"""
Module for low-level audio input-output operations.
Class summary
=============
.. autosummary::
AudioSource
Rewindable
BufferAudioSource
WaveAudioSource
PyAudioSource
StdinAudioSource
PyAudioPlayer
Function summary
================
.. autosummary::
from_file
player_for
"""
from abc import ABCMeta, abstractmethod
import wave
import sys
__all__ = ["AudioSource", "Rewindable", "BufferAudioSource", "WaveAudioSource",
"PyAudioSource", "StdinAudioSource", "PyAudioPlayer", "from_file", "player_for"]
DEFAULT_SAMPLE_RATE = 16000
DEFAULT_SAMPLE_WIDTH = 2
DEFAULT_NB_CHANNELS = 1
[docs]class AudioSource():
"""
Base class for audio source objects.
Subclasses should implement methods to open/close and audio stream
and read the desired amount of audio samples.
:Parameters:
`sampling_rate` : int
Number of samples per second of audio stream. Default = 16000.
`sample_width` : int
Size in bytes of one audio sample. Possible values : 1, 2, 4.
Default = 2.
`channels` : int
Number of channels of audio stream. The current version supports
only mono audio streams (i.e. one channel).
"""
__metaclass__ = ABCMeta
def __init__(self, sampling_rate=DEFAULT_SAMPLE_RATE,
sample_width=DEFAULT_SAMPLE_WIDTH,
channels=DEFAULT_NB_CHANNELS):
if not sample_width in (1, 2, 4):
raise ValueError("Sample width must be one of: 1, 2 or 4 (bytes)")
if channels != 1:
raise ValueError("Only mono audio is currently handled")
self._sampling_rate = sampling_rate
self._sample_width = sample_width
self._channels = channels
[docs] @abstractmethod
def is_open(self):
""" Return True if audio source is open, False otherwise """
[docs] @abstractmethod
def open(self):
""" Open audio source """
[docs] @abstractmethod
def close(self):
""" Close audio source """
[docs] @abstractmethod
def read(self, size):
"""
Read and return `size` audio samples at most.
:Parameters:
`size` : int
the number of samples to read.
:Returns:
Audio data as a string of length 'N' * 'sample_width' * 'channels', where 'N' is:
- `size` if `size` < 'left_samples'
- 'left_samples' if `size` > 'left_samples'
"""
[docs] def get_sampling_rate(self):
""" Return the number of samples per second of audio stream """
return self.sampling_rate
@property
def sampling_rate(self):
""" Number of samples per second of audio stream """
return self._sampling_rate
@property
def sr(self):
""" Number of samples per second of audio stream """
return self._sampling_rate
[docs] def get_sample_width(self):
""" Return the number of bytes used to represent one audio sample """
return self.sample_width
@property
def sample_width(self):
""" Number of bytes used to represent one audio sample """
return self._sample_width
@property
def sw(self):
""" Number of bytes used to represent one audio sample """
return self._sample_width
[docs] def get_channels(self):
""" Return the number of channels of this audio source """
return self.channels
@property
def channels(self):
""" Number of channels of this audio source """
return self._channels
@property
def ch(self):
""" Return the number of channels of this audio source """
return self.channels
[docs]class Rewindable():
"""
Base class for rewindable audio streams.
Subclasses should implement methods to return to the beginning of an
audio stream as well as method to move to an absolute audio position
expressed in time or in number of samples.
"""
__metaclass__ = ABCMeta
[docs] @abstractmethod
def rewind(self):
""" Go back to the beginning of audio stream """
pass
[docs] @abstractmethod
def get_position(self):
""" Return the total number of already read samples """
[docs] @abstractmethod
def get_time_position(self):
""" Return the total duration in seconds of already read data """
[docs] @abstractmethod
def set_position(self, position):
""" Move to an absolute position
:Parameters:
`position` : int
number of samples to skip from the start of the stream
"""
[docs] @abstractmethod
def set_time_position(self, time_position):
""" Move to an absolute position expressed in seconds
:Parameters:
`time_position` : float
seconds to skip from the start of the stream
"""
pass
[docs]class BufferAudioSource(AudioSource, Rewindable):
"""
An :class:`AudioSource` that encapsulates and reads data from a memory buffer.
