Mask-Conformer Speech Recognition with Mask-Predict Decoder

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Solution Overview

Problem

Recent advancements in speech recognition have focused on improving the acoustic encoder, leading to a decline in the influence and development of the decoder, which is crucial for learning output dependencies at the token level, resulting in limited advancements in speech recognition models.

Innovation Solution

The integration of a mask-predict decoder into the acoustic encoder allows for a two-pass process in speech recognition, where a first pass generates initial transcriptions and masked outputs, and a second pass performs cross-attention to refine the transcriptions, enabling the backpropagation of lexical information and improving decoder performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the acoustic encoder capacity is enlarged for pre-training, then speech recognition performance improves, but the decoder's ability to learn output dependencies deteriorates

Engineering Contradiction:
Improvespeech recognition performanceVSAvoiddecoder's ability to learn output dependencies
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent merges the decoder's language modeling capability with the acoustic encoder by integrating a mask-predict decoder into the encoder architecture. This allows the encoder to simultaneously perform acoustic encoding and learn output dependencies through lexical information backpropagation, resolving the contradiction between encoder capacity and decoder adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback by backpropagating lexical information from the decoder to the acoustic encoder through the mask-predict decoder. This feedback mechanism enables the encoder to learn from the decoder's language modeling outcomes, allowing both components to improve together rather than in opposition.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the acoustic encoder is optimized, then transcription accuracy improves, but decoder development and advancement stagnate

Engineering Contradiction:
Improvetranscription accuracyVSAvoiddecoder development progress
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The mask-predict decoder provides multi-functionality by serving both as part of the acoustic encoding process and as a language modeling component. This universal structure allows simultaneous optimization of transcription accuracy through encoder improvements and decoder development through integrated language modeling, eliminating the need to choose between the two.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If lexical information is integrated into the acoustic encoder, then output dependency learning improves, but model complexity increases

Engineering Contradiction:
Improveoutput dependency learningVSAvoidmodel complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

By merging the language modeling function into the acoustic encoder through the mask-predict decoder, the patent reduces overall model complexity. Instead of maintaining separate encoder and decoder components with distinct training objectives, the integrated architecture allows both functions to operate within a unified framework, simplifying the system while improving output dependency learning.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS20240296837A1Mask-conformer augmenting conformer with mask-predict decoder unifying speech recognition and rescoring
Publication Date: 2024.09.05 GOOGLE LLC
  • US20240296837A1 patent drawing
  • US20240296837A1 patent drawing
  • US20240296837A1 patent drawing

AI summary

A method includes receiving a sequence of acoustic frames characterizing an utterance. During a first pass, the method includes generating first-pass audio encodings based on the sequence of acoustic frames using a stack of mask-conformer blocks of an acoustic encoder, generating a first-pass transcription of the utterance based on the first-pass audio encodings using a speech recognition decoder, and generating a first-pass masked output sequence using a mask-predict decoder of the acoustic encoder. During a second pass, the method includes generating second-pass audio encodings by performing cross-attention on the sequence of acoustic frames and the masked first-pass transcription using the stack of mask-conformer blocks of the acoustic encoder and generating a second-pass transcription of the utterance based on the second-pass audio encodings using the speech recognition decoder.