mirror of
https://github.com/python/cpython
synced 2024-09-05 08:17:45 +00:00
635 lines
21 KiB
Python
635 lines
21 KiB
Python
"""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 namedtuple 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 patching 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(b'') or
|
|
close() to patch up the sizes in the header.
|
|
The close() method is called automatically when the class instance
|
|
is destroyed.
|
|
"""
|
|
|
|
from collections import namedtuple
|
|
import builtins
|
|
import struct
|
|
import sys
|
|
|
|
|
|
__all__ = ["open", "Error", "Wave_read", "Wave_write"]
|
|
|
|
class Error(Exception):
|
|
pass
|
|
|
|
WAVE_FORMAT_PCM = 0x0001
|
|
|
|
_array_fmts = None, 'b', 'h', None, 'i'
|
|
|
|
_wave_params = namedtuple('_wave_params',
|
|
'nchannels sampwidth framerate nframes comptype compname')
|
|
|
|
def _byteswap(data, width):
|
|
swapped_data = bytearray(len(data))
|
|
|
|
for i in range(0, len(data), width):
|
|
for j in range(width):
|
|
swapped_data[i + width - 1 - j] = data[i + j]
|
|
|
|
return bytes(swapped_data)
|
|
|
|
|
|
class _Chunk:
|
|
def __init__(self, file, align=True, bigendian=True, inclheader=False):
|
|
import struct
|
|
self.closed = False
|
|
self.align = align # whether to align to word (2-byte) boundaries
|
|
if bigendian:
|
|
strflag = '>'
|
|
else:
|
|
strflag = '<'
|
|
self.file = file
|
|
self.chunkname = file.read(4)
|
|
if len(self.chunkname) < 4:
|
|
raise EOFError
|
|
try:
|
|
self.chunksize = struct.unpack_from(strflag+'L', file.read(4))[0]
|
|
except struct.error:
|
|
raise EOFError from None
|
|
if inclheader:
|
|
self.chunksize = self.chunksize - 8 # subtract header
|
|
self.size_read = 0
|
|
try:
|
|
self.offset = self.file.tell()
|
|
except (AttributeError, OSError):
|
|
self.seekable = False
|
|
else:
|
|
self.seekable = True
|
|
|
|
def getname(self):
|
|
"""Return the name (ID) of the current chunk."""
|
|
return self.chunkname
|
|
|
|
def close(self):
|
|
if not self.closed:
|
|
try:
|
|
self.skip()
|
|
finally:
|
|
self.closed = True
|
|
|
|
def seek(self, pos, whence=0):
|
|
"""Seek to specified position into the chunk.
|
|
Default position is 0 (start of chunk).
|
|
If the file is not seekable, this will result in an error.
|
|
"""
|
|
|
|
if self.closed:
|
|
raise ValueError("I/O operation on closed file")
|
|
if not self.seekable:
|
|
raise OSError("cannot seek")
|
|
if whence == 1:
|
|
pos = pos + self.size_read
|
|
elif whence == 2:
|
|
pos = pos + self.chunksize
|
|
if pos < 0 or pos > self.chunksize:
|
|
raise RuntimeError
|
|
self.file.seek(self.offset + pos, 0)
|
|
self.size_read = pos
|
|
|
|
def tell(self):
|
|
if self.closed:
|
|
raise ValueError("I/O operation on closed file")
|
|
return self.size_read
|
|
|
|
def read(self, size=-1):
|
|
"""Read at most size bytes from the chunk.
|
|
If size is omitted or negative, read until the end
|
|
of the chunk.
|
|
"""
|
|
|
|
if self.closed:
|
|
raise ValueError("I/O operation on closed file")
|
|
if self.size_read >= self.chunksize:
|
|
return b''
|
|
if size < 0:
|
|
size = self.chunksize - self.size_read
|
|
if size > self.chunksize - self.size_read:
|
|
size = self.chunksize - self.size_read
|
|
data = self.file.read(size)
|
|
self.size_read = self.size_read + len(data)
|
|
if self.size_read == self.chunksize and \
|
|
self.align and \
|
|
(self.chunksize & 1):
|
|
dummy = self.file.read(1)
|
|
self.size_read = self.size_read + len(dummy)
|
|
return data
|
|
|
|
def skip(self):
|
|
"""Skip the rest of the chunk.
