Papers › CAT: A CTC-CRF based ASR Toolkit Bridging the Hybrid and the End-to-end Approaches...

CAT: A CTC-CRF based ASR Toolkit Bridging the Hybrid and the End-to-end Approaches towards Data Efficiency and Low Latency

27 May 2020arXiv:2005.13326archive 2025-07-28

Keyu An, Hongyu Xiang, Zhijian Ou

In this paper, we present a new open source toolkit for speech recognition, named CAT (CTC-CRF based ASR Toolkit). CAT inherits the data-efficiency of the hybrid approach and the simplicity of the E2E approach, providing a full-fledged implementation of CTC-CRFs and complete training and testing scripts for a number of English and Chinese benchmarks. Experiments show CAT obtains state-of-the-art results, which are comparable to the fine-tuned hybrid models in Kaldi but with a much simpler training pipeline. Compared to existing non-modularized E2E models, CAT performs better on limited-scale datasets, demonstrating its data efficiency. Furthermore, we propose a new method called contextualized soft forgetting, which enables CAT to do streaming ASR without accuracy degradation. We hope CAT, especially the CTC-CRF based framework and software, will be of broad interest to the community, and can be further explored and improved.

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Tasks

Speech Recognitionspeech-recognition

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Speech Recognition AISHELL-1 CTC-CRF 4gram-LM Word Error Rate (WER) 6.34 #15 of 18 Archive leaderboard report
Speech Recognition Hub5'00 FISHER-SWBD CTC-CRF Word Error Rate (WER) 12 #1 of 1 Archive leaderboard report
Speech Recognition Hub5'00 SwitchBoard CTC-CRF CallHome 18.4 #4 of 5 Archive leaderboard report
Speech Recognition Hub5'00 SwitchBoard CTC-CRF Hub5'00 14.1 #4 of 5 Archive leaderboard report
Speech Recognition Hub5'00 SwitchBoard CTC-CRF SwitchBoard 9.7 #4 of 5 Archive leaderboard report
Speech Recognition WSJ dev93 CTC-CRF VGG-BLSTM Word Error Rate (WER) 5.7 #2 of 4 Archive leaderboard report
Speech Recognition WSJ eval92 CTC-CRF VGG-BLSTM Word Error Rate (WER) 3.2 #9 of 17 Archive leaderboard report

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