# Copyright 2016 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS-IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Provides readers configured for different datasets."""
import tensorflow as tf
import utils
from tensorflow import logging
def resize_axis(tensor, axis, new_size, fill_value=0):
"""Truncates or pads a tensor to new_size on on a given axis.
Truncate or extend tensor such that tensor.shape[axis] == new_size. If the
size increases, the padding will be performed at the end, using fill_value.
Args:
tensor: The tensor to be resized.
axis: An integer representing the dimension to be sliced.
new_size: An integer or 0d tensor representing the new value for
tensor.shape[axis].
fill_value: Value to use to fill any new entries in the tensor. Will be
cast to the type of tensor.
Returns:
The resized tensor.
"""
tensor = tf.convert_to_tensor(tensor)
shape = tf.unstack(tf.shape(tensor))
pad_shape = shape[:]
pad_shape[axis] = tf.maximum(0, new_size - shape[axis])
shape[axis] = tf.minimum(shape[axis], new_size)
shape = tf.stack(shape)
resized = tf.concat([
tf.slice(tensor, tf.zeros_like(shape), shape),
tf.fill(tf.stack(pad_shape), tf.cast(fill_value, tensor.dtype))
], axis)
# Update shape.
new_shape = tensor.get_shape().as_list() # A copy is being made.
new_shape[axis] = new_size
resized.set_shape(new_shape)
return resized
class BaseReader(object):
"""Inherit from this class when implementing new readers."""
def prepare_reader(self, unused_filename_queue):
"""Create a thread for generating prediction and label tensors."""
raise NotImplementedError()
class YT8MAggregatedFeatureReader(BaseReader):
"""Reads TFRecords of pre-aggregated Examples.
The TFRecords must contain Examples with a sparse int64 'labels' feature and
a fixed length float32 feature, obtained from the features in 'feature_name'.
The float features are assumed to be an average of dequantized values.
"""
def __init__(self,
num_classes=4716,
feature_sizes=[1024],
feature_names=["mean_inc3"]):
"""Construct a YT8MAggregatedFeatureReader.
Args:
num_classes: a positive integer for the number of classes.
feature_sizes: positive integer(s) for the feature dimensions as a list.
feature_names: the feature name(s) in the tensorflow record as a list.
"""
assert len(feature_names) == len(feature_sizes), \
"length of feature_names (={}) != length of feature_sizes (={})".format( \
len(feature_names), len(feature_sizes))
self.num_classes = num_classes
self.feature_sizes = feature_sizes
self.feature_names = feature_names
def prepare_reader(self, filename_queue, batch_size=1024):
"""Creates a single reader thread for pre-aggregated YouTube 8M Examples.
Args:
filename_queue: A tensorflow queue of filename locations.
Returns:
A tuple of video indexes, features, labels, and padding data.
"""
reader = tf.TFRecordReader()
_, serialized_examples = reader.read_up_to(filename_queue, batch_size)
tf.add_to_collection("serialized_examples", serialized_examples)
return self.prepare_serialized_examples(serialized_examples)
def prepare_serialized_examples(self, serialized_examples):
# set the mapping from the fields to data types in the proto
num_features = len(self.feature_names)
assert num_features > 0, "self.feature_names is empty!"
assert len(self.feature_names) == len(self.feature_sizes), \
"length of feature_names (={}) != length of feature_sizes (={})".format( \
len(self.feature_names), len(self.feature_sizes))
feature_map = {"video_id": tf.FixedLenFeature([], tf.string),
"labels": tf.VarLenFeature(tf.int64)}
for feature_index in range(num_features):
feature_map[self.feature_names[feature_index]] = tf.FixedLenFeature(
[self.feature_sizes[feature_index]], tf.float32)
features = tf.parse_example(serialized_examples, features=feature_map)
labels = tf.sparse_to_indicator(features["labels"], self.num_classes)
labels.set_shape([None, self.num_classes])
concatenated_features = tf.concat([
features[feature_name] for feature_name in self.feature_names], 1)
return features["video_id"], concatenated_features, labels, tf.ones([tf.shape(serialized_examples)[0]])
class YT8MFrameFeatureReader(BaseReader):
"""Reads TFRecords of SequenceExamples.
The TFRecords must contain SequenceExamples with the sparse in64 'labels'
context feature and a fixed length byte-quantized feature vector, obtained
from the features in 'feature_names'. The quantized features will be mapped
back into a range between min_quantized_value and max_quantized_value.
