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The hidden Markov model (HMM) is widely used to model processes in several real world applications, including speech processing and recognition, image understanding and sensor networks. A problem of concern is that of quantization of the sequence of observations generated by an HMM, which is referred as a hidden Markov source (HMS). Despite the importance of the problem, and the well-defined structure...
In many transform audio codecs, the data set to encode consists of groups of transformed coefficients located in frequency bins. In this paper, we propose to use certain Autoregressive Moving-Average (ARMA) modelling techniques to encode the transformed coefficients by taking into account their perceptual significance. The novelty lies in the fact that the modelling is performed with the transformed...
With the increase of video resolutions used in multimedia applications, solutions for improved compression are sought. The next generation video compression standard, High Efficiency Video Coding (HEVC) is being developed by ITU-T and ISO/IEC MPEG with the goal to provide significant improvements over H.264/AVC. To further increase compression capabilities of HEVC, this paper proposes an additional...
In this standard, a set of tools for efficient video coding is defined, including directional intra prediction, variable block size inter prediction and context adaptive binary arithmetic coding, and the corresponding decoding procedure. The target applications and services include but not limited TV over Internet, user-generated multimedia content, IP-based video conference, IP-based surveillance,...
Digitally encoded signals are robust and less prone to noise contamination over the transmission channel. This work looks for a comparative study of the two popular companding methods used most often for reducing bandwidth requirement. In this paper these two companding methods are observed intensively with complete encoding and regeneration procedure. For a random speech signal the methods have been...
Computer graphics applications especially the applications which produce complex color images produce very large file sizes. Data with very large size creates several problems such as requirement of very large storage space, the need to quickly transmit image data across networks, etc. Hence, image compression has become an active area of research in the field of image processing to reduce file size...
Holography is deemed the ultimate 3D [1]. Holographic displays provide full eye accommodation, thus not causing eye strain or headaches which are an inconvenient side-effect of 3D stereo [2][3]. As the etymological meaning of Holography suggests, digital holograms store full 3D information of the recorded object (including multiple views). For that reason, storage and transmission of digital holographic...
AC-3 audio compression find applications in home cinema, DVD, BD and digital television. This paper addresses the challenge of transparently watermarking AC-3 bit streams instead of the conventional decoding — baseband watermarking — re-encoding approach. We discuss the alternate possibilities to embed watermarks by altering the MDCT coefficients delivered in the bit stream, which consists of mantissas...
For a vector Markov source driven by additive Gaussian noise, we study the existence and structure of optimal quantization policies. The quantizers allowed are the ones which have convex codecells. For the finite horizon problem and bounded cost, we show that an optimal zero-delay quantization policy exists. Then the linear quadratic Gaussian problem is considered as an important extension of the...
This paper proposes an efficient intra-mode coding method using the deviation of neighbor pixels. In HEVC, the number of intra-prediction modes is increased in order to improve coding performance for intra-prediction as compared to H.264/AVC. However, this causes coding inefficiency in intra-mode coding. To improve coding efficiency, we propose a new intra-mode coding method that applies the analysis...
An efficient coding algorithm for depth map images and videos, based on view synthesis distortion estimation, is proposed in this work. We first analyze how a depth error is related to a disparity error and how the disparity vector error affects the energy spectral density of a synthesized color video in the frequency domain. Based on the analysis, we propose an estimation technique to predict the...
In Wyner-Ziv video coding architectures, the available bit budget to each GOP is shared between key frames and Wyner-Ziv frames. In this work, we first propose a model to express the relationship between quantization step size of key and WZ frames based on their motion activity. Then we apply this model to propose an adaptive algorithm adjusting the quantization step size of key and WZ frames to achieve...
High Efficiency Video Coding (HEVC) is the next-generation video coding standard currently under development, which has demonstrated substantial bit savings (rate reduction by approximately half) compared to H.264/AVC. This paper presents the multiple sign bits hiding scheme that was adopted into the committee draft of HEVC at the 8th JCT-VC meeting. In HEVC, the quantized transform coefficients are...
The present paper provides transform bases with improved normality and orthogonality properties based on the integer DCT of high-efficiency video coding (HEVC). The proposed transform bases improve the normality and orthogonality properties compared to the HEVC transform bases. Coding and re-encoding experiments were conducted using HEVC test model (HM) version 6.0 and the proposed method. The experiments...
Since advanced 3D video systems employ depth information to support free-viewpoint navigation and comfortable 3D video viewing, efficient depth map coding is necessary for future 3D video systems. Most residual data in depth map coding are generated along abrupt depth discontinuities, represented by near-zero and high-magnitude values. In this paper, we model the residual data with two representative...
Distributed Video Coding (DVC) is an emerging coding scheme that employs principles of source coding with side information (SI) at the decoder. In this paper, we present a new DVC encoder, named LORD (LOw-complexity, Rate-controlled, Distributed video coding system). No feedback channel is used in our encoder, and an adaptive noise model that varies both spatially and temporally is employed. The SI...
A frame level adaptive rate control scheme for the emerging High Efficiency Video Coding (HEVC) standard is proposed in this paper, where both rate model and distortion model are provided. For rate modeling, a new rate model is proposed based on the weighted complexity estimation of the previously encoded frames. For distortion modeling, the distortion is modeled as an exponential function of the...
With the rapid development of depth data acquisition technology, the high precision depth becomes much easier to access in real-time by depth sensors, and the generated high dynamic range (HDR) depth is widely adopted to benefit the depth assistant applications. Accordingly, the HDR depth compression becomes essential for the efficient depth storage and transmission. In this paper, we introduce a...
This paper proposes an extended median cut quantization method with special median values, which does not have a restriction that the number of signals after quantization is a power of 2. The proposed quantization performs fast and the quantization error of it becomes smaller than that of the linear quantization for images with sparse histogram. When the number of the quantization levels is large,...
We present a framework for cross layer optimized real time transmission of H.264/AVC single layer video signals over wireless channels. In the proposed cross layer adaptation, the channel is characterized by the probability density function of its mutual information and the performance of the H.264/AVC encoder is modeled by a rate distortion model that takes into account the channel errors. This framework...
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