DeepSpeech/DeepSpeech.py

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Python
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import absolute_import, division, print_function
import os
import sys
LOG_LEVEL_INDEX = sys.argv.index('--log_level') + 1 if '--log_level' in sys.argv else 0
os.environ['TF_CPP_MIN_LOG_LEVEL'] = sys.argv[LOG_LEVEL_INDEX] if 0 < LOG_LEVEL_INDEX < len(sys.argv) else '3'
import absl.app
import json
import numpy as np
import progressbar
import shutil
import tensorflow as tf
import tensorflow.compat.v1 as tfv1
import time
from datetime import datetime
from ds_ctcdecoder import ctc_beam_search_decoder, Scorer
from evaluate import evaluate
from six.moves import zip, range
from tensorflow.python.tools import freeze_graph, strip_unused_lib
from util.config import Config, initialize_globals
from util.feeding import create_dataset, samples_to_mfccs, audiofile_to_features
from util.flags import create_flags, FLAGS
from util.logging import log_info, log_error, log_debug, log_progress, create_progressbar
# Graph Creation
# ==============
def variable_on_cpu(name, shape, initializer):
r"""
Next we concern ourselves with graph creation.
However, before we do so we must introduce a utility function ``variable_on_cpu()``
used to create a variable in CPU memory.
"""
# Use the /cpu:0 device for scoped operations
with tf.device(Config.cpu_device):
# Create or get apropos variable
var = tfv1.get_variable(name=name, shape=shape, initializer=initializer)
return var
def create_overlapping_windows(batch_x):
batch_size = tf.shape(input=batch_x)[0]
window_width = 2 * Config.n_context + 1
num_channels = Config.n_input
# Create a constant convolution filter using an identity matrix, so that the
# convolution returns patches of the input tensor as is, and we can create
# overlapping windows over the MFCCs.
eye_filter = tf.constant(np.eye(window_width * num_channels)
.reshape(window_width, num_channels, window_width * num_channels), tf.float32) # pylint: disable=bad-continuation
# Create overlapping windows
batch_x = tf.nn.conv1d(input=batch_x, filters=eye_filter, stride=1, padding='SAME')
# Remove dummy depth dimension and reshape into [batch_size, n_windows, window_width, n_input]
batch_x = tf.reshape(batch_x, [batch_size, -1, window_width, num_channels])
return batch_x
def dense(name, x, units, dropout_rate=None, relu=True):
with tfv1.variable_scope(name):
bias = variable_on_cpu('bias', [units], tfv1.zeros_initializer())
weights = variable_on_cpu('weights', [x.shape[-1], units], tfv1.keras.initializers.VarianceScaling(scale=1.0, mode="fan_avg", distribution="uniform"))
output = tf.nn.bias_add(tf.matmul(x, weights), bias)
if relu:
output = tf.minimum(tf.nn.relu(output), FLAGS.relu_clip)
if dropout_rate is not None:
output = tf.nn.dropout(output, rate=dropout_rate)
return output
def rnn_impl_lstmblockfusedcell(x, seq_length, previous_state, reuse):
with tfv1.variable_scope('cudnn_lstm/rnn/multi_rnn_cell/cell_0'):
fw_cell = tf.contrib.rnn.LSTMBlockFusedCell(Config.n_cell_dim,
forget_bias=0,
reuse=reuse,
name='cudnn_compatible_lstm_cell')
output, output_state = fw_cell(inputs=x,
dtype=tf.float32,
sequence_length=seq_length,
initial_state=previous_state)
return output, output_state
def rnn_impl_cudnn_rnn(x, seq_length, previous_state, _):
assert previous_state is None # 'Passing previous state not supported with CuDNN backend'
