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Save and Load a Performance
===========================

*Example directory* (scamp): `examples/Playback/Other/save_and_load_performance <https://github.com/MarcTheSpark/scamp/tree/main/examples/Playback/Other/save_and_load_performance>`__

*Download:* :download:`save_and_load_performance.zip <downloads/playback_other_save_and_load_performance/save_and_load_performance.zip>`

Contains two scripts: One that plays some music and records a portion of that music to a JSON file, and a second that reads the JSON file and plays the recorded performance repeatedly while accelerating.

*Topics:* :doc:`Playback › Other <playback>`

.. code-block:: python
   :caption: save_performance.py: Saves an Ensemble and a recorded Performance to JSON, for the load_and_play_performance example.

   from scamp import *
   import random
   import math


   s = Session()

   shaku = s.new_part("shakuhachi")
   oboe = s.new_part("oboe")


   def oboe_part():
       while True:
           oboe.play_note(75 + random.random() * 7 + 15 * math.sin(get_beat() / 10), 0.4, 0.25)


   def shaku_part():
       pentatonic = [0, 2, 4, 7, 9]
       while True:
           if random.random() < 0.5:
               shaku.play_note(66 + random.choice(pentatonic) + 12*random.randint(0, 2),
                               Envelope([1.0, 0.2, 1.0, 1.0], [0.15, 0.85, 0.15], [0, 2, 0]),
                               2.5, blocking=True)
               wait(0.5 + random.choice([0, 0.5]))
           else:
               shaku.play_note(66 + random.choice(pentatonic) + 12*random.randint(0, 2), 1.0, 0.2*(1+random.random()*0.3))
               wait(random.choice([1, 2, 3]))


   s.fork(oboe_part)
   s.fork(shaku_part)

   s.set_tempo_target(300, Moment.after_time(30))

   s.wait(15)
   s.start_transcribing()
   print("Starting transcription...")
   s.wait(15)
   performance = s.stop_transcribing()
   print("Stopped transcribing. Saving transcription.")

   performance.save_to_json("perfShakoboe.json")

   s.wait_forever()

.. raw:: html

   <div style="margin:0.6em 0"><audio controls preload="none" src="../_static/media/Playback/Other/save_and_load_performance/save_performance.mp3" style="width:100%;max-width:520px"></audio></div>

.. code-block:: python
   :caption: load_and_play_performance.py: Loads the Ensemble and Performance saved by save_performance.py and plays the performance back under a gradually accelerating tempo.

   from scamp import *

   s = Session()

   shaku = s.new_part("shakuhachi")
   oboe = s.new_part("oboe")

   recorded_performance = Performance.load_from_json("perfShakoboe.json")

   s.tempo = 60
   s.set_tempo_target(300, Moment.after_time(40))

   while True:
       print("(Re)starting performance.")
       # by default, the performance plays on the currently active clock, forking all parts according to
       # the tempo envelope at recording time. So the acceleration inside the recording is compounded with
       # the gradual session-wide acceleration here.
       # also, by default, we use the currently active session for the instruments.
       recorded_performance.play()

.. raw:: html

   <div style="margin:0.6em 0"><audio controls preload="none" src="../_static/media/Playback/Other/save_and_load_performance/load_and_play_performance.mp3" style="width:100%;max-width:520px"></audio></div>