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3601e88cb3
""" Extended chunk so that it can also handle formats that are almost according to EA IFF 85. In particular, added options to handle little-endian and to handle formats that include the header size in the chunk size value. Fixed a bug where the header size was included in the chunk size, which it isn't according to EA IFF 85. Added a new method getsize() to get the size of the chunk (excluding header). Fixed chunk documentation (TIFF doesn't look like it uses chunks). Converted wave to use chunk. Wave uses EA IFF 85 chunks except that it uses little-endian encoding of integer data. Removed __del__ methods from aifc and wave since I got an AttributeError there upon exit. """
471 lines
14 KiB
Python
471 lines
14 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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from chunk import Chunk
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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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def initfp(self, file):
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self._convert = None
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self._soundpos = 0
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self._file = Chunk(file, bigendian = 0)
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if self._file.getname() != 'RIFF':
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raise Error, 'file does not start with RIFF id'
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if self._file.read(4) != 'WAVE':
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raise Error, 'not a WAVE file'
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self._fmt_chunk_read = 0
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self._data_chunk = None
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while 1:
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self._data_seek_needed = 1
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try:
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chunk = Chunk(self._file, bigendian = 0)
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except EOFError:
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break
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chunkname = chunk.getname()
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if 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 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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break
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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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#
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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.seek(0, 0)
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pos = self._soundpos * self._framesize
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if pos:
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self._data_chunk.seek(pos, 0)
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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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chunk = self._data_chunk
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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 > chunk.chunksize - chunk.size_read:
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nitems = (chunk.chunksize - chunk.size_read) / self._sampwidth
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data.fromfile(chunk.file.file, nitems)
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# "tell" data chunk how much was read
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chunk.size_read = chunk.size_read + nitems * self._sampwidth
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# do the same for the outermost chunk
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chunk = chunk.file
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chunk.size_read = 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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def _read_fmt_chunk(self, chunk):
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wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack('<hhllh', chunk.read(14))
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if wFormatTag == WAVE_FORMAT_PCM:
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sampwidth = struct.unpack('<h', chunk.read(2))[0]
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self._sampwidth = (sampwidth + 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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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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def _ensure_header_written(self, datasize):
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if not self._datawritten:
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if not self._nchannels:
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raise Error, '# channels not specified'
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if not self._sampwidth:
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raise Error, 'sample width not specified'
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if not self._framerate:
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raise Error, 'sampling rate not specified'
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self._write_header(datasize)
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def _write_header(self, initlength):
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self._file.write('RIFF')
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if not self._nframes:
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self._nframes = initlength / (self._nchannels * self._sampwidth)
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self._datalength = self._nframes * self._nchannels * self._sampwidth
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self._form_length_pos = self._file.tell()
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self._file.write(struct.pack('<lsslhhllhhs',
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36 + self._datalength, 'WAVE', 'fmt ', 16,
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WAVE_FORMAT_PCM, self._nchannels, self._framerate,
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self._nchannels * self._framerate * self._sampwidth,
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self._nchannels * self._sampwidth,
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self._sampwidth * 8, 'data'))
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self._data_length_pos = self._file.tell()
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self._file.write(struct.pack('<l', self._datalength))
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def _patchheader(self):
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if self._datawritten == self._datalength:
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return
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curpos = self._file.tell()
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self._file.seek(self._form_length_pos, 0)
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self._file.write(struct.pack('<l', 36 + self._datawritten))
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self._file.seek(self._data_length_pos, 0)
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self._file.write(struct.pack('<l', self._datawritten))
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self._file.seek(curpos, 0)
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self._datalength = self._datawritten
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def open(f, mode=None):
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if mode is None:
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if hasattr(f, 'mode'):
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mode = f.mode
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else:
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mode = 'rb'
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if mode in ('r', 'rb'):
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return Wave_read(f)
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elif mode in ('w', 'wb'):
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return Wave_write(f)
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else:
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raise Error, "mode must be 'r', 'rb', 'w', or 'wb'"
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openfp = open # B/W compatibility
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