112 lines
4.1 KiB
Python
112 lines
4.1 KiB
Python
import logging
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import pyaudio
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import numpy
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from numpy import pi
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logging.basicConfig(level=logging.INFO)
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logger = logging.getLogger(__name__)
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standard_sample_rates = 1000 * numpy.array([
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8, 9.6, 11.025, 12, 16, 22.05, 24, 32,
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44.1, 48, 88.2, 96, 192])
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def monitor_pitch(device: int = 5,
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max_freq: float = 6000,
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min_freq: float = 10,
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samples_per_buffer: int = 1024,
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audio: pyaudio.PyAudio = None,
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):
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if audio is None:
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audio = pyaudio.PyAudio()
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supported_sample_rates = []
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devinfo = audio.get_device_info_by_index(device)
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for rate in standard_sample_rates:
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try:
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if audio.is_format_supported(rate,
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input_device=device,
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input_channels=devinfo['maxInputChannels'],
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input_format=pyaudio.paInt16):
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supported_sample_rates.append(rate)
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except ValueError:
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pass
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supported_sample_rates = numpy.array(supported_sample_rates)
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logger.info('Supported rates: {}'.format(supported_sample_rates))
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'''
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max_freq < 2 * sample_rate
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min_freq * 2**(1/12) > freq_resolution (for discrimination), more for accuracy...
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freq_resolution <= sample_rate / (samples_per_buffer * num_buffers)
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'''
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freq_resolution = min_freq * 2**(1/12) / 10
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rate_is_acceptable = supported_sample_rates >= 2 * max_freq
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sample_rate = int(numpy.min(supported_sample_rates[rate_is_acceptable]))
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num_buffers = int(numpy.ceil(sample_rate / (samples_per_buffer * freq_resolution)))
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samples_per_fft = samples_per_buffer * num_buffers
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logger.info('Running on device {} with {} buffers,'.format(device, num_buffers) +
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' {} sample rate, {} samples per buffer'.format(
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device, num_buffers, sample_rate, samples_per_buffer))
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logger.info('Buffers take {:.3g} sec to fully clear'.format(samples_per_fft / sample_rate))
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stream = audio.open(format=pyaudio.paInt16,
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channels=1,
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rate=sample_rate,
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input=True,
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frames_per_buffer=samples_per_buffer)
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stream.start_stream()
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# Hanning window
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window = (1 - numpy.cos(numpy.linspace(0, 2 * pi, samples_per_fft, False))) / 2
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freqs = numpy.fft.fftfreq(samples_per_fft, 1 / sample_rate)
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buf = numpy.zeros(num_buffers * samples_per_buffer, dtype=numpy.float32)
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note_names = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
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while stream.is_active():
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# Shift the buffer down and new data in
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buf[:-samples_per_buffer] = buf[samples_per_buffer:]
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buf[-samples_per_buffer:] = numpy.fromstring(stream.read(samples_per_buffer), numpy.int16)
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fft = numpy.fft.rfft(buf * window)
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# Get frequency of maximum response in range
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ind = numpy.abs(fft[1:]).argmax() + 1
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freq = freqs[ind]
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mag = numpy.abs(fft[ind])
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# Get note number and nearest note
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q = numpy.log2(freq/440)
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n = 12 * q + 69
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n0 = int(round(n))
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delta = n - n0
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logger.info('freq: {:7.2f} Hz mag:{:7.2f} note: {:>3s} {:+.2f}'.format(
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freq, numpy.log10(mag), note_names[n0 % 12] + str(n0//12 - 1), delta))
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delta_part = int(delta // 0.1)
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if delta_part > 0:
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signal = ' ' * 6 + '+' * delta_part
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elif delta_part == 0:
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signal = ' ' * 5 + '|'
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elif delta_part < 0:
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signal = ' ' * (5 + delta_part) + '-' * delta_part
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logger.info(' {}'.format(signal))
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if __name__ == '__main__':
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audio = pyaudio.PyAudio()
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logger.info("Available devices:")
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for device in range(audio.get_device_count()):
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devinfo = audio.get_device_info_by_index(device)
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if devinfo['maxInputChannels'] > 0:
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logger.info('{}: {}'.format(device, devinfo['name']))
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monitor_pitch(device=5, min_freq=20)
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