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Overview

import audio.wave
from numpy import *

df = 44100
dt = 1.0 / df
f = 440.0
T = 3.0
t = r_[0.0:T:dt]
sound = sin(2*pi*f*t)

audio.wave.write(sound, "A4.wav")

audio.wave.write

Wave Audio File Format Writer

Arguments

• data: the audio data.

  The data should be either a 1-dim. numpy array or a 2-dim numpy array with a dimension of 1 (mono) or 2 (stereo) along the first axis.

• output: a bitstream, filename, file object or None (default).

  The object where the data is written in the WAVE format. An empty bitstream is created if no output is specified.

• df: an integer, the sample rate (default: 44100).

• scale: the scaling policy: None, True or False.

  This argument determines the linear transformation that scales data before it is rounded and clipped the to 16-bit integer range. The following table displays what value is mapped to 2**15 given scale and the type of data.

  • scale = None: 2**15 is mapped to 1.0

  • scale = True: amax(abs(data)) is mapped to 1.0

  • scale = False: 2**15 is mapped to 2**15

  scale	scaling (float)	scaling (integer)
  None	1.0 to 2**15	2**15 to 2**15
  True	amax(abs(data)) to 2**15	amax(abs(data)) to 2**15
  False	2**15 to 2**15	2**15 to 2**15

  Advanced scaling policies can be specified:

  • if scale is a number, data is multiplied by this number before the conversion to 16-bit integers. For example, for an array of floats, the scale = None policy could be implemented by setting scale = 2**15.

  • if scale is a function, it is given the data argument and should return a scale number. For example, the policy scale = True is equivalent to the selection of the scaling function defined by scale(data) = 2**15 / amax(data).

Returns

• stream: an output stream if no output was specified, None otherwise.

See Also

• audio.wave.read,
• bitstream.Bitstream.

audio.wave.read

Wave Audio File Format Reader

Arguments

• input: the source of the WAVE data: a filename, file or a bitstream.

• scale: the scaling policy: None (the default), True or False.

  This argument determines the linear transformation that scales the array of 16-bit signed integers stored in input before it is returned. The following table displays the scaling that corresponds to three standard policies:

  scale	scaling
  None	2**15 to 1.0
  True	amax(abs(data)) to 1.0
  False	2**15 to 2**15

  Advanced scaling policies can be specified:

  • if scale is a number, it is used as a multiplier on the 16-bit
    integer data. For example, scale = None corresponds to scale = 1.0 / float(2**15) and scale = False to scale = 1.

  • if scale is a function, it is given the data argument and should return a scale multiplier. For example, the setting scale = True is a shortcut for the function defined by scale(data) = 1.0 / amax(abs(data)).

• returns: a string of comma-separated variable names. When returns is a single variable name, without a trailing comma, the value with this name is returned ; otherwise the named value(s) is (are) returned as a tuple.

Returns

The set of returned values is selected by the returns argument among:

• data: the audio data, as a 2-dim numpy array with a dimension of 1 (mono) or 2 (stereo) along the first axe. Its data type depends on the scaling policy.

• df: the sampling rate, an integer.

See Also

• audio.wave.write,
• bitstream.BitStream.