HDS, a real-time multi-DSP motion estimator for MPEG-4 H.264 AVC high definition video encoding

International audienceH.264 AVC video compression standard achieves high compression rates at the cost of a high encoder complexity. The encoder performances are greatly linked to the motion estimation operation which requires high computation power and memory bandwidth. High definition context magnifies the difficulty of a real-time implementation. EPZS and HME are two well-known motion estimation algorithms. Both EPZS and HME are implemented in a DSP and their performances are compared in terms of both quality and complexity. Based on these results, a new algorithm called HDS for Hierarchical Diamond Search is proposed. HDS motion estimation is integrated in a AVC encoder to extract timings and resulting video qualities reached. A real-time DSP implementation of H.264 quarter-pixel accuracy motion estimation is proposed for SD and HD video format. Furthermore HDS characteristics make this algorithm well suited for H.264 SVC real-time encoding applications

Bio­-inspired approaches to the control and modelling of an anthropomimetic robot

Introducing robots into human environments requires them to handle settings designed specifically for human size and morphology, however, large, conventional humanoid robots with stiff, high powered joint actuators pose a significant danger to humans. By contrast, “anthropomimetic” robots mimic both human morphology and internal structure; skeleton, muscles, compliance and high redundancy. Although far safer, their resultant compliant structure presents a formidable challenge to conventional control. Here we review, and seek to address, characteristic control issues of this class of robot, whilst exploiting their biomimetic nature by drawing upon biological motor control research. We derive a novel learning controller for discovering effective reaching actions created through sustained activation of one or more muscle synergies, an approach which draws upon strong, recent evidence from animal and humans studies, but is almost unexplored to date in musculoskeletal robot literature. Since the best synergies for a given robot will be unknown, we derive a deliberately simple reinforcement learning approach intended to allow their emergence, in particular those patterns which aid linearization of control. We also draw upon optimal control theories to encourage the emergence of smoother movement by incorporating signal dependent noise and trial repetition. In addition, we argue the utility of developing a detailed dynamic model of a complete robot and present a stable, physics-­‐‑based model, of the anthropomimetic ECCERobot, running in real time with 55 muscles and 88 degrees of freedom. Using the model, we find that effective reaching actions can be learned which employ only two sequential motor co-­‐‑activation patterns, each controlled by just a single common driving signal. Factor analysis shows the emergent muscle co-­‐‑activations can be reconstructed to significant accuracy using weighted combinations of only 13 common fragments, labelled “candidate synergies”. Using these synergies as drivable units the same controller learns the same task both faster and better, however, other reaching tasks perform less well, proportional to dissimilarity; we therefore propose that modifications enabling emergence of a more generic set of synergies are required. Finally, we propose a continuous controller for the robot, based on model predictive control, incorporating our model as a predictive component for state estimation, delay-­‐‑ compensation and planning, including merging of the robot and sensed environment into a single model. We test the delay compensation mechanism by controlling a second copy of the model acting as a proxy for the real robot, finding that performance is significantly improved if a precise degree of compensation is applied and show how rapidly an un-­‐‑compensated controller fails as the model accuracy degrades

Block Matching Algorithms for the Estimation of Motion in Image Sequences: Analysis

Several video coding standards and techniques have been introduced for multimedia applications, particularly the h.26x series for video processing. These standards employ motion estimation processing to reduce the amount of data that is required to store or transmit the video. The motion estimation process is an inextricable part of the video coding as it removes the temporal redundancy between successive frames of video sequences. This paper is about these motion estimation algorithms, their search procedures, complexity, advantages, and limitations. A survey of motion estimation algorithms including full search, many fast, and fast full search block-based algorithms has been presented. An evaluation of up-to-date motion estimation algorithms, based on several empirical results on several test video sequences, is presented as well

Fast Motion Estimation’s Configuration Using Diamond Pattern and ECU, CFM, and ESD Modes for Reducing HEVC Computational Complexity

The high performance of the high efficiency video coding (HEVC) video standard makes it more suitable for high-definition resolutions. Nevertheless, this encoding performance is coupled with a tremendous encoding complexity compared to the earlier H264 video codec. The HEVC complexity is mainly a return to the motion estimation (ME) module that represents the important part of encoding time which makes several researches turn around the optimization of this module. Some works are interested in hardware solutions exploiting the parallel processing of FPGA, GPU, or other multicore architectures, and other works are focused on software optimizations by inducing fast mode decision algorithms. In this context, this article proposes a fast HEVC encoder configuration to speed up the encoding process. The fast configuration uses different options such as the early skip detection (ESD), the early CU termination (ECU), and the coded block flag (CBF) fast method (CFM) modes. Regarding the algorithm of ME, the diamond search (DS) is used in the encoding process through several video resolutions. A time saving around 46.75% is obtained with an acceptable distortion in terms of video quality and bitrate compared to the reference test model HM.16.2. Our contribution is compared to other works for better evaluation

Fast pattern matching in Walsh-Hadamard domain and its application in video processing.

