465 lines
16 KiB
Python
465 lines
16 KiB
Python
# ----------------------------------------------------------------------------
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# pyglet
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# Copyright (c) 2006-2008 Alex Holkner
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# Copyright (c) 2008-2021 pyglet contributors
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# * Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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# * Neither the name of pyglet nor the names of its
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# contributors may be used to endorse or promote products
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# derived from this software without specific prior written
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# permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ----------------------------------------------------------------------------
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import os
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import math
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import ctypes
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import struct
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from .codecs.base import Source, AudioFormat, AudioData
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# Envelope classes:
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class _Envelope:
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"""Base class for SynthesisSource amplitude envelopes."""
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def get_generator(self, sample_rate, duration):
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raise NotImplementedError
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class FlatEnvelope(_Envelope):
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"""A flat envelope, providing basic amplitude setting.
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:Parameters:
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`amplitude` : float
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The amplitude (volume) of the wave, from 0.0 to 1.0.
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Values outside of this range will be clamped.
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"""
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def __init__(self, amplitude=0.5):
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self.amplitude = max(min(1.0, amplitude), 0)
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def get_generator(self, sample_rate, duration):
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amplitude = self.amplitude
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while True:
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yield amplitude
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class LinearDecayEnvelope(_Envelope):
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"""A linearly decaying envelope.
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This envelope linearly decays the amplitude from the peak value
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to 0, over the length of the waveform.
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:Parameters:
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`peak` : float
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The Initial peak value of the envelope, from 0.0 to 1.0.
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Values outside of this range will be clamped.
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"""
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def __init__(self, peak=1.0):
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self.peak = max(min(1.0, peak), 0)
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def get_generator(self, sample_rate, duration):
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peak = self.peak
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total_bytes = int(sample_rate * duration)
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for i in range(total_bytes):
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yield (total_bytes - i) / total_bytes * peak
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while True:
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yield 0
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class ADSREnvelope(_Envelope):
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"""A four part Attack, Decay, Suspend, Release envelope.
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This is a four part ADSR envelope. The attack, decay, and release
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parameters should be provided in seconds. For example, a value of
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0.1 would be 100ms. The sustain_amplitude parameter affects the
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sustain volume. This defaults to a value of 0.5, but can be provided
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on a scale from 0.0 to 1.0.
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:Parameters:
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`attack` : float
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The attack time, in seconds.
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`decay` : float
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The decay time, in seconds.
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`release` : float
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The release time, in seconds.
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`sustain_amplitude` : float
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The sustain amplitude (volume), from 0.0 to 1.0.
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"""
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def __init__(self, attack, decay, release, sustain_amplitude=0.5):
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self.attack = attack
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self.decay = decay
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self.release = release
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self.sustain_amplitude = max(min(1.0, sustain_amplitude), 0)
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def get_generator(self, sample_rate, duration):
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sustain_amplitude = self.sustain_amplitude
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total_bytes = int(sample_rate * duration)
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attack_bytes = int(sample_rate * self.attack)
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decay_bytes = int(sample_rate * self.decay)
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release_bytes = int(sample_rate * self.release)
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sustain_bytes = total_bytes - attack_bytes - decay_bytes - release_bytes
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decay_step = (1 - sustain_amplitude) / decay_bytes
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release_step = sustain_amplitude / release_bytes
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for i in range(1, attack_bytes + 1):
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yield i / attack_bytes
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for i in range(1, decay_bytes + 1):
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yield 1 - (i * decay_step)
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for i in range(1, sustain_bytes + 1):
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yield sustain_amplitude
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for i in range(1, release_bytes + 1):
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yield sustain_amplitude - (i * release_step)
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while True:
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yield 0
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class TremoloEnvelope(_Envelope):
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"""A tremolo envelope, for modulation amplitude.
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A tremolo envelope that modulates the amplitude of the
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waveform with a sinusoidal pattern. The depth and rate
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of modulation can be specified. Depth is calculated as
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a percentage of the maximum amplitude. For example:
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a depth of 0.2 and amplitude of 0.5 will fluctuate
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the amplitude between 0.4 an 0.5.
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:Parameters:
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`depth` : float
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The amount of fluctuation, from 0.0 to 1.0.
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`rate` : float
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The fluctuation frequency, in seconds.
