music21 stream (de)serialization via pickle

music21_pickle.py

# It's possible to serialize music21 stream to pickle.
# But for 1 kB of MIDI the pickle is 89 kB (!), after gzip only 8 kB.
# The benefit can be lower loading time compared to parsing MIDI
# at the cost of roughly 8x file size.

import music21
stream = music21.converter.parse("foo.mid")
pickled = music21.converter.freezeStr(stream)
with open("foo.pickle", "wb") as f:
    f.write(pickled)
with open("foo.pickle", "rb") as f:
    pickledFromFile = f.read()
streamFromPickle = music21.converter.thawStr(pickledFromFile)