晚上，
我正在开发一个项目，要求我读取32位浮点数的多通道wav文件。 当我将特定文件（1分钟长，6个通道，48k fs）读入Matlab并使用tic / toc进行测量时，它会在2.456482秒内解析该文件。
用于文件读取速度测量的Matlab代码 抽搐 wavread（ 'C：/data/testData/6ch.wav'）; TOC
当我在python中这样做时（请注意，我对python非常不熟悉）需要18.1655315617秒！ 在我看来，我这样做的方式效率很低（我确实把它从28降到了18，但它仍然太多了......）
我将代码剥离了与此主题相关的内容：
用于文件读取速度测量的Python代码
import wave32
import struct
import time
import numpy as np
def getWavData(inFile)
wavFile = wave32.open(inFile, 'r')
wavParams = wavFile.getparams()
nChannels = wavParams[0]
byteDepth = wavParams[1]
nFrames = wavParams[3]
wavData = np.empty([nFrames, nChannels], np.float32)
frames = wavFile.readframes(nFrames)
for i in range(nFrames):
for j in range(nChannels):
start = ( i * nChannels + j ) * byteDepth
stop = start + byteDepth
wavData[i][j] = struct.unpack('<f', frames[start:stop])[0]
return wavData
inFile = 'C:/data/testData/6ch.wav'
start = time.clock()
data2 = getWavData(inFile)
elapsed = time.clock()
elapsedNew = elapsed - start
print str(elapsedNew)
请注意，wav32是我必须在wave.py上执行的一个小hack，以启用32位浮点读取。
"""Stuff to parse WAVE files.
Usage.
Reading WAVE files:
f = wave.open(file, 'r')
where file is either the name of a file or an open file pointer.
The open file pointer must have methods read(), seek(), and close().
When the setpos() and rewind() methods are not used, the seek()
method is not necessary.
This returns an instance of a class with the following public methods:
getnchannels() -- returns number of audio channels (1 for
mono, 2 for stereo)
getsampwidth() -- returns sample width in bytes
getframerate() -- returns sampling frequency
getnframes() -- returns number of audio frames
getcomptype() -- returns compression type ('NONE' for linear samples)
getcompname() -- returns human-readable version of
compression type ('not compressed' linear samples)
getparams() -- returns a tuple consisting of all of the
above in the above order
getmarkers() -- returns None (for compatibility with the
aifc module)
getmark(id) -- raises an error since the mark does not
exist (for compatibility with the aifc module)
readframes(n) -- returns at most n frames of audio
rewind() -- rewind to the beginning of the audio stream
setpos(pos) -- seek to the specified position
tell() -- return the current position
close() -- close the instance (make it unusable)
The position returned by tell() and the position given to setpos()
are compatible and have nothing to do with the actual position in the
file.
The close() method is called automatically when the class instance
is destroyed.
Writing WAVE files:
f = wave.open(file, 'w')
where file is either the name of a file or an open file pointer.
The open file pointer must have methods write(), tell(), seek(), and
close().
This returns an instance of a class with the following public methods:
setnchannels(n) -- set the number of channels
setsampwidth(n) -- set the sample width
setframerate(n) -- set the frame rate
setnframes(n) -- set the number of frames
setcomptype(type, name)
-- set the compression type and the
human-readable compression type
setparams(tuple)
-- set all parameters at once
tell() -- return current position in output file
writeframesraw(data)
-- write audio frames without pathing up the
file header
writeframes(data)
-- write audio frames and patch up the file header
close() -- patch up the file header and close the
output file
You should set the parameters before the first writeframesraw or
writeframes. The total number of frames does not need to be set,
but when it is set to the correct value, the header does not have to
be patched up.
It is best to first set all parameters, perhaps possibly the
compression type, and then write audio frames using writeframesraw.
When all frames have been written, either call writeframes('') or
close() to patch up the sizes in the header.
The close() method is called automatically when the class instance
is destroyed.
