Contrastive self-supervised speaker embedding with sequential disentanglement

Abstract

Contrastive self-supervised learning has been widely used in speaker embedding to address the labeling challenge. Contrastive speaker embedding assumes that the contrast between the positive and negative pairs of speech segments is attributed to speaker identity only. However, this assumption is incorrect because speech signals contain not only speaker identity but also linguistic content. In this paper, we propose a contrastive learning framework with sequential disentanglement to remove linguistic content by incorporating a disentangled sequential variational autoencoder (DSVAE) into the conventional contrastive learning framework. The DSVAE aims to disentangle speaker factors from content factors in an embedding space so that the speaker factors become the main contributor to the contrastive loss. Because content factors have been removed from contrastive learning, the resulting speaker embeddings will be content-invariant. The learned embeddings are also robust to language mismatch. It is shown that the proposed method consistently outperforms the conventional contrastive speaker embedding on the VoxCeleb1 and CN-Celeb datasets. This finding suggests that applying sequential disentanglement is beneficial to learning speaker-discriminative embeddings.