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Circuits and Systems for Video Technology, IEEE Transactions on

Issue 6 • Date June 2002

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Displaying Results 1 - 18 of 18
  • Introduction to the special issue on wireless communication

    Publication Year: 2002 , Page(s): 357 - 359
    Cited by:  Papers (3)
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    Freely Available from IEEE
  • A format-compliant configurable encryption framework for access control of video

    Publication Year: 2002 , Page(s): 545 - 557
    Cited by:  Papers (54)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    We introduce new methods of performing selective encryption and spatial/frequency shuffling of compressed digital content that maintain syntax compliance after content has been secured. The tools described have been proposed to the MPEG-4 Intellectual Property Management and Protection (IPMP) standardization group and have been adopted into the MPEG-4 IPMP Final Proposed Draft Amendment (FPDAM). We describe the application of the new methods to the protection of MPEG-4 video content in the wireless environment, and illustrate how they are used to leverage established encryption algorithms for the protection of only the information fields in the bitstream that are critical to the reconstructed video quality, while maintaining compliance to the syntax of MPEG-4 video, and thereby reduces the amount of data to be encrypted and guarantees the inheritance of many of the good properties of the unprotected bitstreams that have been carefully studied and built, such as error resiliency and network friendliness. The encrypted content bitstream works with many existing random access, network bandwidth adaptation, and error control techniques that have been developed for standard-compliant compressed video, thus making it especially suitable for wireless multimedia applications. Standard compliance also allows subsequent signal processing techniques to be applied to the encrypted bitstream View full abstract»

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  • Wireless video transport using conditional retransmission and low-delay interleaving

    Publication Year: 2002 , Page(s): 558 - 565
    Cited by:  Papers (22)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (333 KB) |  | HTML iconHTML  

    We consider the scenario of using Automatic Repeat reQuest (ARQ) retransmission for two-way low-bit-rate video communications over wireless Rayleigh fading channels. Low-delay constraint may require that a corrupted retransmitted packet not be retransmitted again, and thus there will be packet errors at the decoder which results in video quality degradation. We propose a scheme to improve the video quality. First, we propose a low-delay interleaving scheme that uses the video encoder buffer as a part of interleaving memory. Second, we propose a conditional retransmission strategy that reduces the number of retransmissions. Simulation results show that our proposed scheme can effectively reduce the number of packet errors and improve the channel utilization. As a result, we reduce the number of skipped frames and obtain a peak signal-to-noise ratio improvement up to about 4 dB compared to H.263 TMN-8 View full abstract»

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  • Matching pursuits multiple description coding for wireless video

    Publication Year: 2002 , Page(s): 566 - 575
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    Multiple description coding (MDC) is an error-resilient source coding scheme that creates multiple bitstreams of approximately equal importance. The reconstructed signal based on any single bitstream has an acceptable quality. However, a higher quality reconstruction can be achieved with a larger number of bitstreams. We develop a multiple description video coding scheme based on a three-loop structure. We modify the discrete cosine transform structure to the matching pursuits framework and evaluate performance gain using maximum-likelihood (ML) enhancement when both descriptions are available. We find that ML enhancement works best for low motion sequences and results in gains of up to 1.3 dB in terms of average PSNR. Rate distortion performance is characterized. Performance comparison is made between our MDC scheme and single description coding (SDC) schemes over lossy channels, including two state Markov channels and Rayleigh fading channels. We find that MDC outperforms SDC in bursty slowly varying environments. In the case of Rayleigh fading channels, interleaving helps SDC close the gap and even outperform MDC depending on the amount of interleaving performed, at the expense of additional delay View full abstract»

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  • Stochastic rate-control of video coders for wireless channels

