deep_speech

DeepSpeech2 Model

Overview

This is an implementation of the DeepSpeech2 model. Current implementation is based on the code from the authors' DeepSpeech code and the implementation in the MLPerf Repo.

DeepSpeech2 is an end-to-end deep neural network for automatic speech recognition (ASR). It consists of 2 convolutional layers, 5 bidirectional RNN layers and a fully connected layer. The feature in use is linear spectrogram extracted from audio input. The network uses Connectionist Temporal Classification CTC as the loss function.

Dataset

The OpenSLR LibriSpeech Corpus are used for model training and evaluation.

The training data is a combination of train-clean-100 and train-clean-360 (~130k examples in total). The validation set is dev-clean which has 2.7K lines. The download script will preprocess the data into three columns: wav_filename, wav_filesize, transcript. data/dataset.py will parse the csv file and build a tf.data.Dataset object to feed data. Within each epoch (except for the first if sortagrad is enabled), the training data will be shuffled batch-wise.

Running Code

Configure Python path

Add the top-level /models folder to the Python path with the command:

export PYTHONPATH="$PYTHONPATH:/path/to/models"

Install dependencies

First install shared dependencies before running the code. Issue the following command:

pip3 install -r requirements.txt

or

pip install -r requirements.txt

Run each step individually

Download and preprocess dataset

To download the dataset, issue the following command:

python data/download.py

Arguments:

• --data_dir: Directory where to download and save the preprocessed data. By default, it is /tmp/librispeech_data.

Use the --help or -h flag to get a full list of possible arguments.

Train and evaluate model

To train and evaluate the model, issue the following command:

python deep_speech.py

Arguments:

• --model_dir: Directory to save model training checkpoints. By default, it is /tmp/deep_speech_model/.
• --train_data_dir: Directory of the training dataset.
• --eval_data_dir: Directory of the evaluation dataset.
• --num_gpus: Number of GPUs to use (specify -1 if you want to use all available GPUs).

There are other arguments about DeepSpeech2 model and training/evaluation process. Use the --help or -h flag to get a full list of possible arguments with detailed descriptions.

Run the benchmark

A shell script run_deep_speech.sh is provided to run the whole pipeline with default parameters. Issue the following command to run the benchmark:

sh run_deep_speech.sh

Note by default, the training dataset in the benchmark include train-clean-100, train-clean-360 and train-other-500, and the evaluation dataset include dev-clean and dev-other.