"""
def __init__(self,
num_classes=4716,
feature_sizes=[1024],
feature_names=["inc3"],
max_frames=300):
"""Construct a YT8MFrameFeatureReader.
Args:
num_classes: a positive integer for the number of classes.
feature_sizes: positive integer(s) for the feature dimensions as a list.
feature_names: the feature name(s) in the tensorflow record as a list.
max_frames: the maximum number of frames to process.
"""
assert len(feature_names) == len(feature_sizes), \
"length of feature_names (={}) != length of feature_sizes (={})".format( \
len(feature_names), len(feature_sizes))
self.num_classes = num_classes
self.feature_sizes = feature_sizes
self.feature_names = feature_names
self.max_frames = max_frames
def get_video_matrix(self,
features,
feature_size,
max_frames,
max_quantized_value,
min_quantized_value):
"""Decodes features from an input string and quantizes it.
Args:
features: raw feature values
feature_size: length of each frame feature vector
max_frames: number of frames (rows) in the output feature_matrix
max_quantized_value: the maximum of the quantized value.
min_quantized_value: the minimum of the quantized value.
Returns:
feature_matrix: matrix of all frame-features
num_frames: number of frames in the sequence
"""
decoded_features = tf.reshape(
tf.cast(tf.decode_raw(features, tf.uint8), tf.float32),
[-1, feature_size])
num_frames = tf.minimum(tf.shape(decoded_features)[0], max_frames)
feature_matrix = utils.Dequantize(decoded_features,
max_quantized_value,
min_quantized_value)
feature_matrix = resize_axis(feature_matrix, 0, max_frames)
return feature_matrix, num_frames
def prepare_reader(self,
filename_queue,
max_quantized_value=2,
min_quantized_value=-2):
"""Creates a single reader thread for YouTube8M SequenceExamples.
Args:
filename_queue: A tensorflow queue of filename locations.
max_quantized_value: the maximum of the quantized value.
min_quantized_value: the minimum of the quantized value.
Returns:
A tuple of video indexes, video features, labels, and padding data.
"""
reader = tf.TFRecordReader()
_, serialized_example = reader.read(filename_queue)
return self.prepare_serialized_examples(serialized_example,
max_quantized_value, min_quantized_value)
def prepare_serialized_examples(self, serialized_example,
max_quantized_value=2, min_quantized_value=-2):
contexts, features = tf.parse_single_sequence_example(
serialized_example,
context_features={"video_id": tf.FixedLenFeature(
[], tf.string),
"labels": tf.VarLenFeature(tf.int64)},
sequence_features={
feature_name : tf.FixedLenSequenceFeature([], dtype=tf.string)
for feature_name in self.feature_names
})
# read ground truth labels
labels = (tf.cast(
tf.sparse_to_dense(contexts["labels"].values, (self.num_classes,), 1,
validate_indices=False),
tf.bool))
# loads (potentially) different types of features and concatenates them
num_features = len(self.feature_names)
assert num_features > 0, "No feature selected: feature_names is empty!"
assert len(self.feature_names) == len(self.feature_sizes), \
"length of feature_names (={}) != length of feature_sizes (={})".format( \
len(self.feature_names), len(self.feature_sizes))
num_frames = -1 # the number of frames in the video
feature_matrices = [None] * num_features # an array of different features
for feature_index in range(num_features):
feature_matrix, num_frames_in_this_feature = self.get_video_matrix(
features[self.feature_names[feature_index]],
self.feature_sizes[feature_index],
self.max_frames,
max_quantized_value,
min_quantized_value)
if num_frames == -1:
num_frames = num_frames_in_this_feature
else:
tf.assert_equal(num_frames, num_frames_in_this_feature)
feature_matrices[feature_index] = feature_matrix
# cap the number of frames at self.max_frames
num_frames = tf.minimum(num_frames, self.max_frames)
# concatenate different features
video_matrix = tf.concat(feature_matrices, 1)
# convert to batch format.
# TODO: Do proper batch reads to remove the IO bottleneck.
batch_video_ids = tf.expand_dims(contexts["video_id"], 0)
batch_video_matrix = tf.expand_dims(video_matrix, 0)
batch_labels = tf.expand_dims(labels, 0)
batch_frames = tf.expand_dims(num_frames, 0)
return batch_video_ids, batch_video_matrix, batch_labels, batch_frames
