Advances in Perceptual Stereo Audio Coding Using Linear Prediction Techniques

A wide range of techniques for coding a single-channel speech and audio signal has been developed over the last few decades. In addition to pure redundancy reduction, sophisticated source and receiver models have been considered for reducing the bit-rate. Traditionally, speech and audio coders are based on different principles and thus each of them offers certain advantages. With the advent of high capacity channels, networks, and storage systems, the bit-rate versus quality compromise will no longer be the major issue; instead, attributes like low-delay, scalability, computational complexity, and error concealments in packet-oriented networks are expected to be the major selling factors. Typical audio coders such as MP3 and AAC are based on subband or transform coding techniques that are not easily reconcilable with a low-delay requirement. The reasons for their inherently longer delay are the relatively long band splitting filters ...

Biswas, Arijit — Technische Universiteit Eindhoven


Mixed structural models for 3D audio in virtual environments

In the world of Information and communications technology (ICT), strategies for innovation and development are increasingly focusing on applications that require spatial representation and real-time interaction with and within 3D-media environments. One of the major challenges that such applications have to address is user-centricity, reflecting e.g. on developing complexity-hiding services so that people can personalize their own delivery of services. In these terms, multimodal interfaces represent a key factor for enabling an inclusive use of new technologies by everyone. In order to achieve this, multimodal realistic models that describe our environment are needed, and in particular models that accurately describe the acoustics of the environment and communication through the auditory modality are required. Examples of currently active research directions and application areas include 3DTV and future internet, 3D visual-sound scene coding, transmission and reconstruction and teleconferencing systems, to name but ...

Geronazzo, Michele — University of Padova


Lossless and nearly lossless digital video coding

In lossless coding, compresssion and decompression of source data result in the exact recovery of the individual elements of the original source data. Lossless image / video coding is necessary in applications where no loss of pixel values is tolerable. Examples are medical imaging, remote sensing, in image/video archives and studio applications where tandem- and trans-coding are used in editing, which can lead to accumulating errors. Nearly-lossless coding is used in applications where a small error, defined as a maximum error or as a root mean square (rms) error, is tolerable. In lossless embedded coding, a losslessly coded bit stream can be decoded at any bit rate lower than the lossless bit rate. In this thesis, research on embedded lossless video coding based on a motion compensated framework, similar to that of MPEG-2, is presented. Transforms that map integers into ...

Abhayaratne, Charith — University of Bath


Sparse Pulsed Auditory Representations For Speech and Audio Coding

Auditory modeling is a well-established methodology that provides insight into human perception and that facilitates the extraction of signal features most relevant to the human listener for coding applications. This thesis deals with the approach of `coding in the perceptual domain' and is based on an invertible auditory model that provides a pulsed auditory representation of the input speech or audio signal. It is natural for pulsed signal representations to encode only the non-zero samples by specifying their positions as side information. For the considered auditory representation, the number of pulses and, therefore, the amount of side information is too high for an efficient encoding at a relatively low bit rate. The focus of this work is to `sparsify' the pulsed signal representation, i.e., to remove its perceptual irrelevance and its redundancy, to obtain a compact signal representation, which facilitates ...

Christian Feldbauer — Graz University of Technology


Stereoscopic depth map estimation and coding techniques for multiview video systems

The dissertation deals with the problems of stereoscopic depth estimation and coding in multiview video systems, which are vital for development of the next generation three-dimensional television. The depth estimation algorithms known from literature, along with theoretical foundations are discussed. The problem of estimation of depth maps with high quality, expressed by means of accuracy, precision and temporal consistency, has been stated. Next, original solutions have been proposed. Author has proposed a novel, theoretically founded approach to depth estimation which employs Maximum A posteriori Probability (MAP) rule for modeling of the cost function used in optimization algorithms. The proposal has been presented along with a method for estimation of parameters of such model. In order to attain that, an analysis of the noise existing in multiview video and a study of inter-view correlation of corresponding samples of pictures have been ...

