384 research outputs found
Distributed video coding for wireless video sensor networks: a review of the state-of-the-art architectures
Distributed video coding (DVC) is a relatively new video coding architecture originated from two fundamental theorems namely, Slepian–Wolf and Wyner–Ziv. Recent research developments have made DVC attractive for applications in the emerging domain of wireless video sensor networks (WVSNs). This paper reviews the state-of-the-art DVC architectures with a focus on understanding their opportunities and gaps in addressing the operational requirements and application needs of WVSNs
Perceptually-Driven Video Coding with the Daala Video Codec
The Daala project is a royalty-free video codec that attempts to compete with
the best patent-encumbered codecs. Part of our strategy is to replace core
tools of traditional video codecs with alternative approaches, many of them
designed to take perceptual aspects into account, rather than optimizing for
simple metrics like PSNR. This paper documents some of our experiences with
these tools, which ones worked and which did not. We evaluate which tools are
easy to integrate into a more traditional codec design, and show results in the
context of the codec being developed by the Alliance for Open Media.Comment: 19 pages, Proceedings of SPIE Workshop on Applications of Digital
Image Processing (ADIP), 201
MASCOT : metadata for advanced scalable video coding tools : final report
The goal of the MASCOT project was to develop new video coding schemes and tools that provide both an increased coding efficiency as well as extended scalability features compared to technology that was available at the beginning of the project. Towards that goal the following tools would be used: - metadata-based coding tools; - new spatiotemporal decompositions; - new prediction schemes. Although the initial goal was to develop one single codec architecture that was able to combine all new coding tools that were foreseen when the project was formulated, it became clear that this would limit the selection of the new tools. Therefore the consortium decided to develop two codec frameworks within the project, a standard hybrid DCT-based codec and a 3D wavelet-based codec, which together are able to accommodate all tools developed during the course of the project
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Mobile Audiovisual Terminal: System Design and Subjective Testing in DECT and UMTS networks
It is anticipated that there will shortly be a requirement
for multimedia terminals that operate via mobile
communications systems. This paper presents a functional specification
for such a terminal operating at 32 kb/s in a digital
European cordless telecommunications (DECT) and universal
mobile telecommunications system (UMTS) radio network. A terminal
has been built, based on a PC with digital signal processor
(DSP) boards for audio and video coding and decoding. Speech
coding is by a phonetically driven code-excited linear prediction
(CELP) speech coder and video coding by a block-oriented hybrid
discrete cosine transform (DCT) coder. Separate channel coding
is provided for the audio and video data. The paper describes the
techniques used for audio and video coding, channel coding, and
synchronization. Methods of subjective testing in a DECT network
and in a UMTS network are also described. These consisted of
subjective tests of first impressions of the mobile audio–visual
terminal (MAVT) quality, interactive tests, and the completion
of an exit questionnaire. The test results showed that the quality
of the audio was sufficiently good for comprehension and the
video was sufficiently good for following and repeating simple
mechanical tasks. However, the quality of the MAVT was not
good enough for general use where high-quality audio and video
was needed, especially when transmission was in a noisy radio
environment
JND-Based Perceptual Video Coding for 4:4:4 Screen Content Data in HEVC
The JCT-VC standardized Screen Content Coding (SCC) extension in the HEVC HM
RExt + SCM reference codec offers an impressive coding efficiency performance
when compared with HM RExt alone; however, it is not significantly perceptually
optimized. For instance, it does not include advanced HVS-based perceptual
coding methods, such as JND-based spatiotemporal masking schemes. In this
paper, we propose a novel JND-based perceptual video coding technique for HM
RExt + SCM. The proposed method is designed to further improve the compression
performance of HM RExt + SCM when applied to YCbCr 4:4:4 SC video data. In the
proposed technique, luminance masking and chrominance masking are exploited to
perceptually adjust the Quantization Step Size (QStep) at the Coding Block (CB)
level. Compared with HM RExt 16.10 + SCM 8.0, the proposed method considerably
reduces bitrates (Kbps), with a maximum reduction of 48.3%. In addition to
this, the subjective evaluations reveal that SC-PAQ achieves visually lossless
coding at very low bitrates.Comment: Preprint: 2018 IEEE International Conference on Acoustics, Speech and
Signal Processing (ICASSP 2018
Data compression techniques applied to high resolution high frame rate video technology
An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended
Contributions in image and video coding
