| 1 | """Stuff to parse WAVE files.
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| 2 |
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| 3 | Usage.
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| 4 |
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| 5 | Reading WAVE files:
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| 6 | f = wave.open(file, 'r')
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| 7 | where file is either the name of a file or an open file pointer.
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| 8 | The open file pointer must have methods read(), seek(), and close().
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| 9 | When the setpos() and rewind() methods are not used, the seek()
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| 10 | method is not necessary.
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| 11 |
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| 12 | This returns an instance of a class with the following public methods:
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| 13 | getnchannels() -- returns number of audio channels (1 for
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| 14 | mono, 2 for stereo)
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| 15 | getsampwidth() -- returns sample width in bytes
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| 16 | getframerate() -- returns sampling frequency
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| 17 | getnframes() -- returns number of audio frames
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| 18 | getcomptype() -- returns compression type ('NONE' for linear samples)
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| 19 | getcompname() -- returns human-readable version of
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| 20 | compression type ('not compressed' linear samples)
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| 21 | getparams() -- returns a tuple consisting of all of the
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| 22 | above in the above order
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| 23 | getmarkers() -- returns None (for compatibility with the
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| 24 | aifc module)
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| 25 | getmark(id) -- raises an error since the mark does not
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| 26 | exist (for compatibility with the aifc module)
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| 27 | readframes(n) -- returns at most n frames of audio
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| 28 | rewind() -- rewind to the beginning of the audio stream
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| 29 | setpos(pos) -- seek to the specified position
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| 30 | tell() -- return the current position
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| 31 | close() -- close the instance (make it unusable)
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| 32 | The position returned by tell() and the position given to setpos()
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| 33 | are compatible and have nothing to do with the actual position in the
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| 34 | file.
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| 35 | The close() method is called automatically when the class instance
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| 36 | is destroyed.
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| 37 |
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| 38 | Writing WAVE files:
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| 39 | f = wave.open(file, 'w')
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| 40 | where file is either the name of a file or an open file pointer.
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| 41 | The open file pointer must have methods write(), tell(), seek(), and
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| 42 | close().
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| 43 |
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| 44 | This returns an instance of a class with the following public methods:
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| 45 | setnchannels(n) -- set the number of channels
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| 46 | setsampwidth(n) -- set the sample width
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| 47 | setframerate(n) -- set the frame rate
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| 48 | setnframes(n) -- set the number of frames
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| 49 | setcomptype(type, name)
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| 50 | -- set the compression type and the
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| 51 | human-readable compression type
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| 52 | setparams(tuple)
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| 53 | -- set all parameters at once
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| 54 | tell() -- return current position in output file
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| 55 | writeframesraw(data)
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| 56 | -- write audio frames without pathing up the
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| 57 | file header
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| 58 | writeframes(data)
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| 59 | -- write audio frames and patch up the file header
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| 60 | close() -- patch up the file header and close the
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| 61 | output file
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| 62 | You should set the parameters before the first writeframesraw or
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| 63 | writeframes. The total number of frames does not need to be set,
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| 64 | but when it is set to the correct value, the header does not have to
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| 65 | be patched up.
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| 66 | It is best to first set all parameters, perhaps possibly the
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| 67 | compression type, and then write audio frames using writeframesraw.
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| 68 | When all frames have been written, either call writeframes('') or
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| 69 | close() to patch up the sizes in the header.
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| 70 | The close() method is called automatically when the class instance
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| 71 | is destroyed.