Stankiewicz, Olgierd — Poznan University of Technology


Contributions to Improved Hard- and Soft-Decision Decoding in Speech and Audio Codecs

Source coding is an essential part in digital communications. In error-prone transmission conditions, even with the help of channel coding, which normally introduces delay, bit errors may still occur. Single bit errors can result in significant distortions. Therefore, a robust source decoder is desired for adverse transmission conditions. Compared to the traditional hard-decision (HD) decoding and error concealment, soft-decision (SD) decoding offers a higher robustness by exploiting the source residual redundancy and utilizing the bit-wise channel reliability information. Moreover, the quantization codebook index can be either mapped to a fixed number of bits using fixed-length (FL) codes, or a variable number of bits employing variable-length (VL) codes. The codebook entry can be either fixed over time or time-variant. However, using a fixed scalar quantization codebook leads to the same performance for correlated and uncorrelated processes. This thesis aims to improve ...

Han, Sai — Technische Universität Braunschweig


Novel Methods in H.264/AVC (Inter Prediction, Data Hiding, Bit Rate Transcoding)

H.264 Advanced Video Coding has become the dominant video coding standard in the market, within a few years after the first version of the standard was completed by the ISO/IEC MPEG and the ITU-T VCEG groups in May 2003. That happened mainly due to the great coding efficiency of H.264. Compared to MPEG-2, the previous dominant standard, the H.264 compression ratio is about twice as higher for the same video quality. That makes H.264 ideal for a numerous of applications, such as video broadcasting, video streaming and video conferencing. However, the H.264 efficiency is achieved at the expense of the codec¢s complexity. H.264 complexity is about four times that of MPEG-2. As a consequence, many video coding issues, which have been addressed in previous standards, need to be re-considered. For example the H.264 encoding of a video in real time ...

Kapotas, Spyridon — Hellenic Open University


Distributed Video Coding for Wireless Lightweight Multimedia Applications

In the modern wireless age, lightweight multimedia technology stimulates attractive commercial applications on a grand scale as well as highly specialized niche markets. In this regard, the design of efficient video compression systems meeting such key requirements as very low encoding complexity, transmission error robustness and scalability, is no straightforward task. The answer can be found in fundamental information theoretic results, according to which efficient compression can be achieved by leveraging knowledge of the source statistics at the decoder only, giving rise to distributed, or alias Wyner-Ziv, video coding. This dissertation engineers efficient lightweight Wyner-Ziv video coding schemes emphasizing on several design aspects and applications. The first contribution of this dissertation focuses on the design of effective side information generation techniques so as to boost the compression capabilities of Wyner-Ziv video coding systems. To this end, overlapped block motion estimation ...

Deligiannis, Nikos — Vrije Universiteit Brussel


TRACKER-AWARE DETECTION: A THEORETICAL AND AN EXPERIMENTAL STUDY

A promising line of research attempts to bridge the gap between detector and tracker by means of considering jointly optimal parameter settings for both of these subsystems. Along this fruitful path, this thesis study focuses on the problem of detection threshold optimization in a tracker-aware manner so that a feedback from the tracker to the detector is established to maximize the overall system performance. Special emphasis is given to the optimization schemes based on two non-simulation performance prediction (NSPP) methodologies for the probabilistic data association filter (PDAF), namely, the modified Riccati equation (MRE) and the hybrid conditional averaging (HYCA) algorithm. The possible improvements are presented in two domains: Non-maneuvering and maneuvering target tracking. In the first domain, a number of algorithmic and experimental evaluation gaps are identified and newly proposed methods are compared with the existing ones in a unified ...

Aslan, Murat Samil — Middle East Technical University


Study on Subband Adaptive Array for Space-Time Codes in Wideband Channel

Recently, many works have been accomplished on transmit diversity for a high-speed data transmission through the wireless channel. A Multiple Input Multiple Output (MIMO) system which employs multiple antennas at transmitter and receiver has been shown to be able to improve transmission data rate and capacity of the system. When the channel state information (CSI) is unknown at the transmitter, an multiple input single output (MISO) system combined with the transmit diversity of space time coding modulation known as space-time block coding (STBC) has taken a great attention. However, the performance of STBC is deteriorated under frequency selective fading due to inter symbol interference (ISI). An STBC employing tapped delay line adaptive array (STBC-TDLAA) is known as a solution for this problem since it utilizes the delayed signals to enhance the desired signal instead of excluding them as interferences. However, ...