It implements methods from :class:`Rewindable` and is therefore a navigable :class:`AudioSource`.
"""
def __init__(self, data_buffer,
sampling_rate=DEFAULT_SAMPLE_RATE,
sample_width=DEFAULT_SAMPLE_WIDTH,
channels=DEFAULT_NB_CHANNELS):
if len(data_buffer) % (sample_width * channels) != 0:
raise ValueError("length of data_buffer must be a multiple of (sample_width * channels)")
AudioSource.__init__(self, sampling_rate, sample_width, channels)
self._buffer = data_buffer
self._index = 0
self._left = 0 if self._buffer is None else len(self._buffer)
self._is_open = False
[docs] def is_open(self):
return self._is_open
[docs] def open(self):
self._is_open = True
[docs] def close(self):
self._is_open = False
self.rewind()
[docs] def read(self, size):
if not self._is_open:
raise IOError("Stream is not open")
if self._left > 0:
to_read = size * self.sample_width * self.channels
if to_read > self._left:
to_read = self._left
data = self._buffer[self._index: self._index + to_read]
self._index += to_read
self._left -= to_read
return data
return None
[docs] def get_data_buffer(self):
""" Return all audio data as one string buffer. """
return self._buffer
[docs] def set_data(self, data_buffer):
""" Set new data for this audio stream.
:Parameters:
`data_buffer` : str, basestring, Bytes
a string buffer with a length multiple of (sample_width * channels)
"""
if len(data_buffer) % (self.sample_width * self.channels) != 0:
raise ValueError("length of data_buffer must be a multiple of (sample_width * channels)")
self._buffer = data_buffer
self._index = 0
self._left = 0 if self._buffer is None else len(self._buffer)
[docs] def append_data(self, data_buffer):
""" Append data to this audio stream
:Parameters:
`data_buffer` : str, basestring, Bytes
a buffer with a length multiple of (sample_width * channels)
"""
if len(data_buffer) % (self.sample_width * self.channels) != 0:
raise ValueError("length of data_buffer must be a multiple of (sample_width * channels)")
self._buffer += data_buffer
self._left += len(data_buffer)
[docs] def rewind(self):
self.set_position(0)
[docs] def get_position(self):
return self._index / self.sample_width
[docs] def get_time_position(self):
return float(self._index) / (self.sample_width * self.sampling_rate)
[docs] def set_position(self, position):
if position < 0:
raise ValueError("position must be >= 0")
if self._buffer is None:
self._index = 0
self._left = 0
return
position *= self.sample_width
self._index = position if position < len(self._buffer) else len(self._buffer)
self._left = len(self._buffer) - self._index
[docs] def set_time_position(self, time_position): # time in seconds
position = int(self.sampling_rate * time_position)
self.set_position(position)
[docs]class WaveAudioSource(AudioSource):
"""
A class for an `AudioSource` that reads data from a wave file.
:Parameters:
`filename` :
path to a valid wave file
"""
def __init__(self, filename):
self._filename = filename
self._audio_stream = None
stream = wave.open(self._filename)
AudioSource.__init__(self, stream.getframerate(),
stream.getsampwidth(),
stream.getnchannels())
stream.close()
[docs] def is_open(self):
return self._audio_stream is not None
[docs] def open(self):
if(self._audio_stream is None):
self._audio_stream = wave.open(self._filename)
[docs] def close(self):
if self._audio_stream is not None:
self._audio_stream.close()
self._audio_stream = None
[docs] def read(self, size):
if self._audio_stream is None:
raise IOError("Stream is not open")
else:
data = self._audio_stream.readframes(size)
if data is None or len(data) < 1:
return None
return data
[docs]class PyAudioSource(AudioSource):
"""
A class for an `AudioSource` that reads data the built-in microphone using PyAudio.
