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- # 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 postion 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__
-
- Error = 'wave.Error'
-
- WAVE_FORMAT_PCM = 0x0001
-
- _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
-
- def _read_long(file):
- x = 0L
- for i in range(4):
- byte = file.read(1)
- if byte == '':
- raise EOFError
- x = x + (ord(byte) << (8 * i))
- if x >= 0x80000000L:
- x = x - 0x100000000L
- return int(x)
-
- def _read_ulong(file):
- x = 0L
- for i in range(4):
- byte = file.read(1)
- if byte == '':
- raise EOFError
- x = x + (ord(byte) << (8 * i))
- return x
-
- def _read_short(file):
- x = 0
- for i in range(2):
- byte = file.read(1)
- if byte == '':
- raise EOFError
- x = x + (ord(byte) << (8 * i))
- if x >= 0x8000:
- x = x - 0x10000
- return x
-
- def _write_short(f, x):
- d, m = divmod(x, 256)
- f.write(chr(m))
- f.write(chr(d))
-
- def _write_long(f, x):
- if x < 0:
- x = x + 0x100000000L
- for i in range(4):
- d, m = divmod(x, 256)
- f.write(chr(int(m)))
- x = d
-
- class Chunk:
- def __init__(self, file):
- self.file = file
- self.chunkname = self.file.read(4)
- if len(self.chunkname) < 4:
- raise EOFError
- self.chunksize = _read_long(self.file)
- self.size_read = 0
- self.offset = self.file.tell()
-
- def rewind(self):
- self.file.seek(self.offset, 0)
- self.size_read = 0
-
- def setpos(self, pos):
- if pos < 0 or pos > self.chunksize:
- raise RuntimeError
- self.file.seek(self.offset + pos, 0)
- self.size_read = pos
-
- def read(self, length):
- if self.size_read >= self.chunksize:
- return ''
- if length > self.chunksize - self.size_read:
- length = self.chunksize - self.size_read
- data = self.file.read(length)
- self.size_read = self.size_read + len(data)
- return data
-
- def skip(self):
- try:
- self.file.seek(self.chunksize - self.size_read, 1)
- except RuntimeError:
- while self.size_read < self.chunksize:
- dummy = self.read(8192)
- 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
-
- ## access _file, _nchannels, _nframes, _sampwidth, _framerate, \
- ## _comptype, _compname, _soundpos, \
- ## _fmt_chunk_read, _data_seek_needed, \
- ## _data_chunk, _framesize: private
-
- def initfp(self, file):
- self._file = file
- self._convert = None
- self._soundpos = 0
- form = self._file.read(4)
- if form != 'RIFF':
- raise Error, 'file does not start with RIFF id'
- formlength = _read_long(self._file)
- if formlength <= 0:
- raise Error, 'invalid FORM chunk data size'
- formdata = self._file.read(4)
- formlength = formlength - 4
- if formdata != 'WAVE':
- raise Error, 'not a WAVE file'
- self._fmt_chunk_read = 0
- while formlength > 0:
- self._data_seek_needed = 1
- chunk = Chunk(self._file)
- if chunk.chunkname == 'fmt ':
- self._read_fmt_chunk(chunk)
- self._fmt_chunk_read = 1
- elif chunk.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
- formlength = formlength - 8 - chunk.chunksize
- if formlength > 0:
- 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):
- if type(f) == type(''):
- f = __builtin__.open(f, 'rb')
- # else, assume it is an open file object already
- self.initfp(f)
-
- def __del__(self):
- if self._file:
- 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
-
- 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.rewind()
- pos = self._soundpos * self._framesize
- if pos:
- self._data_chunk.setpos(pos)
- 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
- data = array.array(_array_fmts[self._sampwidth])
- nitems = nframes * self._nchannels
- if nitems * self._sampwidth > self._data_chunk.chunksize - self._data_chunk.size_read:
- nitems = (self._data_chunk.chunksize - self._data_chunk.size_read) / self._sampwidth
- data.fromfile(self._data_chunk.file, nitems)
- self._data_chunk.size_read = self._data_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.
- #
- ## access *: private
-
- def _read_fmt_chunk(self, chunk):
- wFormatTag = _read_short(chunk)
- self._nchannels = _read_short(chunk)
- self._framerate = _read_long(chunk)
- dwAvgBytesPerSec = _read_long(chunk)
- wBlockAlign = _read_short(chunk)
- if wFormatTag == WAVE_FORMAT_PCM:
- self._sampwidth = (_read_short(chunk) + 7) / 8
- else:
- raise Error, 'unknown format: ' + `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
-
- ## access _file, _comptype, _compname, _nchannels, _sampwidth, \
- ## _framerate, _nframes, _nframeswritten, \
- ## _datalength, _datawritten: private
-
- def __init__(self, f):
- if type(f) == type(''):
- f = __builtin__.open(f, 'wb')
- self.initfp(f)
-
- 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
-
- def __del__(self):
- if self._file:
- 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, (nchannels, sampwidth, framerate, nframes, comptype, compname)):
- 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):
- self._ensure_header_written(0)
- if self._datalength != self._datawritten:
- self._patchheader()
- self._file.flush()
- self._file = None
-
- #
- # Internal methods.
- #
- ## access *: private
-
- def _ensure_header_written(self, datasize):
- if not self._datawritten:
- 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):
- 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()
- _write_long(self._file, 36 + self._datalength)
- self._file.write('WAVE')
- self._file.write('fmt ')
- _write_long(self._file, 16)
- _write_short(self._file, WAVE_FORMAT_PCM)
- _write_short(self._file, self._nchannels)
- _write_long(self._file, self._framerate)
- _write_long(self._file, self._nchannels * self._framerate * self._sampwidth)
- _write_short(self._file, self._nchannels * self._sampwidth)
- _write_short(self._file, self._sampwidth * 8)
- self._file.write('data')
- self._data_length_pos = self._file.tell()
- _write_long(self._file, self._datalength)
-
- def _patchheader(self):
- if self._datawritten == self._datalength:
- return
- curpos = self._file.tell()
- self._file.seek(self._form_length_pos, 0)
- _write_long(self._file, 36 + self._datawritten)
- self._file.seek(self._data_length_pos, 0)
- _write_long(self._file, self._datawritten)
- self._file.seek(curpos, 0)
- self._datalength = self._datawritten
-
- def open(f, mode):
- 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
-