60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
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from .pyogg_error import PyOggError
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class AudioFile:
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"""Abstract base class for audio files.
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This class is a base class for audio files (such as Vorbis, Opus,
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and FLAC). It should not be instatiated directly.
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"""
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def __init__(self):
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raise PyOggError("AudioFile is an Abstract Base Class "+
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"and should not be instantiated")
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def as_array(self):
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"""Returns the buffer as a NumPy array.
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The shape of the returned array is in units of (number of
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samples per channel, number of channels).
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The data type is either 8-bit or 16-bit signed integers,
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depending on bytes_per_sample.
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The buffer is not copied, but rather the NumPy array
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shares the memory with the buffer.
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"""
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# Assumes that self.buffer is a one-dimensional array of
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# bytes and that channels are interleaved.
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import numpy # type: ignore
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assert self.buffer is not None
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assert self.channels is not None
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# The following code assumes that the bytes in the buffer
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# represent 8-bit or 16-bit signed ints. Ensure the number of
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# bytes per sample matches that assumption.
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assert self.bytes_per_sample == 1 or self.bytes_per_sample == 2
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# Create a dictionary mapping bytes per sample to numpy data
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# types
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dtype = {
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1: numpy.int8,
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2: numpy.int16
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}
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# Convert the ctypes buffer to a NumPy array
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array = numpy.frombuffer(
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self.buffer,
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dtype=dtype[self.bytes_per_sample]
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)
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# Reshape the array
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return array.reshape(
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(len(self.buffer)
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// self.bytes_per_sample
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// self.channels,
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self.channels)
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)
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