# Hack: CudnnLSTM works similarly to Keras layers in that when you instantiate
# the object it creates the variables, and then you just call it several times
# to enable variable re-use. Because all of our code is structure in an old
# school TensorFlow structure where you can just call tf.get_variable again with
# reuse=True to reuse variables, we can't easily make use of the object oriented
# way CudnnLSTM is implemented, so we save a singleton instance in the function,
# emulating a static function variable.
if not rnn_impl_cudnn_rnn.cell:
# Forward direction cell:
fw_cell = tf.contrib.cudnn_rnn.CudnnLSTM(num_layers=1,
num_units=Config.n_cell_dim,
input_mode='linear_input',
direction='unidirectional',
dtype=tf.float32)
rnn_impl_cudnn_rnn.cell = fw_cell
output, output_state = rnn_impl_cudnn_rnn.cell(inputs=x,
sequence_lengths=seq_length)
return output, output_state
rnn_impl_cudnn_rnn.cell = None
def rnn_impl_static_rnn(x, seq_length, previous_state, reuse):
with tfv1.variable_scope('cudnn_lstm/rnn/multi_rnn_cell'):
# Forward direction cell:
fw_cell = tfv1.nn.rnn_cell.LSTMCell(Config.n_cell_dim,
reuse=reuse,
name='cudnn_compatible_lstm_cell')
# Split rank N tensor into list of rank N-1 tensors
x = [x[l] for l in range(x.shape[0])]
output, output_state = tfv1.nn.static_rnn(cell=fw_cell,
inputs=x,
sequence_length=seq_length,
initial_state=previous_state,
dtype=tf.float32,
scope='cell_0')
output = tf.concat(output, 0)
return output, output_state
def create_model(batch_x, seq_length, dropout, reuse=False, batch_size=None, previous_state=None, overlap=True, rnn_impl=rnn_impl_lstmblockfusedcell):
layers = {}
# Input shape: [batch_size, n_steps, n_input + 2*n_input*n_context]
if not batch_size:
batch_size = tf.shape(input=batch_x)[0]
# Create overlapping feature windows if needed
if overlap:
batch_x = create_overlapping_windows(batch_x)
# Reshaping `batch_x` to a tensor with shape `[n_steps*batch_size, n_input + 2*n_input*n_context]`.
# This is done to prepare the batch for input into the first layer which expects a tensor of rank `2`.
# Permute n_steps and batch_size
batch_x = tf.transpose(a=batch_x, perm=[1, 0, 2, 3])
# Reshape to prepare input for first layer
batch_x = tf.reshape(batch_x, [-1, Config.n_input + 2*Config.n_input*Config.n_context]) # (n_steps*batch_size, n_input + 2*n_input*n_context)
layers['input_reshaped'] = batch_x
# The next three blocks will pass `batch_x` through three hidden layers with
# clipped RELU activation and dropout.
layers['layer_1'] = layer_1 = dense('layer_1', batch_x, Config.n_hidden_1, dropout_rate=dropout[0])
layers['layer_2'] = layer_2 = dense('layer_2', layer_1, Config.n_hidden_2, dropout_rate=dropout[1])
layers['layer_3'] = layer_3 = dense('layer_3', layer_2, Config.n_hidden_3, dropout_rate=dropout[2])
# `layer_3` is now reshaped into `[n_steps, batch_size, 2*n_cell_dim]`,
# as the LSTM RNN expects its input to be of shape `[max_time, batch_size, input_size]`.
layer_3 = tf.reshape(layer_3, [-1, batch_size, Config.n_hidden_3])
# Run through parametrized RNN implementation, as we use different RNNs
# for training and inference
output, output_state = rnn_impl(layer_3, seq_length, previous_state, reuse)
# Reshape output from a tensor of shape [n_steps, batch_size, n_cell_dim]
# to a tensor of shape [n_steps*batch_size, n_cell_dim]
output = tf.reshape(output, [-1, Config.n_cell_dim])
layers['rnn_output'] = output
layers['rnn_output_state'] = output_state
# Now we feed `output` to the fifth hidden layer with clipped RELU activation
layers['layer_5'] = layer_5 = dense('layer_5', output, Config.n_hidden_5, dropout_rate=dropout[5])
# Now we apply a final linear layer creating `n_classes` dimensional vectors, the logits.
layers['layer_6'] = layer_6 = dense('layer_6', layer_5, Config.n_hidden_6, relu=False)
# Finally we reshape layer_6 from a tensor of shape [n_steps*batch_size, n_hidden_6]
# to the slightly more useful shape [n_steps, batch_size, n_hidden_6].
# Note, that this differs from the input in that it is time-major.
layer_6 = tf.reshape(layer_6, [-1, batch_size, Config.n_hidden_6], name='raw_logits')
layers['raw_logits'] = layer_6
# Output shape: [n_steps, batch_size, n_hidden_6]
return layer_6, layers
# Accuracy and Loss
# =================
# In accord with 'Deep Speech: Scaling up end-to-end speech recognition'
# (http://arxiv.org/abs/1412.5567),
# the loss function used by our network should be the CTC loss function
# (http://www.cs.toronto.edu/~graves/preprint.pdf).
# Conveniently, this loss function is implemented in TensorFlow.
# Thus, we can simply make use of this implementation to define our loss.
def calculate_mean_edit_distance_and_loss(iterator, dropout, reuse):
r'''
This routine beam search decodes a mini-batch and calculates the loss and mean edit distance.
Next to total and average loss it returns the mean edit distance,
the decoded result and the batch's original Y.
