/usr/lib/python2.7/dist-packages/audioread/rawread.py is in python-audioread 1.0.3-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 | # This file is part of audioread.
# Copyright 2011, Adrian Sampson.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
"""Uses standard-library modules to read AIFF, AIFF-C, and WAV files."""
import wave
import aifc
import audioop
import struct
from . import DecodeError
TARGET_WIDTH = 2
class UnsupportedError(DecodeError):
"""File is neither an AIFF nor a WAV file."""
def byteswap(s):
"""Swaps the endianness of the bytesting s, which must be an array
of shorts (16-bit signed integers). This is probably less efficient
than it should be.
"""
assert len(s) % 2 == 0
parts = []
for i in xrange(0, len(s), 2):
chunk = s[i:i+2]
newchunk =struct.pack('<h', *struct.unpack('>h', chunk))
parts.append(newchunk)
return ''.join(parts)
class RawAudioFile(object):
"""An AIFF or WAV file that can be read by the Python standard
library modules ``wave`` and ``aifc``.
"""
def __init__(self, filename):
self._fh = open(filename, 'rb')
try:
self._file = aifc.open(self._fh)
except aifc.Error:
# Return to the beginning of the file to try the WAV reader.
self._fh.seek(0)
else:
self._is_aif = True
return
try:
self._file = wave.open(self._fh)
except wave.Error:
pass
else:
self._is_aif = False
return
raise UnsupportedError()
def close(self):
"""Close the underlying file."""
self._file.close()
self._fh.close()
@property
def channels(self):
"""Number of audio channels."""
return self._file.getnchannels()
@property
def samplerate(self):
"""Sample rate in Hz."""
return self._file.getframerate()
@property
def duration(self):
"""Length of the audio in seconds (a float)."""
return float(self._file.getnframes()) / self.samplerate
def read_data(self, block_samples=1024):
"""Generates blocks of PCM data found in the file."""
old_width = self._file.getsampwidth()
while True:
data = self._file.readframes(block_samples)
if not data:
break
# Make sure we have the desired bitdepth and endianness.
data = audioop.lin2lin(data, old_width, TARGET_WIDTH)
if self._is_aif and self._file.getcomptype() != 'sowt':
# Big-endian data. Swap endianness.
data = byteswap(data)
yield data
# Context manager.
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
return False
# Iteration.
def __iter__(self):
return self.read_data()
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