Section: Software

WinSnoori

contact : Yves Laprie (Yves.Laprie@loria.fr)

WinSnoori is a speech analysis software that we have been developing for 15 years. It is intended to facilitate the work of the scientist in automatic speech recognition, phonetics or speech signal processing. Basic functions of Snorri enable several types of spectrograms to be calculated and the fine edition of speech signals (cut, paste, and a number of filters) as the spectrogram allows the acoustical consequences of all the modifications to be evaluated. Beside this set of basic functions, there are various functionalities to annotate phonetically or orthographically speech files, to extract fundamental frequency, to pilot the Klatt synthesizer and to utilize PSOLA resynthesis.

The main improvement concerns automatic formant tracking which is now available with other tools for copy synthesis. It is now possible to determine parameters for the formant synthesizer of Klatt quite automatically. The first step is formant tracking, then the determination of F0 parameters and finally the adjustment of formant amplitudes for the parallel branch of the Klatt synthesizer enable a synthetic speech signal to be generated. The automatic formant tracking that has been implemented is an improved version of the concurrent curve formant tracking [60] . One key point of this tracking algorithm is the construction of initial rough estimates of formant trajectories. The previous algorithm used a mobile average applied onto LPC roots. The window is sufficiently large (200 ms) to remove fast varying variations due to the detection of spurious roots. The counterpart of this long duration is that the mobile average prevents formants fairly far from the mobile average to be kept. This is particularly sensitive in the case of F2 which presents low frequency values for back vowels. A simple algorithm to detect back vowels from the overall spectral shape and particularly energy levels has been added in order to keep extreme values of F2 which are relevant.

Together with other improvements reported during the last years, formant tracking enables copy synthesis. The current version of WinSnoori is available on http://www.winsnoori.fr .