Converting Anyone's Voice: End-to-End Expressive Voice Conversion with a Conditional Diffusion Model
Zongyang Du, Junchen Lu, Kun Zhou, Lakshmish Kaushik, Berrak Sisman
TL;DR
This paper addresses expressive voice conversion for emotional speakers and the limitations of vocoder-reliant approaches. It introduces DEVC, a fully end-to-end expressive VC framework that uses a conditional diffusion model with content conditioning from soft speech units and deep features from speech emotion recognition and speaker verification. The authors show that speaker embeddings learned from neutral speech contain speaker-dependent emotional cues and that combining speaker-dependent and speaker-independent emotional representations enables any-to-any conversion. Experiments on the ESD dataset demonstrate improvements in objective and subjective metrics, and the method operates without a vocoder, enabling flexible, high-quality expressive VC for seen and unseen speakers.
Abstract
Expressive voice conversion (VC) conducts speaker identity conversion for emotional speakers by jointly converting speaker identity and emotional style. Emotional style modeling for arbitrary speakers in expressive VC has not been extensively explored. Previous approaches have relied on vocoders for speech reconstruction, which makes speech quality heavily dependent on the performance of vocoders. A major challenge of expressive VC lies in emotion prosody modeling. To address these challenges, this paper proposes a fully end-to-end expressive VC framework based on a conditional denoising diffusion probabilistic model (DDPM). We utilize speech units derived from self-supervised speech models as content conditioning, along with deep features extracted from speech emotion recognition and speaker verification systems to model emotional style and speaker identity. Objective and subjective evaluations show the effectiveness of our framework. Codes and samples are publicly available.
