Speaker Codes Research Articles

Deep Gaussian process based multi-speaker speech synthesis with latent speaker representation

This paper proposes deep Gaussian process (DGP)-based frameworks for multi-speaker speech synthesis and speaker representation learning. A DGP has a deep architecture of Bayesian kernel regression, and it has been reported that DGP-based single speaker speech synthesis outperforms deep neural network (DNN)-based ones in the framework of statistical parametric speech synthesis. By extending this method to multiple speakers, it is expected that higher speech quality can be achieved with a smaller number of training utterances from each speaker. To apply DGPs to multi-speaker speech synthesis, we propose two methods: one using DGP with one-hot speaker codes, and the other using a deep Gaussian process latent variable model (DGPLVM). The DGP with one-hot speaker codes uses additional GP layers to transform speaker codes into latent speaker representations. The DGPLVM directly models the distribution of latent speaker representations and learns it jointly with acoustic model parameters. In this method, acoustic speaker similarity is expressed in terms of the similarity of the speaker representations, and thus, the voices of similar speakers are efficiently modeled. We experimentally evaluated the performance of the proposed methods in comparison with those of conventional DNN and variational autoencoder (VAE)-based frameworks, in terms of acoustic feature distortion and subjective speech quality. The experimental results demonstrate that (1) the proposed DGP-based and DGPLVM-based methods improve subjective speech quality compared with a feed-forward DNN-based method, and (2) even when the amount of training data for target speakers is limited, the DGPLVM-based method outperforms other methods, including the VAE-based one. Additionally, (3) by using a speaker representation randomly sampled from the learned speaker space, the DGPLVM-based method can generate voices of non-existent speakers.

DNN-Based Speech Synthesis Using Speaker Codes

DNN-Based Speech Synthesis Using Speaker Codes

Fast Adaptation of Deep Neural Network Based on Discriminant Codes for Speech Recognition

Fast adaptation of deep neural networks (DNN) is an important research topic in deep learning. In this paper, we have proposed a general adaptation scheme for DNN based on discriminant condition codes, which are directly fed to various layers of a pre-trained DNN through a new set of connection weights. Moreover, we present several training methods to learn connection weights from training data as well as the corresponding adaptation methods to learn new condition code from adaptation data for each new test condition. In this work, the fast adaptation scheme is applied to supervised speaker adaptation in speech recognition based on either frame-level cross-entropy or sequence-level maximum mutual information training criterion. We have proposed three different ways to apply this adaptation scheme based on the so-called speaker codes: i) Nonlinear feature normalization in feature space; ii) Direct model adaptation of DNN based on speaker codes; iii) Joint speaker adaptive training with speaker codes. We have evaluated the proposed adaptation methods in two standard speech recognition tasks, namely TIMIT phone recognition and large vocabulary speech recognition in the Switchboard task. Experimental results have shown that all three methods are quite effective to adapt large DNN models using only a small amount of adaptation data. For example, the Switchboard results have shown that the proposed speaker-code-based adaptation methods may achieve up to 8-10% relative error reduction using only a few dozens of adaptation utterances per speaker. Finally, we have achieved very good performance in Switchboard (12.1% in WER) after speaker adaptation using sequence training criterion, which is very close to the best performance reported in this task (“Deep convolutional neural networks for LVCSR,” T. N. Sainath , Proc. IEEE Acoust., Speech, Signal Process., 2013).