Sistema de codificão de vídeo baseado em transformadas tridimensionais, rápidas e progressivas

Testoni, Vanessa

doi:10.47749/t/unicamp.2007.397229

Cited by 1 publication

(8 citation statements)

References 17 publications

(33 reference statements)

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“…Similarly, the divisions must be performed in the decoder because the same transform is used in the inverse operation, as the Hadamard transform is real, symmetric and orthogonal. In order to avoid the square root operation, the fractional coefficients generated by these divisions and to reduce the coefficient magnitudes resulting from the three Hadamard transform calculations, a new 3-D implementation method is proposed in [2].…”

Section: Dynamic Range Gainmentioning

confidence: 99%

“…There is no other division term to be grouped with this division in order to remove the square root operation. This problem is solved in [2] by transferring to the encoder the first of the Hadamard transform calculations performed by the decoder. This can be done because the same Hadamard transform is applied by the decoder and the first decoding operation is the coefficient division by √ N .…”

Section: Dynamic Range Gainmentioning

confidence: 99%

“…In order to illustrate the conventional and the order of operations proposed in [2], the conventional coding and decoding 3-D Hadamard transforms are shown, respectively, by the left and right sides of Eq. (2.4), where PC means Pixels Cube, CC means Coefficients Cube and…”

Section: Dynamic Range Gainmentioning

confidence: 99%

“…The environment where the performance of the block-based 3-D transforms is being compared is the color video codec named FEVC (Fast Embedded Video Codec). The FEVC was firstly described at the author's MSc dissertation [2]. The codec is designed in C# language, especially to be executed in a video set-top box device.…”

Section: Introductionmentioning

confidence: 99%

“…The explanation of each video redundancy and some alternative works in the area literature that aim to reduce them are included in [2]. Sections 2.5 and 2.6 present the overall implementation results and conclude the chapter.…”

Section: Introductionmentioning

confidence: 99%

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Contribuições em codificação de imagens e vídeo

Testoni¹

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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 v 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 work.

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Section: Dynamic Range Gainmentioning

confidence: 99%

Section: Dynamic Range Gainmentioning

confidence: 99%

Section: Dynamic Range Gainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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