Stateful Conformer with Cache-based Inference for Streaming Automatic Speech Recognition

Fuente: arXiv
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Main Authors: Noroozi, Vahid, Majumdar, Somshubra, Kumar, Ankur, Balam, Jagadeesh, Ginsburg, Boris
Format: Preprint
Published: 2023
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author Noroozi, Vahid
Majumdar, Somshubra
Kumar, Ankur
Balam, Jagadeesh
Ginsburg, Boris
author_facet Noroozi, Vahid
Majumdar, Somshubra
Kumar, Ankur
Balam, Jagadeesh
Ginsburg, Boris
contents In this paper, we propose an efficient and accurate streaming speech recognition model based on the FastConformer architecture. We adapted the FastConformer architecture for streaming applications through: (1) constraining both the look-ahead and past contexts in the encoder, and (2) introducing an activation caching mechanism to enable the non-autoregressive encoder to operate autoregressively during inference. The proposed model is thoughtfully designed in a way to eliminate the accuracy disparity between the train and inference time which is common for many streaming models. Furthermore, our proposed encoder works with various decoder configurations including Connectionist Temporal Classification (CTC) and RNN-Transducer (RNNT) decoders. Additionally, we introduced a hybrid CTC/RNNT architecture which utilizes a shared encoder with both a CTC and RNNT decoder to boost the accuracy and save computation. We evaluate the proposed model on LibriSpeech dataset and a multi-domain large scale dataset and demonstrate that it can achieve better accuracy with lower latency and inference time compared to a conventional buffered streaming model baseline. We also showed that training a model with multiple latencies can achieve better accuracy than single latency models while it enables us to support multiple latencies with a single model. Our experiments also showed the hybrid architecture would not only speedup the convergence of the CTC decoder but also improves the accuracy of streaming models compared to single decoder models.
format Preprint
id arxiv_https___arxiv_org_abs_2312_17279
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Stateful Conformer with Cache-based Inference for Streaming Automatic Speech Recognition
Noroozi, Vahid
Majumdar, Somshubra
Kumar, Ankur
Balam, Jagadeesh
Ginsburg, Boris
Computation and Language
Audio and Speech Processing
In this paper, we propose an efficient and accurate streaming speech recognition model based on the FastConformer architecture. We adapted the FastConformer architecture for streaming applications through: (1) constraining both the look-ahead and past contexts in the encoder, and (2) introducing an activation caching mechanism to enable the non-autoregressive encoder to operate autoregressively during inference. The proposed model is thoughtfully designed in a way to eliminate the accuracy disparity between the train and inference time which is common for many streaming models. Furthermore, our proposed encoder works with various decoder configurations including Connectionist Temporal Classification (CTC) and RNN-Transducer (RNNT) decoders. Additionally, we introduced a hybrid CTC/RNNT architecture which utilizes a shared encoder with both a CTC and RNNT decoder to boost the accuracy and save computation. We evaluate the proposed model on LibriSpeech dataset and a multi-domain large scale dataset and demonstrate that it can achieve better accuracy with lower latency and inference time compared to a conventional buffered streaming model baseline. We also showed that training a model with multiple latencies can achieve better accuracy than single latency models while it enables us to support multiple latencies with a single model. Our experiments also showed the hybrid architecture would not only speedup the convergence of the CTC decoder but also improves the accuracy of streaming models compared to single decoder models.
title Stateful Conformer with Cache-based Inference for Streaming Automatic Speech Recognition
topic Computation and Language
Audio and Speech Processing
url https://arxiv.org/abs/2312.17279