"""
def __init__(self, sampling_rate=DEFAULT_SAMPLE_RATE,
sample_width=DEFAULT_SAMPLE_WIDTH,
channels=DEFAULT_NB_CHANNELS,
frames_per_buffer=1024,
input_device_index=None):
AudioSource.__init__(self, sampling_rate, sample_width, channels)
self._chunk_size = frames_per_buffer
self.input_device_index = input_device_index
import pyaudio
self._pyaudio_object = pyaudio.PyAudio()
self._pyaudio_format = self._pyaudio_object.get_format_from_width(self.sample_width)
self._audio_stream = None
[docs] def is_open(self):
return self._audio_stream is not None
[docs] def open(self):
self._audio_stream = self._pyaudio_object.open(format=self._pyaudio_format,
channels=self.channels,
rate=self.sampling_rate,
input=True,
output=False,
input_device_index=self.input_device_index,
frames_per_buffer=self._chunk_size)
[docs] def close(self):
if self._audio_stream is not None:
self._audio_stream.stop_stream()
self._audio_stream.close()
self._audio_stream = None
[docs] def read(self, size):
if self._audio_stream is None:
raise IOError("Stream is not open")
if self._audio_stream.is_active():
data = self._audio_stream.read(size)
if data is None or len(data) < 1:
return None
return data
return None
[docs]class StdinAudioSource(AudioSource):
"""
A class for an :class:`AudioSource` that reads data from standard input.
"""
def __init__(self, sampling_rate=DEFAULT_SAMPLE_RATE,
sample_width=DEFAULT_SAMPLE_WIDTH,
channels=DEFAULT_NB_CHANNELS):
AudioSource.__init__(self, sampling_rate, sample_width, channels)
self._is_open = False
[docs] def is_open(self):
return self._is_open
[docs] def open(self):
self._is_open = True
[docs] def close(self):
self._is_open = False
[docs] def read(self, size):
if not self._is_open:
raise IOError("Stream is not open")
to_read = size * self.sample_width * self.channels
if sys.version_info >= (3, 0):
data = sys.stdin.buffer.read(to_read)
else:
data = sys.stdin.read(to_read)
if data is None or len(data) < 1:
return None
return data
[docs]class PyAudioPlayer():
"""
A class for audio playback using Pyaudio
"""
def __init__(self, sampling_rate=DEFAULT_SAMPLE_RATE,
sample_width=DEFAULT_SAMPLE_WIDTH,
channels=DEFAULT_NB_CHANNELS):
if not sample_width in (1, 2, 4):
raise ValueError("Sample width must be one of: 1, 2 or 4 (bytes)")
self.sampling_rate = sampling_rate
self.sample_width = sample_width
self.channels = channels
import pyaudio
self._p = pyaudio.PyAudio()
self.stream = self._p.open(format=self._p.get_format_from_width(self.sample_width),
channels=self.channels, rate=self.sampling_rate,
input=False, output=True)
def play(self, data):
if self.stream.is_stopped():
self.stream.start_stream()
for chunk in self._chunk_data(data):
self.stream.write(chunk)
self.stream.stop_stream()
def stop(self):
if not self.stream.is_stopped():
self.stream.stop_stream()
self.stream.close()
self._p.terminate()
def _chunk_data(self, data):
# make audio chunks of 100 ms to allow interruption (like ctrl+c)
chunk_size = int((self.sampling_rate * self.sample_width * self.channels) / 10)
start = 0
while start < len(data):
yield data[start: start + chunk_size]
start += chunk_size
[docs]def from_file(filename):
"""
Create an `AudioSource` object using the audio file specified by `filename`.
The appropriate :class:`AudioSource` class is guessed from file's extension.
:Parameters:
`filename` :
path to an audio file.
:Returns:
an `AudioSource` object that reads data from the given file.
"""
if filename.lower().endswith(".wav"):
return WaveAudioSource(filename)
raise Exception("Can not create an AudioSource object from '%s'" % (filename))
[docs]def player_for(audio_source):
"""
Return a :class:`PyAudioPlayer` that can play data from `audio_source`.
:Parameters:
`audio_source` :
an `AudioSource` object.
:Returns:
`PyAudioPlayer` that has the same sampling rate, sample width and number of channels
as `audio_source`.
"""
return PyAudioPlayer(audio_source.get_sampling_rate(),
audio_source.get_sample_width(),
audio_source.get_channels())