Granularity Scalable Video, Xiaoyan Sun, Feng Wu et al. · 2001
The Progressive Fine Granularity Scalable (PFGS) coding is a promising technique for streaming video applications. However, since the original PFGS only chooses its references as framebased, it is very difficult to achieve a good trade-off between high coding efficiency and low drifting errors. In this paper, we present a flexible and effective scheme to control the PFGS coding at the macroblock level. Three INTER modes are first proposed for the enhancement macroblock coding. One of these modes provides a novel method to effectively reduce the drifting errors at low bit rates. Then, a decision-making mechanism based on temporal prediction is developed to choose the optimal coding mode for each enhancement macroblock, which offers a significant coding efficiency improvement for the fine granularity scalable coding scheme. Moreover, the proposed control mechanism can be easily implemented without any additional computation. The experimental results show that the proposed macroblock-based PFGS coding scheme can effectively reduce the drifting errors at low bit rates, while providing further coding efficiency improvement over the FGS and the original PFGS scheme at moderate or high bit rates.
Cited by 0
EdsonM Hung, Debargha Mukherjee · 2006
In theH.264/AVCvideocodingstandard, motion compensation canbeperformed bypartitioning macroblocks intosquare orrectangular sub-macroblocks inaquadtree decomposition. Thispaperstudies amotion compensation method using wedges, i.e. partitioning macroblocks orsubmacroblocks into tworegions byanarbitrary line segment. Thistechnique allows theshapes ofthedivided regions to better matchtheboundaries betweenmovingobjects. However, there arealarge numberofwaystoslice ablock andsearching exhaustively overallofthemwouldbean extremely computer-intensive task. Thus, wepropose afast algorithm whichdetects thepredominant edgeorientations within ablock inorder topre-select candidate wedgelines. Finally acomparison amongmacroblock partition methods isperformed, whichpoints tothehigher performance ofthe wedgepartition method.
Cited by 0
On An Fpga-Augmented · 2001
This paper describes an experiment which aims to reveal the potential impact on performance yielded by augmenting a TriMedia-CPU64 processor with a multiple-context FPGA core. We first propose an extension of the TriMediaCPU64 architecture, which consists of a Reconfigurable Functional Unit and its associated instructions. Then, we address the decoding of variable-length codes on such extended TriMedia and describe the architecture and FPGAimplementation of a Variable-Length Decoder (VLD) computing facility. When mapped on an ACEX EP1K100 FPGA, the proposed VLD exhibits a latency of # cycles. Preliminary results indicate that by configuring each of the VLD and 1-D IDCT (which is described elsewhere) facilities on a different FPGA context, and by activating the contexts as needed, the augmented TriMedia can perform macroblock parsing followed up by pel reconstruction with an improvement of ## # ### over the standard TriMedia.
Cited by 0
Fan Zhang, Xudong Zhang · 2005
H.264 (MPEG4 AVC) is a new video coding standard jointly developed by ITU-T and ISO MPEG. H.264 derives most of its coding efficiency improvements from motion estimation which, on the other hand, has greatly increased the computational complexity of the CODEC, so many fast motion estimation algorithms have been proposed, such as MVFAST, HEXBS and so on. In this paper, we propose a fast mode decision method which can greatly reduce the computational complexity of subpixel motion estimation and speed up the encoder.
Cited by 3
Rui He, Qing Li, Yu Qian et al. · 2023
SummaryThe mobile video quality can be improved by video super-resolution (SR) especially when bandwidth is limited. To achieve real-time SR, the latest work, ClassSR (CVPR 19), divides frames into equal-size image blocks (IBs), and different-complexity SR models are used respectively to reduce the computational burden.
Cited by 0
Majed Alhaisoni, M. Ghanbari, Antonio Liotta · TU/e Research Portal · 2010
Abstract- Peer-to-peer (P2P) is a promising technology for video streaming, and offers advantages in terms of re-configurability and scalability. It gains advantage from and share the resources owned by the end-users who are distributed around the Internet. P2P has shown an alternative solution for the traditional Client-Server approach limitations. However, due to the churn of peers, issues of video quality arise such as packet loss. This in turn degrades the QoS, then the QoE. Moreover, in current networking conditions, congestions and bottlenecks cannot be circumvented easily due to the increase in Internet traffic. Therefore, this paper introduces a novel combination of two well known techniques known as “locality awareness ” and “Flexible Macroblock Ordering ” (FMO). Locality-awareness plays a vital role in reducing the transmission cost among the peers whilst FMO is shown to be superior to other error resilience techniques in case of packet loss. However these two approaches have not been studied in conjunction. A comparative simulation-based study has been carried out for the proposed approach against a benchmark system, i.e., without introducing any error resilience technique. The results have shown better performance of the proposed approach in terms of End-to-End delay and video quality, as measured by PSNR.