Li Ngai.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references.Abstracts in English and Chinese.Chapter Chapter 1. --- Introduction --- p.1-1Chapter 1.1. --- A Brief Review on Pattern Matching --- p.1-1Chapter 1.2. --- Objective of the Research Work --- p.1-5Chapter 1.3. --- Organization of the Thesis --- p.1-6Chapter 1.4. --- Notes on Publications --- p.1-7Chapter Chapter 2. --- Background Information --- p.2-1Chapter 2.1. --- Introduction --- p.2-1Chapter 2.2. --- Review of Block Based Pattern Matching --- p.2-3Chapter 2.2.1 --- Gradient Descent Strategy --- p.2-3Chapter 2.2.2 --- Simplified Matching Operations --- p.2-10Chapter 2.2.3 --- Fast Full-Search Methods --- p.2-14Chapter 2.2.4 --- Transform-domain Manipulations --- p.2-19Chapter Chapter 3. --- Statistical Rejection Threshold for Pattern Matching --- p.3-1Chapter 3.1. --- Introduction --- p.3-1Chapter 3.2. --- Walsh Hadamard Transform --- p.3-3Chapter 3.3. --- Coarse-to-fine Pattern Matching in Walsh Hadamard Domain --- p.3-4Chapter 3.3.1. --- Bounding Euclidean Distance in Walsh Hadamard Domain --- p.3-5Chapter 3.3.2. --- Fast Projection Scheme --- p.3-9Chapter 3.3.3. --- Using the Projection Scheme for Pattern Matching --- p.3-17Chapter 3.4. --- Statistical Rejection Threshold --- p.3-18Chapter 3.5. --- Experimental Results --- p.3-22Chapter 3.6. --- Conclusions --- p.3-29Chapter 3.7. --- Notes on Publication --- p.3-30Chapter Chapter 4. --- Fast Walsh Search --- p.4-1Chapter 4.1. --- Introduction --- p.4-1Chapter 4.2. --- Approximating Sum-of-absolute Difference Using PS AD --- p.4-3Chapter 4.3. --- Two-level Threshold Scheme --- p.4-6Chapter 4.4. --- Block Matching Using SADDCC --- p.4-10Chapter 4.5. --- Optimization of Threshold and Number of Coefficients in PSAD --- p.4-15Chapter 4.6. --- Candidate Elimination by the Mean of PSAD --- p.4-23Chapter 4.7. --- Computation Requirement --- p.4-28Chapter 4.8. --- Experimental Results --- p.4-32Chapter 4.9. --- Conclusions --- p.4-45Chapter 4.10. --- Notes on Publications --- p.4-46Chapter Chapter 5. --- Conclusions & Future Works --- p.5-1Chapter 5.1. --- Contributions and Conclusions --- p.5-1Chapter 5.1.1. --- Statistical Rejection Threshold for Pattern Matching --- p.5-2Chapter 5.1.2. --- Fast Walsh Search --- p.5-3Chapter 5.2. --- Future Works --- p.5-4References --- p.

Improvement and optimization of H.264 video codec.

