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566 lines
17 KiB
Python
566 lines
17 KiB
Python
# Stuff to parse WAVE files.
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#
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# Usage.
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#
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# Reading WAVE files:
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# f = wave.open(file, 'r')
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# where file is either the name of a file or an open file pointer.
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# The open file pointer must have methods read(), seek(), and close().
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# When the setpos() and rewind() methods are not used, the seek()
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# method is not necessary.
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#
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# This returns an instance of a class with the following public methods:
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# getnchannels() -- returns number of audio channels (1 for
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# mono, 2 for stereo)
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# getsampwidth() -- returns sample width in bytes
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# getframerate() -- returns sampling frequency
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# getnframes() -- returns number of audio frames
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# getcomptype() -- returns compression type ('NONE' for linear samples)
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# getcompname() -- returns human-readable version of
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# compression type ('not compressed' linear samples)
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# getparams() -- returns a tuple consisting of all of the
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# above in the above order
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# getmarkers() -- returns None (for compatibility with the
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# aifc module)
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# getmark(id) -- raises an error since the mark does not
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# exist (for compatibility with the aifc module)
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# readframes(n) -- returns at most n frames of audio
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# rewind() -- rewind to the beginning of the audio stream
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# setpos(pos) -- seek to the specified position
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# tell() -- return the current position
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# close() -- close the instance (make it unusable)
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# The position returned by tell() and the position given to setpos()
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# are compatible and have nothing to do with the actual postion in the
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# file.
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# The close() method is called automatically when the class instance
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# is destroyed.
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#
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# Writing WAVE files:
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# f = wave.open(file, 'w')
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# where file is either the name of a file or an open file pointer.
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# The open file pointer must have methods write(), tell(), seek(), and
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# close().
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#
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# This returns an instance of a class with the following public methods:
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# setnchannels(n) -- set the number of channels
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# setsampwidth(n) -- set the sample width
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# setframerate(n) -- set the frame rate
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# setnframes(n) -- set the number of frames
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# setcomptype(type, name)
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# -- set the compression type and the
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# human-readable compression type
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# setparams(tuple)
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# -- set all parameters at once
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# tell() -- return current position in output file
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# writeframesraw(data)
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# -- write audio frames without pathing up the
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# file header
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# writeframes(data)
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# -- write audio frames and patch up the file header
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# close() -- patch up the file header and close the
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# output file
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# You should set the parameters before the first writeframesraw or
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# writeframes. The total number of frames does not need to be set,
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# but when it is set to the correct value, the header does not have to
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# be patched up.
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# It is best to first set all parameters, perhaps possibly the
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# compression type, and then write audio frames using writeframesraw.
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# When all frames have been written, either call writeframes('') or
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# close() to patch up the sizes in the header.
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# The close() method is called automatically when the class instance
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# is destroyed.
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import __builtin__
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Error = 'wave.Error'
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WAVE_FORMAT_PCM = 0x0001
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_array_fmts = None, 'b', 'h', None, 'l'
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# Determine endian-ness
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import struct
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if struct.pack("h", 1) == "\000\001":
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big_endian = 1
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else:
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big_endian = 0
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def _read_long(file):
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x = 0L
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for i in range(4):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x + (ord(byte) << (8 * i))
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if x >= 0x80000000L:
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x = x - 0x100000000L
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return int(x)
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def _read_ulong(file):
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x = 0L
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for i in range(4):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x + (ord(byte) << (8 * i))
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return x
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def _read_short(file):
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x = 0
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for i in range(2):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x + (ord(byte) << (8 * i))
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if x >= 0x8000:
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x = x - 0x10000
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return x
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def _write_short(f, x):
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d, m = divmod(x, 256)
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f.write(chr(m))
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f.write(chr(d))
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def _write_long(f, x):
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if x < 0:
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x = x + 0x100000000L
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for i in range(4):
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d, m = divmod(x, 256)
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f.write(chr(int(m)))
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x = d
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class Chunk:
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def __init__(self, file):
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self.file = file
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self.chunkname = self.file.read(4)
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if len(self.chunkname) < 4:
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raise EOFError
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self.chunksize = _read_long(self.file)
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self.size_read = 0
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self.offset = self.file.tell()
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def rewind(self):
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self.file.seek(self.offset, 0)
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self.size_read = 0
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def setpos(self, pos):
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if pos < 0 or pos > self.chunksize:
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raise RuntimeError
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self.file.seek(self.offset + pos, 0)
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self.size_read = pos
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def read(self, length):
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if self.size_read >= self.chunksize:
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return ''
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if length > self.chunksize - self.size_read:
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length = self.chunksize - self.size_read
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data = self.file.read(length)
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self.size_read = self.size_read + len(data)
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return data
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def skip(self):
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try:
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self.file.seek(self.chunksize - self.size_read, 1)
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except RuntimeError:
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while self.size_read < self.chunksize:
