Recent Advances in Google Real-time HMM-driven Unit Selection Synthesizer

Siamak Tazari
Hanna Silen
International Speech Communication Association (ISCA), Sep 8--12, San Francisco, USA, pp. 2238-2242

Abstract

This paper presents advances in Google's hidden Markov model (HMM)-driven unit selection speech synthesis system. We describe several improvements to the run-time system; these include minimal
latency, high-quality and fast refresh cycle for new voices. Traditionally unit selection synthesizers are limited in terms of the amount of data they can handle and the real applications they
are built for. That is even more critical for real-life large-scale applications where high-quality is expected and low latency is required given the available computational resources. In this paper we present an optimized engine to handle a large database at runtime, a composite unit search approach for combining diphones and phrase-based units. In addition a new voice building strategy for handling big
databases and keeping the building times low is presented.