Ramli, Nordin Bin — University of Electro-Communications, Japan


Low-Complexity Iterative Detection Algorithms for Multi-Antenna Systems

Multiple input multiple output (MIMO) techniques have been widely employed by dif- ferent wireless systems with many advantages. By using multiple antennas, the system is able to transmit multiple data streams simultaneously and within the same frequency band. The methods known as spatial multiplexing (SM) and spatial diversity (SD) im- proves the high spectral efficiency and link reliability of wireless communication systems without requiring additional transmitting power. By introducing channel coding in the transmission procedure, the information redundancy is introduced to further improve the reliability of SM links and the quality of service for the next generation communication systems. However, the throughput performance of these systems is limited by interference. A number of different interference suppression techniques have been reported in the literature. Theses techniques can be generally categorised into two aspects: the preprocessing techniques at the transmitter side and ...

Peng Li — University of York


Advanced Transceiver Design for Continuous Phase Modulation

This dissertation proposes advanced transceiver designs applying turbo and space-time (ST) concepts to continuous phase modulation (CPM), which is preferred in numerous power- and band-limited communication systems for its constant envelope and spectral efficiency. Despite its highly attractive spectral properties, maximum-likelihood detection of CPM over the frequency-selective multipath fading channels can bring impractical complexity issues because of the intensive search over a single super trellis which combines the effects of the modulation and the multipath channel. Application of the reduced-state trellis search algorithms results in lower complexity but the computational load could still be prohibitively large to obtain high performance in long channel impulse responses. In the dissertation, instead of employing trellis-based combined detection methods, equalization and demodulation functions are separated and novel low-complexity receivers with soft-input soft-output (SISO) time-domain and frequency-domain linear equalizers are proposed for bit-interleaved coded CPM, ...

Ozgul, Baris — Bogazici University


Dynamic Scheme Selection in Image Coding

This thesis deals with the coding of images with multiple coding schemes and their dynamic selection. In our society of information highways, electronic communication is taking everyday a bigger place in our lives. The number of transmitted images is also increasing everyday. Therefore, research on image compression is still an active area. However, the current trend is to add several functionalities to the compression scheme such as progressiveness for more comfortable browsing of web-sites or databases. Classical image coding schemes have a rigid structure. They usually process an image as a whole and treat the pixels as a simple signal with no particular characteristics. Second generation schemes use the concept of objects in an image, and introduce a model of the human visual system in the design of the coding scheme. Dynamic coding schemes, as their name tells us, make ...

Fleury, Pascal — Swiss Federal Institute of Technology


Multiple Objective Optimization for Video Streaming

In this thesis, we propose Multiple Objective Optimization (MOO) frameworks for efficient video streaming. Firstly, we introduce pre-roll delay-distortion optimization (DDO) for uninterrupted content-adaptive video streaming over low capacity, constant bitrate (CBR) channels using MOO. Content analysis is used to divide the input video into shots with assigned relevance levels. The video is adaptively encoded and streamed aiming minimum pre-roll delay and distortion with the optimal spatial and temporal resolutions and quantization parameters for each shot. With buffer and distortion constraints, the bitrate of unimportant shots is reduced to achieve an acceptable quality in important shots. Secondly, we introduce a cross-layer optimized video rate adaptation and scheduling scheme to achieve maximum "application layer" Quality-of-Service (QoS), maximum video throughput (video seconds per transmission slot), and QoS fairness for wireless video streaming. Using the MOO framework, these objectives are jointly optimized such ...

Ozcelebi, Tanir — Koc University


Reduced-Complexity Code Synchronization in Multipath Channels for BOC Modulated CDMA Signals with Applications in Galileo and Modernized GPS Systems

Applications for the new generations of Global Navigation Satellite Systems (GNSS) are developing rapidly and attract a great interest. Both US Global Positioning System (GPS) and European Galileo signals use Direct Sequence-Code Division Multiple Access (DS-CDMA) technology, where code and frequency synchronization are important stages at the receiver. The GNSS receivers estimate jointly the code phase and the Doppler spread through a two-dimensional searching process in time-frequency plane. Since both GPS and Galileo systems will send several signals on the same carriers, a new modulation type - the Binary Offset Carrier (BOC) modulation, has been selected. The main target of this modulation is to provide a better spectral separation with the existing BPSK-modulated GPS signals, while allowing optimal usage of the available bandwidth for different GNSS signals. The BOC modulation family includes several BOC variants, such as sine BOC (SinBOC), ...

Burian, Adina — Universitat Trier

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