Cited by 0
Gilles Chaumat, Pasquale Gallo, G. Le Marois et al. · Journal of Nuclear Materials · 1996
Cited by 7
Feng Wu, Shipeng Li, Xiaoyan Sun et al. · 2001
A novel highly efficient macroblock-based progressive fine granularity scalable (MBPFGS) video coding scheme that can optimally balance drifting errors and coding efficiency is proposed in this paper. In order to improve coding efficiency, the existing PFGS video coding scheme uses a set of high quality references to predict the enhancement layers. However, potential drifting errors may arise since high quality references may not always be available at the decoder when channel bandwidth fluctuates. To solve this problem, we first analyze when drifting errors occur and how they will propagate. Then, an iterative model is established to estimate the drifting errors at the encoder. Meanwhile, three new INTER modes are proposed for the coding of macroblocks at the enhancement layers. One of these modes provides an effective and flexible method to reduce the drifting errors at low enhancement bit rates. Furthermore, we present a decision-making mechanism to select the proper coding mode for each macroblock at the enhancement layers. Experimental results show that the proposed techniques can dramatically reduce drifting errors at low enhancement bit rates, while significantly improving coding efficiency, up to 2.3dB in average PSNR, compared with MPEG-4 FGS at moderate or high bit rates.
Cited by 0
Jizheng Xu, Feng Wu, Shipeng Li · 2001
In this paper, we propose a transcoding scheme for progressive fine granularity scalable video coding (PFGS). Unlike transcoding schemes for non-scalable video coding aiming to change the bit-rate of the video, the transcoding scheme proposed here is to improve the coding performance of scalable video signals when bandwidth has large change. We design a simple transcoder that can perform PFGS transcoding efficiently and in a low complexity way. Experimental results show that our transcoding scheme can significantly improve the bitstream’s performance while bandwidth changes largely. 1.
Cited by 0
Yves Dhondt, Peter Lambert, Rik Van de Walle · 2006
This paper proposes an enhanced error protection scheme using flexible macroblock ordering in H.264/AVC. The algorithm uses a two-phase system. In the first phase, the importance of every macroblock is calculated based on its influence on the current frame and future frames. In the second phase, the macroblocks with the highest impact factor are grouped together in a separate slice group using the flexible macroblock ordering feature of H.264/AVC. By using an unequal error protection scheme, the slice group containing the most important macroblocks can be better protected than the other slice group. The proposed algorithm offers better concealment opportunities than the algorithms which are predefined for flexible macroblock ordering in H.264/AVC.
Cited by 32
Granularity Scalable Video, Xiaodong Fan, Guobin Shen et al. · 2002
This paper proposes a complete scheme of a ratedistortion optimal progressive fine granularity scalable (PFGS) video codec. Firstly, it introduces the use of multiple enhancement layer references and a modified mode decision algorithm based on the analysis of the unique characteristic of the residue data of the enhancement layer. Secondly, the rate-distortion optimal method to select the enhancement layers is discussed and a fast algorithm is proposed to solve the rate-distortion optimization problem by tracing the convex hull of the rate-distortion (R-D) curve. The experimental results show that the coding efficiency can be improved by 0.5dB on average in PSNR as compared to the current PFGS codec in [4].
Cited by 0
Mitchell, Nathan, Doescher, Michael, Sifakis, Eftychios · Eurographics · 2016
We introduce a new numerical approach for the solution of grid-based discretizations of nonlinear elastic models. Our method targets the linearized system of equations within each iteration of the Newton method, and combines elements of a direct factorization scheme with an iterative Conjugate Gradient method. The goal of our hybrid scheme is to inherit as many of the advantages of its constituent approaches, while curtailing several of their respective drawbacks. In particular, our algorithm converges in far fewer iterations than Conjugate Gradients, especially for systems with less-than-ideal conditioning. On the other hand, our approach largely avoids the storage footprint and memory-bound nature of direct methods, such as sparse Cholesky factorization, while offering very direct opportunities for both SIMD and thread-based parallelism. Conceptually, our method aggregates a rectangular neighborhood of grid cells (typically a 16x8x8 subgrid) into a composite element that we refer to as a ''macroblock''. Similar to conventional tetrahedral or hexahedral elements, macroblocks receive nodal inputs (e.g., displacements) and compute nodal outputs (e.g., forces). However, this input/output interface now only includes nodes on the boundary of the 16x8x8 macroblock; interior nodes are always solved exactly, by means of a direct, highly optimized solver. Models built from macroblocks are solved using Conjugate Gradients, which is accelerated due to the reduced number of degrees of freedom and improved robustness against poor conditioning thanks to the direct solver within each macroblock. We explain how we attain these benefits with just a small increase of the per-iteration cost over the simplest traditional solvers.
