into multiple description packet streams before transmission. Two levels of rate allocation are introduced: intraobject rate allocation provides unequal error protection to the Embedded Bitstream of each object and minimizes its associated mean distortion; interobject rate allocation aims at minimizing the weighted mean distortion by adaptively allocating the rate budget among different objects according to their importance. Furthermore, our proposed packetization scheme ensures independent access and manipulation of individual image object. A detailed comparison between CUEP, IUEP, and WUEP is presented along with the experimental results, so that one can choose the most suitable approach according to the requirements.
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ICASSP (5) - Sliding-window packetization for forward error correction based multiple description transcoding
2003 IEEE International Conference on Acoustics Speech and Signal Processing 2003. Proceedings. (ICASSP '03)., 1Co-Authors: Tong GanAbstract:Forward error correction based multiple description (MD-FEC) transcoding, which performs unequal loss protection (ULP) for an Embedded Bitstream, allows robust video transmission over packet erasure channels. However, most of the existing works focus on rate-distortion optimization of individual encoding unit, e.g., a group of pictures (GOP), and do not examine the problem of rate allocation among different units. Such a transcoding strategy would lead to noticeable video quality variations when the video signal is highly nonstationary, and/or when large transmission rate fluctuations occur. In this paper, a novel window-based packetization scheme is proposed for reducing such quality variation through GOP interleaving. Performance evaluations are conducted by using a 3D-SPIHT Embedded video encoder.
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ICIP (3) - Sliding-window packetization for unequal loss protection based multiple description coding
Proceedings 2003 International Conference on Image Processing (Cat. No.03CH37429), 1Co-Authors: Tong GanAbstract:Unequal loss protection (ULP) for transmitting Embedded Bitstream over packet erasure networks has been extensively studied. However, most of the existing works focused on rate-distortion optimization of individual encoding unit, e.g., a group of pictures (GOP), which may lead to noticeable video quality variations due to varying channel conditions. In this paper, a novel sliding-window packetization scheme is proposed, which combat bursty packet loss through GOP interleaving. Two levels of rate allocation are introduced: intra-GOP rate allocation minimizes the distortion of individual GOP, and provides hybrid FEC/retransmission packet loss recovery; while inter-GOP rate allocation intends to reduce video quality fluctuations by adaptively allocating bandwidth according to video signal characteristics. Through this way, more consistent video quality can be achieved under various packet loss probability, as verified by our experimental results.
Zixiang Xiong - One of the best experts on this subject based on the ideXlab platform.
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Wavelet Image Compression
The Essential Guide to Image Processing, 2009Co-Authors: Zixiang Xiong, Kannan RamchandranAbstract:Publisher Summary This chapter provides the simple high-level insights, based on the intuitive concept of time frequency representations, into why wavelets are good for image coding. As a way of highlighting the benefits of having a sparse representation, such as that provided by the wavelet decomposition, consider the lowest frequency band in the top level of the three-level wavelet hierarchy. This band is just a down sampled and smoothed version of the original image. A very simple way of achieving compression is to simply retain this lowpass version and throw away the rest of the wavelet data, instantly achieving a compression ratio of 64:1. Another attractive aspect of the coarse-to-fine nature of the wavelet representation naturally facilitates a transmission scheme that progressively refines the received image quality. That is, it would be highly beneficial to have an encoded Bitstream that can be chopped off at any desired point to provide a commensurate reconstruction image quality. This is known as a progressive transmission feature or as an Embedded Bitstream. This is ideally suited, for example, to Internet image applications. These are some of the high-level reasons why wavelets represent a superior alternative to traditional Fourier-based methods for compressing natural images: that is why the Joint Photographic Experts Group 2000 standard uses wavelets instead of the Fourier-based discrete cosine transform.
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Fast algorithm for distortion-based error protection of Embedded image codes
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, 2005Co-Authors: Raouf Hamzaoui, Vladimir Stankovic, Zixiang XiongAbstract:We consider a joint source-channel coding system that protects an Embedded Bitstream using a finite family of channel codes with error detection and error correction capability. The performance of this system may be measured by the expected distortion or by the expected number of correctly decoded source bits. Whereas a rate-based optimal solution can be found in linear time, the computation of a distortion-based optimal solution is prohibitive. Under the assumption of the convexity of the operational distortion-rate function of the source coder, we give a lower bound on the expected distortion of a distortion-based optimal solution that depends only on a rate-based optimal solution. Then, we propose a local search (LS) algorithm that starts from a rate-based optimal solution and converges in linear time to a local minimum of the expected distortion. Experimental results for a binary symmetric channel show that our LS algorithm is near optimal, whereas its complexity is much lower than that of the previous best solution.
