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wavfile.py (enhanced)
# wavfile.py (Enhanced)
# Date: 20180430_2335 Joseph Basquin
#
# URL: https://gist.github.com/josephernest/3f22c5ed5dabf1815f16efa8fa53d476
# Source: scipy/io/wavfile.py
#
# Added:
# * read: also returns bitrate, cue markers + cue marker labels (sorted), loops, pitch
# See https://web.archive.org/web/20141226210234/http://www.sonicspot.com/guide/wavefiles.html#labl
# * read: 24 bit & 32 bit IEEE files support (inspired from wavio_weckesser.py from Warren Weckesser)
# * read: added normalized (default False) that returns everything as float in [-1, 1]
# * read: added forcestereo that returns a 2-dimensional array even if input is mono
#
# * write: can write cue markers, cue marker labels, loops, pitch
# * write: 24 bit support
# * write: can write from a float normalized in [-1, 1]
# * write: 20180430_2335: bug fixed when size of data chunk is odd (previously, metadata could become unreadable because of this)
#
# * removed RIFX support (big-endian) (never seen one in 10+ years of audio production/audio programming), only RIFF (little-endian) are supported
# * removed read(..., mmap)
#
#
# Test:
# ..\wav\____wavfile_demo.py
"""
Module to read / write wav files using numpy arrays
Functions
---------
`read`: Return the sample rate (in samples/sec) and data from a WAV file.
`write`: Write a numpy array as a WAV file.
"""
from __future__ import division, print_function, absolute_import
import numpy
import struct
import warnings
import collections
from operator import itemgetter
class WavFileWarning(UserWarning):
pass
_ieee = False
# assumes file pointer is immediately
# after the 'fmt ' id
def _read_fmt_chunk(fid):
res = struct.unpack('<ihHIIHH',fid.read(20))
size, comp, noc, rate, sbytes, ba, bits = res
if (comp != 1 or size > 16):
if (comp == 3):
global _ieee
_ieee = True
#warnings.warn("IEEE format not supported", WavFileWarning)
else:
warnings.warn("Unfamiliar format bytes", WavFileWarning)
if (size>16):
fid.read(size-16)
return size, comp, noc, rate, sbytes, ba, bits
# assumes file pointer is immediately
# after the 'data' id
def _read_data_chunk(fid, noc, bits, normalized=False):
size = struct.unpack('<i',fid.read(4))[0]
if bits == 8 or bits == 24:
dtype = 'u1'
bytes = 1
else:
bytes = bits//8
dtype = '<i%d' % bytes
if bits == 32 and _ieee:
dtype = 'float32'
data = numpy.fromfile(fid, dtype=dtype, count=size//bytes)
if bits == 24:
a = numpy.empty((len(data) // 3, 4), dtype='u1')
a[:, :3] = data.reshape((-1, 3))
a[:, 3:] = (a[:, 3 - 1:3] >> 7) * 255
data = a.view('<i4').reshape(a.shape[:-1])
if noc > 1:
data = data.reshape(-1,noc)
if bool(size & 1): # if odd number of bytes, move 1 byte further (data chunk is word-aligned)
fid.seek(1,1)
if normalized:
if bits == 8 or bits == 16 or bits == 24:
normfactor = 2 ** (bits-1)
data = numpy.float32(data) * 1.0 / normfactor
return data
def _skip_unknown_chunk(fid):
data = fid.read(4)
size = struct.unpack('<i', data)[0]
if bool(size & 1): # if odd number of bytes, move 1 byte further (data chunk is word-aligned)
size += 1
fid.seek(size, 1)
def _read_riff_chunk(fid):
str1 = fid.read(4)
if str1 != b'RIFF':
raise ValueError("Not a WAV file.")
fsize = struct.unpack('<I', fid.read(4))[0] + 8
str2 = fid.read(4)
if (str2 != b'WAVE'):
raise ValueError("Not a WAV file.")
return fsize
def read(file, readmarkers=False, readmarkerlabels=False, readmarkerslist=False, readloops=False, readpitch=False, normalized=False, forcestereo=False):
"""
Return the sample rate (in samples/sec) and data from a WAV file
Parameters
----------
file : file
Input wav file.
Returns
-------
rate : int
Sample rate of wav file
data : numpy array
Data read from wav file
Notes
-----
* The file can be an open file or a filename.
* The returned sample rate is a Python integer
* The data is returned as a numpy array with a
data-type determined from the file.
"""
if hasattr(file,'read'):
fid = file
else:
fid = open(file, 'rb')
fsize = _read_riff_chunk(fid)
noc = 1
bits = 8
#_cue = []
#_cuelabels = []
_markersdict = collections.defaultdict(lambda: {'position': -1, 'label': ''})
loops = []
pitch = 0.0
while (fid.tell() < fsize):
# read the next chunk
chunk_id = fid.read(4)
if chunk_id == b'fmt ':
size, comp, noc, rate, sbytes, ba, bits = _read_fmt_chunk(fid)
elif chunk_id == b'data':
data = _read_data_chunk(fid, noc, bits, normalized)
elif chunk_id == b'cue ':
str1 = fid.read(8)
size, numcue = struct.unpack('<ii',str1)
for c in range(numcue):
str1 = fid.read(24)
id, position, datachunkid, chunkstart, blockstart, sampleoffset = struct.unpack('<iiiiii', str1)
#_cue.append(position)
_markersdict[id]['position'] = position # needed to match labels and markers
elif chunk_id == b'LIST':
str1 = fid.read(8)
size, type = struct.unpack('<ii', str1)
elif chunk_id in [b'ICRD', b'IENG', b'ISFT', b'ISTJ']: # see http://www.pjb.com.au/midi/sfspec21.html#i5
_skip_unknown_chunk(fid)
elif chunk_id == b'labl':
str1 = fid.read(8)
size, id = struct.unpack('<ii',str1)