Orientador: Max Henrique Machado CostaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia ElĂ©trica e de ComputaçãoResumo: A comunidade de codificação de imagens e vĂdeo vem tambĂ©m trabalhando em inovações que vĂŁo alĂ©m das tradicionais tĂ©cnicas de codificação de imagens e vĂdeo. Este trabalho Ă© um conjunto de contribuições a vários tĂłpicos que tĂŞm recebido crescente interesse de pesquisadores na comunidade, nominalmente, codificação escalável, codificação de baixa complexidade para dispositivos mĂłveis, codificação de vĂdeo de mĂşltiplas vistas e codificação adaptativa em tempo real. A primeira contribuição estuda o desempenho de trĂŞs transformadas 3-D rápidas por blocos em um codificador de vĂdeo de baixa complexidade. O codificador recebeu o nome de Fast Embedded Video Codec (FEVC). Novos mĂ©todos de implementação e ordens de varredura sĂŁo propostos para as transformadas. Os coeficiente 3-D sĂŁo codificados por planos de bits pelos codificadores de entropia, produzindo um fluxo de bits (bitstream) de saĂda totalmente embutida. Todas as implementações sĂŁo feitas usando arquitetura com aritmĂ©tica inteira de 16 bits. Somente adições e deslocamentos de bits sĂŁo necessários, o que reduz a complexidade computacional. Mesmo com essas restrições, um bom desempenho em termos de taxa de bits versus distorção pĂ´de ser obtido e os tempos de codificação sĂŁo significativamente menores (em torno de 160 vezes) quando comparados ao padrĂŁo H.264/AVC. A segunda contribuição Ă© a otimização de uma recente abordagem proposta para codificação de vĂdeo de mĂşltiplas vistas em aplicações de video-conferĂŞncia e outras aplicações do tipo "unicast" similares. O cenário alvo nessa abordagem Ă© fornecer vĂdeo com percepção real em 3-D e ponto de vista livre a boas taxas de compressĂŁo. Para atingir tal objetivo, pesos sĂŁo atribuĂdos a cada vista e mapeados em parâmetros de quantização. Neste trabalho, o mapeamento ad-hoc anteriormente proposto entre pesos e parâmetros de quantização Ă© mostrado ser quase-Ăłtimo para uma fonte Gaussiana e um mapeamento Ăłtimo Ă© derivado para fonte tĂpicas de vĂdeo. A terceira contribuição explora várias estratĂ©gias para varredura adaptativa dos coeficientes da transformada no padrĂŁo JPEG XR. A ordem de varredura original, global e adaptativa do JPEG XR Ă© comparada com os mĂ©todos de varredura localizados e hĂbridos propostos neste trabalho. Essas novas ordens nĂŁo requerem mudanças nem nos outros estágios de codificação e decodificação, nem na definição da bitstream A quarta e Ăşltima contribuição propõe uma transformada por blocos dependente do sinal. As transformadas hierárquicas usualmente exploram a informação residual entre os nĂveis no estágio da codificação de entropia, mas nĂŁo no estágio da transformada. A transformada proposta neste trabalho Ă© uma tĂ©cnica de compactação de energia que tambĂ©m explora as similaridades estruturais entre os nĂveis de resolução. A idĂ©ia central da tĂ©cnica Ă© incluir na transformada hierárquica um nĂşmero de funções de base adaptativas derivadas da resolução menor do sinal. Um codificador de imagens completo foi desenvolvido para medir o desempenho da nova transformada e os resultados obtidos sĂŁo discutidos neste trabalhoAbstract: The image and video coding community has often been working on new advances that go beyond traditional image and video architectures. This work is a set of contributions to various topics that have received increasing attention from researchers in the community, namely, scalable coding, low-complexity coding for portable devices, multiview video coding and run-time adaptive coding. The first contribution studies the performance of three fast block-based 3-D transforms in a low complexity video codec. The codec has received the name Fast Embedded Video Codec (FEVC). New implementation methods and scanning orders are proposed for the transforms. The 3-D coefficients are encoded bit-plane by bit-plane by entropy coders, producing a fully embedded output bitstream. All implementation is performed using 16-bit integer arithmetic. Only additions and bit shifts are necessary, thus lowering computational complexity. Even with these constraints, reasonable rate versus distortion performance can be achieved and the encoding time is significantly smaller (around 160 times) when compared to the H.264/AVC standard. The second contribution is the optimization of a recent approach proposed for multiview video coding in videoconferencing applications or other similar unicast-like applications. The target scenario in this approach is providing realistic 3-D video with free viewpoint video at good compression rates. To achieve such an objective, weights are computed for each view and mapped into quantization parameters. In this work, the previously proposed ad-hoc mapping between weights and quantization parameters is shown to be quasi-optimum for a Gaussian source and an optimum mapping is derived for a typical video source. The third contribution exploits several strategies for adaptive scanning of transform coefficients in the JPEG XR standard. The original global adaptive scanning order applied in JPEG XR is compared with the localized and hybrid scanning methods proposed in this work. These new orders do not require changes in either the other coding and decoding stages or in the bitstream definition. The fourth and last contribution proposes an hierarchical signal dependent block-based transform. Hierarchical transforms usually exploit the residual cross-level information at the entropy coding step, but not at the transform step. The transform proposed in this work is an energy compaction technique that can also exploit these cross-resolution-level structural similarities. The core idea of the technique is to include in the hierarchical transform a number of adaptive basis functions derived from the lower resolution of the signal. A full image codec is developed in order to measure the performance of the new transform and the obtained results are discussed in this workDoutoradoTelecomunicações e TelemáticaDoutor em Engenharia ElĂ©tric
Motion compensation for image compression: pel-recursive motion estimation algorithm
In motion pictures there is a certain amount of redundancy between consecutive frames. These redundancies can be exploited by using interframe prediction techniques. To further enhance the efficiency of interframe prediction, motion estimation and compensation, various motion compensation techniques can be used. There are two distinct techniques for motion estimation block matching and pel-recursive block matching has been widely used as it produces a better signal-to-noise ratio or a lower bit rate for transmission than the pel-recursive method. In this thesis, various pel-recursive motion estimation techniques such as steepest descent gradient algorithm have been considered and simulated. [Continues.
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