Speech Coding is pivotal in the ability of networks to support multimedia services. The technique currently used for speech coding is Linear Prediction. It models the throat as an all-pole filter i.e. using a linear difference equation. However, the physical nature of the throat is itself a clue to its nonlinear nature. Developing a nonlinear model is difficult as in the solution of nonlinear e...

This paper investigates lossless coding of wideband speech by adding a lossless enhancement layer to the lossy baselayer produced by a standardised wideband speech coder. Both the ITU-T G.722 and G.722.2 speech coders are examined. Entropy results show that potential compression rates are dependent on the type and bit rate of the baselayer coder as well as the symbol size used by the lossless c...

The typical approach to steganography is to compress the covert data in order to limit its size, which is reasonable in the context of a limited steganographic bandwidth. TranSteg (Trancoding Steganography) is a new IP telephony steganographic method that was recently proposed that offers high steganographic bandwidth while retaining good voice quality. In TranSteg, compression of the overt dat...

This paper presents the architecture and design of an enhanced VoIP gateway, which is based on the H.323 protocol. The key characteristics of this gateway include: scalability separating signaling from media transformation and use of protocols such as MGCP/MEGACO for the communication between signaling part and media gateway; lightweight by using SCTP transport protocol to convey H.323 and MGCP...

Usable speech criteria are proposed to extract minimally corrupted speech for speaker identification in cochannel speech. Extracted usable segments are separated in time and need to be organized into speaker streams for speaker identification system. In this paper, we focus to organize extracted usable speech segment into a single stream for the same speaker by speaker assignment system. We ext...

Advances in speech coding technologies have enabled speech coders to achieve bit-rate reductions at a great extent while maintaining roughly the same speech quality. One of the most important driving forces behind this feat is the analysis-by-synthesis paradigm. Code Excited Linear Predictive coder (CELP) is the quite efficient closed loop analysis-by-synthesis method for narrow and medium band...

The objective is to describe analysis methods that enable tracking vocal dysperiodicities in running speech. Vocal dysperiodicities here refer to deviations from strict periodicity in voiced speech sounds. Two methods are described. They respectively enable the sample-by-sample extraction of vocal noise from the speech signal or the isolation of speech cycles in voiced segments to quantify pert...

With the more widespread use of lower bit rate speech coders, the evaluation of speaker recognizability becomes a major issue to be addressed as well as the evaluation of overall voice quality. Furthermore, subjective quality evaluation of speech coders may produce di erent results depending on the voice character of the speakers used in the evaluation process. It follows naturally that methods...