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`amplitude` : float
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The peak amplitude (volume), from 0.0 to 1.0.
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"""
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def __init__(self, depth, rate, amplitude=0.5):
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self.depth = max(min(1.0, depth), 0)
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self.rate = rate
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self.amplitude = max(min(1.0, amplitude), 0)
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def get_generator(self, sample_rate, duration):
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total_bytes = int(sample_rate * duration)
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period = total_bytes / duration
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max_amplitude = self.amplitude
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min_amplitude = max(0.0, (1.0 - self.depth) * self.amplitude)
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step = (math.pi * 2) / period / self.rate
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for i in range(total_bytes):
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value = math.sin(step * i)
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yield value * (max_amplitude - min_amplitude) + min_amplitude
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while True:
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yield 0
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# Source classes:
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class SynthesisSource(Source):
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"""Base class for synthesized waveforms.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, sample_rate=44800, envelope=None):
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self._duration = float(duration)
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self.audio_format = AudioFormat(channels=1, sample_size=16, sample_rate=sample_rate)
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self._offset = 0
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self._sample_rate = sample_rate
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self._bytes_per_sample = 2
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self._bytes_per_second = self._bytes_per_sample * sample_rate
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self._max_offset = int(self._bytes_per_second * self._duration)
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self.envelope = envelope or FlatEnvelope(amplitude=1.0)
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self._envelope_generator = self.envelope.get_generator(sample_rate, duration)
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# Align to sample:
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self._max_offset &= 0xfffffffe
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def get_audio_data(self, num_bytes, compensation_time=0.0):
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"""Return `num_bytes` bytes of audio data."""
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num_bytes = min(num_bytes, self._max_offset - self._offset)
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if num_bytes <= 0:
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return None
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timestamp = float(self._offset) / self._bytes_per_second
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duration = float(num_bytes) / self._bytes_per_second
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data = self._generate_data(num_bytes)
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self._offset += num_bytes
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return AudioData(data, num_bytes, timestamp, duration, [])
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def _generate_data(self, num_bytes):
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"""Generate `num_bytes` bytes of data.
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Return data as ctypes array or string.
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"""
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raise NotImplementedError('abstract')
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def seek(self, timestamp):
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self._offset = int(timestamp * self._bytes_per_second)
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# Bound within duration
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self._offset = min(max(self._offset, 0), self._max_offset)
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# Align to sample
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self._offset &= 0xfffffffe
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self._envelope_generator = self.envelope.get_generator(self._sample_rate, self._duration)
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class Silence(SynthesisSource):
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"""A silent waveform."""
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def _generate_data(self, num_bytes):
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return b'\0' * num_bytes
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class WhiteNoise(SynthesisSource):
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"""A white noise, random waveform."""
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def _generate_data(self, num_bytes):
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return os.urandom(num_bytes)
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class Sine(SynthesisSource):
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"""A sinusoid (sine) waveform.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`frequency` : int
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The frequency, in Hz of the waveform you wish to produce.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, frequency=440, **kwargs):
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super().__init__(duration, **kwargs)
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self.frequency = frequency
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def _generate_data(self, num_bytes):
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samples = num_bytes >> 1
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amplitude = 32767
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data = (ctypes.c_short * samples)()
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step = self.frequency * (math.pi * 2) / self.audio_format.sample_rate
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envelope = self._envelope_generator
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for i in range(samples):
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data[i] = int(math.sin(step * i) * amplitude * next(envelope))
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return bytes(data)
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class Triangle(SynthesisSource):
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"""A triangle waveform.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`frequency` : int
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The frequency, in Hz of the waveform you wish to produce.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, frequency=440, **kwargs):
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super().__init__(duration, **kwargs)
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self.frequency = frequency
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def _generate_data(self, num_bytes):
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samples = num_bytes >> 1
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value = 0
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maximum = 32767
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minimum = -32768
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data = (ctypes.c_short * samples)()
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step = (maximum - minimum) * 2 * self.frequency / self.audio_format.sample_rate
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envelope = self._envelope_generator
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for i in range(samples):
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value += step
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if value > maximum:
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value = maximum - (value - maximum)
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step = -step
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if value < minimum:
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value = minimum - (value - minimum)
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step = -step
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data[i] = int(value * next(envelope))
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return bytes(data)
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class Sawtooth(SynthesisSource):
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"""A sawtooth waveform.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`frequency` : int