'''
# Obtain the next batch of data
batch_filenames, (batch_x, batch_seq_len), batch_y = iterator.get_next()
if FLAGS.use_cudnn_rnn:
rnn_impl = rnn_impl_cudnn_rnn
else:
rnn_impl = rnn_impl_lstmblockfusedcell
# Calculate the logits of the batch
logits, _ = create_model(batch_x, batch_seq_len, dropout, reuse=reuse, rnn_impl=rnn_impl)
# Compute the CTC loss using TensorFlow's `ctc_loss`
total_loss = tfv1.nn.ctc_loss(labels=batch_y, inputs=logits, sequence_length=batch_seq_len)
# Check if any files lead to non finite loss
non_finite_files = tf.gather(batch_filenames, tfv1.where(~tf.math.is_finite(total_loss)))
# Calculate the average loss across the batch
avg_loss = tf.reduce_mean(input_tensor=total_loss)
# Finally we return the average loss
return avg_loss, non_finite_files
# Adam Optimization
# =================
# In contrast to 'Deep Speech: Scaling up end-to-end speech recognition'
# (http://arxiv.org/abs/1412.5567),
# in which 'Nesterov's Accelerated Gradient Descent'
# (www.cs.toronto.edu/~fritz/absps/momentum.pdf) was used,
# we will use the Adam method for optimization (http://arxiv.org/abs/1412.6980),
# because, generally, it requires less fine-tuning.
def create_optimizer():
optimizer = tfv1.train.AdamOptimizer(learning_rate=FLAGS.learning_rate,
beta1=FLAGS.beta1,
beta2=FLAGS.beta2,
epsilon=FLAGS.epsilon)
return optimizer
# Towers
# ======
# In order to properly make use of multiple GPU's, one must introduce new abstractions,
# not present when using a single GPU, that facilitate the multi-GPU use case.
# In particular, one must introduce a means to isolate the inference and gradient
# calculations on the various GPU's.
# The abstraction we intoduce for this purpose is called a 'tower'.
# A tower is specified by two properties:
# * **Scope** - A scope, as provided by `tf.name_scope()`,
# is a means to isolate the operations within a tower.
# For example, all operations within 'tower 0' could have their name prefixed with `tower_0/`.
# * **Device** - A hardware device, as provided by `tf.device()`,
# on which all operations within the tower execute.
# For example, all operations of 'tower 0' could execute on the first GPU `tf.device('/gpu:0')`.
def get_tower_results(iterator, optimizer, dropout_rates):
r'''
With this preliminary step out of the way, we can for each GPU introduce a
tower for which's batch we calculate and return the optimization gradients
and the average loss across towers.
'''
# To calculate the mean of the losses
tower_avg_losses = []
# Tower gradients to return
tower_gradients = []
# Aggregate any non finite files in the batches
tower_non_finite_files = []
with tfv1.variable_scope(tfv1.get_variable_scope()):
# Loop over available_devices
for i in range(len(Config.available_devices)):
# Execute operations of tower i on device i
device = Config.available_devices[i]
with tf.device(device):
# Create a scope for all operations of tower i
with tf.name_scope('tower_%d' % i):
# Calculate the avg_loss and mean_edit_distance and retrieve the decoded
# batch along with the original batch's labels (Y) of this tower
avg_loss, non_finite_files = calculate_mean_edit_distance_and_loss(iterator, dropout_rates, reuse=i > 0)
# Allow for variables to be re-used by the next tower
tfv1.get_variable_scope().reuse_variables()
# Retain tower's avg losses
tower_avg_losses.append(avg_loss)
# Compute gradients for model parameters using tower's mini-batch
gradients = optimizer.compute_gradients(avg_loss)
# Retain tower's gradients
tower_gradients.append(gradients)
tower_non_finite_files.append(non_finite_files)
avg_loss_across_towers = tf.reduce_mean(input_tensor=tower_avg_losses, axis=0)
tfv1.summary.scalar(name='step_loss', tensor=avg_loss_across_towers, collections=['step_summaries'])
all_non_finite_files = tf.concat(tower_non_finite_files, axis=0)
# Return gradients and the average loss
return tower_gradients, avg_loss_across_towers, all_non_finite_files
def average_gradients(tower_gradients):
r'''
A routine for computing each variable's average of the gradients obtained from the GPUs.
Note also that this code acts as a synchronization point as it requires all
GPUs to be finished with their mini-batch before it can run to completion.