"""
import __builtin__
__all__ = ["open", "openfp", "Error"]
class Error(Exception):
pass
WAVE_FORMAT_PCM = 0x0001
WAVE_FORMAT_IEEE_FLOAT = 0x0003
_array_fmts = None, 'b', 'h', None, 'l'
# Determine endian-ness
import struct
if struct.pack("h", 1) == "\000\001":
big_endian = 1
else:
big_endian = 0
from chunk import Chunk
class Wave_read:
"""Variables used in this class:
These variables are available to the user though appropriate
methods of this class:
_file -- the open file with methods read(), close(), and seek()
set through the __init__() method
_nchannels -- the number of audio channels
available through the getnchannels() method
_nframes -- the number of audio frames
available through the getnframes() method
_sampwidth -- the number of bytes per audio sample
available through the getsampwidth() method
_framerate -- the sampling frequency
available through the getframerate() method
_comptype -- the AIFF-C compression type ('NONE' if AIFF)
available through the getcomptype() method
_compname -- the human-readable AIFF-C compression type
available through the getcomptype() method
_soundpos -- the position in the audio stream
available through the tell() method, set through the
setpos() method
These variables are used internally only:
_fmt_chunk_read -- 1 iff the FMT chunk has been read
_data_seek_needed -- 1 iff positioned correctly in audio
file for readframes()
_data_chunk -- instantiation of a chunk class for the DATA chunk
_framesize -- size of one frame in the file
"""
def initfp(self, file):
self._convert = None
self._soundpos = 0
self._file = Chunk(file, bigendian = 0)
if self._file.getname() != 'RIFF':
raise Error, 'file does not start with RIFF id'
if self._file.read(4) != 'WAVE':
raise Error, 'not a WAVE file'
self._fmt_chunk_read = 0
self._data_chunk = None
while 1:
self._data_seek_needed = 1
try:
chunk = Chunk(self._file, bigendian = 0)
except EOFError:
break
chunkname = chunk.getname()
if chunkname == 'fmt ':
self._read_fmt_chunk(chunk)
self._fmt_chunk_read = 1
elif chunkname == 'data':
if not self._fmt_chunk_read:
raise Error, 'data chunk before fmt chunk'
self._data_chunk = chunk
self._nframes = chunk.chunksize // self._framesize
self._data_seek_needed = 0
break
chunk.skip()
if not self._fmt_chunk_read or not self._data_chunk:
raise Error, 'fmt chunk and/or data chunk missing'
def __init__(self, f):
self._i_opened_the_file = None
if isinstance(f, basestring):
f = __builtin__.open(f, 'rb')
self._i_opened_the_file = f
# else, assume it is an open file object already
try:
self.initfp(f)
except:
if self._i_opened_the_file:
f.close()
raise
def __del__(self):
self.close()
#
# User visible methods.
#
def getfp(self):
return self._file
def rewind(self):
self._data_seek_needed = 1
self._soundpos = 0
def close(self):
if self._i_opened_the_file:
self._i_opened_the_file.close()
self._i_opened_the_file = None
self._file = None
def tell(self):
return self._soundpos
def getnchannels(self):
return self._nchannels
def getnframes(self):
return self._nframes
def getsampwidth(self):
return self._sampwidth
def getframerate(self):
return self._framerate
def getcomptype(self):
return self._comptype
def getcompname(self):
return self._compname
def getparams(self):
return self.getnchannels(), self.getsampwidth(), \
self.getframerate(), self.getnframes(), \
self.getcomptype(), self.getcompname()
def getmarkers(self):
return None
def getmark(self, id):
raise Error, 'no marks'
def setpos(self, pos):
if pos < 0 or pos > self._nframes:
raise Error, 'position not in range'
self._soundpos = pos
self._data_seek_needed = 1
def readframes(self, nframes):
if self._data_seek_needed:
self._data_chunk.seek(0, 0)
pos = self._soundpos * self._framesize
if pos:
self._data_chunk.seek(pos, 0)
self._data_seek_needed = 0
if nframes == 0:
return ''
if self._sampwidth > 1 and big_endian:
# unfortunately the fromfile() method does not take
# something that only looks like a file object, so
# we have to reach into the innards of the chunk object
import array
chunk = self._data_chunk
data = array.array(_array_fmts[self._sampwidth])
nitems = nframes * self._nchannels
if nitems * self._sampwidth > chunk.chunksize - chunk.size_read:
nitems = (chunk.chunksize - chunk.size_read) / self._sampwidth
data.fromfile(chunk.file.file, nitems)
# "tell" data chunk how much was read
chunk.size_read = chunk.size_read + nitems * self._sampwidth
# do the same for the outermost chunk
chunk = chunk.file
chunk.size_read = chunk.size_read + nitems * self._sampwidth
data.byteswap()
data = data.tostring()
else:
data = self._data_chunk.read(nframes * self._framesize)
if self._convert and data:
data = self._convert(data)
self._soundpos = self._soundpos + len(data) // (self._nchannels * self._sampwidth)
