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1 # Generate 'perfect' sine wave sounds
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2
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3 # Design notes: produces ~= 0.5s raw CDDA audio - 44100 Hz, 16 bit signed values
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4 # Input is freq in Hz - 440 for A, etc. - must be an integer
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5 # Output is written the file beep<freq>.pcm
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6 # Convert to ogg with oggenc -r <file>
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7
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8 import sys
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9 import math
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10 import struct
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11
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12
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13 CDDA_RATE = 44100
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14 MAX = 105*256 # Max value for sine wave
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15
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16 def gen_sine(freq):
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17 filename = 'beep%s.pcm' % freq
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18 # We need to generate freq cycles and sample that CDDA_RATE times
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19 samples_per_cycle = CDDA_RATE / freq
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20 data = []
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21 for x in range(samples_per_cycle):
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22 rad = float(x) / samples_per_cycle * 2 * math.pi
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23 y = MAX * math.sin(rad)
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24 data.append(struct.pack('<i', y))
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25 output = open(filename, 'w')
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26 for x in range(freq/2):
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27 output.write(''.join(data))
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28 output.close()
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29
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30
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31 if __name__ == "__main__":
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32 freq = int(sys.argv[1])
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33 gen_sine(freq)
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