G.729

摘要： 共轭结构代数码激励线性预测编码算法(Conjugate-Structure Algebraic-Code Excited Linear-Prediction, CS-ACELP)的固定码书搜索算法通过嵌套循环计算出码书矢量,这个算法的重要缺陷是嵌套循环深度大,时间复杂度高,计算量大.在重排序搜索(Reordering Search Sequence)算法的基础上,对搜索结构进行改进.将预搜索部分获得的组合脉冲直接用于下一步的全搜索,将嵌套循环的深度由4层降至2层,降低时间复杂度和计算量.并且与固定码书搜索的几个经典算法相比,搜索次数减少了30%到98%不等,同时具有优于G.729A算法的优越编解码音质.

摘要： 本文通过对G.729语音编码算法的分析,根据实时语音处理的特性,设计一种以三帧语音数据为整体的帧轮转结构;对于算法中的相关值计算过程、滤波过程、以及硬件设计时SRAM的读取特性,结合并行结构和流水线结构,实现了语音编码算法的高吞吐量设计.完成相同计算所需时钟周期仅为优化后DSP设计的1/68.采用一组加入pink-noise噪音的语音对设计芯片进行了编解码后的PESQ音质评分测试,在信噪比不小于5 dB的情况下,语音PESQ评分均大于4.0分,完成了高吞吐率、高音质的语音实时压缩.

摘要： VoIP以语音流为传输媒介,具有传输数据量大和应用广泛的优点.但VoIP系统也面临数据安全和隐私泄露的安全威胁.针对编码标准G.729固定码本搜索的非遍历特性和具有一定冗余性的特点,该文提出基于G.729语音编码非零脉冲位置信息的隐藏算法.该算法在固定码本搜索过程中,利用秘密信息控制码本的搜索过程,并在非零脉冲位置和秘密信息之间构建函数进行信息隐藏.在搜索过程中利用最不重要脉冲替换思想并采用最小化失真准则控制由秘密信息的嵌入带来的音质失真.实验结果表明:算法隐藏容量可达400 bit/s,算法具有良好的隐蔽性(PESQ平均值约为3.45).%VoIP (Voice over Internet Protocol) is based on voice stream, which has the advantages of large data transmission and wide application. But the VoIP system is confronted with the security threats of data security and privacy disclosure. Thus, according to nonergodicity and redundancy of the fixed codebook search, an information hiding algorithm based on fixed codebook search process is proposed. This information hiding algorithm is carried out by a functional relationship between the nonzero pulse positions and secret information. The idea of least significant pulse replacement is used in the search process and a distortion minimization criterion is proposed to control the distortion of speech quality caused by the embedding of secret information. The experimental results show that the hiding capacity of the proposed algorithm is up to 400 bit/s and the average PESQ score is 3.45 which indicate that the algorithm has good imperceptibility.

摘要： VoIP系统面临数据安全和隐私泄露的安全威胁.基于此,本文针对编码标准G.729固定码本搜索的非遍历特性特点,提出了在固定码本搜索过程中,利用秘密信息控制码本的搜索过程并在非零脉冲位置和秘密信息之间构建函数进行信息隐藏.实验结果表明:算法隐藏容量可达400bit/s,算法具有良好的隐蔽性.

摘要： 通信系统中的语音编解码多基于DSP来实现,采用相应的DSP硬件设计及软件算法,可以较方便地实现多路语音处理.而在某些小型的G.729格式的通信系统中,采用硬件编解码的模式,结合FPGA来协同设计,可以将语音编解码更为方便地应用在通信系统的终端设备中,大大减少了设备设计的复杂度.

摘要： If G.729 algorithm is run directly on the hardware platform without optimization, it has a very low efficiency, which can not meet the requirements of real-time call. Computational algorithm is mainly consumed in the pretreatment, LSP vector quantization, fixation and adaptive codebook search module. The paper is to optimize LSP vector quantization module, based on the analysis of vector quantization principle. Experimental results show that after the algorithm optimization, the synthesized speech quality improves significantly with the reduction of algorithm complexity and raising of the coding efficiency .%G.729算法如果不经过优化直接在硬件平台上运行,效率是很低的,不能满足实时通话的要求.算法的计算量主要消耗在预处理、LSP矢量量化、固定及自适应码书搜寻模块.本研究在分析矢量量化原理的基础上,针对LSP矢量量化模块进行优化.实验结果证明,优化后算法计算复杂度降低,编码效率提高,合成语音质量有明显的改进.

