Optimizing Contextual Speech Recognition Using Vector Quantization for Efficient Retrieval

Fuente: arXiv
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Main Authors: Flemotomos, Nikolaos, Hsiao, Roger, Swietojanski, Pawel, Hori, Takaaki, Can, Dogan, Zhuang, Xiaodan
Format: Preprint
Published: 2024
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author Flemotomos, Nikolaos
Hsiao, Roger
Swietojanski, Pawel
Hori, Takaaki
Can, Dogan
Zhuang, Xiaodan
author_facet Flemotomos, Nikolaos
Hsiao, Roger
Swietojanski, Pawel
Hori, Takaaki
Can, Dogan
Zhuang, Xiaodan
contents Neural contextual biasing allows speech recognition models to leverage contextually relevant information, leading to improved transcription accuracy. However, the biasing mechanism is typically based on a cross-attention module between the audio and a catalogue of biasing entries, which means computational complexity can pose severe practical limitations on the size of the biasing catalogue and consequently on accuracy improvements. This work proposes an approximation to cross-attention scoring based on vector quantization and enables compute- and memory-efficient use of large biasing catalogues. We propose to use this technique jointly with a retrieval based contextual biasing approach. First, we use an efficient quantized retrieval module to shortlist biasing entries by grounding them on audio. Then we use retrieved entries for biasing. Since the proposed approach is agnostic to the biasing method, we investigate using full cross-attention, LLM prompting, and a combination of the two. We show that retrieval based shortlisting allows the system to efficiently leverage biasing catalogues of several thousands of entries, resulting in up to 71% relative error rate reduction in personal entity recognition. At the same time, the proposed approximation algorithm reduces compute time by 20% and memory usage by 85-95%, for lists of up to one million entries, when compared to standard dot-product cross-attention.
format Preprint
id arxiv_https___arxiv_org_abs_2411_00664
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimizing Contextual Speech Recognition Using Vector Quantization for Efficient Retrieval
Flemotomos, Nikolaos
Hsiao, Roger
Swietojanski, Pawel
Hori, Takaaki
Can, Dogan
Zhuang, Xiaodan
Audio and Speech Processing
Computation and Language
Neural contextual biasing allows speech recognition models to leverage contextually relevant information, leading to improved transcription accuracy. However, the biasing mechanism is typically based on a cross-attention module between the audio and a catalogue of biasing entries, which means computational complexity can pose severe practical limitations on the size of the biasing catalogue and consequently on accuracy improvements. This work proposes an approximation to cross-attention scoring based on vector quantization and enables compute- and memory-efficient use of large biasing catalogues. We propose to use this technique jointly with a retrieval based contextual biasing approach. First, we use an efficient quantized retrieval module to shortlist biasing entries by grounding them on audio. Then we use retrieved entries for biasing. Since the proposed approach is agnostic to the biasing method, we investigate using full cross-attention, LLM prompting, and a combination of the two. We show that retrieval based shortlisting allows the system to efficiently leverage biasing catalogues of several thousands of entries, resulting in up to 71% relative error rate reduction in personal entity recognition. At the same time, the proposed approximation algorithm reduces compute time by 20% and memory usage by 85-95%, for lists of up to one million entries, when compared to standard dot-product cross-attention.
title Optimizing Contextual Speech Recognition Using Vector Quantization for Efficient Retrieval
topic Audio and Speech Processing
Computation and Language
url https://arxiv.org/abs/2411.00664