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The frequency, in Hz of the waveform you wish to produce.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, frequency=440, **kwargs):
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super().__init__(duration, **kwargs)
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self.frequency = frequency
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def _generate_data(self, num_bytes):
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samples = num_bytes >> 1
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value = 0
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maximum = 32767
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minimum = -32768
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data = (ctypes.c_short * samples)()
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step = (maximum - minimum) * self.frequency / self._sample_rate
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envelope = self._envelope_generator
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for i in range(samples):
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value += step
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if value > maximum:
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value = minimum + (value % maximum)
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data[i] = int(value * next(envelope))
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return bytes(data)
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class Square(SynthesisSource):
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"""A square (pulse) waveform.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`frequency` : int
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The frequency, in Hz of the waveform you wish to produce.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, frequency=440, **kwargs):
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super().__init__(duration, **kwargs)
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self.frequency = frequency
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def _generate_data(self, num_bytes):
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samples = num_bytes >> 1
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amplitude = 32767
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value = 1
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count = 0
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data = (ctypes.c_short * samples)()
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half_period = self.audio_format.sample_rate / self.frequency / 2
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envelope = self._envelope_generator
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for i in range(samples):
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if count >= half_period:
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value = -value
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count %= half_period
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count += 1
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data[i] = int(value * amplitude * next(envelope))
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return bytes(data)
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class SimpleFM(SynthesisSource):
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"""A simple FM waveform.
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This is a simplistic frequency modulated waveform, based on the
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concepts by John Chowning. Basic sine waves are used for both
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frequency carrier and modulator inputs, of which the frequencies can
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be provided. The modulation index, or amplitude, can also be adjusted.
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:Parameters:
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`duration` : float
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The length, in seconds, of audio that you wish to generate.
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`carrier` : int
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The carrier frequency, in Hz.
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`modulator` : int
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The modulator frequency, in Hz.
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`mod_index` : int
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The modulation index.
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`sample_rate` : int
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Audio samples per second. (CD quality is 44100).
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"""
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def __init__(self, duration, carrier=440, modulator=440, mod_index=1, **kwargs):
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super().__init__(duration, **kwargs)
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self.carrier = carrier
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self.modulator = modulator
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self.mod_index = mod_index
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def _generate_data(self, num_bytes):
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samples = num_bytes >> 1
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amplitude = 32767
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c_step = 2 * math.pi * self.carrier
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m_step = 2 * math.pi * self.modulator
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m_index = self.mod_index
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sample_rate = self._sample_rate
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envelope = self._envelope_generator
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sin = math.sin
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# FM equation: sin((2 * pi * carrier) + sin(2 * pi * modulator))
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data = []
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for i in range(samples):
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increment = i / sample_rate
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data.append(int(sin(c_step * increment + m_index * sin(m_step * increment)) * amplitude * next(envelope)))
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return struct.pack(str(samples) + 'h', *data)
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#############################################
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# Experimental multi-operator FM synthesis:
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#############################################
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def operator(samplerate=44800, frequency=440, index=1, modulator=None, envelope=None):
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# A sine generator that can be optionally modulated with another generator.
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# FM equation: sin((i * 2 * pi * carrier_frequency) + sin(i * 2 * pi * modulator_frequency))
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sin = math.sin
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step = 2 * math.pi * frequency / samplerate
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i = 0
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envelope = envelope or FlatEnvelope(1).get_generator(samplerate, duration=None)
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if modulator:
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while True:
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yield sin(i * step + index * next(modulator)) * next(envelope)
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i += 1
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else:
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while True:
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yield math.sin(i * step) * next(envelope)
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i += 1
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def composite_generator(*operators):
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return (sum(samples) / len(samples) for samples in zip(*operators))
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class Encoder(SynthesisSource):
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def __init__(self, duration, generator, **kwargs):
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super().__init__(duration, **kwargs)
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self._generator = generator
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def _generate_data(self, num_bytes):
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envelope = self._envelope_generator
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generator = self._generator
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samples = num_bytes >> 1
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amplitude = 32767
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data = (int(next(generator) * amplitude * next(envelope)) for i in range(samples))
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return struct.pack(f"{samples}h", *data)
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