'''
# List of average gradients to return to the caller
average_grads = []
# Run this on cpu_device to conserve GPU memory
with tf.device(Config.cpu_device):
# Loop over gradient/variable pairs from all towers
for grad_and_vars in zip(*tower_gradients):
# Introduce grads to store the gradients for the current variable
grads = []
# Loop over the gradients for the current variable
for g, _ in grad_and_vars:
# Add 0 dimension to the gradients to represent the tower.
expanded_g = tf.expand_dims(g, 0)
# Append on a 'tower' dimension which we will average over below.
grads.append(expanded_g)
# Average over the 'tower' dimension
grad = tf.concat(grads, 0)
grad = tf.reduce_mean(input_tensor=grad, axis=0)
# Create a gradient/variable tuple for the current variable with its average gradient
grad_and_var = (grad, grad_and_vars[0][1])
# Add the current tuple to average_grads
average_grads.append(grad_and_var)
# Return result to caller
return average_grads
# Logging
# =======
def log_variable(variable, gradient=None):
r'''
We introduce a function for logging a tensor variable's current state.
It logs scalar values for the mean, standard deviation, minimum and maximum.
Furthermore it logs a histogram of its state and (if given) of an optimization gradient.
'''
name = variable.name.replace(':', '_')
mean = tf.reduce_mean(input_tensor=variable)
tfv1.summary.scalar(name='%s/mean' % name, tensor=mean)
tfv1.summary.scalar(name='%s/sttdev' % name, tensor=tf.sqrt(tf.reduce_mean(input_tensor=tf.square(variable - mean))))
tfv1.summary.scalar(name='%s/max' % name, tensor=tf.reduce_max(input_tensor=variable))
tfv1.summary.scalar(name='%s/min' % name, tensor=tf.reduce_min(input_tensor=variable))
tfv1.summary.histogram(name=name, values=variable)
if gradient is not None:
if isinstance(gradient, tf.IndexedSlices):
grad_values = gradient.values
else:
grad_values = gradient
if grad_values is not None:
tfv1.summary.histogram(name='%s/gradients' % name, values=grad_values)
def log_grads_and_vars(grads_and_vars):
r'''
Let's also introduce a helper function for logging collections of gradient/variable tuples.
'''
for gradient, variable in grads_and_vars:
log_variable(variable, gradient=gradient)
def try_loading(session, saver, checkpoint_filename, caption):
try:
checkpoint = tf.train.get_checkpoint_state(FLAGS.checkpoint_dir, checkpoint_filename)
if not checkpoint:
return False
checkpoint_path = checkpoint.model_checkpoint_path
saver.restore(session, checkpoint_path)
restored_step = session.run(tfv1.train.get_global_step())
log_info('Restored variables from %s checkpoint at %s, step %d' % (caption, checkpoint_path, restored_step))
return True
except tf.errors.InvalidArgumentError as e:
log_error(str(e))
log_error('The checkpoint in {0} does not match the shapes of the model.'
' Did you change alphabet.txt or the --n_hidden parameter'
' between train runs using the same checkpoint dir? Try moving'
' or removing the contents of {0}.'.format(checkpoint_path))
sys.exit(1)
def train():
do_cache_dataset = True
# pylint: disable=too-many-boolean-expressions
if (FLAGS.data_aug_features_multiplicative > 0 or
FLAGS.data_aug_features_additive > 0 or
FLAGS.augmentation_spec_dropout_keeprate < 1 or
FLAGS.augmentation_freq_and_time_masking or
FLAGS.augmentation_pitch_and_tempo_scaling or
FLAGS.augmentation_speed_up_std > 0):
do_cache_dataset = False
# Create training and validation datasets
train_set = create_dataset(FLAGS.train_files.split(','),
batch_size=FLAGS.train_batch_size,
cache_path=FLAGS.feature_cache if do_cache_dataset else None,
train_phase=True)
iterator = tfv1.data.Iterator.from_structure(tfv1.data.get_output_types(train_set),
tfv1.data.get_output_shapes(train_set),
output_classes=tfv1.data.get_output_classes(train_set))
# Make initialization ops for switching between the two sets
train_init_op = iterator.make_initializer(train_set)