    Publication Year: 2002 , Page(s): 496 - 510
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    We introduce a new approach to deal with the transmission of real-time video over wireless channels, based on a priori stochastic models for both source and channel. This new problem formulation captures in a natural way the stochastic nature of the channel as well as the uncertainty regarding the properties of the video sequence. Our formulation leads to an optimal control problem that can be solved off-line, employing standard stochastic dynamic programming techniques. The outcome of this optimization is an off-line control policy that is optimal in the sense of minimizing the average coding distortion. The on-line computational cost of the new approach is thus very low: all that is required during run-time is to identify the state of the system (source and channel). Unlike other optimization-based rate control techniques, which require a search for the optimal operating point, the operating points here for each allowable state of the system have been precalculated. We consider wireless packet-based transmission with Automatic Repeat reQuest (ARQ) error control. While a standard model has been adopted to characterize the channel behavior, a new model based on the concept of coding complexity has been devised in order to characterize the video source. Simulation results based on this new approach are provided and compared to other proposed rate-control strategies. They show how the use of model-based optimal policies has negligible on-line computational cost while providing a transmission quality comparable to that achieved with more costly deterministic dynamic programming techniques, and significantly better than for simpler algorithms that do not explicitly take into account the channel state View full abstract»

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  • Joint source channel rate-distortion analysis for adaptive mode selection and rate control in wireless video coding

    Publication Year: 2002 , Page(s): 511 - 523
    Cited by:  Papers (140)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    We first develop a rate-distortion (R-D) model for DCT-based video coding incorporating the macroblock (MB) intra refreshing rate. For any given bit rate and intra refreshing rate, this model is capable of estimating the corresponding coding distortion even before a video frame is coded. We then present a theoretical analysis of the picture distortion caused by channel errors and the subsequent inter-frame propagation. Based on this analysis, we develop a statistical model to estimate such channel errors induced distortion for different channel conditions and encoder settings. The proposed analytic model mathematically describes the complex behavior of channel errors in a video coding and transmission system. Unlike other experimental approaches for distortion estimation reported in the literature, this analytic model has very low computational complexity and implementation cost, which are highly desirable in wireless video applications. Simulation results show that this model is able to accurately estimate the channel errors induced distortion with a minimum delay in processing. Based on the proposed source coding R-D model and the analytic channel-distortion estimation, we derive an analytic solution for adaptive intra mode selection and joint source-channel rate control under time-varying wireless channel conditions. Extensive experimental results demonstrate that this scheme significantly improves the end-to-end video quality in wireless video coding and transmission View full abstract»

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  • A robust fine granularity scalability using trellis-based predictive leak

    Publication Year: 2002 , Page(s): 372 - 385
    Cited by:  Papers (27)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (486 KB) |  | HTML iconHTML  

    Recently, the MPEG-4 committee has approved the MPEG-4 fine granularity scalability (FGS) profile as a streaming video tool. We propose novel techniques to improve further the temporal prediction at the enhancement layer so that coding efficiency is superior to the existing FGS. Our approach utilizes two parameters, the number of bitplanes, β (0⩽β⩽maximal number of bitplanes), and the amount of predictive leak, α (0⩽α⩽1), to control the construction of the reference frame at the enhancement layer. Parameters α and β can be selected for each frame to provide tradeoffs between coding efficiency and error drift. Our approach offers a general and flexible framework that allows further optimization. It also includes several well-known motion-compensated FGS techniques as special cases with particular sets of α and β. We analyze the theoretical advantages when α and β are used, and provide an adaptive technique to select α and β, which yields an improved performance as compared to that of fixed parameters. An identical technique is applied to the base layer for further improvement. Our experimental results show over 4 dB improvements in coding efficiency using the MPEG-4 testing conditions. Removal of error propagation is demonstrated with several typical channel transmission scenarios View full abstract»

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  • Joint error control and power allocation for video transmission over CDMA networks with multiuser detection

