1,247 research outputs found
A Comparative Study on Transformer vs RNN in Speech Applications
Sequence-to-sequence models have been widely used in end-to-end speech
processing, for example, automatic speech recognition (ASR), speech translation
(ST), and text-to-speech (TTS). This paper focuses on an emergent
sequence-to-sequence model called Transformer, which achieves state-of-the-art
performance in neural machine translation and other natural language processing
applications. We undertook intensive studies in which we experimentally
compared and analyzed Transformer and conventional recurrent neural networks
(RNN) in a total of 15 ASR, one multilingual ASR, one ST, and two TTS
benchmarks. Our experiments revealed various training tips and significant
performance benefits obtained with Transformer for each task including the
surprising superiority of Transformer in 13/15 ASR benchmarks in comparison
with RNN. We are preparing to release Kaldi-style reproducible recipes using
open source and publicly available datasets for all the ASR, ST, and TTS tasks
for the community to succeed our exciting outcomes.Comment: Accepted at ASRU 201
Low-Latency Sequence-to-Sequence Speech Recognition and Translation by Partial Hypothesis Selection
Encoder-decoder models provide a generic architecture for
sequence-to-sequence tasks such as speech recognition and translation. While
offline systems are often evaluated on quality metrics like word error rates
(WER) and BLEU, latency is also a crucial factor in many practical use-cases.
We propose three latency reduction techniques for chunk-based incremental
inference and evaluate their efficiency in terms of accuracy-latency trade-off.
On the 300-hour How2 dataset, we reduce latency by 83% to 0.8 second by
sacrificing 1% WER (6% rel.) compared to offline transcription. Although our
experiments use the Transformer, the hypothesis selection strategies are
applicable to other encoder-decoder models. To avoid expensive re-computation,
we use a unidirectionally-attending encoder. After an adaptation procedure to
partial sequences, the unidirectional model performs on-par with the original
model. We further show that our approach is also applicable to low-latency
speech translation. On How2 English-Portuguese speech translation, we reduce
latency to 0.7 second (-84% rel.) while incurring a loss of 2.4 BLEU points (5%
rel.) compared to the offline system
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