return data
#
# Internal methods.
#
def _read_fmt_chunk(self, chunk):
wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack('<hhllh', chunk.read(14))
if wFormatTag == WAVE_FORMAT_PCM or wFormatTag==WAVE_FORMAT_IEEE_FLOAT:
sampwidth = struct.unpack('<h', chunk.read(2))[0]
self._sampwidth = (sampwidth + 7) // 8
else:
#sampwidth = struct.unpack('<h', chunk.read(2))[0]
#self._sampwidth = (sampwidth + 7) // 8
raise Error, 'unknown format: %r' % (wFormatTag,)
self._framesize = self._nchannels * self._sampwidth
self._comptype = 'NONE'
self._compname = 'not compressed'
class Wave_write:
"""Variables used in this class:
These variables are user settable through appropriate methods
of this class:
_file -- the open file with methods write(), close(), tell(), seek()
set through the __init__() method
_comptype -- the AIFF-C compression type ('NONE' in AIFF)
set through the setcomptype() or setparams() method
_compname -- the human-readable AIFF-C compression type
set through the setcomptype() or setparams() method
_nchannels -- the number of audio channels
set through the setnchannels() or setparams() method
_sampwidth -- the number of bytes per audio sample
set through the setsampwidth() or setparams() method
_framerate -- the sampling frequency
set through the setframerate() or setparams() method
_nframes -- the number of audio frames written to the header
set through the setnframes() or setparams() method
These variables are used internally only:
_datalength -- the size of the audio samples written to the header
_nframeswritten -- the number of frames actually written
_datawritten -- the size of the audio samples actually written
"""
def __init__(self, f):
self._i_opened_the_file = None
if isinstance(f, basestring):
f = __builtin__.open(f, 'wb')
self._i_opened_the_file = f
try:
self.initfp(f)
except:
if self._i_opened_the_file:
f.close()
raise
def initfp(self, file):
self._file = file
self._convert = None
self._nchannels = 0
self._sampwidth = 0
self._framerate = 0
self._nframes = 0
self._nframeswritten = 0
self._datawritten = 0
self._datalength = 0
self._headerwritten = False
def __del__(self):
self.close()