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product code error protection of packetized multimedia Bitstreams
International Conference on Image Processing, 2003Co-Authors: Vladimir Stankovic, Raouf Hamzaoui, Zixiang XiongAbstract:Sherwood and Zeger (1997) proposed a source-channel coding system where the source code is an Embedded Bitstream and the channel code is a product code such that each row code is a concatenation of a cyclic redundancy check (CRC) and rate-compatible punctured convolutional codes (RCPC) and the column codes are Reed-Solomon (RS) codes. We improve this system for wireless applications by efficiently reorganizing the source code into a set of independently decodable packets, which makes it more robust in varying channels. We also give a linear-time algorithm for finding an optimal equal error protection for the resulting system. Experimental results show that the performance of our system significantly outperforms that of the current state-of-the-art in fading channels with varying statistics.
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Rate-based versus distortion-based optimal error protection of Embedded codes
2003Co-Authors: Raouf Hamzaoui, Vladimir Stankovic, Zixiang XiongAbstract:We consider a joint source-channel coding system that protects an Embedded Bitstream using a finite family of channel codes with error detection and error correction capability. The performance of this system may be measured by the expected distortion or by the expected number of correctly decoded source bits. Whereas a rate-based optimal solution can be found in linear time, the computation of a distortion-based optimal solution is prohibitive. Under the assumption of the convexity of the operational distortion-rate function of the source coder, we give a lower bound on the expected distortion of a distortion-based optimal solution that depends only on a rate-based optimal solution. Then, we conjecture that a distortion-based optimal solution uses the same number or fewer information bits than a rate-based optimal solution. Finally, we propose a local search algorithm that starts from a rate-based optimal solution and converges in linear time to a local minimum of the expected distortion. Experimental results for a binary symmetric channel show that our local search algorithm is near optimal, whereas its complexity is much lower than that of the previous best solution.
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high performance 3 d Embedded wavelet video ewv coding
Multimedia Signal Processing, 2001Co-Authors: Zixiang Xiong, Xiaolin WuAbstract:This paper presents a rate-distortion (R-D) optimized 3-D Embedded wavelet video (EWV) coder by extending the concept of EBCOT from 2-D to 3-D. After a lifting based 3-D wavelet transform, different subbands are coded independently using bit plane coding with different context models to provide flexible scalability in both spatial and temporal domain. A global R-D optimization procedure is used to generate an Embedded Bitstream for a target bit rate. Experiments show that, even without motion estimation, the EWV coder outperforms both MPEG-4 and 3-D ESCOT for most low motion video sequences.
Vladimir Stankovic - One of the best experts on this subject based on the ideXlab platform.
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View-Popularity-Driven Joint Source and Channel Coding of View and Rate Scalable Multi-View Video
IEEE Journal of Selected Topics in Signal Processing, 2015Co-Authors: Jacob Chakareski, Vladan Velisavljevic, Vladimir StankovicAbstract:We study the scenario of multicasting multi-view video content, recorded in the video plus depth format, to a collection of heterogeneous clients featuring Internet access links of diverse packet loss and transmission bandwidth values. We design a popularity-aware joint source-channel coding optimization framework that allocates source and channel coding rates to the captured content, such that the aggregate video quality of the reconstructed content across the client population is maximized, for the given packet loss and bandwidth characteristics of the clients and their view selection preferences. The source coding component of our framework features a procedure for generating a view and rate Embedded Bitstream that is optimally decodable at multiple data rates and accounts for the different popularity of diverse video perspectives of the scene of interest, among the clients. The channel coding component of our framework comprises an expanding-window rateless coding procedure that optimally allocates parity protection bits to the source encoded layers, in order to address packet loss across the unreliable client access links. We develop an optimization method that jointly computes the source and channel coding decisions of our framework, and also design a fast local-search-based solution that exhibits a negligible performance loss relative to the full optimization. We carry out comprehensive simulation experiments and demonstrate significant performance gains over competitive state-of-the-art methods (based on H.264/AVC and network coding, and H.264/SVC and our own channel coding procedure), across different scenario settings and parameter values.
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User-Action-Driven View and Rate Scalable Multiview Video Coding
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, 2013Co-Authors: Jacob Chakareski, Vladan Velisavljevic, Vladimir StankovicAbstract:We derive an optimization framework for joint view and rate scalable coding of multi-view video content represented in the texture plus depth format. The optimization enables the sender to select the subset of coded views and their encoding rates such that the aggregate distortion over a continuum of synthesized views is minimized. We construct the view and rate Embedded Bitstream such that it delivers optimal performance simultaneously over a discrete set of transmission rates. In conjunction, we develop a user interaction model that characterizes the view selection actions of the client as a Markov chain over a discrete state-space. We exploit the model within the context of our optimization to compute user-action-driven coding strategies that aim at enhancing the client's performance in terms of latency and video quality. Our optimization outperforms the state-of-the-art H.264 SVC codec as well as a multi-view wavelet-based coder equipped with a uniform rate allocation strategy, across all scenarios studied in our experiments. Equally important, we can achieve an arbitrarily fine granularity of encoding bit rates, while providing a novel functionality of view Embedded encoding, unlike the other encoding methods that we examined. Finally, we observe that the interactivity-aware coding delivers superior performance over conventional allocation techniques that do not anticipate the client's view selection actions in their operation.