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| 72 | """
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| 73 |
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| 74 | import __builtin__
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| 75 |
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| 76 | __all__ = ["open", "openfp", "Error"]
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| 77 |
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| 78 | class Error(Exception):
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| 79 | pass
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| 80 |
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| 81 | WAVE_FORMAT_PCM = 0x0001
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| 82 |
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| 83 | _array_fmts = None, 'b', 'h', None, 'i'
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| 84 |
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| 85 | # Determine endian-ness
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| 86 | import struct
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| 87 | if struct.pack("h", 1) == "\000\001":
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| 88 | big_endian = 1
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| 89 | else:
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| 90 | big_endian = 0
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| 91 |
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| 92 | from chunk import Chunk
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| 93 |
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| 94 | class Wave_read:
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| 95 | """Variables used in this class:
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| 96 |
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| 97 | These variables are available to the user though appropriate
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| 98 | methods of this class:
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| 99 | _file -- the open file with methods read(), close(), and seek()
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| 100 | set through the __init__() method
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| 101 | _nchannels -- the number of audio channels
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| 102 | available through the getnchannels() method
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| 103 | _nframes -- the number of audio frames
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| 104 | available through the getnframes() method
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| 105 | _sampwidth -- the number of bytes per audio sample
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| 106 | available through the getsampwidth() method
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| 107 | _framerate -- the sampling frequency
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| 108 | available through the getframerate() method
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| 109 | _comptype -- the AIFF-C compression type ('NONE' if AIFF)
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| 110 | available through the getcomptype() method
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| 111 | _compname -- the human-readable AIFF-C compression type
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| 112 | available through the getcomptype() method
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| 113 | _soundpos -- the position in the audio stream
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| 114 | available through the tell() method, set through the
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| 115 | setpos() method
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| 116 |
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| 117 | These variables are used internally only:
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| 118 | _fmt_chunk_read -- 1 iff the FMT chunk has been read
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| 119 | _data_seek_needed -- 1 iff positioned correctly in audio
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| 120 | file for readframes()
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| 121 | _data_chunk -- instantiation of a chunk class for the DATA chunk
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| 122 | _framesize -- size of one frame in the file
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| 123 | """
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| 124 |
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| 125 | def initfp(self, file):
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| 126 | self._convert = None
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| 127 | self._soundpos = 0
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| 128 | self._file = Chunk(file, bigendian = 0)
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| 129 | if self._file.getname() != 'RIFF':
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| 130 | raise Error, 'file does not start with RIFF id'
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| 131 | if self._file.read(4) != 'WAVE':
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| 132 | raise Error, 'not a WAVE file'
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| 133 | self._fmt_chunk_read = 0
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| 134 | self._data_chunk = None
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| 135 | while 1:
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| 136 | self._data_seek_needed = 1
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| 137 | try:
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| 138 | chunk = Chunk(self._file, bigendian = 0)
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| 139 | except EOFError:
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| 140 | break
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| 141 | chunkname = chunk.getname()
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| 142 | if chunkname == 'fmt ':
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| 143 | self._read_fmt_chunk(chunk)
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| 144 | self._fmt_chunk_read = 1
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| 145 | elif chunkname == 'data':
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| 146 | if not self._fmt_chunk_read:
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| 147 | raise Error, 'data chunk before fmt chunk'
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| 148 | self._data_chunk = chunk
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| 149 | self._nframes = chunk.chunksize // self._framesize
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| 150 | self._data_seek_needed = 0
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| 151 | break
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| 152 | chunk.skip()
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| 153 | if not self._fmt_chunk_read or not self._data_chunk:
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| 154 | raise Error, 'fmt chunk and/or data chunk missing'
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| 155 |
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| 156 | def __init__(self, f):
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| 157 | self._i_opened_the_file = None
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| 158 | if isinstance(f, basestring):
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| 159 | f = __builtin__.open(f, 'rb')
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| 160 | self._i_opened_the_file = f
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| 161 | # else, assume it is an open file object already
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| 162 | try:
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| 163 | self.initfp(f)
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| 164 | except:
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| 165 | if self._i_opened_the_file:
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| 166 | f.close()
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| 167 | raise
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| 168 |
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| 169 | def __del__(self):
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| 170 | self.close()
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| 171 | #
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| 172 | # User visible methods.
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| 173 | #
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| 174 | def getfp(self):
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| 175 | return self._file
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| 176 |
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| 177 | def rewind(self):
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| 178 | self._data_seek_needed = 1
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| 179 | self._soundpos = 0
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| 180 |
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| 181 | def close(self):
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| 182 | if self._i_opened_the_file:
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| 183 | self._i_opened_the_file.close()
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| 184 | self._i_opened_the_file = None
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| 185 | self._file = None
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| 186 |
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| 187 | def tell(self):
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| 188 | return self._soundpos
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| 189 |
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| 190 | def getnchannels(self):
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| 191 | return self._nchannels
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| 192 |
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| 193 | def getnframes(self):
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| 194 | return self._nframes
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| 195 |
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| 196 | def getsampwidth(self):
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| 197 | return self._sampwidth
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| 198 |
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| 199 | def getframerate(self):
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| 200 | return self._framerate
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| 201 |
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| 202 | def getcomptype(self):
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| 203 | return self._comptype
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| 204 |
