Fast, Simpler and More Accurate Hybrid ASR Systems Using Wordpieces
Table 5: Experiment results on internal VideoASR tasks
['Unit', 'Criterion', 'German WER', 'German RTF', 'Turkish WER', 'Turkish RTF']
Stride 2 is used for CE, 4 for chenone-CTC and 8 for WP-CTC training. We find that both CTC systems outperform the baseline CE system. It’s also consistent that chenone-CTC outperforms WP-CTC in terms of WER. On the other hand, WP-CTC system is significantly better in terms of real-time factor (RTF) due to the larger stride used. Blank frame skipping during decoding also contributes to the speedup. We skip frames if blank label posterior is greater than 99%. Empirically, we found that over 20% of the frames in chenone-CTC and over 50% of frames in WP-CTC were skipped.