""" 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 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 @abstractmethod def is_open(self): """ Return True if audio source is open, False otherwise """ @abstractmethod def open(self): """ Open audio source """ @abstractmethod def close(self): """ Close audio source """ @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' * 'smaple_width' * 'channels', where 'N' is: - `size` if `size` < 'left_samples' - 'left_samples' if `size` > 'left_samples' """ def get_sampling_rate(self): """ Return the number of samples per second of audio stream """ return self.sampling_rate def get_sample_width(self): """ Return the number of bytes used to represent one audio sample """ return self.sample_width def get_channels(self): """ Return the number of channels of this audio source """ return self.channels 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 @abstractmethod def rewind(self): """ Go back to the beginning of audio stream """ pass @abstractmethod def get_position(self): """ Return the total number of already read samples """ @abstractmethod def get_time_position(self): """ Return the total duration in seconds of already read data """ @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 """ @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 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 def is_open(self): return self._is_open def open(self): self._is_open = True def close(self): self._is_open = False self.rewind() 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 def get_data_buffer(self): """ Return all audio data as one string buffer. """ return self._buffer 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) 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) def rewind(self): self.set_position(0) def get_position(self): return self._index / self.sample_width def get_time_position(self): return float(self._index) / (self.sample_width * self.sampling_rate) 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 def set_time_position(self, time_position): # time in seconds position = int(self.sampling_rate * time_position) self.set_position(position) 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() def is_open(self): return self._audio_stream is not None def open(self): if(self._audio_stream is None): self._audio_stream = wave.open(self._filename) def close(self): if self._audio_stream is not None: self._audio_stream.close() self._audio_stream = None 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 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): AudioSource.__init__(self, sampling_rate, sample_width, channels) self._chunk_size = frames_per_buffer import pyaudio self._pyaudio_object = pyaudio.PyAudio() self._pyaudio_format = self._pyaudio_object.get_format_from_width(self.sample_width) self._audio_stream = None def is_open(self): return self._audio_stream is not None 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, frames_per_buffer = self._chunk_size) def close(self): if self._audio_stream is not None: self._audio_stream.stop_stream() self._audio_stream.close() self._audio_stream = None 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 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 def is_open(self): return self._is_open def open(self): self._is_open = True def close(self): self._is_open = False def read(self, size): if not self._is_open: raise IOError("Stream is not open") to_read = size * self.sample_width * self.channels data = sys.stdin.read(to_read) if data is None or len(data) < 1: return None return data 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 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)) 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())