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| 205 | def getcompname(self):
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| 206 | return self._compname
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| 207 |
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| 208 | def getparams(self):
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| 209 | return self.getnchannels(), self.getsampwidth(), \
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| 210 | self.getframerate(), self.getnframes(), \
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| 211 | self.getcomptype(), self.getcompname()
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| 212 |
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| 213 | def getmarkers(self):
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| 214 | return None
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| 215 |
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| 216 | def getmark(self, id):
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| 217 | raise Error, 'no marks'
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| 218 |
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| 219 | def setpos(self, pos):
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| 220 | if pos < 0 or pos > self._nframes:
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| 221 | raise Error, 'position not in range'
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| 222 | self._soundpos = pos
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| 223 | self._data_seek_needed = 1
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| 224 |
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| 225 | def readframes(self, nframes):
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| 226 | if self._data_seek_needed:
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| 227 | self._data_chunk.seek(0, 0)
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| 228 | pos = self._soundpos * self._framesize
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| 229 | if pos:
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| 230 | self._data_chunk.seek(pos, 0)
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| 231 | self._data_seek_needed = 0
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| 232 | if nframes == 0:
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| 233 | return ''
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| 234 | if self._sampwidth > 1 and big_endian:
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| 235 | # unfortunately the fromfile() method does not take
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| 236 | # something that only looks like a file object, so
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| 237 | # we have to reach into the innards of the chunk object
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| 238 | import array
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| 239 | chunk = self._data_chunk
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| 240 | data = array.array(_array_fmts[self._sampwidth])
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| 241 | assert data.itemsize == self._sampwidth
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| 242 | nitems = nframes * self._nchannels
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| 243 | if nitems * self._sampwidth > chunk.chunksize - chunk.size_read:
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| 244 | nitems = (chunk.chunksize - chunk.size_read) / self._sampwidth
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| 245 | data.fromfile(chunk.file.file, nitems)
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| 246 | # "tell" data chunk how much was read
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| 247 | chunk.size_read = chunk.size_read + nitems * self._sampwidth
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| 248 | # do the same for the outermost chunk
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| 249 | chunk = chunk.file
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| 250 | chunk.size_read = chunk.size_read + nitems * self._sampwidth
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| 251 | data.byteswap()
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| 252 | data = data.tostring()
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| 253 | else:
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| 254 | data = self._data_chunk.read(nframes * self._framesize)
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| 255 | if self._convert and data:
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| 256 | data = self._convert(data)
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| 257 | self._soundpos = self._soundpos + len(data) // (self._nchannels * self._sampwidth)
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| 258 | return data
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| 259 |
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| 260 | #
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| 261 | # Internal methods.
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| 262 | #
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| 263 |
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| 264 | def _read_fmt_chunk(self, chunk):
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| 265 | wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack('<HHLLH', chunk.read(14))
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| 266 | if wFormatTag == WAVE_FORMAT_PCM:
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| 267 | sampwidth = struct.unpack('<H', chunk.read(2))[0]
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| 268 | self._sampwidth = (sampwidth + 7) // 8
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| 269 | else:
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| 270 | raise Error, 'unknown format: %r' % (wFormatTag,)
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| 271 | self._framesize = self._nchannels * self._sampwidth
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| 272 | self._comptype = 'NONE'
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| 273 | self._compname = 'not compressed'
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| 274 |
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| 275 | class Wave_write:
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| 276 | """Variables used in this class:
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| 277 |
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| 278 | These variables are user settable through appropriate methods
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| 279 | of this class:
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| 280 | _file -- the open file with methods write(), close(), tell(), seek()
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| 281 | set through the __init__() method
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| 282 | _comptype -- the AIFF-C compression type ('NONE' in AIFF)
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| 283 | set through the setcomptype() or setparams() method
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| 284 | _compname -- the human-readable AIFF-C compression type
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| 285 | set through the setcomptype() or setparams() method
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| 286 | _nchannels -- the number of audio channels
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| 287 | set through the setnchannels() or setparams() method
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| 288 | _sampwidth -- the number of bytes per audio sample
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| 289 | set through the setsampwidth() or setparams() method
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| 290 | _framerate -- the sampling frequency
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| 291 | set through the setframerate() or setparams() method
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| 292 | _nframes -- the number of audio frames written to the header
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| 293 | set through the setnframes() or setparams() method
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| 294 |
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| 295 | These variables are used internally only:
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| 296 | _datalength -- the size of the audio samples written to the header
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| 297 | _nframeswritten -- the number of frames actually written
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| 298 | _datawritten -- the size of the audio samples actually written
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| 299 | """
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| 300 |
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| 301 | def __init__(self, f):
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| 302 | self._i_opened_the_file = None
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| 303 | if isinstance(f, basestring):
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| 304 | f = __builtin__.open(f, 'wb')
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| 305 | self._i_opened_the_file = f
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| 306 | try:
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| 307 | self.initfp(f)
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| 308 | except:
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| 309 | if self._i_opened_the_file:
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| 310 | f.close()
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| 311 | raise
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| 312 |
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| 313 | def initfp(self, file):
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| 314 | self._file = file
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| 315 | self._convert = None
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| 316 | self._nchannels = 0
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| 317 | self._sampwidth = 0
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| 318 | self._framerate = 0
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| 319 | self._nframes = 0
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| 320 | self._nframeswritten = 0
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| 321 | self._datawritten = 0
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| 322 | self._datalength = 0
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| 323 | self._headerwritten = False
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| 324 |
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| 325 | def __del__(self):
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| 326 | self.close()
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| 327 |
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| 328 | #
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| 329 | # User visible methods.