Tang, Kai Lam.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.Includes bibliographical references.Abstracts in English and Chinese.Acknowledgement --- p.iAbstract --- p.iiContents --- p.ivPublication List --- p.viiChapter Chapter 1 --- Introduction --- p.1-1Chapter 1.1 --- Video Coding --- p.1-1Chapter 1.1.1 --- Temporal prediction --- p.1-5Chapter 1.1.2 --- Transform Coding --- p.1-9Chapter 1.1.3 --- Quantization --- p.1-12Chapter 1.1.4 --- Entropy Coding --- p.1-14Chapter 1.2 --- H.264/MPEG-4 Part 10 --- p.1-15Chapter 1.2.1 --- Overview --- p.1-16Chapter 1.2.2 --- Intra Prediction --- p.1-19Chapter 1.2.3 --- Inter Prediction --- p.1-20Chapter 1.2.4 --- Transform and Quantization --- p.1-23Chapter 1.2.5 --- Entropy Coding --- p.1-25Chapter 1.2.6 --- Deblocking Filter --- p.1-29Chapter 1.3 --- Organization of the Thesis --- p.1-32Chapter 1.3.1 --- Review of Motion Estimation Techniques --- p.1-32Chapter 1.3.2 --- The Proposed Algorithms --- p.1-33Chapter 1.3.3 --- Optimization of the Codec --- p.1-34Chapter 1.4 --- Contributions --- p.1-35Chapter Chapter 2 --- Review of Motion Estimation Techniques --- p.2-1Chapter 2.1 --- Fast Full Search --- p.2-2Chapter 2.2 --- Hybrid Unsymmetrical-cross Multi-Hexagon-grid Search --- p.2-4Chapter 2.3 --- Center biased Fractional Pel Search --- p.2-6Chapter 2.4 --- Enhanced Predictive Zonal Search --- p.2-7Chapter Chapter 3 --- Enhancement Techniques for Intra Block Matching --- p.3-1Chapter 3.1 --- Introduction --- p.3-1Chapter 3.1.1 --- Fundamental Principles --- p.3-1Chapter 3.1.2 --- Variable Block Size Intra Block Matching --- p.3-3Chapter 3.2 --- Proposed Techniques --- p.3-5Chapter 3.2.1 --- Padding --- p.3-5Chapter 3.2.2 --- Modes --- p.3-9Chapter 3.2.3 --- Performance Enhancement Tools --- p.3-12Chapter 3.2.3.1 --- Multiple Best Matches --- p.3-12Chapter 3.2.3.2 --- Adaptive Integer and Sub-pixel Intra Block Matching --- p.3-13Chapter 3.2.4 --- Pseudo Intra Block Matching --- p.3-14Chapter 3.3 --- Proposed Fast Algorithms --- p.3-16Chapter 3.3.1 --- Fast Intra Block Matching Decision --- p.3-16Chapter 3.3.2 --- Skipping some Intra Block Matching Processes --- p.3-18Chapter 3.3.3 --- Early Termination --- p.3-19Chapter 3.3.4 --- SAD Reuse Techniques --- p.3-21Chapter 3.4 --- Experimental Results --- p.3-22Chapter Chapter 4 --- Enhanced SAD Reuse Fast Motion Estimation --- p.4-1Chapter 4.1 --- Introduction --- p.4-1Chapter 4.2 --- Proposed Fast Motion Estimation Algorithm --- p.4-3Chapter 4.2.1 --- Best Initial Motion Vector --- p.4-3Chapter 4.2.2 --- Initial Search Pattern --- p.4-4Chapter 4.2.3 --- Initial Search Process and Search Pattern Improvement Process --- p.4-7Chapter 4.2.3.1 --- BISPCSP Motion Estimation or Refinement Process Decision --- p.4-8Chapter 4.2.3.2 --- ISP Motion Estimation or Refinement Process Decision --- p.4-9Chapter 4.2.4 --- Motion Estimation Process and Refinement Process --- p.4-9Chapter 4.2.4.1 --- Motion Estimation Process --- p.4-9Chapter 4.2.4.2 --- Refinement Process --- p.4-11Chapter 4.2.5 --- Motion Estimation Skip Process for B Pictures --- p.4-12Chapter 4.3 --- Experimental Results --- p.4-13Chapter Chapter 5 --- Development of Real-Time H.264 Codec on Pocket PC --- p.5-1Chapter 5.1 --- Algorithmic Optimizations --- p.5-2Chapter 5.1.1 --- Fast Sub-Pixel Motion Estimation --- p.5-2Chapter 5.1.2 --- Interpolation --- p.5-5Chapter 5.1.2.1 --- Revision of Luma Interpolation --- p.5-5Chapter 5.1.2.2 --- Fast Interpolation --- p.5-8Chapter 5.1.3 --- Skipping Inverse ICT and Inverse Quantization Depends on Coded Block Pattern --- p.5-10Chapter 5. 2 --- Code Level Optimizations --- p.5-12Chapter 5.2.1 --- Merging Loops --- p.5-12Chapter 5.2.2 --- Moving Independent Code outside the Loop --- p.5-13Chapter 5.2.3 --- Unrolling Loops --- p.5-14Chapter 5.3 --- Experimental Results --- p.5-16Chapter 5.4 --- Applications --- p.5-26Chapter Chapter 6 --- Conclusions and Future Development --- p.6-1Chapter 6.1 --- Conclusions --- p.6-1Chapter 6.1.1 --- Enhancement Techniques for Intra Block Matching --- p.6-1Chapter 6.1.2 --- Enhanced SAD Reuse Fast Motion Estimation --- p.6-1Chapter 6.1.3 --- Development of Real-Time H.264 Codec on Pocket PC --- p.6-2Chapter 6.2 --- Future Development --- p.6-3Bibliography --- p.

An Adaptive Motion Estimation Scheme for Video Coding

The unsymmetrical-cross multihexagon-grid search (UMHexagonS) is one of the best fast Motion Estimation (ME) algorithms in video encoding software. It achieves an excellent coding performance by using hybrid block matching search pattern and multiple initial search point predictors at the cost of the computational complexity of ME increased. Reducing time consuming of ME is one of the key factors to improve video coding efficiency. In this paper, we propose an adaptive motion estimation scheme to further reduce the calculation redundancy of UMHexagonS. Firstly, new motion estimation search patterns have been designed according to the statistical results of motion vector (MV) distribution information. Then, design a MV distribution prediction method, including prediction of the size of MV and the direction of MV. At last, according to the MV distribution prediction results, achieve self-adaptive subregional searching by the new estimation search patterns. Experimental results show that more than 50% of total search points are dramatically reduced compared to the UMHexagonS algorithm in JM 18.4 of H.264/AVC. As a result, the proposed algorithm scheme can save the ME time up to 20.86% while the rate-distortion performance is not compromised