48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
import math
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from pyaudio import PyAudio, paUInt8
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def generate_sine_wave(frequency, duration, volume=0.2, sample_rate=22050):
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''' Generate a tone at the given frequency.
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Limited to unsigned 8-bit samples at a given sample_rate.
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The sample rate should be at least double the frequency.
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'''
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if sample_rate < (frequency * 2):
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print('Warning: sample_rate must be at least double the frequency '
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f'to accurately represent it:\n sample_rate {sample_rate}'
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f' ≯ {frequency*2} (frequency {frequency}*2)')
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num_samples = int(sample_rate * duration)
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rest_frames = num_samples % sample_rate
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pa = PyAudio()
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stream = pa.open(
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format=paUInt8,
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channels=1, # mono
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rate=sample_rate,
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output=True,
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)
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# make samples
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s = lambda i: volume * math.sin(2 * math.pi * frequency * i / sample_rate)
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samples = (int(s(i) * 0x7F + 0x80) for i in range(num_samples))
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# write several samples at a time
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for buf in zip( *([samples] * sample_rate) ):
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stream.write(bytes(buf))
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# fill remainder of frameset with silence
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stream.write(b'\x80' * rest_frames)
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stream.stop_stream()
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stream.close()
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pa.terminate()
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generate_sine_wave(
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# see http://www.phy.mtu.edu/~suits/notefreqs.html
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frequency=440, # Hz, waves per second C6
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duration=0.2, # seconds to play sound
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volume=0.25, # 0..1 how loud it is
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sample_rate=44100, # number of samples per second: 11025, 22050, 44100
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)
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