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| 330 | #
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| 331 | def setnchannels(self, nchannels):
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| 332 | if self._datawritten:
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| 333 | raise Error, 'cannot change parameters after starting to write'
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| 334 | if nchannels < 1:
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| 335 | raise Error, 'bad # of channels'
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| 336 | self._nchannels = nchannels
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| 337 |
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| 338 | def getnchannels(self):
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| 339 | if not self._nchannels:
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| 340 | raise Error, 'number of channels not set'
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| 341 | return self._nchannels
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| 342 |
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| 343 | def setsampwidth(self, sampwidth):
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| 344 | if self._datawritten:
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| 345 | raise Error, 'cannot change parameters after starting to write'
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| 346 | if sampwidth < 1 or sampwidth > 4:
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| 347 | raise Error, 'bad sample width'
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| 348 | self._sampwidth = sampwidth
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| 349 |
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| 350 | def getsampwidth(self):
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| 351 | if not self._sampwidth:
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| 352 | raise Error, 'sample width not set'
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| 353 | return self._sampwidth
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| 354 |
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| 355 | def setframerate(self, framerate):
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| 356 | if self._datawritten:
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| 357 | raise Error, 'cannot change parameters after starting to write'
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| 358 | if framerate <= 0:
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| 359 | raise Error, 'bad frame rate'
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| 360 | self._framerate = framerate
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| 361 |
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| 362 | def getframerate(self):
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| 363 | if not self._framerate:
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| 364 | raise Error, 'frame rate not set'
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| 365 | return self._framerate
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| 366 |
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| 367 | def setnframes(self, nframes):
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| 368 | if self._datawritten:
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| 369 | raise Error, 'cannot change parameters after starting to write'
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| 370 | self._nframes = nframes
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| 371 |
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| 372 | def getnframes(self):
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| 373 | return self._nframeswritten
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| 374 |
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| 375 | def setcomptype(self, comptype, compname):
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| 376 | if self._datawritten:
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| 377 | raise Error, 'cannot change parameters after starting to write'
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| 378 | if comptype not in ('NONE',):
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| 379 | raise Error, 'unsupported compression type'
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| 380 | self._comptype = comptype
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| 381 | self._compname = compname
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| 382 |
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| 383 | def getcomptype(self):
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| 384 | return self._comptype
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| 385 |
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| 386 | def getcompname(self):
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| 387 | return self._compname
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| 388 |
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| 389 | def setparams(self, params):
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| 390 | nchannels, sampwidth, framerate, nframes, comptype, compname = params
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| 391 | if self._datawritten:
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| 392 | raise Error, 'cannot change parameters after starting to write'
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| 393 | self.setnchannels(nchannels)
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| 394 | self.setsampwidth(sampwidth)
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| 395 | self.setframerate(framerate)
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| 396 | self.setnframes(nframes)
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| 397 | self.setcomptype(comptype, compname)
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| 398 |
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| 399 | def getparams(self):
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| 400 | if not self._nchannels or not self._sampwidth or not self._framerate:
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| 401 | raise Error, 'not all parameters set'
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| 402 | return self._nchannels, self._sampwidth, self._framerate, \
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| 403 | self._nframes, self._comptype, self._compname
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| 404 |
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| 405 | def setmark(self, id, pos, name):
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| 406 | raise Error, 'setmark() not supported'
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| 407 |
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| 408 | def getmark(self, id):
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| 409 | raise Error, 'no marks'
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| 410 |
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| 411 | def getmarkers(self):
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| 412 | return None
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| 413 |
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| 414 | def tell(self):
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| 415 | return self._nframeswritten
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| 416 |
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| 417 | def writeframesraw(self, data):
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| 418 | self._ensure_header_written(len(data))
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| 419 | nframes = len(data) // (self._sampwidth * self._nchannels)
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| 420 | if self._convert:
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| 421 | data = self._convert(data)
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| 422 | if self._sampwidth > 1 and big_endian:
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| 423 | import array
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| 424 | data = array.array(_array_fmts[self._sampwidth], data)
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| 425 | assert data.itemsize == self._sampwidth
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| 426 | data.byteswap()
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| 427 | data.tofile(self._file)
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| 428 | self._datawritten = self._datawritten + len(data) * self._sampwidth
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| 429 | else:
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| 430 | self._file.write(data)
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| 431 | self._datawritten = self._datawritten + len(data)
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| 432 | self._nframeswritten = self._nframeswritten + nframes
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| 433 |
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| 434 | def writeframes(self, data):
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| 435 | self.writeframesraw(data)
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| 436 | if self._datalength != self._datawritten:
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| 437 | self._patchheader()
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| 438 |
|
|---|
| 439 | def close(self):
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| 440 | if self._file:
|
|---|
| 441 | try:
|
|---|
| 442 | self._ensure_header_written(0)
|
|---|
| 443 | if self._datalength != self._datawritten:
|
|---|
| 444 | self._patchheader()
|
|---|
| 445 | self._file.flush()
|
|---|
| 446 | finally:
|
|---|
| 447 | self._file = None
|
|---|
| 448 | if self._i_opened_the_file:
|
|---|
| 449 | self._i_opened_the_file.close()
|
|---|
| 450 | self._i_opened_the_file = None
|
|---|
| 451 |
|
|---|
| 452 | #
|
|---|
| 453 | # Internal methods.
