Power and Speed-Efficient Code Transformation of Video Compression Algorithms for RISC Processors

Upcoming multi-media compression applications will require high memory bandwidth. In this paper, we estimate that a software reference implementation of an MPEG-4 video decoder typically requires 200 Mtransfers/s to memory to decode 1 CIF (352×288) Video Object Plane (VOP) at 30 frames/s. This imposes a high penalty in terms of power but also performance.However, we also show that we can heavily improve on the memory transfers, without sacrificing speed (even gaining about 10% on cache misses and cycles for a DEC Alpha), by aggressive code transformations. For this purpose, we have manually applied an extended version of our data transfer and storage exploration (DTSE) methodology, which was originally developed for custom hardware implementations.     

H.263甚低码率视频编码标准的码率控制方法

主要提出ＩＴＵ组织的Ｈ．２６３甚低码率视频压缩编码标准输出码率的控制方案。着重分析了一种通过调整宏观量化器的量化参数来控制Ｈ．２６３编码器输出码率的方法,它能满足在ＰＳＴＮ网上低时延中的码率输出要求。     

基于均方误差准则的半象素精度运动估计方法的改进及其DSP实现

本文在比较了运动估计的各种匹配准则计算复杂度的基础上,提出在ＤＳＰ上实现极低码率动态图象编码标准Ｈ．２６３时,选择均方误差（ＭＳＥ）做为匹配准则的半象素精度运动估计的方法。由于在半象素精度运动估计时,丁邻半象素点的均方误差的计算具有重复性,利用这种重复性对均方误差计算方法进行改进,可以在不影响图像质量的同时,提高压缩比。模拟结果显示,改进的方法在ＤＳＰ实现时更能显示其优越性,在运算时间和存储空间上     

Influence of γ′ and grain boundary carbide on tensile fracture behaviors of Nimonic 263

Tensile fracture behaviors of Nimonic 263 after three different heat treatments have been investigated. Standard heat treatment produces 10% γ′ coupled with precipitate free zones (PFZs), and M₂₃C₆ carbide densely distributed at grain boundaries (GBs). Alternative heat treatment causes dense distribution of GB carbides and precipitation of 1–3% γ′ with the absence of PFZs. Solution-treated sample has neither γ′ nor M₂₃C₆ carbide. Room temperature tensile tests indicate both standard and alternative heat-treated samples show intergranular fracture, but the elongation of the latter is two times larger than that of the former. The combined effect of GB carbides and intensive slip bands accounts for the intergranular fracture. The γ′ volume fraction affects elongation. Solution-treated sample displays transgranular fracture mode. Lack of restriction to dislocation mobility in grains interior and the weak interaction between GBs and dislocations are responsible for the transgranular fracture. The effect of PFZs on fracture mode may be negligible.     

基于预测搜索距的快速块匹配运动估计算法

提出了一种基于搜索距的快速运动搜索算法。该算法采用多个初始预测候选运动矢量集进行运动估计,通过对与该宏块时空域相邻宏块的搜索距来预测当前宏块的搜索距,根据当前宏块搜索距和块失真特性统计的不同动态采用不同的搜索模板。模拟试验表明：提出算法能获得更好的视频质量,拥有良好的搜索速度伸缩性,优于传统的PMVFAST算法。     

Heat Killed Lactobacillus reuteri GMNL-263 Reduces Fibrosis Effects on the Liver and Heart in High Fat Diet-Hamsters via TGF-β Suppression

Obesity is one of the major risk factors for nonalcoholic fatty liver disease (NAFLD), and NAFLD is highly associated with an increased risk of cardiovascular disease (CVD). Scholars have suggested that certain probiotics may significantly impact cardiovascular health, particularly certain Lactobacillus species, such as Lactobacillus reuteri GMNL-263 (Lr263) probiotics, which have been shown to reduce obesity and arteriosclerosis in vivo. In the present study, we examined the potential of heat-killed bacteria to attenuate high fat diet (HFD)-induced hepatic and cardiac damages and the possible underlying mechanism of the positive effects of heat-killed Lr263 oral supplements. Heat-killed Lr263 treatments (625 and 3125 mg/kg-hamster/day) were provided as a daily supplement by oral gavage to HFD-fed hamsters for eight weeks. The results show that heat-killed Lr263 treatments reduce fatty liver syndrome. Moreover, heat-killed Lactobacillus reuteri GMNL-263 supplementation in HFD hamsters also reduced fibrosis in the liver and heart by reducing transforming growth factor β (TGF-β) expression levels. In conclusion, heat-killed Lr263 can reduce lipid metabolic stress in HFD hamsters and decrease the risk of fatty liver and cardiovascular disease.     

一个基于RTP/RTCP的手机报警系统

在研究RTP/RTCP协议特点与功能的基础上,讨论了基于RTP/RTCP协议实时视频传输的控制方法。通过此控制方法可以有效地提高RTP流的平稳性,减小抖动,增加网络带宽的利用率,流畅地传输多媒体数据。利用GPS、RTP/RTCP等协议实现了手机报警系统。     

基于CDMA 1X的无线视频传输系统

设计并实现了基于CDMA 1X的无线视频传输系统,详细论述了传输模块中PPP连接、RTP封装和Socket通信的设计过程.并针对CDMA 1X信道的特点.进行了视频差错控制技术方面的研究,在平衡图像质量和编码比特率这对矛盾方面获得了良好的效果.     

DSP极低码率的远程视频监控系统

笔者以TI的低成本DSP芯片F206为例,介绍了一种基于此芯片的极低码率双绞线视频图像监控系统,包括它的整体方案,及实现时的一些难点解析。实践表明:此系统经济、实用且具有广播能力。     

H.263视频编码的码率控制算法及硬件实现

提出了一种H．263低码率视频压缩编码的自适应码率控制方法，这种方法可以用FPGA来实现，为了达到实时性的要求，对硬件实现的具体方法进行了优化。所提出的码率控制优化方法已在H．263标准的硬件系统中实现。