if FLAGS.dev_files:
dev_csvs = FLAGS.dev_files.split(',')
dev_sets = [create_dataset([csv], batch_size=FLAGS.dev_batch_size, train_phase=False) for csv in dev_csvs]
dev_init_ops = [iterator.make_initializer(dev_set) for dev_set in dev_sets]
# Dropout
dropout_rates = [tfv1.placeholder(tf.float32, name='dropout_{}'.format(i)) for i in range(6)]
dropout_feed_dict = {
dropout_rates[0]: FLAGS.dropout_rate,
dropout_rates[1]: FLAGS.dropout_rate2,
dropout_rates[2]: FLAGS.dropout_rate3,
dropout_rates[3]: FLAGS.dropout_rate4,
dropout_rates[4]: FLAGS.dropout_rate5,
dropout_rates[5]: FLAGS.dropout_rate6,
}
no_dropout_feed_dict = {
rate: 0. for rate in dropout_rates
}
# Building the graph
optimizer = create_optimizer()
gradients, loss, non_finite_files = get_tower_results(iterator, optimizer, dropout_rates)
# Average tower gradients across GPUs
avg_tower_gradients = average_gradients(gradients)
log_grads_and_vars(avg_tower_gradients)
# global_step is automagically incremented by the optimizer
global_step = tfv1.train.get_or_create_global_step()
apply_gradient_op = optimizer.apply_gradients(avg_tower_gradients, global_step=global_step)
# Summaries
step_summaries_op = tfv1.summary.merge_all('step_summaries')
step_summary_writers = {
'train': tfv1.summary.FileWriter(os.path.join(FLAGS.summary_dir, 'train'), max_queue=120),
'dev': tfv1.summary.FileWriter(os.path.join(FLAGS.summary_dir, 'dev'), max_queue=120)
}
# Checkpointing
checkpoint_saver = tfv1.train.Saver(max_to_keep=FLAGS.max_to_keep)
checkpoint_path = os.path.join(FLAGS.checkpoint_dir, 'train')
checkpoint_filename = 'checkpoint'
best_dev_saver = tfv1.train.Saver(max_to_keep=1)
best_dev_path = os.path.join(FLAGS.checkpoint_dir, 'best_dev')
best_dev_filename = 'best_dev_checkpoint'
# Save flags next to checkpoints
os.makedirs(FLAGS.checkpoint_dir, exist_ok=True)
flags_file = os.path.join(FLAGS.checkpoint_dir, 'flags.txt')
with open(flags_file, 'w') as fout:
fout.write(FLAGS.flags_into_string())
initializer = tfv1.global_variables_initializer()
with tfv1.Session(config=Config.session_config) as session:
log_debug('Session opened.')
# Loading or initializing
loaded = False
# Initialize training from a CuDNN RNN checkpoint
if FLAGS.cudnn_checkpoint:
if FLAGS.use_cudnn_rnn:
log_error('Trying to use --cudnn_checkpoint but --use_cudnn_rnn '
'was specified. The --cudnn_checkpoint flag is only '
'needed when converting a CuDNN RNN checkpoint to '
'a CPU-capable graph. If your system is capable of '
'using CuDNN RNN, you can just specify the CuDNN RNN '
'checkpoint normally with --checkpoint_dir.')
exit(1)
log_info('Converting CuDNN RNN checkpoint from {}'.format(FLAGS.cudnn_checkpoint))
ckpt = tfv1.train.load_checkpoint(FLAGS.cudnn_checkpoint)
missing_variables = []
# Load compatible variables from checkpoint
for v in tfv1.global_variables():
try:
v.load(ckpt.get_tensor(v.op.name), session=session)
except tf.errors.NotFoundError:
missing_variables.append(v)
# Check that the only missing variables are the Adam moment tensors
if any('Adam' not in v.op.name for v in missing_variables):
log_error('Tried to load a CuDNN RNN checkpoint but there were '
'more missing variables than just the Adam moment '
'tensors.')
exit(1)
# Initialize Adam moment tensors from scratch to allow use of CuDNN
# RNN checkpoints.
log_info('Initializing missing Adam moment tensors.')
init_op = tfv1.variables_initializer(missing_variables)
session.run(init_op)
loaded = True
tfv1.get_default_graph().finalize()
if not loaded and FLAGS.load in ['auto', 'last']:
loaded = try_loading(session, checkpoint_saver, checkpoint_filename, 'most recent')
if not loaded and FLAGS.load in ['auto', 'best']:
loaded = try_loading(session, best_dev_saver, best_dev_filename, 'best validation')
if not loaded:
if FLAGS.load in ['auto', 'init']:
log_info('Initializing variables...')
