Streaming Transformer

This repo contains the streaming Transformer of our work On the Comparison of Popular End-to-End Models for Large Scale Speech Recognition, which is based on ESPnet0.6.0. The streaming Transformer includes a streaming encoder, either chunk-based or look-ahead based, and a trigger-attention based decoder.

We will release following models and show reproducible results on Librispeech

• Streaming_transformer-chunk32 with ESPnet Conv2d Encoder. (https://drive.google.com/file/d/1LSBY_vK50Jxvw_GeiYrPwRtJ0DsKU6zL/view?usp=sharing)

• Streaming_transformer-chunk32 with VGG Encoder. (https://drive.google.com/file/d/12P6TsxtOCxrHezqgtk0USjSKBsYHIe7K/view?usp=sharing)

• Streaming_transformer-lookahead with ESPnet Conv2d Encoder. (https://drive.google.com/file/d/1YJQaofzsk9_KsL2W9Zb42sGLRRIKRs9X/view?usp=sharing)

• Streaming_transformer-lookahead with VGG Encoder. (https://drive.google.com/file/d/1LO_0pPxU5XJffqJMgtx4W4IL-Aih5m0M/view?usp=sharing)

Results on Librispeech (beam=10)

Model	test-clean	test-other	latency	size
streaming_transformer-chunk32-conv2d	2.8	7.5	640ms	78M
streaming_transformer-chunk32-vgg	2.8	7.0	640ms	78M
streaming_transformer-lookahead2-conv2d	3.0	8.6	1230ms	78M
streaming_transformer-lookahead2-vgg	2.8	7.5	1230ms	78M

Installation

Our installation follow the installation process of ESPnet

Step 1. setting of the environment

CUDAROOT=/path/to/cuda

export PATH=$CUDAROOT/bin:$PATH
export LD_LIBRARY_PATH=$CUDAROOT/lib64:$LD_LIBRARY_PATH
export CFLAGS="-I$CUDAROOT/include $CFLAGS"
export CUDA_HOME=$CUDAROOT
export CUDA_PATH=$CUDAROOT`

Step 2. installation including Kaldi

cd tools
make -j 10

Build a streaming Transformer model

Step 1. Data Prepare

cd egs/librispeech/asr1
./run.sh 

By default. the processed data will stored in the current directory. You can change the path by editing the scripts.

Step 2. Viterbi decoding

To train a TA based streaming Transformer, the alignments between CTC paths and transcriptions are required. In our work, we apply Viterbi decoding using the offline Transformer model.

cd egs/librispeech/asr1
./viterbi_decode.sh /path/to/model

Step 3. Train a streaming Transformer

Here, we train a chunk-based streaming Transformer which is initialized with an offline Transformer provided by ESPnet. Set enc-init in conf/train_streaming_transformer.yaml to the path of your offline model.

cd egs/librispeech/asr1
./train.sh

If you want to train a look-ahead based streaming Transformer, set chunk to False and change the left-window, right-window, dec-left-window, dec-right-window arguments. The training log is written in exp/streaming_transformer/train.log. You can monitor the output through tail -f exp/streaming_transformer/train.log

Step 4. Decoding

Execute the following script with to decoding on test_clean and test_other sets

./decode.sh num_of_gpu job_per_gpu

Offline Transformer Reference

Regarding the offline Transformer model, Please visit here