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dummy = self.read(8192)
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if not dummy:
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raise EOFError
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class Wave_read:
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# Variables used in this class:
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#
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# These variables are available to the user though appropriate
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# methods of this class:
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# _file -- the open file with methods read(), close(), and seek()
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# set through the __init__() method
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# _nchannels -- the number of audio channels
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# available through the getnchannels() method
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# _nframes -- the number of audio frames
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# available through the getnframes() method
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# _sampwidth -- the number of bytes per audio sample
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# available through the getsampwidth() method
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# _framerate -- the sampling frequency
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# available through the getframerate() method
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# _comptype -- the AIFF-C compression type ('NONE' if AIFF)
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# available through the getcomptype() method
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# _compname -- the human-readable AIFF-C compression type
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# available through the getcomptype() method
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# _soundpos -- the position in the audio stream
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# available through the tell() method, set through the
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# setpos() method
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#
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# These variables are used internally only:
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# _fmt_chunk_read -- 1 iff the FMT chunk has been read
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# _data_seek_needed -- 1 iff positioned correctly in audio
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# file for readframes()
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# _data_chunk -- instantiation of a chunk class for the DATA chunk
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# _framesize -- size of one frame in the file
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## access _file, _nchannels, _nframes, _sampwidth, _framerate, \
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## _comptype, _compname, _soundpos, \
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## _fmt_chunk_read, _data_seek_needed, \
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## _data_chunk, _framesize: private
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def initfp(self, file):
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self._file = file
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self._convert = None
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self._soundpos = 0
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form = self._file.read(4)
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if form != 'RIFF':
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raise Error, 'file does not start with RIFF id'
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formlength = _read_long(self._file)
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if formlength <= 0:
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raise Error, 'invalid FORM chunk data size'
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formdata = self._file.read(4)
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formlength = formlength - 4
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if formdata != 'WAVE':
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raise Error, 'not a WAVE file'
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self._fmt_chunk_read = 0
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while formlength > 0:
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self._data_seek_needed = 1
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chunk = Chunk(self._file)
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if chunk.chunkname == 'fmt ':
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self._read_fmt_chunk(chunk)
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self._fmt_chunk_read = 1
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elif chunk.chunkname == 'data':
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if not self._fmt_chunk_read:
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raise Error, 'data chunk before fmt chunk'
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self._data_chunk = chunk
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self._nframes = chunk.chunksize / self._framesize
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self._data_seek_needed = 0
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formlength = formlength - 8 - chunk.chunksize
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if formlength > 0:
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chunk.skip()
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if not self._fmt_chunk_read or not self._data_chunk:
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raise Error, 'fmt chunk and/or data chunk missing'
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def __init__(self, f):
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if type(f) == type(''):
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f = __builtin__.open(f, 'rb')
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# else, assume it is an open file object already
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self.initfp(f)
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def __del__(self):
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if self._file:
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self.close()
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#
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# User visible methods.
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#
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def getfp(self):
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return self._file
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def rewind(self):
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self._data_seek_needed = 1
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self._soundpos = 0
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def close(self):
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self._file = None
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def tell(self):
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return self._soundpos
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def getnchannels(self):
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return self._nchannels
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def getnframes(self):
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return self._nframes
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def getsampwidth(self):
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return self._sampwidth
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def getframerate(self):
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return self._framerate
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def getcomptype(self):
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return self._comptype
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def getcompname(self):
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return self._compname
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def getparams(self):
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return self.getnchannels(), self.getsampwidth(), \
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self.getframerate(), self.getnframes(), \
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self.getcomptype(), self.getcompname()
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def getmarkers(self):
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return None
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def getmark(self, id):
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raise Error, 'no marks'
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def setpos(self, pos):
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if pos < 0 or pos > self._nframes:
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raise Error, 'position not in range'
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self._soundpos = pos
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self._data_seek_needed = 1
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def readframes(self, nframes):
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if self._data_seek_needed:
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self._data_chunk.rewind()
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pos = self._soundpos * self._framesize
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if pos:
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self._data_chunk.setpos(pos)
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self._data_seek_needed = 0
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if nframes == 0:
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return ''
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if self._sampwidth > 1 and big_endian:
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# unfortunately the fromfile() method does not take
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# something that only looks like a file object, so
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# we have to reach into the innards of the chunk object
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import array
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data = array.array(_array_fmts[self._sampwidth])
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nitems = nframes * self._nchannels
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if nitems * self._sampwidth > self._data_chunk.chunksize - self._data_chunk.size_read:
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nitems = (self._data_chunk.chunksize - self._data_chunk.size_read) / self._sampwidth
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data.fromfile(self._data_chunk.file, nitems)
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self._data_chunk.size_read = self._data_chunk.size_read + nitems * self._sampwidth
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data.byteswap()
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data = data.tostring()
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else:
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data = self._data_chunk.read(nframes * self._framesize)
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if self._convert and data:
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data = self._convert(data)
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self._soundpos = self._soundpos + len(data) / (self._nchannels * self._sampwidth)
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return data
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#
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# Internal methods.