#
# User visible methods.
#
def setnchannels(self, nchannels):
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
if nchannels < 1:
raise Error, 'bad # of channels'
self._nchannels = nchannels
def getnchannels(self):
if not self._nchannels:
raise Error, 'number of channels not set'
return self._nchannels
def setsampwidth(self, sampwidth):
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
if sampwidth < 1 or sampwidth > 4:
raise Error, 'bad sample width'
self._sampwidth = sampwidth
def getsampwidth(self):
if not self._sampwidth:
raise Error, 'sample width not set'
return self._sampwidth
def setframerate(self, framerate):
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
if framerate <= 0:
raise Error, 'bad frame rate'
self._framerate = framerate
def getframerate(self):
if not self._framerate:
raise Error, 'frame rate not set'
return self._framerate
def setnframes(self, nframes):
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
self._nframes = nframes
def getnframes(self):
return self._nframeswritten
def setcomptype(self, comptype, compname):
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
if comptype not in ('NONE',):
raise Error, 'unsupported compression type'
self._comptype = comptype
self._compname = compname
def getcomptype(self):
return self._comptype
def getcompname(self):
return self._compname
def setparams(self, params):
nchannels, sampwidth, framerate, nframes, comptype, compname = params
if self._datawritten:
raise Error, 'cannot change parameters after starting to write'
self.setnchannels(nchannels)
self.setsampwidth(sampwidth)
self.setframerate(framerate)
self.setnframes(nframes)
self.setcomptype(comptype, compname)
def getparams(self):
if not self._nchannels or not self._sampwidth or not self._framerate:
raise Error, 'not all parameters set'
return self._nchannels, self._sampwidth, self._framerate, \
self._nframes, self._comptype, self._compname
def setmark(self, id, pos, name):
raise Error, 'setmark() not supported'
def getmark(self, id):
raise Error, 'no marks'
def getmarkers(self):
return None
def tell(self):
return self._nframeswritten
def writeframesraw(self, data):
self._ensure_header_written(len(data))
nframes = len(data) // (self._sampwidth * self._nchannels)
if self._convert:
data = self._convert(data)
if self._sampwidth > 1 and big_endian:
import array
data = array.array(_array_fmts[self._sampwidth], data)
data.byteswap()
data.tofile(self._file)
self._datawritten = self._datawritten + len(data) * self._sampwidth
else:
self._file.write(data)
self._datawritten = self._datawritten + len(data)
self._nframeswritten = self._nframeswritten + nframes
def writeframes(self, data):
self.writeframesraw(data)
if self._datalength != self._datawritten:
self._patchheader()
def close(self):
if self._file:
self._ensure_header_written(0)
if self._datalength != self._datawritten:
self._patchheader()
self._file.flush()
self._file = None
if self._i_opened_the_file:
self._i_opened_the_file.close()
self._i_opened_the_file = None
#
# Internal methods.
#
def _ensure_header_written(self, datasize):
if not self._headerwritten:
if not self._nchannels:
raise Error, '# channels not specified'
if not self._sampwidth:
raise Error, 'sample width not specified'
if not self._framerate:
raise Error, 'sampling rate not specified'
self._write_header(datasize)
def _write_header(self, initlength):
assert not self._headerwritten
self._file.write('RIFF')
if not self._nframes:
self._nframes = initlength / (self._nchannels * self._sampwidth)
self._datalength = self._nframes * self._nchannels * self._sampwidth
self._form_length_pos = self._file.tell()
self._file.write(struct.pack('<l4s4slhhllhh4s',
36 + self._datalength, 'WAVE', 'fmt ', 16,
WAVE_FORMAT_PCM, self._nchannels, self._framerate,
