Parametric Vocoder Parameter Prediction from Prosodic Features

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Solution Overview

Problem

Existing text-to-speech (TTS) models, particularly parametric vocoders, struggle to effectively model prosody, leading to synthesized speech that lacks expressiveness as they require additional vocoder parameters beyond prosodic features like pitch, energy, and phoneme duration.

Innovation Solution

A method and system that predict parametric vocoder parameters from prosodic features using a combination of a prosody model and a neural network vocoder model, where the prosody model predicts initial prosodic features and the vocoder model generates the remaining required parameters, such as Mel-cepstrum coefficients and voicing components, to drive the parametric vocoder for improved prosody in synthesized speech.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional concatenative and parametric synthesis models are used, then intelligible speech can be generated, but the synthesized speech lacks expressiveness due to ineffective prosody modeling

Engineering Contradiction:
ImproveintelligibilityVSAvoidexpressiveness
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system segments the speech synthesis process into distinct modules: a prosody model that generates prosodic features (duration, pitch contour, energy contour) and a vocoder model that converts these features into vocoder parameters. This segmentation allows each module to specialize in specific aspects of speech synthesis, with the prosody model focusing on expressive prosodic features and the vocoder model handling the conversion to final speech parameters, thereby resolving the contradiction between maintaining intelligibility and improving expressiveness.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If variational autoencoders are used to predict prosodic features, then prosody modeling is improved, but the predicted features are insufficient for driving parametric vocoders which require additional vocoder parameters

Engineering Contradiction:
Improveprosody modeling capabilityVSAvoidvocoder parameters
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The prosody model performs preliminary action by predicting prosodic features (duration, pitch contour, energy contour) in advance, which are then used as input to the vocoder model. The vocoder model subsequently generates the additional vocoder parameters (Mel-cepstrum coefficients, aperiodicity, voicing) that are necessary for driving the parametric vocoder. This preliminary action approach ensures that all necessary parameters are prepared before final speech synthesis, resolving the information gap between prosody prediction and vocoder requirements.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If prosodic features alone are provided to a parametric vocoder, then the system is simple to operate, but the vocoder cannot generate speech with proper prosody due to insufficient parameters

Engineering Contradiction:
Improvesystem simplicityVSAvoidprosody accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The vocoder model serves as an intermediary between the prosody model and the parametric vocoder. It receives prosodic features from the prosody model and transforms them into complete vocoder parameters by predicting additional features (Mel-cepstrum coefficients, aperiodicity, voicing) that the parametric vocoder requires. This intermediary role maintains system simplicity while ensuring prosody accuracy, as the vocoder model automatically generates all necessary parameters without requiring complex manual configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS12125469B2Predicting parametric vocoder parameters from prosodic features
Publication Date: 2024.10.22 GOOGLE LLC
  • US12125469B2 patent drawing
  • US12125469B2 patent drawing
  • US12125469B2 patent drawing

AI summary

A method for predicting parametric vocoder parameter includes receiving a text utterance having one or more words, each word having one or more syllables, and each syllable having one or more phonemes. The method also includes receiving, as input to a vocoder model, prosodic features that represent an intended prosody for the text utterance and a linguistic specification. The prosodic features include a duration, pitch contour, and energy contour for the text utterance, while the linguistic specification includes sentence-level linguistic features, word-level linguistic features for each word, syllable-level linguistic features for each syllable, and phoneme-level linguistic features for each phoneme. The method also includes predicting vocoder parameters based on the prosodic features and the linguistic specification. The method also includes providing the predicted vocoder parameters and the prosodic features to a parametric vocoder configured to generate a synthesized speech representation of the text utterance having the intended prosody.