size = size + (size % 2) # the size should be even, see WAV specfication, e.g. 16=>16, 23=>24
label = fid.read(size-4).rstrip('\x00') # remove the trailing null characters
#_cuelabels.append(label)
_markersdict[id]['label'] = label # needed to match labels and markers
elif chunk_id == b'smpl':
str1 = fid.read(40)
size, manuf, prod, sampleperiod, midiunitynote, midipitchfraction, smptefmt, smpteoffs, numsampleloops, samplerdata = struct.unpack('<iiiiiIiiii', str1)
cents = midipitchfraction * 1./(2**32-1)
pitch = 440. * 2 ** ((midiunitynote + cents - 69.)/12)
for i in range(numsampleloops):
str1 = fid.read(24)
cuepointid, type, start, end, fraction, playcount = struct.unpack('<iiiiii', str1)
loops.append([start, end])
else:
warnings.warn("Chunk " + chunk_id + " skipped", WavFileWarning)
_skip_unknown_chunk(fid)
fid.close()
if data.ndim == 1 and forcestereo:
data = numpy.column_stack((data, data))
_markerslist = sorted([_markersdict[l] for l in _markersdict], key=lambda k: k['position']) # sort by position
_cue = [m['position'] for m in _markerslist]
_cuelabels = [m['label'] for m in _markerslist]
return (rate, data, bits, ) \
+ ((_cue,) if readmarkers else ()) \
+ ((_cuelabels,) if readmarkerlabels else ()) \
+ ((_markerslist,) if readmarkerslist else ()) \
+ ((loops,) if readloops else ()) \
+ ((pitch,) if readpitch else ())
def write(filename, rate, data, bitrate=None, markers=None, loops=None, pitch=None, normalized=False):
"""
Write a numpy array as a WAV file
Parameters
----------
filename : file
The name of the file to write (will be over-written).
rate : int
The sample rate (in samples/sec).
data : ndarray
A 1-D or 2-D numpy array of integer data-type.
Notes
-----
* Writes a simple uncompressed WAV file.
* The bits-per-sample will be determined by the data-type.
* To write multiple-channels, use a 2-D array of shape
(Nsamples, Nchannels).
"""
# normalization and 24-bit handling
if bitrate == 24: # special handling of 24 bit wav, because there is no numpy.int24...
if normalized:
data[data > 1.0] = 1.0
data[data < -1.0] = -1.0
a32 = numpy.asarray(data * (2 ** 23 - 1), dtype=numpy.int32)
else:
a32 = numpy.asarray(data, dtype=numpy.int32)
if a32.ndim == 1:
a32.shape = a32.shape + (1,) # Convert to a 2D array with a single column.
a8 = (a32.reshape(a32.shape + (1,)) >> numpy.array([0, 8, 16])) & 255 # By shifting first 0 bits, then 8, then 16, the resulting output is 24 bit little-endian.
data = a8.astype(numpy.uint8)
else:
if normalized: # default to 32 bit int
data[data > 1.0] = 1.0
data[data < -1.0] = -1.0
data = numpy.asarray(data * (2 ** 31 - 1), dtype=numpy.int32)
fid = open(filename, 'wb')
fid.write(b'RIFF')
fid.write(b'\x00\x00\x00\x00')
fid.write(b'WAVE')
# fmt chunk
fid.write(b'fmt ')
if data.ndim == 1:
noc = 1
else:
noc = data.shape[1]
bits = data.dtype.itemsize * 8 if bitrate != 24 else 24
sbytes = rate * (bits // 8) * noc
ba = noc * (bits // 8)
fid.write(struct.pack('<ihHIIHH', 16, 1, noc, rate, sbytes, ba, bits))
# cue chunk
if markers: # != None and != []
if isinstance(markers[0], dict): # then we have [{'position': 100, 'label': 'marker1'}, ...]
labels = [m['label'] for m in markers]
markers = [m['position'] for m in markers]
else:
labels = ['' for m in markers]
fid.write(b'cue ')
size = 4 + len(markers) * 24
fid.write(struct.pack('<ii', size, len(markers)))
for i, c in enumerate(markers):
s = struct.pack('<iiiiii', i + 1, c, 1635017060, 0, 0, c) # 1635017060 is struct.unpack('<i',b'data')
fid.write(s)
lbls = ''
for i, lbl in enumerate(labels):
lbls += b'labl'
label = lbl + ('\x00' if len(lbl) % 2 == 1 else '\x00\x00')
size = len(lbl) + 1 + 4 # because \x00
lbls += struct.pack('<ii', size, i + 1)
lbls += label
fid.write(b'LIST')
size = len(lbls) + 4
fid.write(struct.pack('<i', size))
fid.write(b'adtl') # https://web.archive.org/web/20141226210234/http://www.sonicspot.com/guide/wavefiles.html#list
fid.write(lbls)
# smpl chunk
if loops or pitch:
if not loops:
loops = []
if pitch:
midiunitynote = 12 * numpy.log2(pitch * 1.0 / 440.0) + 69
midipitchfraction = int((midiunitynote - int(midiunitynote)) * (2**32-1))
midiunitynote = int(midiunitynote)
#print(midipitchfraction, midiunitynote)
else:
midiunitynote = 0
midipitchfraction = 0
fid.write(b'smpl')
size = 36 + len(loops) * 24
sampleperiod = int(1000000000.0 / rate)
fid.write(struct.pack('<iiiiiIiiii', size, 0, 0, sampleperiod, midiunitynote, midipitchfraction, 0, 0, len(loops), 0))
for i, loop in enumerate(loops):
fid.write(struct.pack('<iiiiii', 0, 0, loop[0], loop[1], 0, 0))
# data chunks
fid.write(b'data')
fid.write(struct.pack('<i', data.nbytes))
import sys
if data.dtype.byteorder == '>' or (data.dtype.byteorder == '=' and sys.byteorder == 'big'):
data = data.byteswap()
data.tofile(fid)
if data.nbytes % 2 == 1: # add an extra padding byte if data.nbytes is odd: https://web.archive.org/web/20141226210234/http://www.sonicspot.com/guide/wavefiles.html#data
fid.write('\x00')
# Determine file size and place it in correct
# position at start of the file.
size = fid.tell()
fid.seek(4)
fid.write(struct.pack('<i', size-8))
fid.close()
@X-Raym

