共查询到19条相似文献,搜索用时 109 毫秒
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本文介绍对一种基于线性预测方法的信包丢失重建算法[1]的改进研究.通过对基于线形预测方法的原始重建信号在时域和幅度域上的进一步处理,重建信号在相位连续性和样点幅度变化上的表现更加合理.经过非正式试听和ITU-T P.862协议所推荐的PESQ[2]算法客观测量,大量改进后测试语音信号的质量比原来均有提高. 相似文献
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用线性预测法实现气声语音的重建 总被引:1,自引:1,他引:0
本文介绍了一种用线性预测参数实现气声语音重建的方法。首先提取气声语音的线性预测参数,用这些参数建立信号产生模型,然后进行合成,合成时加入基音周期,使其恢复到正常语音。 相似文献
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一种高质量的4 Kb/s RCELP语音编码算法 总被引:1,自引:0,他引:1
给出一种高质量的4Kb/s更新式码激励线性预测(RCELP)语音编码算法。该算法的编码器帧长为20ms,主要特点是使用了从自适应激励信号中分析得到的码本作为固定码本,采用预测式两级分裂矢量量化器量化线谱对(LSP)参数。主观试听表明,该算法的MOS值为3.67,其语音质量与32Kb/s ADPCM基本相当。 相似文献
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4kb/s有限状态代数码激励线性预测语音编码算法FS-ACELP是一种具有延时较短,合成语音质量高、算法复杂度较低的语音编码算法.在线性预测(LP)参数量化上,利用了语音帧内和帧间的相关性,对线谱对(LSP)参数使用预测式分裂式矢量量化,获得很高的量化效率.在自适应码本搜索上,采用了有限状态控制分数延时搜索的算法.在保证合成语音质量的同时,有效地降低了运算量.对于随机码本,采用了具有多模结构的代数码本,提高语音合成质量.对于激励码序列的增益,采用了预测式矢量量化,有效地提高了量化精度.经非正式听音测试,4kb/s FS-ACELP的合成语音质量超过了北美8kb/s VSELP,接近G.729 8kb/s CS-ACELP,MOS分约为3.9. 相似文献
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4kb/s有限状态代数码激励线性预测语音编码算法FS-ACELP是一种具有延时较短、合成语音质量高、算法复杂度较低的语音编码算法.在线性预测(LP)参数量化上,利用了语音帧内和帧间的相关性,对线谱对(LSP)参数使用预测式分裂式矢量量化,获得很高的量化效率.在自适应码本搜索上,采用了有限状态控制分数延时搜索的算法,在保证合成语音质量的同时,有效地降低了运算量.对于随机码本,采用了具有多模结构的代数码本,提高语音合成质量.对于激励码序列的增益,采用了预测式矢量量化,有效地提高了量化精度.经非正式听音测试,4kb/s
FS-ACELP的合成语音质量超过了北美8kb/s VSELP,接近G.729 8kb/s CS-ACELP,MOS分约为3.9. 相似文献
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基于神经网络的线性预测语音编码算法 总被引:1,自引:0,他引:1
语音压缩是多媒体通信技术的重要环节,线性预测编码(LPC)技术是参数编码技术的重要内容,线性预测是语音信号处理中最有效的方法之一.文中从LPC原理入手,阐述了最佳LPC系数的计算,针对目前自相关法和协方差等存在着估计误差的特点,提出一种基于神经网络的线性预测算法,最后通过实验数据证明这种方法既提高了解的精度,又保证了系统的稳定性. 相似文献
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实时IP 语音通信在数据包会丢失的情况下,语音质量会受到严重影响。为了恢复传输过程中丢失的语音信息,本文提出了一种基于瞬时相位差(Instantaneous Phase Deviation, IPD)和深度神经网络(Deep Neural Network, DNN)的丢包隐藏 (Packet Loss Concealment, PLC)方法。在训练阶段,将语音的对数功率谱(Log Power Spectrum, LPS)和IPD作为训练DNN的输入特征,以学习从接收包到丢失包的映射关系;在重构阶段,将丢包前接收到的语音包送入训练好的DNN中,恢复出丢失包的语音。实验结果表明,在不同丢包率下,所提方法的性能优于传统的基于LPS和DNN的PLC方法。 相似文献
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Sofiene Jelassi Habib Youssef Christian Hoene Guy Pujolle 《Telecommunication Systems》2012,49(1):17-34
The perceptual quality of VoIP conversations depends tightly on the pattern of packet losses, i.e., the distribution and duration
of packet loss runs. The wider (resp. smaller) the inter-loss gap (resp. loss gap) duration, the lower is the quality degradation.
