In the current Video-based Dynamic Mesh coding (V-DMC) standard, inter-frame coding is restricted to mesh frames with constant topology. Consequently, temporal redundancy is not fully leveraged, resulting in suboptima...
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ISBN:
(纸本)9798331529543;9798331529550
In the current Video-based Dynamic Mesh coding (V-DMC) standard, inter-frame coding is restricted to mesh frames with constant topology. Consequently, temporal redundancy is not fully leveraged, resulting in suboptimal compression efficacy. To address this limitation, this paper introduces a novel coarse-to-fine scheme to generate anchor meshes for frames with time-varying topology. Initially, we generate a coarse anchor mesh using an octree-based nearest neighbor search. Motion estimation compensates for regions with significant motion changes during this process. However, the quality of the coarse mesh is low due to its suboptimal vertices. To enhance details, the fine anchor mesh is further optimized using the Quadric Error Metrics (QEM) algorithm to calculate more precise anchor points. The inter-frame anchor mesh generated herein retains the connectivity of the reference base mesh, while concurrently preserving superior quality. Experimental results show that our method achieves 7.2% similar to 10.3% BD-rate gain compared to the existing V-DMC test model version 7.
The inter-frame coding of dynamic meshes with time varying topology is still under development in the current Video-based Dynamic Mesh coding (V-DMC) standard. To address this issue and improve the coding efficiency, ...
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ISBN:
(纸本)9781728198354
The inter-frame coding of dynamic meshes with time varying topology is still under development in the current Video-based Dynamic Mesh coding (V-DMC) standard. To address this issue and improve the coding efficiency, we propose a temporally-consistent re-meshing method. In particular, we introduce a robust inter-surface mapping framework to re-mesh the input meshes so that they have one-to-one vertex and face correspondence. Then, we simultaneously decimate the re-meshed input meshes to generate temporally-consistent base meshes, which is a key requirement for applying inter-frame coding in V-DMC. The evaluations on Moving Picture Experts Group (MPEG) test sequences demonstrate that our method can achieve rate-distortion performance superior to that of V-DMC.
High Efficiency Video coding (HEVC) has doubled the video compression ratio with equivalent subjective quality as compared to its predecessor H.264/AVC. The significant coding efficiency improvement is attributed to m...
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High Efficiency Video coding (HEVC) has doubled the video compression ratio with equivalent subjective quality as compared to its predecessor H.264/AVC. The significant coding efficiency improvement is attributed to many new techniques. inter-frame coding is one of the most powerful yet complicated techniques therein and has posed high computational burden thus main obstacle in HEVC-based real-time applications. Recently, plenty of research has been done to optimize the inter-frame coding, either to reduce the complexity for real-time applications, or to further enhance the encoding efficiency. In this paper, we provide a comprehensive review of the state-of-the-art techniques for HEVC inter-frame coding from three aspects, namely fast intercoding solutions, implementation on different hardware platforms as well as advanced intercoding techniques. More specifically, different algorithms in each aspect are further subdivided into sub-categories and compared in terms of pros, cons, coding efficiency and coding complexity. To the best of our knowledge, this is the first such comprehensive review of the recent advances of the inter-frame coding for HEVC and hopefully it would help the improvement, implementation and applications of HEVC as well as the ongoing development of the next generation video coding standard.
In this paper, we propose a simple but effective intra-mode skip algorithm to reduce the computational cost for inter-frame coding. It makes use of motion, temporal, and spatial homogeneity characteristics of video se...
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In this paper, we propose a simple but effective intra-mode skip algorithm to reduce the computational cost for inter-frame coding. It makes use of motion, temporal, and spatial homogeneity characteristics of video sequences. Specifically, the motion homogeneity is defined by using the mean deviation of motion vectors (MV) of the 4x4 blocks. The temporal and spatial homogeneity are computed by the sum of absolute difference (SAD) between an original block and its prediction block of the best inter-mode and the intra-mode with large block size, respectively. Based on the three types of homogeneity, the proposed method skip the full intra-mode search for inter-frame coding to reduce the encoding time when a region has the motion homogeneity and temporal homogeneity is stronger than the spatial one. Experimental results demonstrate that the proposed algorithm significantly increases the skip decision accuracy by up to 20% and reduces the total encoding time by about 3 similar to 10% as compared to the existing methods with negligible loss in PSNR and small increment of bit rate.(1)
Scalable video coding is an ongoing standard, and the current working draft (VM) is an extension of H.264/AVC. In the WD, an exhaustive search technique is employed to select the best coding mode for each macroblock. ...
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Scalable video coding is an ongoing standard, and the current working draft (VM) is an extension of H.264/AVC. In the WD, an exhaustive search technique is employed to select the best coding mode for each macroblock. This technique achieves the highest possible coding efficiency, but it results in extremely large encoding time which obstructs it from practical use. This paper proposes a fast mode decision algorithm for inter-frame coding for spatial, coarse grain signal-to-noise ratio, and temporal scalability. It makes use of the mode-distribution correlation between the base layer and enhancement layers. Specifically, after the exhaustive search technique is performed at the base layer, the candidate modes for enhancement layers can be reduced to a small number based on the correlation. Experimental results show that the fast mode decision scheme reduces the computational complexity significantly with negligible coding loss and bit-rate increases.
In the hybrid video codingframework, quantization is the key technique to achieve lossy compression. The information loss caused by the quantization may be reduced to improve compression efficiency, by using either e...
