deepasr 0.0.2

Keras(Tensorflow) implementations of Automatic Speech Recognition

DeepAsr

DeepAsr is an open-source implementation of end-to-end Automatic Speech Recognition (ASR) engine.

DeepAsr will provide multiple Speech Recognition architectures, Currenly it provides Baidu's Deep Speech 2 using Keras (Tensorflow).

Using DeepAsr you can:

• perform speech-to-text using pre-trained models
• tune pre-trained models to your needs
• create new models on your own

DeepAsr key features:

• Multi GPU support: You can do much more like distribute the training using the Strategy, or experiment with mixed precision policy.
• CuDNN support: Model using CuDNNLSTM implementation by NVIDIA Developers. CPU devices is also supported.
• DataGenerator: The feature extraction (on CPU) can be parallel to model training (on GPU).

import numpy as np
import pandas as pd
import tensorflow as tf
import deepasr as asr

def get_config(features, multi_gpu):
    alphabet_en = asr.vocab.Alphabet(lang='en')
    if features == 'fbank':
        features_extractor = asr.features.FilterBanks(features_num=161,
                                                      winlen=0.02,
                                                      winstep=0.01,
                                                      winfunc=np.hanning)
    else:
        features_extractor = asr.features.Spectrogram(
            features_num=161,
            samplerate=16000,
            winlen=0.02,
            winstep=0.01,
            winfunc=np.hanning
        )
    model = asr.model.get_deepspeech2_v1(
        input_dim=161,
        output_dim=29,
        is_mixed_precision=True
        )
    optimizer = tf.keras.optimizers.Adam(
        lr=1e-4,
        beta_1=0.9,
        beta_2=0.999,
        epsilon=1e-8
        )
    decoder = asr.decoder.GreedyDecoder()

    pipeline = asr.pipeline.ctc_pipeline.CTCPipeline(
        alphabet=alphabet_en, features_extractor=features_extractor, model=model, optimizer=optimizer, decoder=decoder,
        sample_rate=16000, mono=True, multi_gpu=multi_gpu
    )
    return pipeline

def run(train_data, test_data, features='fbank', batch_size=32, epochs=10, multi_gpu=True):
    pipeline = get_config(features, multi_gpu)
    history = pipeline.fit_generator(train_data, batch_size=batch_size, epochs=epochs)
    pipeline.save('./checkpoints')
    print("Truth:", test_data['transcripts'].to_list()[0])
    print("Prediction", pipeline.predict(test_data['path'].to_list()[0]))
    return history

train = pd.read_csv('train_data.csv')
test = pd.read_csv('test_data.csv')
run(train, test, features='fbank', batch_size=32, epochs=100, multi_gpu=True)

Installation

You can use pip:

pip install deepasr

Getting started

The speech recognition is a tough task. You don't need to know all details to use one of the pretrained models. However it's worth to understand conceptional crucial components:

• Input: WAVE files with mono 16-bit 16 kHz (up to 5 seconds)
• FeaturesExtractor: Convert audio files using MFCC Features or Spectrogram
• Model: CTC model defined in Keras (references: [1], [2])
• Decoder: Greedy algorithm with the language model support decode a sequence of probabilities using Alphabet
• DataGenerator: Stream data to the model via generator
• Callbacks: Set of functions monitoring the training

Loaded pre-trained model has all components. The prediction can be invoked just by calling pipline.predict().

import pandas as pd
import deepasr as asr
pipeline = asr.pipeline.get_pipeline.load('./checkpoints')
test_data = pd.read_csv('test_data.csv')
print("Truth:", test_data['transcripts'].to_list()[0])
print("Prediction", pipeline.predict(test_data['path'].to_list()[0]))

References

The fundamental repositories:

• Baidu - DeepSpeech2 - A PaddlePaddle implementation of DeepSpeech2 architecture for ASR
• NVIDIA - Toolkit for efficient experimentation with Speech Recognition, Text2Speech and NLP
• TensorFlow - The implementation of DeepSpeech2 model
• Mozilla - DeepSpeech - A TensorFlow implementation of Baidu's DeepSpeech architecture
• Espnet - End-to-End Speech Processing Toolkit
• Automatic Speech Recognition - Distill the Automatic Speech Recognition research