79 lines
2.4 KiB
Python
79 lines
2.4 KiB
Python
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# Copyright 2016 Google Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""For reading/writing serialized NoteSequence protos to/from TFRecord files."""
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import hashlib
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# internal imports
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import tensorflow as tf
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from magenta.protobuf import music_pb2
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def generate_id(filename, collection_name, source_type):
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"""Generates a unique ID for a sequence.
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The format is:'/id/<type>/<collection name>/<hash>'.
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Args:
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filename: The string path to the source file relative to the root of the
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collection.
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collection_name: The collection from which the file comes.
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source_type: The source type as a string (e.g. "midi" or "abc").
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Returns:
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The generated sequence ID as a string.
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"""
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# TODO(adarob): Replace with FarmHash when it becomes a part of TensorFlow.
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filename_fingerprint = hashlib.sha1(filename.encode('utf-8'))
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return '/id/%s/%s/%s' % (
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source_type.lower(), collection_name, filename_fingerprint.hexdigest())
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def note_sequence_record_iterator(path):
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"""An iterator that reads and parses NoteSequence protos from a TFRecord file.
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Args:
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path: The path to the TFRecord file containing serialized NoteSequences.
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Yields:
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NoteSequence protos.
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Raises:
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IOError: If `path` cannot be opened for reading.
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"""
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reader = tf.python_io.tf_record_iterator(path)
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for serialized_sequence in reader:
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yield music_pb2.NoteSequence.FromString(serialized_sequence)
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class NoteSequenceRecordWriter(tf.python_io.TFRecordWriter):
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"""A class to write serialized NoteSequence protos to a TFRecord file.
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This class implements `__enter__` and `__exit__`, and can be used in `with`
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blocks like a normal file.
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@@__init__
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@@write
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@@close
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"""
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def write(self, note_sequence):
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"""Serializes a NoteSequence proto and writes it to the file.
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Args:
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note_sequence: A NoteSequence proto to write.
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"""
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tf.python_io.TFRecordWriter.write(self, note_sequence.SerializeToString())
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