    Publication Year: 2002 , Page(s): 425 - 437
    Cited by:  Papers (27)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    Error control and power allocation for transmitting wireless video over CDMA networks are considered in conjunction with multiuser detection. We map a layered video bitstream to several CDMA fading channels and inject multiple source/parity layers into each of these channels at the transmitter. At the receiver, we employ a linear minimum mean-square error (MMSE) multiuser detector in the uplink and two types of blind linear MMSE detectors, i.e., the direct-matrix-inversion blind detector and the subspace blind detector, in the downlink, for demodulating the received data. For given constraints on the available bandwidth and transmit power, the transmitter determines the optimal power allocation among different CDMA fading channels and the optimal number of source and parity packets to send that offer the best video quality. We formulate a combined optimization problem and give the optimal joint rate and power allocation for each of these three receivers. Simulation results show a performance gain of up to 3.5 dB with joint optimization over with rate optimization only View full abstract»

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  • Multicast and unicast real-time video streaming over wireless LANs

    Publication Year: 2002 , Page(s): 524 - 534
    Cited by:  Papers (95)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB)  

    We address the problem of real-time video streaming over wireless LANs for both unicast and multicast transmission. The wireless channel is modeled as a packet-erasure channel at the IP level. For the unicast scenario, we describe a novel hybrid Automatic Repeat reQuest (ARQ) algorithm that efficiently combines forward error control (FEC) coding with the ARQ protocol. For the multiple-users scenario, we formulate the problem of real-time video multicast as an optimization of a maximum regret cost function across the multicast user space. The proposed solution efficiently combines progressive source coding with FEC coding. We present a theoretical analysis of the unicast and multicast cases, as well as experimental results that demonstrate the performance advantages of the proposed algorithms over existing methods View full abstract»

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  • Error-resilient video coding using multiple description motion compensation

    Publication Year: 2002 , Page(s): 438 - 452
    Cited by:  Papers (59)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (430 KB) |  | HTML iconHTML  

    A new approach for multiple description video coding is proposed. It employs a second-order predictor for motion-compensation, which predicts a current frame from two previously coded frames. The coder generates two descriptions, containing the coded even and odd frames, respectively. When only a single description (say, that containing even frames) is received, the decoder can only use previous even frames for prediction. The mismatch between the predicted frames at the encoder and decoder is explicitly coded to avoid error propagation in the ideal MD channels, where a description is either received intact or lost completely. By using the second-order predictor and coding the mismatch signal, one can also suppress error propagation in packet lossy networks where packets in either description can be lost. The predictor and the mismatch signal quantizer can be varied to achieve a wide range of tradeoffs between coding efficiency and error resilience View full abstract»

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  • Power-minimized bit allocation for video communication over wireless channels

    Publication Year: 2002 , Page(s): 398 - 410
    Cited by:  Papers (48)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    Video communication over wireless links using handheld devices is a challenging task due to the time-varying characteristics of the wireless channels and limited battery resources. Rate-distortion (RD) analysis plays a key role in video coding and communication systems, and usually the RD relation does not assume any power constraint. We investigate the relations of rate, distortion and power consumption. Based on those relations, we propose a power-minimized bit-allocation scheme considering the processing power, for source coding and channel coding, jointly with the transmission power. The total bits are allocated between source and channel coders, according to wireless channel conditions and video quality requirements, to minimize the total power consumption for a single user and a group of users in a cell, respectively. Simulation results show that our proposed joint power-control and bit-allocation scheme achieves high power savings compared to the conventional scheme View full abstract»

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  • Adaptive motion-compensation fine-granular-scalability (AMC-FGS) for wireless video

    Publication Year: 2002 , Page(s): 360 - 371
    Cited by:  Papers (31)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (429 KB)  

