synthio: add a host demo of all major features

Author: jepler

tests/circuitpython-manual/synthio/note/demo.py

@@ -0,0 +1,282 @@
+import random
+import audiocore
+import synthio
+from ulab import numpy as np
+import adafruit_wave as wave
+
+h = np.array(
+    [
+        -0.001229734800309099,
+        -0.008235561806605458,
+        -0.015082497016061390,
+        -0.020940136918319988,
+        -0.024981800822463429,
+        -0.026464233332370746,
+        -0.024803890156806906,
+        -0.019642276775473012,
+        -0.010893620860173042,
+        0.001230341899766145,
+        0.016221637398855598,
+        0.033304135659230648,
+        0.051486665261155681,
+        0.069636961761409016,
+        0.086570197432542767,
+        0.101144354207918147,
+        0.112353938422488253,
+        0.119413577288191297,
+        0.121823886314051028,
+        0.119413577288191297,
+        0.112353938422488253,
+        0.101144354207918147,
+        0.086570197432542767,
+        0.069636961761409016,
+        0.051486665261155681,
+        0.033304135659230648,
+        0.016221637398855598,
+        0.001230341899766145,
+        -0.010893620860173042,
+        -0.019642276775473012,
+        -0.024803890156806906,
+        -0.026464233332370746,
+        -0.024981800822463429,
+        -0.020940136918319988,
+        -0.015082497016061390,
+        -0.008235561806605458,
+        -0.001229734800309099,
+    ]
+)
+
+filter_coeffs = np.array(h[::-1] * 32768, dtype=np.int16)
+
+
+def randf(lo, hi):
+    return random.random() * (hi - lo) + lo
+
+
+SAMPLE_SIZE = 1024
+VOLUME = 14700
+sine = np.array(
+    np.sin(np.linspace(0, 2 * np.pi, SAMPLE_SIZE, endpoint=False)) * VOLUME, dtype=np.int16
+)
+square = np.array([24000] * (SAMPLE_SIZE // 2) + [-24000] * (SAMPLE_SIZE // 2), dtype=np.int16)
+
+noise = np.array(
+    [random.randint(-32768, 32767) for i in range(SAMPLE_SIZE)],
+    dtype=np.int16,
+)
+
+envelope = synthio.Envelope(
+    attack_time=0.1, decay_time=0.05, release_time=0.2, attack_level=1, sustain_level=0.8
+)
+
+instant = synthio.Envelope(
+    attack_time=0, decay_time=0, release_time=0, attack_level=1, sustain_level=1
+)
+synth = synthio.Synthesizer(
+    sample_rate=48000, envelope=None, filter=filter_coeffs, channel_count=2
+)
+
+
+def synthesize(synth):
+    print(
+        """you can use arbitrary waveforms, including ones calculated on the fly or read from wave files (up to 1024 points)"""
+    )
+
+    waveform = np.zeros(SAMPLE_SIZE, dtype=np.int16)
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=waveform, envelope=envelope)
+        for n in (60, 64, 67, 70)
+    ]
+    synth.press(chord)
+
+    for i in range(256):
+        ctrl = i / 255
+        waveform[:] = np.array(square * (1 - ctrl) + sine * ctrl, dtype=np.int16)
+        yield 4
+
+
+def synthesize2(synth):
+    print("""Envelope controls how notes fade in or out""")
+
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=instant)
+        for n in (60, 64, 67, 70)
+    ]
+
+    for i in range(4):
+        for c in chord:
+            synth.release_all_then_press((c,))
+            yield 24
+    synth.release_all()
+
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=envelope)
+        for n in (60, 64, 67, 70)
+    ]
+
+    for i in range(4):
+        for c in chord:
+            old = (c,)
+            synth.release_all_then_press((c,))
+            yield 24
+
+
+def synthesize3(synth):
+    print("""A noise waveform creates percussive sounds""")
+
+    env = synthio.Envelope(
+        attack_time=0,
+        decay_time=0.2,
+        sustain_level=0,
+    )
+
+    notes = [
