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In this work, two new design techniques for matched (adaptive) orthogonal block transforms (BT) based partly on Vector Quantization (VQ) are presented. Both techniques start from reference vectors that are adapted to the characteristics of the signal to be coded. Then the corresponding orthogonal block transform is obtained in the first technique via signed permutations of the reference vector, while...
This paper deals with the mode decision in an MPEG-2 framework. An algorithm for mode decision is introduced. This algorithm is based on a rate-distortion criterion and takes into account the temporal dependency of the frames. This approach can allow a quality gain of more than one dB compared to the Test Model 5 (TM5) mode decision algorithm.
Algorithm customizable modules in video encoder play important roles in coding performance, and their algorithms can be optimized by adjusting multiple coding control parameters under a certain rate distortion complexity constraint. There are inter-correlated relationships among these modules. This paper analyzes the inter-module influence mechanism among algorithm customizable modules, and gives...
The unequal error protection (UEP) has shown promising results for transmitting video over error-prone wireless channels. In this paper, we investigate the cross-layer design of forward error correction (FEC) schemes by using the UEP Raptor codes at the application layer (AL) and UEP rate compatible punctured convolutional (RCPC) codes at physical layer (PHY) for prioritized video packets. The video...
Rate-distortion optimization is widely used in modern video codecs to make various encoder decisions in order to optimize the trade-off between bit-rate and quality. The distortion models used in HEVC are mean squared error (MSE) and sum of absolute difference (SAD), both of which are not always reflective of perceptual quality. In this paper, we show that SSIM, which has been found to be a good indicator...
The Structural SIMilarity (SSIM) index has been attracting an increasing amount of attention recently in the video coding community as a perceptual criterion for testing and optimizing video codecs. Meanwhile, the arrival of the new MPEG-H/H.265 High Efficiency Video Coding (HEVC) standard creates new opportunities and challenges in perceptual video coding. In this paper, we first elaborate what are...
By using 60GHz spectrum in high frequency carrier, IEEE 802.11ad is widely used in the transmission of high-definition videos. In this paper, an adaptive cross-layer optimization scheme is proposed based on IEEE 802.11ad which involves modulation and coding at the physical layer, retransmission policy at the medium access control layer and source coding at the video coding layer. The scheme aims at...
We introduce the use of a dynamically reconfigurable architecture system for time-varying image constraints (DRASTIC) and consider applications in HEVC intra encoding. DRASTIC provides a framework for jointly optimizing complexity-rate-distortion for different operating modes. DRASTIC optimization involves dynamically reconfiguring parameters (e.g., the quantization parameter, encoding configuration...
As a novel branch of widely used Wi-Fi technology, IEEE 802.11n has improved its maximum data rate to 600Mbps, which makes the transmission of high-definition video possible. Although many techniques have been adopted to maximize data rate for high definition(HD) video transmission, very few researches keep an eye on video distortion in parallel with proper data rate. In this paper, we present a cross-layer...
Video compression technologies developed recently have taken advantage of a hybrid approach for better coding efficiency. For example, in the MPEG-4 Advanced Video Coding standard and also the new High Efficiency Video Coding, there are numerous possibilities of motion representation and residual coding options in transform domain. The coding parameters, including block modes, motion vectors, and...
This paper presents an adaptive weighted distortion optimization algorithm used in the Rate-Distortion Optimization (RDO) process of the High Efficiency Video Coding (HEVC). RDO is an important tool to improve the coding efficiency. Usually the distortion weights of different color components are equal or predetermined. In this paper, an adaptive weighted distortion optimization algorithm is introduced...
The improved reversible data hiding scheme which is a part of JPEG coding process is introduced. Generally, one of the common constraints imposed on digital watermarking in frequency domain is a small payload that can be embedded without causing high degradation of a JPEG stego image. Moreover, even at small hidden payload the stego image file size will increase to some extent. In no existing data...
Rateless codes allow a user to incrementally send additional redundancy, so they can be useful for heterogeneous and time-varying networks for which the choice of redundancy level in advance is difficult. Rateless codes are an attractive application layer forward error correction solution due to their flexibility and capacity-approaching performance. The original rateless codes were developed for...
We consider an application of sparse optimization in the error concealment area. State-of-the-art spatial and temporal error concealment method is improved and compared. By solving for limited numbers of significant predictors using the sparse optimization, our algorithm performs subjectively and objective better for the concealed result.
We analyze the performance of the geometric distortion, incurred when coding depth maps in 3D Video, as an estimator of the distortion of synthesized views. Our analysis is motivated by the need of reducing the computational complexity required for the computation of synthesis distortion in 3D video encoders. We propose several geometric distortion models that capture (i) the geometric distortion...
In 3D video coding, the Multi-View Video plus Depth (MVD) representation format enables the interpolation of virtual intermediate views in between the original recorded camera views, as well as the extrapolation of views outside this range using view synthesis algorithms. For this, MVD includes depth maps as additional information to be transmitted. The performance of the associated depth data coding...
Most common video coding standards employ spatiotemporal prediction techniques to increase coding efficiency. As a result, compressed video data is sensitive to the transmission error due to error propagation. An adaptive reference picture selection (RPS) is proposed to improve the error resilience in real-time video transmission. A global rate-distortion optimization (RDO) is developed to intelligently...
Rate-distortion optimization is widely used in modern video codecs to make various encoder decisions in order to optimize the rate-distortion trade-off. Typically, the distortion measure used is either sum-of-square error (SSE) or sum-of-absolute distance (SAD), both of which are convenient when used in the RDO framework but not always reflective of perceptual quality. In this paper, we show that...
A scalable multiple description scalar quantizer (SMDSQ) is a quantization based framework used for scalable multiple description coding (SMDC). In this paper, we introduce a novel generalization of the Lloyd-Max algorithm to realize locally optimal SMDSQs. Both level-constrained and entropy-constrained cases are considered. For both cases, locally optimal solutions are realized by iterative execution...
This paper presents efficient coding tools for depth data in depth-enhanced video formats. The method is based on the high-efficiency video codec (HEVC). The developed tools include new depth modeling modes (DMMs), in particular using non-rectangular wedgelet and contour block partitions. As the depth data is used for synthesis of new video views, a specific 3D video encoder optimization is used....
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