    Transmission of video over wireless and mobile networks requires a scalable solution that is capable of adapting to the varying channel conditions in real-time (bit-rate scalability). Furthermore, video content needs to be coded in a scalable fashion to match the capabilities of a variety of devices (complexity scalability). These two scalability properties provide the flexibility that is necessary to satisfy the "anywhere, anytime and anyone" network paradigm of wireless systems. MPEG-4 fine-granular-scalability (FGS) is a flexible low-complexity solution for video streaming over heterogeneous networks (e.g., the Internet and wireless networks) and is highly resilient to packet losses. However, the flexibility and packet-loss resilience come at the expense of decreased coding efficiency compared with nonscalable coding. A novel scalable video-coding framework and corresponding compression methods for wireless video streaming is introduced. Building on the FGS approach, the proposed framework, which we refer to as adaptive motion-compensation FGS (AMC-FGS), provides improved video quality of up to 2 dB. Furthermore, the new scalability structures provide the FGS framework with the flexibility to provide tradeoffs between resilience, higher coding efficiency and terminal complexity for more efficient wireless transmission View full abstract»

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  • Joint source coding and transmission power management for energy efficient wireless video communications

    Publication Year: 2002 , Page(s): 411 - 424
    Cited by:  Papers (58)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (371 KB) |  | HTML iconHTML  

    We consider a situation where a video sequence is to be compressed and transmitted over a wireless channel. Our goal is to limit the amount of distortion in the received video sequence, while minimizing transmission energy. To accomplish this goal, we consider error resilience and concealment techniques at the source coding level, and transmission power management at the physical layer. We jointly consider these approaches in a novel framework. In this setting, we formulate and solve an optimization problem that corresponds to minimizing the energy required to transmit video under distortion and delay constraints. Experimental results show that simultaneously adjusting the source coding and transmission power is more energy efficient than considering these factors separately View full abstract»

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  • Model-based error concealment for wireless video

    Publication Year: 2002 , Page(s): 483 - 495
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (419 KB)  

    We introduce model-based schemes for error concealment of networked video. We build appearance models for specific objects in the scene and use these models to replenish any lost information. Due to the models being designed specifically for the object, they are able to capture the statistical variations in the object appearance more effectively, thereby leading to better error-concealment performance. We examine statistical modeling techniques from the literature and introduce a new efficient and accurate linear model for data representation, called the mixture of principal components (MPC), and use these models for error concealment. We simulate lossy network conditions and show that these model-based concealment schemes outperform traditional concealment schemes across a variety of loss probabilities and bit rates for the coded video View full abstract»

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  • Error-resilient video transcoding for robust internetwork communications using GPRS

    Publication Year: 2002 , Page(s): 453 - 464
    Cited by:  Papers (23)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    A novel fully comprehensive mobile video communications system is proposed. The system exploits the useful rate management features of video transcoders and combines them with error resilience for the transmission of coded video streams over general packet radio service (GPRS) mobile-access networks. The error-resilient video transcoding operation takes place at a centralized point, referred to as a video proxy, which provides the necessary output transmission rates with the required amount of robustness. With the use of this proposed algorithm, error resilience can be added to an already compressed video stream at an intermediate stage at the edge of two or more different networks through two resilience schemes, namely the adaptive intra refresh (AIR) and feedback control signaling (FCS) methods. Both resilience tools impose an output rate increase which can also be prevented with the proposed novel technique. Thus, the presented scheme gives robust video outputs at near target transmission rates that only require the same number of GPRS timeslots as non-resilient schemes. Moreover, an ultimate robustness is also accomplished with the combination of the two resilience algorithms at the video proxy. Extensive computer simulations demonstrate the effectiveness of the proposed system View full abstract»

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  • Optimal nonlinear sampling for video streaming at low bit rates

    Publication Year: 2002 , Page(s): 535 - 544
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (430 KB)  

