Initial commit

audio_python/sound.py

@@ -0,0 +1,68 @@
+import math
+import struct
+from itertools import chain
+from operator import mul
+from random import random
+
+from player import AplaySink
+
+SAMPLE_RATE = 44100
+
+
+def sin(f, amplitude, duration):
+    samples = (amplitude*math.sin(2*math.pi*f*(t/SAMPLE_RATE)) for t in range(int(duration*SAMPLE_RATE)))
+    return samples
+
+
+def square(f, amplitude, duration):
+    period = SAMPLE_RATE / f
+    half_period = period / 2
+    for t in range(int(duration*SAMPLE_RATE)):
+        if t % period < half_period:
+            yield amplitude
+        else:
+            yield -amplitude
+
+
+def noise(amplitude, duration):
+    return (amplitude*(2*random()-1) for _ in range(int(duration*SAMPLE_RATE)))
+
+
+def envelope(samples, attack_duration, release_duration):
+    # TODO: rewrite ADSR envelope
+    def compose(a, b):
+        return map(lambda x: mul(*x), zip(a, b))
+
+    a = int(attack_duration * SAMPLE_RATE)
+    r = int(release_duration * SAMPLE_RATE)
+    samples = list(samples)
+    attack = (x/a for x in range(0, a))
+    sustain = len(samples) - a - r
+    release = (x/r for x in range(r, -1, -1))
+
+    return chain(
+            compose(samples[:a], attack),
+            samples[a:a+sustain],
+            compose(samples[a+sustain:], release))
+
+
+def mix(*sources):
+    return (sum(x) for x in zip(*sources))
+
+
+def pack(samples) -> bytes:
+    return b"".join(struct.pack("<f", sample) for sample in samples)
+
+
+def main():
+    with AplaySink(SAMPLE_RATE) as sink:
+        data = mix(
+            sin(440, 0.05, 1),
+            sin(440*2**(4/12), 0.05, 1),
+            sin(440*2**(7/12), 0.05, 1))
+        packed = pack(data)
+        sink.submit(packed)
+
+
+if __name__ == "__main__":
+    main()