Vincent Pagel

The MBROLA project: towards a set of high quality speech synthesizers free of use for non commercial purposes

The aim of the MBROLA project, initiated by the Faculte Polytechnique de Mons (Belgium), is to obtain a set of speech synthesizers for as many voices, languages and dialects as possible, free of use for non-commercial and non-military applications. The ultimate goal is to boost academic research on speech synthesis, and particularly on prosody generation, known as one of the biggest challenges taken up by text-to-speech synthesizers for the years to come. Central to the MBROLA project is MBROLA 2.00, a speech synthesizer based on the concatenation of diphones. Executable files of this synthesizer have been made freely available for many computers/operating systems, as well as a first diphone database for a French male voice. We describe the terms of participation to the project, as a user, as an associated developer, or as a database provider.

Envelope-invariant analytical speech resynthesis using periodic signals derived from reharmonized frame spectrum

Method envelope-invariant for audio signal synthesis from elementary audio waveforms stored in a dictionary wherein: the waveforms are perfectly periodic, and stored as one of their period, synthesis is obtained by overlap-adding of the waveforms obtained from time-domain repetition of the periodic waveforms with a weighting window whose size is approximately two times the period of the signals to weight, and whose relative position inside of the period is fixed to any value identical for all the periods, each extracted from a reharmonized and thus periodic waveform, obtained by modifying, without changing the spectral envelope, the frequencies and amplitudes of harmonics in the spectrum of a frame of the original continuous speech waveform, whereby the time shift between two successive waveforms obtained by weighting the original signals is set to the imposed fundamental frequency of the signal to synthesize.

New techniques for the compression of synthesizer databases

Most state-of-the-art TTS synthesizers are based on a technique known as synthesis by concatenation, in which speech is produced by concatenating elementary speech units. The design of a high-quality TTS implies the storage of a high number of segments. To facilitate the storage of these segments, this paper proposes a very low complexity coder to compress these databases with a toll quality. A particular interest has been taken in the databases of the MBROLA synthesizer constituted of fixed size frames. The developed coder uses this special characteristic to reach compression rates from 7 to 9 without degradation of the speech quality produced by the synthesizer.