Streaming Transformer-based Acoustic Models Using Self-attention with Augmented Memory
Table 1: Effect of segment, left and right context length on LibriSpeech. Length is measured by number of frames, where frames are shifted in a 10ms frame rate.
['Left', 'Segment', 'Right', 'test-clean', 'test-other']
The first block shows the results without context. By increasing the segment length from 64 to 128 frames, the word error rate (WER) decreased. Next, various context settings were investigated with the segment length fixed to 128 frames. The second and third blocks illustrate the effect of left and right contexts, respectively. Either left or right contexts contributed to alleviating the boundary effect. A more extended context was shown to improve the recognition accuracy. Finally, the effect of using both contexts was shown in the fourth block. The left and right contexts showed some level of complementarity; thus, the performance further improved.