|
|
If you are not interested in the contents of the chunk,
|
|
this method should be called so that the file points to
|
|
the start of the next chunk.
|
|
"""
|
|
|
|
if self.closed:
|
|
raise ValueError("I/O operation on closed file")
|
|
if self.seekable:
|
|
try:
|
|
n = self.chunksize - self.size_read
|
|
# maybe fix alignment
|
|
if self.align and (self.chunksize & 1):
|
|
n = n + 1
|
|
self.file.seek(n, 1)
|
|
self.size_read = self.size_read + n
|
|
return
|
|
except OSError:
|
|
pass
|
|
while self.size_read < self.chunksize:
|
|
n = min(8192, self.chunksize - self.size_read)
|
|
dummy = self.read(n)
|
|
if not dummy:
|
|
raise EOFError
|
|
|
|
|
|
|
|
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() != b'RIFF':
|
|
raise Error('file does not start with RIFF id')
|
|
if self._file.read(4) != b'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 == b'fmt ':
|
|
self._read_fmt_chunk(chunk)
|
|
self._fmt_chunk_read = 1
|
|
elif chunkname == b'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, str):
|
|
f = builtins.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()
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, *args):
|
|
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):
|
|
self._file = None
|
|
file = self._i_opened_the_file
|
|
if file:
|
|
self._i_opened_the_file = None
|
|
file.close()
|
|
|
|
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 _wave_params(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 b''
|
|
data = self._data_chunk.read(nframes * self._framesize)
|
|
if self._sampwidth != 1 and sys.byteorder == 'big':
|
|
data = _byteswap(data, self._sampwidth)
|
|
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):
|
|
try:
|
|
wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack_from('<HHLLH', chunk.read(14))
|
|
except struct.error:
|
|
raise EOFError from None
|
|
if wFormatTag == WAVE_FORMAT_PCM:
|
|
try:
|
|
sampwidth = struct.unpack_from('<H', chunk.read(2))[0]
|
|
except struct.error:
|
|
raise EOFError from None
|
|
self._sampwidth = (sampwidth + 7) // 8
|
|
if not self._sampwidth:
|
|
raise Error('bad sample width')
|
|
else:
|
|
raise Error('unknown format: %r' % (wFormatTag,))
|
|
if not self._nchannels:
|
|
raise Error('bad # of channels')
|
|
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, str):
|
|
f = builtins.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()
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, *args):
|
|
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 = int(round(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 _wave_params(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):
|
|
if not isinstance(data, (bytes, bytearray)):
|
|
data = memoryview(data).cast('B')
|
|
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 sys.byteorder == 'big':
|
|
data = _byteswap(data, self._sampwidth)
|
|
self._file.write(data)
|
|
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):
|
|
try:
|
|
if self._file:
|
|
self._ensure_header_written(0)
|
|
if self._datalength != self._datawritten:
|
|
self._patchheader()
|
|
self._file.flush()
|
|
finally:
|
|
self._file = None
|
|
file = self._i_opened_the_file
|
|
if file:
|
|
self._i_opened_the_file = None
|
|
file.close()
|
|
|
|
#
|
|
# 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(b'RIFF')
|
|
if not self._nframes:
|
|
self._nframes = initlength // (self._nchannels * self._sampwidth)
|
|
self._datalength = self._nframes * self._nchannels * self._sampwidth
|
|
try:
|
|
self._form_length_pos = self._file.tell()
|
|
except (AttributeError, OSError):
|
|
self._form_length_pos = None
|
|
self._file.write(struct.pack('<L4s4sLHHLLHH4s',
|
|
36 + self._datalength, b'WAVE', b'fmt ', 16,
|
|
WAVE_FORMAT_PCM, self._nchannels, self._framerate,
|
|
self._nchannels * self._framerate * self._sampwidth,
|
|
self._nchannels * self._sampwidth,
|
|
self._sampwidth * 8, b'data'))
|
|
if self._form_length_pos is not None:
|
|
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'")
|