# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
# * Neither the name of pyglet nor the names of its
# contributors may be used to endorse or promote products
# derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# ----------------------------------------------------------------------------
# $Id:$
from pyglet.media import Source,AudioFormat,AudioData
import ctypes
import os
import math
class ProceduralSource(Source):
def __init__(self, duration, sample_rate=44800, sample_size=16):
self._duration = float(duration)
self.audio_format = AudioFormat(
channels=1,
sample_size=sample_size,
sample_rate=sample_rate)
self._offset = 0
self._bytes_per_sample = sample_size >> 3
self._bytes_per_second = self._bytes_per_sample * sample_rate
self._max_offset = int(self._bytes_per_second * self._duration)
if self._bytes_per_sample == 2:
self._max_offset &= 0xfffffffe
def _get_audio_data(self, bytes):
bytes = min(bytes, self._max_offset - self._offset)
if bytes <= 0:
return None
timestamp = float(self._offset) / self._bytes_per_second
duration = float(bytes) / self._bytes_per_second
data = self._generate_data(bytes, self._offset)
self._offset += bytes
is_eos = self._offset >= self._max_offset
return AudioData(data,
bytes,
timestamp,
duration)
def _generate_data(self, bytes, offset):
'''Generate `bytes` bytes of data.
Return data as ctypes array or string.
'''
raise NotImplementedError('abstract')
def _seek(self, timestamp):
self._offset = int(timestamp * self._bytes_per_second)
# Bound within duration
self._offset = min(max(self._offset, 0), self._max_offset)
# Align to sample
if self._bytes_per_sample == 2:
self._offset &= 0xfffffffe
class Silence(ProceduralSource):
def _generate_data(self, bytes, offset):
if self._bytes_per_sample == 1:
return '\127' * bytes
else:
return '\0' * bytes
class WhiteNoise(ProceduralSource):
def _generate_data(self, bytes, offset):
return os.urandom(bytes)
class Sine(ProceduralSource):
def __init__(self, duration, frequency=440, **kwargs):
super(Sine, self).__init__(duration, **kwargs)
self.frequency = frequency
def _generate_data(self, bytes, offset):
if self._bytes_per_sample == 1:
start = offset
samples = bytes
bias = 127
amplitude = 127
data = (ctypes.c_ubyte * samples)()
else:
start = offset >> 1
samples = bytes >> 1
bias = 0
amplitude = 32767
data = (ctypes.c_short * samples)()
step = self.frequency * (math.pi * 2) / self.audio_format.sample_rate
for i in range(samples):
data[i] = int(math.sin(step * (i + start)) * amplitude + bias)
return data
class Saw(ProceduralSource):
def __init__(self, duration, frequency=440, **kwargs):
super(Saw, self).__init__(duration, **kwargs)
self.frequency = frequency
def _generate_data(self, bytes, offset):
# XXX TODO consider offset
if self._bytes_per_sample == 1:
samples = bytes
value = 127
max = 255
min = 0
data = (ctypes.c_ubyte * samples)()
else:
samples = bytes >> 1
value = 0
max = 32767
min = -32768
data = (ctypes.c_short * samples)()
step = (max - min) * 2 * self.frequency / self.audio_format.sample_rate
for i in range(samples):
value += step
if value > max:
value = max - (value - max)
step = -step
if value < min:
value = min - (value - min)
step = -step
data[i] = value
return data
class Square(ProceduralSource):
def __init__(self, duration, frequency=440, **kwargs):
super(Square, self).__init__(duration, **kwargs)
self.frequency = frequency
def _generate_data(self, bytes, offset):
# XXX TODO consider offset
if self._bytes_per_sample == 1:
samples = bytes
value = 0
amplitude = 255
data = (ctypes.c_ubyte * samples)()
else:
samples = bytes >> 1
value = -32768
amplitude = 65535
data = (ctypes.c_short * samples)()
period = self.audio_format.sample_rate / self.frequency / 2
count = 0
for i in range(samples):
count += 1
if count == period:
value = amplitude - value
count = 0
data[i] = value
return data
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