Teacher-Student Vocoder Network for Efficient Waveform Synthesis

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Solution Overview

Problem

Existing generative models, such as GANs and VAEs, face challenges in producing realistic and efficient waveform synthesis for speech and image generation due to instability in adversarial optimization and slow inference times, while flow-based models offer invertibility and exact likelihood computation but are computationally inefficient.

Innovation Solution

A teacher-student network is implemented, where a pre-trained flow-based model with invertible blocks serves as the teacher and an untrained feed-forward model with non-invertible blocks acts as the student, allowing for knowledge distillation to create a more compact and efficient model for speech synthesis and super-resolution applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flow-based models are used for waveform generation, then invertibility and exact likelihood computation are achieved, but computational efficiency deteriorates

Engineering Contradiction:
Improveinvertibility and exact likelihood computationVSAvoidcomputational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The model is segmented into two distinct components: a flow-based teacher model that provides invertibility and exact likelihood computation, and a feed-forward student model that provides computational efficiency. Each segment handles different aspects of the generation task, allowing the system to benefit from both approaches without the trade-offs of using a single model type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The student model acts as an intermediary between the teacher model and the actual generation task. It learns to approximate the teacher's output distribution and can generate samples without requiring the computationally intensive invertible transformations, thus mediating between the need for reliability and productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If GANs are used for waveform synthesis, then generation quality improves, but training stability deteriorates

Engineering Contradiction:
Improvegeneration qualityVSAvoidtraining stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The teacher-student framework serves as an intermediary training mechanism that avoids the adversarial game between generator and discriminator. The student model is trained to match the teacher's output distribution using direct supervision from the teacher's samples and likelihoods, eliminating the training instability of GANs while preserving generation quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The student model copies the generation capabilities of the pre-trained teacher model by learning to reproduce its output distribution. This copying approach allows the system to achieve high generation quality without needing to re-train the complex adversarial dynamics of GANs, thus improving training stability.

Inventive Principle:
Principle #26Copying

3Productivity

If feed-forward models are used for waveform generation, then inference speed improves, but model quality deteriorates

Engineering Contradiction:
Improveinference speedVSAvoidmodel quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The teacher model is pre-trained to achieve high generation quality using flow-based methods. This preliminary action of pre-training the teacher allows the subsequent student model to learn from high-quality samples without needing to develop its own complex inversion mechanisms, thus achieving fast inference while maintaining quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The student model copies the high-quality generation capabilities of the teacher by learning its output distribution. This copying strategy enables the feed-forward architecture to achieve inference speeds comparable to simple models while maintaining the generation quality of the complex flow-based teacher.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS12175995B2Method and a server for generating a waveform
Publication Date: 2024.12.24 Y E HUB ARMENIA LLC
  • US12175995B2 patent drawing
  • US12175995B2 patent drawing
  • US12175995B2 patent drawing

AI summary

There is provided servers and methods of generating a waveform based on a spectrogram and a noise input. The method includes acquiring a trained flow-based vocoder including invertible blocks, and an untrained feed-forward vocoder including non-invertible blocks, which form a student-teacher network. The method includes executing a training process in the student-teacher network during which the server generates (i) a teacher waveform by the trained flow-based vocoder using a first spectrogram and a first noise input, (ii) a student waveform by the untrained feed-forward vocoder using the first spectrogram and the first noise input, and (iii) a loss value for the given training iteration using the teacher waveform and the student waveform. The server then trains the untrained feed-forward vocoder to generate the waveform. The trained feed-forward vocoder in then used lieu of the trained flow-based vocoder for generating waveforms based on spectrograms and noise inputs.