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authorGuido van Rossum <guido@python.org>1994-02-15 15:57:15 (GMT)
committerGuido van Rossum <guido@python.org>1994-02-15 15:57:15 (GMT)
commit3ed23cc158f6609742229a7d912ace5533595a86 (patch)
treee4b60fc3842eb172a210839337e1ec7bdf49c6de /Lib/wave.py
parente1056b3c32701bfcaabdc96472fea700e5c9c6a9 (diff)
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aifc, sunau: make rate an int; os: restruct; ospath: obsolete; rfc822:
date and addr parsing; string: force result of atof to float and support atoi, atol, atof in strop; tzparcs: don't call test().
Diffstat (limited to 'Lib/wave.py')
-rw-r--r--Lib/wave.py559
1 files changed, 559 insertions, 0 deletions
diff --git a/Lib/wave.py b/Lib/wave.py
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+++ b/Lib/wave.py
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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 AIFF files)
+# getcompname() -- returns human-readable version of
+# compression type ('not compressed' for AIFF files)
+# 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(nchannels, sampwidth, framerate, nframes, comptype, compname)
+# -- 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'
+
+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, 'r')
+ # 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:
+ # 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'
+ 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, 'w')
+ 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:
+ 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(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 == 'r':
+ return Wave_read(f)
+ elif mode == 'w':
+ return Wave_write(f)
+ else:
+ raise Error, "mode must be 'r' or 'w'"
+
+openfp = open # B/W compatibility