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In the hybrid video codingframework, quantization is the key technique to achieve lossy compression. The information loss caused by the quantization may be reduced to improve compression efficiency, by using either encoder-side rate-distortion optimized quantization or decoder-side filtering. Nonetheless, the existing studies did not extensively use the already encoded information, i.e., context, to reduce the quantization loss. We address this issue and propose a context-adaptive inverse quantization method, namely, CAIQ. Specifically, for inter-frame coding, we analyze the correlation between the prediction signal (generated by motion compensated prediction) and the residual signal, as well as the correlation within the residual signal itself. We then present linear as well as nonlinear yet lightweight models to exploit the observed correlations in the frequency domain. Our models provide an optional inverse quantization mode by referring to the prediction signal, which is available at the decoder side. Next, block-level mode selection regarding the CAIQ method is used at the encoder side. We integrate the proposed CAIQ method into the reference software of Versatile Video coding. We perform an extensive study of the models and analyze their resulting compression efficiency gain and encoding/decoding complexity. Experimental results show that our CAIQ method improves compression performance especially for high-resolution videos and at high bit rates.
Image-to-image translation tasks which have been widely investigated with generative adversarial networks (GAN) aim to map an image from the source domain to the target domain. The translated image can be inversely ma...
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ISBN:
(纸本)9781728185514
Image-to-image translation tasks which have been widely investigated with generative adversarial networks (GAN) aim to map an image from the source domain to the target domain. The translated image can be inversely mapped to the reconstructed source image. However, existing GAN-based schemes lack the ability to accomplish reversible translation. To remedy this drawback, a nearly reversible image-to-image translation scheme where the reconstructed source image is approximately distortion-free compared with the corresponding source image is proposed in this paper. The proposed scheme jointly considers inter-frame coding and embedding. Firstly, we organize the GAN-generated reconstructed source image and the source image into a pseudo video. Furthermore, the bitstream obtained by inter-frame coding is reversibly embedded in the translated image for nearly lossless source image reconstruction. Extensive experimental results and analysis demonstrate that the proposed scheme can achieve a high level of performance in image quality and security.
The Video-based Dynamic Mesh coding (V-DMC) standard exploits the temporal correlation by tracing the motions of the vertices, which applies only to tracked frames with one-to-one vertex correspondence. For non-tracke...
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ISBN:
(纸本)9798350344868;9798350344851
The Video-based Dynamic Mesh coding (V-DMC) standard exploits the temporal correlation by tracing the motions of the vertices, which applies only to tracked frames with one-to-one vertex correspondence. For non-tracked frames, only intra mode is applied. This paper proposes an embedded graph representation method that can efficiently represent inter-frame differences for both tracked and non-tracked frames. First, we construct an embedded graph by simplifying the given mesh. Then, we compute a set of affine transformations on graph nodes and use their linear combinations to represent the inter-frame difference. Finally, we apply our implementation to increase the number of predicted frames (P-frames) and thus improve the resulting coding performance. Evaluations on Moving Picture Experts Group (MPEG) test sequences demonstrate the significant rate distortion improvements achieved by our method over V-DMC. The proposed method is highly compliant with V-DMC, and a part of it has been adopted into the V-DMC reference software during the MPEG-3DGH 144th meeting.
A template matching estimation reliant on gathering of reconstructed pixels that surrounding a block target that helps in estimation of pixels in the target block without considering the motion data. The target block ...
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ISBN:
(纸本)9781538623619
A template matching estimation reliant on gathering of reconstructed pixels that surrounding a block target that helps in estimation of pixels in the target block without considering the motion data. The target block estimator is obtained by reducing the template matching fault. Because of the freedom, the template had possessed, the target blocks residual may have larger values in flat regions. The method uses spatial and temporal correlations to predict the encoding pixels. This prediction is obtained by the mechanism based on template matching, with previously reconstructed pixels as reference and are used to fill the target region pixels.
The Moving Picture Experts Group (MPEG) has published the geometry-based point cloud compression (G-PCC) standard. It converts the compression of irregular point coordinates to the coding of structured binary octree n...
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The Moving Picture Experts Group (MPEG) has published the geometry-based point cloud compression (G-PCC) standard. It converts the compression of irregular point coordinates to the coding of structured binary octree node occupancy, where the Context-based Adaptive Binary Arithmetic coding (CABAC) can be applied. The context model, constructed by intra and inter-octree layer information, drives the probability update of the arithmetic coder with a so-called Optimal Binarization with Update On-the-Fly (OBUF) scheme. The original OBUF design, while effective, lacks a probability range limitation for each binary coder, leading to issues in probability estimation accuracy and convergence speed. Moreover, when coding dynamic point clouds, the inter-frame information is not efficiently considered in OBUF, leading to excessive memory consumption for storing and tracking context states. To address these challenges, we propose an initialization strategy for both fine-grained context states (Fine-CtxS) and coarse-grained context states (Coarse-CtxS) in OBUF, alongside an adaptive probability bound determination method for each Coarse-CtxS to confine probability estimation. Furthermore, the paper delves into improvements for inter-frame geometry coding, including the construction of Fine-CtxS, and reducing memory consumption of Fine-CtxS in OBUF. The proposed methods have been adopted in recent G-PCC Edition 2 standardization activities, demonstrating enhanced performance.
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