session.run(initializer)
else:
log_error('Unable to load %s model from specified checkpoint dir'
' - consider using load option "auto" or "init".' % FLAGS.load)
sys.exit(1)
def run_set(set_name, epoch, init_op, dataset=None):
is_train = set_name == 'train'
train_op = apply_gradient_op if is_train else []
feed_dict = dropout_feed_dict if is_train else no_dropout_feed_dict
total_loss = 0.0
step_count = 0
step_summary_writer = step_summary_writers.get(set_name)
checkpoint_time = time.time()
# Setup progress bar
class LossWidget(progressbar.widgets.FormatLabel):
def __init__(self):
progressbar.widgets.FormatLabel.__init__(self, format='Loss: %(mean_loss)f')
def __call__(self, progress, data, **kwargs):
data['mean_loss'] = total_loss / step_count if step_count else 0.0
return progressbar.widgets.FormatLabel.__call__(self, progress, data, **kwargs)
prefix = 'Epoch {} | {:>10}'.format(epoch, 'Training' if is_train else 'Validation')
widgets = [' | ', progressbar.widgets.Timer(),
' | Steps: ', progressbar.widgets.Counter(),
' | ', LossWidget()]
suffix = ' | Dataset: {}'.format(dataset) if dataset else None
pbar = create_progressbar(prefix=prefix, widgets=widgets, suffix=suffix).start()
# Initialize iterator to the appropriate dataset
session.run(init_op)
# Batch loop
while True:
try:
_, current_step, batch_loss, problem_files, step_summary = \
session.run([train_op, global_step, loss, non_finite_files, step_summaries_op],
feed_dict=feed_dict)
except tf.errors.OutOfRangeError:
break
if problem_files.size > 0:
problem_files = [f.decode('utf8') for f in problem_files[..., 0]]
log_error('The following files caused an infinite (or NaN) '
'loss: {}'.format(','.join(problem_files)))
total_loss += batch_loss
step_count += 1
pbar.update(step_count)
step_summary_writer.add_summary(step_summary, current_step)
if is_train and FLAGS.checkpoint_secs > 0 and time.time() - checkpoint_time > FLAGS.checkpoint_secs:
checkpoint_saver.save(session, checkpoint_path, global_step=current_step)
checkpoint_time = time.time()
pbar.finish()
mean_loss = total_loss / step_count if step_count > 0 else 0.0
return mean_loss, step_count
log_info('STARTING Optimization')
train_start_time = datetime.utcnow()
best_dev_loss = float('inf')
dev_losses = []
try:
for epoch in range(FLAGS.epochs):
# Training
log_progress('Training epoch %d...' % epoch)
train_loss, _ = run_set('train', epoch, train_init_op)
log_progress('Finished training epoch %d - loss: %f' % (epoch, train_loss))
checkpoint_saver.save(session, checkpoint_path, global_step=global_step)
if FLAGS.dev_files:
# Validation
dev_loss = 0.0
total_steps = 0
for csv, init_op in zip(dev_csvs, dev_init_ops):
log_progress('Validating epoch %d on %s...' % (epoch, csv))
set_loss, steps = run_set('dev', epoch, init_op, dataset=csv)
dev_loss += set_loss * steps
total_steps += steps
log_progress('Finished validating epoch %d on %s - loss: %f' % (epoch, csv, set_loss))
dev_loss = dev_loss / total_steps
dev_losses.append(dev_loss)
if dev_loss < best_dev_loss:
best_dev_loss = dev_loss
save_path = best_dev_saver.save(session, best_dev_path, global_step=global_step, latest_filename=best_dev_filename)
log_info("Saved new best validating model with loss %f to: %s" % (best_dev_loss, save_path))
# Early stopping
if FLAGS.early_stop and len(dev_losses) >= FLAGS.es_steps:
mean_loss = np.mean(dev_losses[-FLAGS.es_steps:-1])
std_loss = np.std(dev_losses[-FLAGS.es_steps:-1])
dev_losses = dev_losses[-FLAGS.es_steps:]
log_debug('Checking for early stopping (last %d steps) validation loss: '
'%f, with standard deviation: %f and mean: %f' %
(FLAGS.es_steps, dev_losses[-1], std_loss, mean_loss))
if dev_losses[-1] > np.max(dev_losses[:-1]) or \
(abs(dev_losses[-1] - mean_loss) < FLAGS.es_mean_th and std_loss < FLAGS.es_std_th):
log_info('Early stop triggered as (for last %d steps) validation loss:'
' %f with standard deviation: %f and mean: %f' %
(FLAGS.es_steps, dev_losses[-1], std_loss, mean_loss))
break
except KeyboardInterrupt:
pass
log_info('FINISHED optimization in {}'.format(datetime.utcnow() - train_start_time))
log_debug('Session closed.')
