MF-TDMA人防卫星通信高清视频编解码算法研究

通用视频编解码器或视频会议终端在人防卫星网传输高清视频时,存在带宽需求高、应用模式单一、视音频卡顿及设备死机等现象,无法满足人民防空应急指挥多路高清视频组网通信的需求。本文提出适用MF-TDMA卫星通信体制的高清视频编解码算法优化方法,作为人防行业专用卫星高清视频编解码器研制的理论基础,以供参考。

空间光通信自适应编解码技术研究

空间光通信受到大气湍流影响的衰落时间可持续数毫秒,严重影响通信系统的可靠性。提出了一种适合于空间光通信的自适应编解码方案,并且给出了具体的实现方法。针对信道当前不同的状况,采取不同的编解码方案降低系统的误码率。并且采取阈值切换的方法,避免了由于信道状况在设计阈值周边波动时出现的编解码方案频繁切换的现象。经过MATLAB仿真,验证了该方案的可行性。

基于多层分块自适应压缩感知的图像编解码方法

压缩感知中,测量矩阵对图像进行单一采样率的压缩采样。传统的测量矩阵虽然能够获得比较好的重构效果,但因采样数目较多,故而资源耗费也较多。为了解决上述问题,提出了多层分块自适应编码算法(multi-layered block adaptive coding algorithm,MLBA)以及多层分块自适应压缩感知编解码方法(multi-layered block adaptive compressed sensing codec method,MLBACS)。MLBACS编解码方法基于MLBA编码算法,能够根据图像局部结构进行不同层数和大小的分块,并自适应分配采样率。仿真结果表明,在同等重构性能的前提下,相对于单一采样率下的压缩感知,MLBACS编解码方法能够不同程度地降低重构图像所需的采样数目。

AMR语音编解码器在C55xDSP上的实现

本文主要介绍了在手持终端上实现自适应多速率(AMR)语音业务功能的DSP解决方案,并分析了AMR语音编解码器标准及TMS320VC5510 DSP的性能特征.

Screen image sequence compression method utilizing adaptive block size coding and hierarchical GOP structure

To compress screen image sequence in real-time remote and interactive applications,a novel compression method is proposed.The proposed method is named as CABHG.CABHG employs hybrid coding schemes that consist of intra-frame and inter-frame coding modes.The intra-frame coding is a rate-distortion optimized adaptive block size that can be also used for the compression of a single screen image.The inter-frame coding utilizes hierarchical group of pictures(GOP) structure to improve system performance during random accesses and fast-backward scans.Experimental results demonstrate that the proposed CABHG method has approximately 47%-48% higher compression ratio and 46%-53% lower CPU utilization than professional screen image sequence codecs such as TechSmith Ensharpen codec and Sorenson 3 codec.Compared with general video codecs such as H.264 codec,XviD MPEG-4 codec and Apple's Animation codec,CABHG also shows 87%-88% higher compression ratio and 64%-81% lower CPU utilization than these general video codecs.