self._nchannels * self._framerate * self._sampwidth,
self._nchannels * self._sampwidth,
self._sampwidth * 8, 'data'))
self._data_length_pos = self._file.tell()
self._file.write(struct.pack('<l', self._datalength))
self._headerwritten = True
def _patchheader(self):
assert self._headerwritten
if self._datawritten == self._datalength:
return
curpos = self._file.tell()
self._file.seek(self._form_length_pos, 0)
self._file.write(struct.pack('<l', 36 + self._datawritten))
self._file.seek(self._data_length_pos, 0)
self._file.write(struct.pack('<l', self._datawritten))
self._file.seek(curpos, 0)
self._datalength = self._datawritten
def open(f, mode=None):
if mode is None:
if hasattr(f, 'mode'):
mode = f.mode
else:
mode = 'rb'
if mode in ('r', 'rb'):
return Wave_read(f)
elif mode in ('w', 'wb'):
return Wave_write(f)
else:
raise Error, "mode must be 'r', 'rb', 'w', or 'wb'"
openfp = open # B/W compatibility
抱歉长码BTW：）
所以我的问题是：wave.py模块本身是否很慢（修复此问题的其他选择？）还是我做的事情效率低下？
我想我可以用自定义函数读取wav标题并以不同的方式读取文件，但似乎这将是很多工作，特别是因为我不太了解约1）python和2）文件处理
亲切的问候，
ķ。
编辑：我尝试了unutbu的建议，但这不起作用，因为scipy不接受＆gt; 16位。
当我尝试通过scipy wavreader解析wav文件时，我收到此消息：
C:\Users\King Broos\AppData\Local\Enthought\Canopy32\System\lib\site-packages\scipy\io\wavfile.py:31: WavFileWarning: Unfamiliar format bytes
warnings.warn("Unfamiliar format bytes", WavFileWarning)
C:\Users\King Broos\AppData\Local\Enthought\Canopy32\System\lib\site-packages\scipy\io\wavfile.py:121: WavFileWarning: chunk not understood
warnings.warn("chunk not understood", WavFileWarning)
查看wavfile.py的代码，这是抛出异常的行：
if (comp != 1 or size > 16):
warnings.warn("Unfamiliar format bytes", WavFileWarning)
我真的需要24或32位，所以我猜scipy不是一个选项？
答案 0 :(得分：1)
如果您可以安装或scipy，请使用wavfile.read：
import scipy.io.wavfile as wavfile
sample_rate, x = wavfile.read(filename)
您可能还想学习source code, here。
请注意，scipy.io.wavfile不使用Python的wave模块。我不确定它是否会读取您的IEEE_FLOAT格式，但它不会像wave.py那样进行检查：
if wFormatTag == WAVE_FORMAT_PCM or wFormatTag==WAVE_FORMAT_IEEE_FLOAT:
sampwidth = struct.unpack('<h', chunk.read(2))[0]
self._sampwidth = (sampwidth + 7) // 8
else:
#sampwidth = struct.unpack('<h', chunk.read(2))[0]
#self._sampwidth = (sampwidth + 7) // 8
raise Error, 'unknown format: %r' % (wFormatTag,)
所以也许它可以开箱即用。
顺便说一句，您可以使用猴子修补程序，而不是使用自己的模块wave32.py，它与标准库中的wave.py几乎完全相同：
import wave
import struct
WAVE_FORMAT_IEEE_FLOAT = 0x0003
def _read_fmt_chunk(self, chunk):
wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack('<hhllh', chunk.read(14))
if wFormatTag == WAVE_FORMAT_PCM or wFormatTag == WAVE_FORMAT_IEEE_FLOAT:
sampwidth = struct.unpack('<h', chunk.read(2))[0]
self._sampwidth = (sampwidth + 7) // 8
else:
raise Error, 'unknown format: %r' % (wFormatTag,)
self._framesize = self._nchannels * self._sampwidth
self._comptype = 'NONE'
self._compname = 'not compressed'
wave.Wave_read._read_fmt_chunk = _read_fmt_chunk
答案 1 :(得分：0)
您也可以直接使用numpy：
import numpy as np
fs = np.fromfile(filename, dtype=np.int32, count=1, offset=24)[0] # Hz
byte_length = np.fromfile(filename, dtype=np.int32, count=1, offset=40)[0]
手动读取元数据。我建议使用十六进制编辑器和波形格式引用来验证元数据片段的位置，以及offset到数据块开头的位置（可能不是40或44字节）。
要读取32位WAVE_FORMAT_IEEE_FLOAT：
data = np.fromfile(filename, dtype=np.float32, count=byte_length // 4, offset=44)
要读取24位WAVE_FORMAT_PCM：
# prepend zero-byte to each sample (since there's no np.int24)
# then flatten, convert normally and byte-shift to correct for extra byte
data = np.zeros([byte_length // 3, 4], dtype=np.int8)
data[:, 1:] = np.fromfile(filename, dtype=np.int8, count=byte_length, offset=44).reshape(-1, 3)
data = np.right_shift(data.reshape(-1).view(dtype=np.int32), 8)
data = data / 2 ** 23 # if you want to normalize
取决于wavefile和计算机，但这似乎比4.4 MB 24位.wav文件的循环快约120倍，但是对于较大的文件，可能会有更大的性能提升（直到需要进行交换，我认为大约执行了5个内存副本，包括归一化操作。）
这假定：
offset=参数错误.reshape(num_channels, -1, order='F')