End-to-End Automatic Speech RecognitionIntegrated With CTC-Based Voice Activity Detection
Table 5: Effect of decoding hyperparameters (bi-directional).
['[ITALIC] ms', '[ITALIC] me', 'dev [%]', 'test [%]']
Base2 obtained a lower CER than Base1. This indicates the effectiveness of the data-driven VAD method. Prop achieved further improvement over Base2. CTC is a mapping from acoustic features to characters whereas the standard data-driven VAD is a mapping from acoustic features to a simple binary symbol indicating speech or non-speech. The performance gain may be because the proposed method was able to detect speech considering linguistic information provided by CTC. Prop obtained the best CER regardless of the decoder type. In the following experiments, the joint decoding using the CTC prefix score was used.