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Fast algorithm for distortion-based error protection of Embedded image codes
IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, 2005Co-Authors: Raouf Hamzaoui, Vladimir Stankovic, Zixiang XiongAbstract:We consider a joint source-channel coding system that protects an Embedded Bitstream using a finite family of channel codes with error detection and error correction capability. The performance of this system may be measured by the expected distortion or by the expected number of correctly decoded source bits. Whereas a rate-based optimal solution can be found in linear time, the computation of a distortion-based optimal solution is prohibitive. Under the assumption of the convexity of the operational distortion-rate function of the source coder, we give a lower bound on the expected distortion of a distortion-based optimal solution that depends only on a rate-based optimal solution. Then, we propose a local search (LS) algorithm that starts from a rate-based optimal solution and converges in linear time to a local minimum of the expected distortion. Experimental results for a binary symmetric channel show that our LS algorithm is near optimal, whereas its complexity is much lower than that of the previous best solution.
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product code error protection of packetized multimedia Bitstreams
International Conference on Image Processing, 2003Co-Authors: Vladimir Stankovic, Raouf Hamzaoui, Zixiang XiongAbstract:Sherwood and Zeger (1997) proposed a source-channel coding system where the source code is an Embedded Bitstream and the channel code is a product code such that each row code is a concatenation of a cyclic redundancy check (CRC) and rate-compatible punctured convolutional codes (RCPC) and the column codes are Reed-Solomon (RS) codes. We improve this system for wireless applications by efficiently reorganizing the source code into a set of independently decodable packets, which makes it more robust in varying channels. We also give a linear-time algorithm for finding an optimal equal error protection for the resulting system. Experimental results show that the performance of our system significantly outperforms that of the current state-of-the-art in fading channels with varying statistics.
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Rate-based versus distortion-based optimal error protection of Embedded codes
2003Co-Authors: Raouf Hamzaoui, Vladimir Stankovic, Zixiang XiongAbstract:We consider a joint source-channel coding system that protects an Embedded Bitstream using a finite family of channel codes with error detection and error correction capability. The performance of this system may be measured by the expected distortion or by the expected number of correctly decoded source bits. Whereas a rate-based optimal solution can be found in linear time, the computation of a distortion-based optimal solution is prohibitive. Under the assumption of the convexity of the operational distortion-rate function of the source coder, we give a lower bound on the expected distortion of a distortion-based optimal solution that depends only on a rate-based optimal solution. Then, we conjecture that a distortion-based optimal solution uses the same number or fewer information bits than a rate-based optimal solution. Finally, we propose a local search algorithm that starts from a rate-based optimal solution and converges in linear time to a local minimum of the expected distortion. Experimental results for a binary symmetric channel show that our local search algorithm is near optimal, whereas its complexity is much lower than that of the previous best solution.
Sanjit K. Mitra - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Generalized variable dimensional set partitioning for Embedded wavelet image compression
1999 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999Co-Authors: Debargha Mukherjee, Sanjit K. MitraAbstract:A vector enhancement of Said and Pearlman's (1996) set partitioning in hierarchical trees (SPIHT) methodology, named VSPIHT, has recently been proposed for Embedded wavelet image compression. While the VSPIHT algorithm works better than scalar SPIHT for most images, a common vector dimension to use for coding an entire image may not be optimal. Since statistics vary widely within an image, a greater efficiency can be achieved if different vector dimensions are used for coding the wavelet coefficients from different portions of the image. We present a generalized methodology for developing a variable dimensional set partitioning coder, where different parts of an image may be coded in different vectoring modes, with different scale factors, and up to different number of passes. A Lagrangian rate-distortion criterion is used to make the optimum coding choices. Coding passes are made jointly for the vectoring modes to produce an Embedded Bitstream.