def test():
evaluate(FLAGS.test_files.split(','), create_model, try_loading)
if FLAGS.test_output_file:
# Save decoded tuples as JSON, converting NumPy floats to Python floats
json.dump(samples, open(FLAGS.test_output_file, 'w'), default=float)
def create_inference_graph(batch_size=1, n_steps=16, tflite=False):
batch_size = batch_size if batch_size > 0 else None
# Create feature computation graph
input_samples = tfv1.placeholder(tf.float32, [Config.audio_window_samples], 'input_samples')
samples = tf.expand_dims(input_samples, -1)
mfccs, _ = samples_to_mfccs(samples, FLAGS.audio_sample_rate)
mfccs = tf.identity(mfccs, name='mfccs')
# Input tensor will be of shape [batch_size, n_steps, 2*n_context+1, n_input]
# This shape is read by the native_client in DS_CreateModel to know the
# value of n_steps, n_context and n_input. Make sure you update the code
# there if this shape is changed.
input_tensor = tfv1.placeholder(tf.float32, [batch_size, n_steps if n_steps > 0 else None, 2 * Config.n_context + 1, Config.n_input], name='input_node')
seq_length = tfv1.placeholder(tf.int32, [batch_size], name='input_lengths')
if batch_size <= 0:
# no state management since n_step is expected to be dynamic too (see below)
previous_state = None
else:
previous_state_c = tfv1.placeholder(tf.float32, [batch_size, Config.n_cell_dim], name='previous_state_c')
previous_state_h = tfv1.placeholder(tf.float32, [batch_size, Config.n_cell_dim], name='previous_state_h')
previous_state = tf.nn.rnn_cell.LSTMStateTuple(previous_state_c, previous_state_h)
# One rate per layer
no_dropout = [None] * 6
if tflite:
rnn_impl = rnn_impl_static_rnn
else:
rnn_impl = rnn_impl_lstmblockfusedcell
logits, layers = create_model(batch_x=input_tensor,
batch_size=batch_size,
seq_length=seq_length if not FLAGS.export_tflite else None,
dropout=no_dropout,
previous_state=previous_state,
overlap=False,
rnn_impl=rnn_impl)
# TF Lite runtime will check that input dimensions are 1, 2 or 4
# by default we get 3, the middle one being batch_size which is forced to
# one on inference graph, so remove that dimension
if tflite:
logits = tf.squeeze(logits, [1])
# Apply softmax for CTC decoder
logits = tf.nn.softmax(logits, name='logits')
if batch_size <= 0:
if tflite:
raise NotImplementedError('dynamic batch_size does not support tflite nor streaming')
if n_steps > 0:
raise NotImplementedError('dynamic batch_size expect n_steps to be dynamic too')
return (
{
'input': input_tensor,
'input_lengths': seq_length,
},
{
'outputs': logits,
},
layers
)
new_state_c, new_state_h = layers['rnn_output_state']
new_state_c = tf.identity(new_state_c, name='new_state_c')
new_state_h = tf.identity(new_state_h, name='new_state_h')
inputs = {
'input': input_tensor,
'previous_state_c': previous_state_c,
'previous_state_h': previous_state_h,
'input_samples': input_samples,
}
if not FLAGS.export_tflite:
inputs['input_lengths'] = seq_length
outputs = {
'outputs': logits,
'new_state_c': new_state_c,
'new_state_h': new_state_h,
'mfccs': mfccs,
}
return inputs, outputs, layers
def file_relative_read(fname):
return open(os.path.join(os.path.dirname(__file__), fname)).read()
def export():
r'''
Restores the trained variables into a simpler graph that will be exported for serving.
'''
log_info('Exporting the model...')