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X-Raym commented Jun 7, 2018

@josephernest
Hi ! thx for the 24bits supports !

I got an error with a file with 3 markers:

from wavfile import read, write

retval = read('1.wav', readmarkers=True)
print(retval)
Traceback (most recent call last):
  File "E:\Bureau\test\test.py", line 3, in <module>
    retval = read('1.wav', readmarkers=True)
  File "E:\Bureau\test\wavfile.py", line 198, in read
    warnings.warn("Chunk " + chunk_id + " skipped", WavFileWarning)
TypeError: must be str, not bytes

What is wrong ?

Also, have considered pushing your changes to the original wavfile.py project ?

@X-Raym

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X-Raym commented Jun 7, 2018

Write markers function is also broken but I corrected it.

@josephernest

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Owner

josephernest commented Jun 8, 2018

Thank you @X-Raym for your additions. Being curious: what was wrong in the read/write markers when there are 3 markers?

Also, have considered pushing your changes to the original wavfile.py project ?

Here is the issue: scipy/scipy#6849
and the pull request: scipy/scipy#6852
but it's still in progress.
Maybe the API needs to be cleaner than both my version + the original version :)

@X-Raym

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X-Raym commented Jun 8, 2018

@josephernest Thanks for your answer ! (do you get a notification from Gist or did you saw my message from the github pull request or my disqus comment ?)

There is other issues which needs to be fixed though, it is a bit too deep for me maybe you can help ? Here is by order of importance:

  • Unsupported chunk aren't return from read functions, and cannot be pass to write functions. This means that if you had bext infos (Originator, Description etc) it will stripped if you read + write file. This isn't good. :(
  • write doesn't follow the most used conventions for written waves, like having LIST in the end of the file (I think this is supposed to allows faster addition / deletion without having to offfset everything)
  • The Loops feature is broken I think it is needed to have the cue points ID in both the read and write function. Else, labels aren't associated with regions for some reason.

Thanks for your support ! 👍

@X-Raym

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X-Raym commented Jun 8, 2018

@josephernest If I remember well there wasn't a problem with three markers in particular, I just told what I was trying to do. In fact the bug occured with 1 marker. There was some missing bytes conversion in the write function. You can check my commit history. 👍

(not having your notification because of Gist is frustrating. I created a new real repo for my fork, so we can have issues trackers, and notifications. Here is the link: https://github.com/X-Raym/wavefile.py I invite you to join me there for the discussion 😄 )

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