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ICIP (1) - Vector set-partitioning with successive refinement Voronoi lattice VQ for Embedded wavelet image coding
Proceedings 1998 International Conference on Image Processing. ICIP98 (Cat. No.98CB36269), 1Co-Authors: Debargha Mukherjee, Sanjit K. MitraAbstract:While lattice vector quantization (LVQ) can solve the complexity problem of LBG based vector quantizers, and also yield very general codebooks, a single stage lattice VQ, when applied to high variance vectors result in very large and unwieldy indices, making it unsuitable for applications requiring successive refinement. The goal of this work is to develop a unified framework for progressive uniform quantization of vectors, without having to sacrifice the mean-squared-error advantage of lattice quantization. A successive refinement uniform vector quantization paradigm is developed, where the codebooks in successive stages are all lattice codebooks, each in the shape of the Voronoi region of the lattice at the previous stage. The Voronoi shaped lattice codebook at each stage is called Voronoi lattice VQ (VLVQ). Measures of efficiency of successive refinement are developed. The developed methodology is applied to successively refine vectors of wavelet coefficients in the vector set-partitioning (VSPIHT) framework to obtain an Embedded Bitstream. The results are compared against the previous successive approximation wavelet vector quantization (SA-W-VQ) results of Sampson, da Silva, and Ghanbari (see IEEE Trans. Image Processing, vol.5, no.2, p.299-310, 1996) for image coding.
Debargha Mukherjee - One of the best experts on this subject based on the ideXlab platform.
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ICASSP - Generalized variable dimensional set partitioning for Embedded wavelet image compression
1999 IEEE International Conference on Acoustics Speech and Signal Processing. Proceedings. ICASSP99 (Cat. No.99CH36258), 1999Co-Authors: Debargha Mukherjee, Sanjit K. MitraAbstract:A vector enhancement of Said and Pearlman's (1996) set partitioning in hierarchical trees (SPIHT) methodology, named VSPIHT, has recently been proposed for Embedded wavelet image compression. While the VSPIHT algorithm works better than scalar SPIHT for most images, a common vector dimension to use for coding an entire image may not be optimal. Since statistics vary widely within an image, a greater efficiency can be achieved if different vector dimensions are used for coding the wavelet coefficients from different portions of the image. We present a generalized methodology for developing a variable dimensional set partitioning coder, where different parts of an image may be coded in different vectoring modes, with different scale factors, and up to different number of passes. A Lagrangian rate-distortion criterion is used to make the optimum coding choices. Coding passes are made jointly for the vectoring modes to produce an Embedded Bitstream.
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Vector set partitioning with classified successive refinement VQ for Embedded wavelet image coding
ISCAS '98. Proceedings of the 1998 IEEE International Symposium on Circuits and Systems (Cat. No.98CH36187), 1Co-Authors: Debargha Mukherjee, S.k. MitraAbstract:Set Partitioning in Hierarchical Trees (SPIHT), proposed by Said and Pearlman [1996], is generally regarded as a very efficient wavelet-based still image compression scheme. The algorithm uses an efficient, joint scanning and bit-allocation mechanism for quantizing the scalar wavelet coefficients, and produces a perfectly Embedded Bitstream. This work extends set partitioning to scan vectors of wavelet coefficients, and uses successive refinement VQ techniques such as multistage and tree-structured VQ, to quantize several wavelet coefficients at once. The new scheme is named VSPIHT (Vector SPIHT). Coding results are presented to demonstrate that the vector-based approach (without arithmetic coding) surpasses the scalar counterpart (also without arithmetic coding), in the mean-squared-error sense, for most images at low bitrates. The superiority of the vector-based approach is more pronounced for images that are generally regarded as difficult to code (such as Barbara) because of a large amount of detail.
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ICIP (1) - Vector set-partitioning with successive refinement Voronoi lattice VQ for Embedded wavelet image coding
Proceedings 1998 International Conference on Image Processing. ICIP98 (Cat. No.98CB36269), 1Co-Authors: Debargha Mukherjee, Sanjit K. MitraAbstract:While lattice vector quantization (LVQ) can solve the complexity problem of LBG based vector quantizers, and also yield very general codebooks, a single stage lattice VQ, when applied to high variance vectors result in very large and unwieldy indices, making it unsuitable for applications requiring successive refinement. The goal of this work is to develop a unified framework for progressive uniform quantization of vectors, without having to sacrifice the mean-squared-error advantage of lattice quantization. A successive refinement uniform vector quantization paradigm is developed, where the codebooks in successive stages are all lattice codebooks, each in the shape of the Voronoi region of the lattice at the previous stage. The Voronoi shaped lattice codebook at each stage is called Voronoi lattice VQ (VLVQ). Measures of efficiency of successive refinement are developed. The developed methodology is applied to successively refine vectors of wavelet coefficients in the vector set-partitioning (VSPIHT) framework to obtain an Embedded Bitstream. The results are compared against the previous successive approximation wavelet vector quantization (SA-W-VQ) results of Sampson, da Silva, and Ghanbari (see IEEE Trans. Image Processing, vol.5, no.2, p.299-310, 1996) for image coding.