from tensorflow.python.framework.ops import Tensor, Operation
inputs, outputs, _ = create_inference_graph(batch_size=FLAGS.export_batch_size, n_steps=FLAGS.n_steps, tflite=FLAGS.export_tflite)
output_names_tensors = [tensor.op.name for tensor in outputs.values() if isinstance(tensor, Tensor)]
output_names_ops = [op.name for op in outputs.values() if isinstance(op, Operation)]
output_names = ",".join(output_names_tensors + output_names_ops)
# Create a saver using variables from the above newly created graph
saver = tfv1.train.Saver()
# Restore variables from training checkpoint
checkpoint = tf.train.get_checkpoint_state(FLAGS.checkpoint_dir)
checkpoint_path = checkpoint.model_checkpoint_path
output_filename = 'output_graph.pb'
if FLAGS.remove_export:
if os.path.isdir(FLAGS.export_dir):
log_info('Removing old export')
shutil.rmtree(FLAGS.export_dir)
try:
output_graph_path = os.path.join(FLAGS.export_dir, output_filename)
if not os.path.isdir(FLAGS.export_dir):
os.makedirs(FLAGS.export_dir)
def do_graph_freeze(output_file=None, output_node_names=None, variables_blacklist=''):
frozen = freeze_graph.freeze_graph_with_def_protos(
input_graph_def=tfv1.get_default_graph().as_graph_def(),
input_saver_def=saver.as_saver_def(),
input_checkpoint=checkpoint_path,
output_node_names=output_node_names,
restore_op_name=None,
filename_tensor_name=None,
output_graph=output_file,
clear_devices=False,
variable_names_blacklist=variables_blacklist,
initializer_nodes='')
input_node_names = []
return strip_unused_lib.strip_unused(
input_graph_def=frozen,
input_node_names=input_node_names,
output_node_names=output_node_names.split(','),
placeholder_type_enum=tf.float32.as_datatype_enum)
if not FLAGS.export_tflite:
frozen_graph = do_graph_freeze(output_node_names=output_names)
frozen_graph.version = int(file_relative_read('GRAPH_VERSION').strip())
# Add a no-op node to the graph with metadata information to be loaded by the native client
metadata = frozen_graph.node.add()
metadata.name = 'model_metadata'
metadata.op = 'NoOp'
metadata.attr['sample_rate'].i = FLAGS.audio_sample_rate
metadata.attr['feature_win_len'].i = FLAGS.feature_win_len
metadata.attr['feature_win_step'].i = FLAGS.feature_win_step
if FLAGS.export_language:
metadata.attr['language'].s = FLAGS.export_language.encode('ascii')
with open(output_graph_path, 'wb') as fout:
fout.write(frozen_graph.SerializeToString())
else:
frozen_graph = do_graph_freeze(output_node_names=output_names)
output_tflite_path = os.path.join(FLAGS.export_dir, output_filename.replace('.pb', '.tflite'))
converter = tf.lite.TFLiteConverter(frozen_graph, input_tensors=inputs.values(), output_tensors=outputs.values())
converter.optimizations = [ tf.lite.Optimize.DEFAULT ]
# AudioSpectrogram and Mfcc ops are custom but have built-in kernels in TFLite
converter.allow_custom_ops = True
tflite_model = converter.convert()
with open(output_tflite_path, 'wb') as fout:
fout.write(tflite_model)
log_info('Exported model for TF Lite engine as {}'.format(os.path.basename(output_tflite_path)))
log_info('Models exported at %s' % (FLAGS.export_dir))
except RuntimeError as e:
log_error(str(e))
def do_single_file_inference(input_file_path):
with tfv1.Session(config=Config.session_config) as session:
inputs, outputs, _ = create_inference_graph(batch_size=1, n_steps=-1)
# Create a saver using variables from the above newly created graph
saver = tfv1.train.Saver()
# Restore variables from training checkpoint
# TODO: This restores the most recent checkpoint, but if we use validation to counteract
# over-fitting, we may want to restore an earlier checkpoint.
checkpoint = tf.train.get_checkpoint_state(FLAGS.checkpoint_dir)
if not checkpoint:
log_error('Checkpoint directory ({}) does not contain a valid checkpoint state.'.format(FLAGS.checkpoint_dir))
exit(1)
checkpoint_path = checkpoint.model_checkpoint_path
saver.restore(session, checkpoint_path)
features, features_len = audiofile_to_features(input_file_path)
previous_state_c = np.zeros([1, Config.n_cell_dim])
previous_state_h = np.zeros([1, Config.n_cell_dim])
# Add batch dimension
features = tf.expand_dims(features, 0)
features_len = tf.expand_dims(features_len, 0)
# Evaluate
features = create_overlapping_windows(features).eval(session=session)
features_len = features_len.eval(session=session)
logits = outputs['outputs'].eval(feed_dict={
inputs['input']: features,
inputs['input_lengths']: features_len,
inputs['previous_state_c']: previous_state_c,
inputs['previous_state_h']: previous_state_h,
}, session=session)
logits = np.squeeze(logits)
if FLAGS.lm_binary_path:
scorer = Scorer(FLAGS.lm_alpha, FLAGS.lm_beta,
FLAGS.lm_binary_path, FLAGS.lm_trie_path,
Config.alphabet)
else:
scorer = None
decoded = ctc_beam_search_decoder(logits, Config.alphabet, FLAGS.beam_width, scorer=scorer)
# Print highest probability result
print(decoded[0][1])
def main(_):
initialize_globals()
if FLAGS.train_files:
tfv1.reset_default_graph()
tfv1.set_random_seed(FLAGS.random_seed)
train()
if FLAGS.test_files:
tfv1.reset_default_graph()
test()
if FLAGS.export_dir:
tfv1.reset_default_graph()
export()
if FLAGS.one_shot_infer:
tfv1.reset_default_graph()
do_single_file_inference(FLAGS.one_shot_infer)
if __name__ == '__main__':
create_flags()
absl.app.run(main)