摘要： G.729语音压缩算法的源代码存在运算量大、在DSP上实现效率低等缺点.为加强其在低功耗便携式设备上的应用,结合C55X平台和G.729算法特点,采用合理的全汇编实现方案,开发l款高度优化的G.729全汇编代码,并给出并行指令优化和指令流水线延迟优化2种汇编代码优化方法及存储空间的优化思路.在TMS320VC5505 EVM上完成全汇编代码的测试和实时实现.测试结果显示代码运算量从l 259.9(mega cycles)/s降为25.3(mega cycles)/s,利用软件工具测得语音质量的MOS得分在3.87左右.

摘要： 为了研究TETRA中的ACELP与ITU-TG.729中CS-ACELP两种语音压缩编码算法的异同,分别就以下几个方面对这两种算法进行了比较:预处理、线性预测分析(LPC)、自适应码本的搜索和固定码本的搜索.然后在VC++6.0环境下实现了这两种算法,并对算法的仿真结果进行了对比分析.最后采用ITU-TP.862.1标准感知语音质量评价(PESQ_LQO)对两种算法合成语音的质量进行客观测评,测试结果表明,G.729合成语音的质量比TETRA合成语音的质量要好.%In order to study the difference of two kinds of speech coding algorithm,TETRA ACELP and ITU-T G.729 CS-ACELP,some aspects of those two kinds of algorithms are compared:pre-processing,linear prediction analysis(LPC),adaptive-codebook searching and fixed codebook searching.The two kinds of algorithm are respectively carried out on VC + + 6.0,and the results of simulation are analyzed.Finally,ITU-T P 862.1 standard PESQ_LQO(perception speech quality evaluation)is used to objectively evaluate the quality of the synthetic speech to give the result of comparative analysis.Simulation results show that the quality of the synthetic speech of G.729 is better than that of TETRA.

摘要： 提出了一种基于Kademlia算法的P2P语音通信模型.通话语音采用G.729压缩,寻址采用基于Kademlia算法的P2P协议,结合NAT穿越技术,实现了无需语音服务器的端到端语音传输.通过Kademlia发布和搜索,实现P2P语音通信用户的分布式维护.实验的结果也验证了提出的P2P语音通信模型的有效性及可靠性.%A P2P VoIP Model based on Kademlia protocol is proposed.Voice stream is packed and compressed by G.729 algorithm.The search of a node is based on Kademlia P2P protocol.Combining with NAT traversing technology,the end-to-end voice transmission without Voice Servers is realized.Kademlia protocol can realize node publishing,searching and maintenance of the P2P user.The results from experiments have proved the validity and reliability of the proposed P2P voice communication model.

摘要： 深入研究G.729语音压缩算法，统计压缩比特流不重要位，提出在G.729压缩语音流中嵌入秘密信息的信息隐藏算法。并在此算法基础上设计出IP网络语音隐蔽通信系统，使其能够在普通的中低速IP网络中通过网络语音通话，进行隐蔽通信，提高秘密信息传输的安全性。%Through the intensive study of G.729 voice compression algorithm and statistics of unimportant bit in the com-pressed bit stream,an information hiding algorithm that embeds secret messages in G.729 compressed voice bit stream is pro-posed. An IP net voice covert communication system is designed based on this algorithm to realize the covert communication in nor-mal mid-low speed IP net through network voice communication and improve the security of the secret information transformation.

摘要： 本文在美国Analog Device公司最新推出的Blackfin537 DSP芯片上,实现了ITU-T的G729A语音编解码算法,并对算法进行优化,提高了运算效率。

摘要： 本文在美国Analog Device公司最新推出的Blackfin537 DSP芯片上,实现了ITU-T的G729A语音编解码算法,并对算法进行优化,提高了运算效率。

摘要： 本文在美国Analog Device公司最新推出的Blackfin537 DSP芯片上,实现了ITU-T的G729A语音编解码算法,并对算法进行优化,提高了运算效率。

摘要： 本文在美国Analog Device公司最新推出的Blackfin537 DSP芯片上,实现了ITU-T的G729A语音编解码算法,并对算法进行优化,提高了运算效率。

摘要： 本文在美国Analog Device公司最新推出的Blackfin537 DSP芯片上,实现了ITU-T的G729A语音编解码算法,并对算法进行优化,提高了运算效率。