    Over low-bit-rate channels, we adopt the streaming of nonlinearly sampled video frames (i.e., key-frame slideshow) synchronized with the audio stream. Given the channel and buffer limits, we wish to obtain a set of sampled frames that is not only feasible (i.e., streamable), but also optimal in terms of maximal information flow (given that the semantic information contents of each frame can be quantified either automatically or manually). Different application scenarios are considered and modeled in a principle way, for which we propose computationally efficient algorithms for finding the global optimal solution. The contributions of this paper include the novel modeling schemes for channel and buffer limits in the video temporal sampling problem, the analysis and development of the corresponding efficient algorithms for finding the global optimal solution, and the extension and analysis of these algorithms for practical application scenarios. The proposed algorithms have made possible the automated production of the new form of video streaming over low bit rate channels for devices with limited storage capabilities View full abstract»

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  • Feedback and error protection strategies for wireless progressive video transmission

    Publication Year: 2002 , Page(s): 465 - 482
    Cited by:  Papers (20)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB) |  | HTML iconHTML  

    Simple but meaningful models for a mobile radio channel are introduced and a channel-coding system based on high-memory rate-compatible punctured convolutional codes with an appropriate sequential decoding algorithm, the far-end error decoder (FEED), are presented. In combination with puncturing, we devise a method for unequal error protection (UEP) and error localization within a progressively coded source message without any additional error detection code. The FEED-based channel-coding system does not aim to minimize the bit or word error probability, but to delay the first error within a data frame as far as possible. This channel-coding scheme and the FEED algorithm can be used efficiently with automatic repeat request (ARQ). We present different ARQ strategies. For all forward error-correction (FEC) schemes, bounds are specified which allow the estimation of the performance and appropriate rate allocation. We briefly discuss an efficient fine granular scalable video compression scheme, the progressive texture video codec (PTVC). The proposed scheme generates an embedded bit-stream for each frame and allows reference frames to be adjusted. These source and channel-coding algorithms are used to design several video communication systems based on FEC and ARQ methods. The resulting systems are presented and compared. Performance estimations based on bounding techniques and optimized rate-allocation algorithms are derived and applied. Experimental results show the improvement potential of the proposed systems compared to standard schemes. Video communication over very low bit-rate mobile channels with varying channel conditions is thus made possible View full abstract»

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  • Three-dimensional subband coding techniques for wireless video communications

    Publication Year: 2002 , Page(s): 386 - 397
    Cited by:  Papers (4)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (439 KB)  

    We present a new 3D subband coding framework that achieves a good balance between high compression performance and channel error resilience. Various data transform methods for video decorrelation were examined and compared. The coding stage of the algorithm is based on a generalized adaptive quantization framework which is applied to the 3D transformed coefficients. It features a simple coding structure based on quadtree coding and lattice vector quantization. In typical applications, good performance at high compression ratios is obtained, often without entropy coding. Because temporal decorrelation is absorbed by the transform, traditional motion compensated prediction becomes unnecessary, resulting in a significant computational advantage over standard video coders. Error-resilience is achieved through classifying the compressed data streams into separated sub-streams with different error sensitivity levels. This enables a good adaptation to different channel models according to their noise statistics and error-protection protocols. Experimental results have shown that the subband video coder is able to achieve highly competitive performance relative to MPEG-2 in both noiseless and noisy environments. Lapped transforms are shown experimentally to outperform other transforms in the 3D subband environment. The subband coding framework provides a practical solution for video communications over wireless channels, where efficiency, error resilience and computational simplicity are vital in providing superior quality of service View full abstract»

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Aims & Scope

The emphasis is focused on, but not limited to:
1. Video A/D and D/ A
2. Video Compression Techniques and Signal Processing
3. Multi-Dimensional Filters and Transforms
4. High Speed Real-Tune Circuits
5. Multi-Processors Systems—Hardware and Software
6. VLSI Architecture and Implementation for Video Technology 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dan Schonfeld
Multimedia Communications Laboratory
ECE Dept. (M/C 154)
University of Illinois at Chicago (UIC)
Chicago, IL 60607-7053
tcsvt-eic@tcad.polito.it

Managing Editor
Jaqueline Zelkowitz
tcsvt@tcad.polito.it