Cited by 0Open access
Meilin Yang, Mary L. Comer, Edward J. Delp · 2012
Multiple Description Coding (MDC) is one of the most efficient error resilient video coding methods especially when retransmissions are not acceptable. For applications in scalable, multicast and P2P environments, it is advantageous to use more than two descriptions. In this paper, we present two macroblock-level adaptive error concealment methods to improve the performance of MDC with four descriptions. A Gilbert model is used as the channel model to simulate burst packet loss. Experimental results demonstrate the efficacy of the two proposed methods.
Cited by 3
K.L. Oehler, J.L.H. Webb · 2002
We consider two MSE-based strategies for selecting the best quantization parameter (Q) for each coded macroblock in H.263 video coding. In the first study, Q was adjusted to match a target mean-squared error (MSE) for each block. The goal was to avoid having large errors in a few macroblocks that detract from the overall perceived image quality. Effectively, we minimized the peak MSE over all macroblocks. In the second study, we sought to minimize the average MSE, modifying a gradient-search technique that has been applied to H.261. The choice of quantizers was limited by the H.263 syntactical constraints on changes in Q between successively-coded macroblocks. The results were compared with fixed Q encoding. The resulting sequences displayed only small perceptual differences. For the cases studied, the primary advantage of varying Q was to control the delay.
Cited by 10
Sanghyun Park · The Journal of the Korean Institute of Information and Communication Engineering · 2010
본 논문에서는 목표 비트량에 맞게 영상을 압축하는 모델 기반 매크로블록 레이어 비트율 제어 알고리즘을 제안한다. H.264 비디오 압축 표준은 다양한 압축 모드 및 최적화 방법을 사용하여 압축률을 향상 시키지만 복잡한 인코더 구조는 정확한 트래픽 제어를 어렵게 한다. 제안된 알고리즘에서는 매크로블록 단위에서 비트율과 양자화 파라미터의 관계 및 화면간 영상 변화량에 따른 MAD 값을 선형회귀분석을 통해 예측한다. 예측된 데이터를 바탕으로 각 매크로블록의 양자화 파라미터를 라그랑지 곱수 방법을 이용하여 결정한다. 이 값은 다시 한 프레임에 할당된 비트량과 발생한 비트량의 차이에 따라 수정하여 한 프레임을 압축했을 때 결과 비트량이 목표치에 근접할 수 있게 한다. 제안하는 알고리즘과 기존 알고리즘간의 비교 실험은 제안하는 알고리즘이 목표 비트량과 일치하는 결과 비트량을 생성하는 것을 보여준다. This paper presents a new adaptive macroblock quantization algorithm which generates the output bits corresponding to the target bit budget. The H.264 standard uses various coding modes and optimization methods to improve the compression performance, which makes it difficult to control the amount of the generated traffic accurately. In the proposed scheme, linear regression analysis is used to analyze the relationship between the bit rate of each macroblock and the quantization parameter and to predict the MAD values. Using the predicted values, the quantization parameter of each macroblock is determined by the Lagrange multiplier method and then modified according to the difference between the bit budget and the generated bits. It is shown by experimental results that the new algorithm can generate output bits accurately corresponding to the target bit rates.
Cited by 0
Zhenyu Wang, Shengfu Dong, Ronggang Wang et al. · Journal of Visual Communication and Image Representation · 2015
Cited by 4
Wai Lung Li · 2006
Cited by 0
Bastian Katz, Shlomo Greenberg · 2006
This paper presents a new flexible macroblock ordering (FMO) type for error-resilient transmission of compressed video over wireless packet loss networks. The proposed FMO type outperforms all other types supported by the H.264 standard in terms of both PSNR and Scatter criterion, a criterion that evaluates the extent of error scattering within the frame.
Cited by 0
Yafan Zhao, Iain E. G. Richardson · Signal Processing Image Communication · 2003
Cited by 7
Julia Schmidt, Kenneth Rose · 2008
This paper revisits the problem of source-channel coding for error-resilient video streaming. We propose a new method to enable adaptive redundancy in the bitstream: fine-grain retransmission. Redundancy decisions are made per macroblock (MB), which are locally adaptive and of low overhead, as opposed to coarse packet-level redundancy (e.g. forward error correction). In this scheme, the encoder jointly optimizes the coding mode and redundancy per MB. A corresponding algorithm is presented for exploiting this redundancy at the decoder. The proposed method is general in nature, and can be implemented on top of any (hybrid) video codec. An example implementation is provided, which uses the redundant slice mechanism of H.264 (JM 13.2 reference software). Simulation results show significant performance gains over conventional error-resilient coding techniques.
Cited by 4