|
|---|
| 454 | #
|
|---|
| 455 |
|
|---|
| 456 | def _ensure_header_written(self, datasize):
|
|---|
| 457 | if not self._headerwritten:
|
|---|
| 458 | if not self._nchannels:
|
|---|
| 459 | raise Error, '# channels not specified'
|
|---|
| 460 | if not self._sampwidth:
|
|---|
| 461 | raise Error, 'sample width not specified'
|
|---|
| 462 | if not self._framerate:
|
|---|
| 463 | raise Error, 'sampling rate not specified'
|
|---|
| 464 | self._write_header(datasize)
|
|---|
| 465 |
|
|---|
| 466 | def _write_header(self, initlength):
|
|---|
| 467 | assert not self._headerwritten
|
|---|
| 468 | self._file.write('RIFF')
|
|---|
| 469 | if not self._nframes:
|
|---|
| 470 | self._nframes = initlength / (self._nchannels * self._sampwidth)
|
|---|
| 471 | self._datalength = self._nframes * self._nchannels * self._sampwidth
|
|---|
| 472 | self._form_length_pos = self._file.tell()
|
|---|
| 473 | self._file.write(struct.pack('<L4s4sLHHLLHH4s',
|
|---|
| 474 | 36 + self._datalength, 'WAVE', 'fmt ', 16,
|
|---|
| 475 | WAVE_FORMAT_PCM, self._nchannels, self._framerate,
|
|---|
| 476 | self._nchannels * self._framerate * self._sampwidth,
|
|---|
| 477 | self._nchannels * self._sampwidth,
|
|---|
| 478 | self._sampwidth * 8, 'data'))
|
|---|
| 479 | self._data_length_pos = self._file.tell()
|
|---|
| 480 | self._file.write(struct.pack('<L', self._datalength))
|
|---|
| 481 | self._headerwritten = True
|
|---|
| 482 |
|
|---|
| 483 | def _patchheader(self):
|
|---|
| 484 | assert self._headerwritten
|
|---|
| 485 | if self._datawritten == self._datalength:
|
|---|
| 486 | return
|
|---|
| 487 | curpos = self._file.tell()
|
|---|
| 488 | self._file.seek(self._form_length_pos, 0)
|
|---|
| 489 | self._file.write(struct.pack('<L', 36 + self._datawritten))
|
|---|
| 490 | self._file.seek(self._data_length_pos, 0)
|
|---|
| 491 | self._file.write(struct.pack('<L', self._datawritten))
|
|---|
| 492 | self._file.seek(curpos, 0)
|
|---|
| 493 | self._datalength = self._datawritten
|
|---|
| 494 |
|
|---|
| 495 | def open(f, mode=None):
|
|---|
| 496 | if mode is None:
|
|---|
| 497 | if hasattr(f, 'mode'):
|
|---|
| 498 | mode = f.mode
|
|---|
| 499 | else:
|
|---|
| 500 | mode = 'rb'
|
|---|
| 501 | if mode in ('r', 'rb'):
|
|---|
| 502 | return Wave_read(f)
|
|---|
| 503 | elif mode in ('w', 'wb'):
|
|---|
| 504 | return Wave_write(f)
|
|---|
| 505 | else:
|
|---|
| 506 | raise Error, "mode must be 'r', 'rb', 'w', or 'wb'"
|
|---|
| 507 |
|
|---|
| 508 | openfp = open # B/W compatibility
|
|---|