Moreover, a set of speech sequences impaired using an identical packet loss pattern results in a different degree of perceptual
quality degradation because dropped voice packets have unequal impact on the perceived quality. Therefore, we consider the
voicing feature of speech wave included in lost packets in addition to packet loss pattern to estimate speech quality scores. We distinguish
between voiced, unvoiced, and silence packets. This enables to achieve better correlation and accuracy between human-based subjective and machine-calculated objective scores. 相似文献
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长期演进(Long Term Evolution,LTE)已经成为4G无线技术标准。目前,LTE分组调度的下行链路调度被大多数研究者研究,上行链路的研究相对较少。针对上行链路调度无法保证实时业务分组在延迟期限内传输,存在公平性较差、分组丢弃多的问题。因此,提出了一种新的上行链路调度算法。该算法根据实时业务的延迟约束条件建立目标整数线性规划模型,再根据目标整数线性规划模型进行调度。实验结果表明,该算法能保证实时业务分组在延迟期限内传输,适用于实时业务,能确保公平性,最小化分组丢弃,具有较好的适用性。 相似文献
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We have studied the effects of random packet losses in digital speech systems based on 12-bit PCM and 4-bit adaptive DPCM coding. The effects are a function of packet lengthB and probability of packet loss PL . We have also studied tbe benefits of an odd-even sample-interpolation procedure that mitigates these effects (at the cost of increased decoding delay). The procedure is based on arranging a2B -block of codewords into twoB -sample packets, an odd-sample packet and an even-sample packet. If one of these packets is lost, the odd (or even) samples of the2B -block are estimated from the even (or odd) samples by means of adaptive interpolation. Perceptual considerations indicate that packet lengths most robust to losses are in the range 16-32 ms, irrespective of whether interpolation is used or not. With these packet lengths, tolerable PL values, which are strictly input-speech-dependent, can be as high as 2 to 5 percent without interpolation and 5 to 10 percent with interpolation. These observations are based on a computer simulation with three sentence-length speech inputs, and on informal listening tests. 相似文献
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Wireless multimedia synchronization is concerned with distributed multimedia packets such as video, audio, text and graphics being played-out onto the mobile clients via a base station (BS) that services the mobile client with the multimedia packets. Our focus is on improving the Quality of Service (QoS) of the mobile client's on-time-arrival of distributed multimedia packets through network multimedia synchronization. We describe a media synchronization scheme for wireless networks, and we investigate the multimedia packet scheduling algorithms at the base station to accomplish our goal. In this paper, we extend the media synchronization algorithm by investigating four packet scheduling algorithms: First-In-First-Out (FIFO), Highest-Priority-First (PQ), Weighted Fair-Queuing (WFQ) and Round-Robin (RR). We analyze the effect of the four packet scheduling algorithms in terms of multimedia packet delivery time and the delay between concurrent multimedia data streams. We show that the play-out of multimedia units on the mobile clients by the base station plays an important role in enhancing the mobile client's quality of service in terms of intra-stream synchronization and inter-stream synchronization. Our results show that the Round-Robin (RR) packet scheduling algorithm is, by far, the best of the four packet scheduling algorithms in terms of mobile client buffer usage. We analyze the four packet scheduling algorithms and make a correlation between play-out of multimedia packets, by the base station, onto the mobile clients and wireless network multimedia synchronization. We clarify the meaning of buffer usage, buffer overflow, buffer underflow, message complexity and multimedia packet delay in terms of synchronization between distributed multimedia servers, base stations and mobile clients. 相似文献
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A packet speech multiplexer is analysed using a fluid approximation for the flow of packets in and out of the multiplexer. Delay distributions and fractional packet loss are determined with a small amount of computation. Comparisons with a simulation using real speech show the analysis to be accurate. 相似文献
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A selective packet discarding procedure for voice communication is presented in which packets are labelled at the transmitter and, if necessary, discarded by network nodes according to their significance to reconstructed speech quality. Simulation and subjective tests show improved tolerance to missing packets in comparison with unselective methods where packets are discarded at random.<> 相似文献