+        synthio.Note(
+            frequency=synthio.midi_to_hz(1 + i),
+            waveform=noise,
+            envelope=env,
+        )
+        for i in range(12)
+    ]
+
+    random.seed(9)
+    for _ in range(16):
+        n = random.choice(notes)
+        d = random.randint(30, 60)
+        synth.press((n,))
+        yield d
+
+
+def synthesize4(synth):
+    print("""Tremolo varies the note volume within a range at a low frequency""")
+
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=None) for n in (60, 64, 67, 70)
+    ]
+
+    synth.press(chord)
+    for i in range(16):
+        for c in chord:
+            c.tremolo_depth = i / 50
+            c.tremolo_rate = (i + 1) / 4
+        yield 48
+    yield 36
+
+
+def synthesize5(synth):
+    print("""You can add vibrato or frequency sweep to notes""")
+
+    chord = [synthio.Note(synthio.midi_to_hz(n), waveform=sine) for n in (60, 64, 67, 70)]
+
+    synth.press(chord)
+    for i in range(16):
+        for c in chord:
+            c.bend_depth = 1 / 24
+            c.bend_rate = (i + 1) / 2
+        yield 24
+    synth.release_all()
+    yield 100
+
+    for c in chord:
+        synth.release_all()
+        c.bend_mode = synthio.BendMode.SWEEP_IN
+        c.bend_depth = randf(-1, 1)
+        c.bend_rate = 1 / 2
+    synth.press(chord)
+    yield 320
+
+
+def synthesize6(synth):
+    print("""Ring modulation multiplies two waveforms together to create rich sounds""")
+
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=square, ring_waveform=sine, envelope=envelope)
+        for n in (60,)
+    ]
+
+    synth.press(chord)
+    yield 200
+
+    random.seed(75)
+
+    for _ in range(3):
+        synth.release_all()
+        yield 36
+        for note in chord:
+            note.ring_frequency = note.frequency * (random.random() * 35 / 1200 + 8)
+        synth.press(chord)
+        yield 200
+
+
+def synthesize7(synth):
+    print("""FIR filtering can reproduce low, high, notch and band filters""")
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=square, filter=False)
+        for n in (60, 64, 67, 70)
+    ]
+
+    for i in range(4):
+        for c in chord:
+            synth.release_all_then_press((c,))
+            yield 24
+    synth.release_all()
+
+    for note in chord:
+        note.filter = True
+
+    for i in range(4):
+        for c in chord:
+            synth.release_all_then_press((c,))
+            yield 24
+
+
+def synthesize8(synth):
+    print("""Notes can be panned between channels""")
+    chord = [
+        synthio.Note(synthio.midi_to_hz(n), waveform=square, envelope=envelope)
+        for n in (60, 64, 67, 70)
+    ]
+    synth.press(chord)
+    for p in range(-10, 11, 1):
+        for note in chord:
+            note.panning = p / 10
+        yield 36
+
+
+def delay(synth):
+    synth.release_all()
+    yield 200
+
+
+def chain(*args):
+    for a in args:
+        yield from a
+
+
+# sox -r 48000 -e signed -b 16 -c 1 tune.raw tune.wav
+with wave.open("demo.wav", "w") as f:
+    f.setnchannels(2)
+    f.setsampwidth(2)
+    f.setframerate(48000)
+    import array
+
+    for n in chain(
+        synthesize(synth),
+        delay(synth),
+        synthesize2(synth),
+        delay(synth),
+        synthesize3(synth),
+        delay(synth),
+        synthesize4(synth),
+        delay(synth),
+        synthesize5(synth),
+        delay(synth),
+        synthesize6(synth),
+        delay(synth),
+        synthesize7(synth),
+        delay(synth),
+        synthesize8(synth),
+    ):
+        for i in range(n):
+            result, data = audiocore.get_buffer(synth)
+            f.writeframes(data)