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#
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## access *: private
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def _read_fmt_chunk(self, chunk):
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wFormatTag = _read_short(chunk)
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self._nchannels = _read_short(chunk)
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self._framerate = _read_long(chunk)
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dwAvgBytesPerSec = _read_long(chunk)
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wBlockAlign = _read_short(chunk)
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if wFormatTag == WAVE_FORMAT_PCM:
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self._sampwidth = (_read_short(chunk) + 7) / 8
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else:
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raise Error, 'unknown format: ' + `wFormatTag`
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self._framesize = self._nchannels * self._sampwidth
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self._comptype = 'NONE'
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self._compname = 'not compressed'
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class Wave_write:
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# Variables used in this class:
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#
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# These variables are user settable through appropriate methods
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# of this class:
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# _file -- the open file with methods write(), close(), tell(), seek()
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# set through the __init__() method
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# _comptype -- the AIFF-C compression type ('NONE' in AIFF)
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# set through the setcomptype() or setparams() method
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# _compname -- the human-readable AIFF-C compression type
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# set through the setcomptype() or setparams() method
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# _nchannels -- the number of audio channels
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# set through the setnchannels() or setparams() method
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# _sampwidth -- the number of bytes per audio sample
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# set through the setsampwidth() or setparams() method
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# _framerate -- the sampling frequency
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# set through the setframerate() or setparams() method
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# _nframes -- the number of audio frames written to the header
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# set through the setnframes() or setparams() method
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#
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# These variables are used internally only:
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# _datalength -- the size of the audio samples written to the header
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# _nframeswritten -- the number of frames actually written
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# _datawritten -- the size of the audio samples actually written
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## access _file, _comptype, _compname, _nchannels, _sampwidth, \
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## _framerate, _nframes, _nframeswritten, \
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## _datalength, _datawritten: private
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def __init__(self, f):
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if type(f) == type(''):
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f = __builtin__.open(f, 'wb')
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self.initfp(f)
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def initfp(self, file):
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self._file = file
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self._convert = None
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self._nchannels = 0
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self._sampwidth = 0
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self._framerate = 0
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self._nframes = 0
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self._nframeswritten = 0
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self._datawritten = 0
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self._datalength = 0
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def __del__(self):
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if self._file:
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self.close()
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#
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# User visible methods.
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#
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def setnchannels(self, nchannels):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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if nchannels < 1:
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raise Error, 'bad # of channels'
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self._nchannels = nchannels
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def getnchannels(self):
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if not self._nchannels:
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raise Error, 'number of channels not set'
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return self._nchannels
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def setsampwidth(self, sampwidth):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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if sampwidth < 1 or sampwidth > 4:
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raise Error, 'bad sample width'
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self._sampwidth = sampwidth
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def getsampwidth(self):
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if not self._sampwidth:
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raise Error, 'sample width not set'
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return self._sampwidth
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def setframerate(self, framerate):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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if framerate <= 0:
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raise Error, 'bad frame rate'
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self._framerate = framerate
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def getframerate(self):
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if not self._framerate:
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raise Error, 'frame rate not set'
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return self._framerate
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def setnframes(self, nframes):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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self._nframes = nframes
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def getnframes(self):
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return self._nframeswritten
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def setcomptype(self, comptype, compname):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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if comptype not in ('NONE',):
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raise Error, 'unsupported compression type'
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self._comptype = comptype
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self._compname = compname
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def getcomptype(self):
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return self._comptype
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def getcompname(self):
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return self._compname
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def setparams(self, (nchannels, sampwidth, framerate, nframes, comptype, compname)):
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if self._datawritten:
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raise Error, 'cannot change parameters after starting to write'
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self.setnchannels(nchannels)
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self.setsampwidth(sampwidth)
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self.setframerate(framerate)
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self.setnframes(nframes)
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self.setcomptype(comptype, compname)
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def getparams(self):
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if not self._nchannels or not self._sampwidth or not self._framerate:
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raise Error, 'not all parameters set'
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return self._nchannels, self._sampwidth, self._framerate, \
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self._nframes, self._comptype, self._compname
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def setmark(self, id, pos, name):
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raise Error, 'setmark() not supported'
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def getmark(self, id):
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raise Error, 'no marks'
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def getmarkers(self):
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return None
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def tell(self):
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return self._nframeswritten
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def writeframesraw(self, data):
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self._ensure_header_written(len(data))
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nframes = len(data) / (self._sampwidth * self._nchannels)
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if self._convert:
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data = self._convert(data)
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if self._sampwidth > 1 and big_endian:
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import array
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data = array.array(_array_fmts[self._sampwidth], data)
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data.byteswap()
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data.tofile(self._file)
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self._datawritten = self._datawritten + len(data) * self._sampwidth
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else:
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self._file.write(data)
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self._datawritten = self._datawritten + len(data)
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self._nframeswritten = self._nframeswritten + nframes
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def writeframes(self, data):
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self.writeframesraw(data)
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if self._datalength != self._datawritten:
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self._patchheader()
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def close(self):
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self._ensure_header_written(0)
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if self._datalength != self._datawritten:
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self._patchheader()
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self._file.flush()
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self._file = None
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#
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# Internal methods.
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#
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## access *: private
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|
|
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
|