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- # Stuff to parse AIFF-C and AIFF files.
- #
- # Unless explicitly stated otherwise, the description below is true
- # both for AIFF-C files and AIFF files.
- #
- # An AIFF-C file has the following structure.
- #
- # +-----------------+
- # | FORM |
- # +-----------------+
- # | <size> |
- # +----+------------+
- # | | AIFC |
- # | +------------+
- # | | <chunks> |
- # | | . |
- # | | . |
- # | | . |
- # +----+------------+
- #
- # An AIFF file has the string "AIFF" instead of "AIFC".
- #
- # A chunk consists of an identifier (4 bytes) followed by a size (4 bytes,
- # big endian order), followed by the data. The size field does not include
- # the size of the 8 byte header.
- #
- # The following chunk types are recognized.
- #
- # FVER
- # <version number of AIFF-C defining document> (AIFF-C only).
- # MARK
- # <# of markers> (2 bytes)
- # list of markers:
- # <marker ID> (2 bytes, must be > 0)
- # <position> (4 bytes)
- # <marker name> ("pstring")
- # COMM
- # <# of channels> (2 bytes)
- # <# of sound frames> (4 bytes)
- # <size of the samples> (2 bytes)
- # <sampling frequency> (10 bytes, IEEE 80-bit extended
- # floating point)
- # in AIFF-C files only:
- # <compression type> (4 bytes)
- # <human-readable version of compression type> ("pstring")
- # SSND
- # <offset> (4 bytes, not used by this program)
- # <blocksize> (4 bytes, not used by this program)
- # <sound data>
- #
- # A pstring consists of 1 byte length, a string of characters, and 0 or 1
- # byte pad to make the total length even.
- #
- # Usage.
- #
- # Reading AIFF files:
- # f = aifc.open(file, 'r')
- # where file is either the name of a file or an open file pointer.
- # The open file pointer must have methods read(), seek(), and close().
- # In some types of audio files, if the setpos() method is not used,
- # the seek() method is not necessary.
- #
- # This returns an instance of a class with the following public methods:
- # getnchannels() -- returns number of audio channels (1 for
- # mono, 2 for stereo)
- # getsampwidth() -- returns sample width in bytes
- # getframerate() -- returns sampling frequency
- # getnframes() -- returns number of audio frames
- # getcomptype() -- returns compression type ('NONE' for AIFF files)
- # getcompname() -- returns human-readable version of
- # compression type ('not compressed' for AIFF files)
- # getparams() -- returns a tuple consisting of all of the
- # above in the above order
- # getmarkers() -- get the list of marks in the audio file or None
- # if there are no marks
- # getmark(id) -- get mark with the specified id (raises an error
- # if the mark does not exist)
- # readframes(n) -- returns at most n frames of audio
- # rewind() -- rewind to the beginning of the audio stream
- # setpos(pos) -- seek to the specified position
- # tell() -- return the current position
- # close() -- close the instance (make it unusable)
- # The position returned by tell(), the position given to setpos() and
- # the position of marks are all compatible and have nothing to do with
- # the actual postion in the file.
- # The close() method is called automatically when the class instance
- # is destroyed.
- #
- # Writing AIFF files:
- # f = aifc.open(file, 'w')
- # where file is either the name of a file or an open file pointer.
- # The open file pointer must have methods write(), tell(), seek(), and
- # close().
- #
- # This returns an instance of a class with the following public methods:
- # aiff() -- create an AIFF file (AIFF-C default)
- # aifc() -- create an AIFF-C file
- # setnchannels(n) -- set the number of channels
- # setsampwidth(n) -- set the sample width
- # setframerate(n) -- set the frame rate
- # setnframes(n) -- set the number of frames
- # setcomptype(type, name)
- # -- set the compression type and the
- # human-readable compression type
- # setparams(tuple)
- # -- set all parameters at once
- # setmark(id, pos, name)
- # -- add specified mark to the list of marks
- # tell() -- return current position in output file (useful
- # in combination with setmark())
- # writeframesraw(data)
- # -- write audio frames without pathing up the
- # file header
- # writeframes(data)
- # -- write audio frames and patch up the file header
- # close() -- patch up the file header and close the
- # output file
- # You should set the parameters before the first writeframesraw or
- # writeframes. The total number of frames does not need to be set,
- # but when it is set to the correct value, the header does not have to
- # be patched up.
- # It is best to first set all parameters, perhaps possibly the
- # compression type, and then write audio frames using writeframesraw.
- # When all frames have been written, either call writeframes('') or
- # close() to patch up the sizes in the header.
- # Marks can be added anytime. If there are any marks, ypu must call
- # close() after all frames have been written.
- # The close() method is called automatically when the class instance
- # is destroyed.
- #
- # When a file is opened with the extension '.aiff', an AIFF file is
- # written, otherwise an AIFF-C file is written. This default can be
- # changed by calling aiff() or aifc() before the first writeframes or
- # writeframesraw.
-
- import struct
- import __builtin__
-
- Error = 'aifc.Error'
-
- _AIFC_version = 0xA2805140 # Version 1 of AIFF-C
-
- _skiplist = 'COMT', 'INST', 'MIDI', 'AESD', \
- 'APPL', 'NAME', 'AUTH', '(c) ', 'ANNO'
-
- def _read_long(file):
- try:
- return struct.unpack('>l', file.read(4))[0]
- except struct.error:
- raise EOFError
-
- def _read_ulong(file):
- try:
- return struct.unpack('>L', file.read(4))[0]
- except struct.error:
- raise EOFError
-
- def _read_short(file):
- try:
- return struct.unpack('>h', file.read(2))[0]
- except struct.error:
- raise EOFError
-
- def _read_string(file):
- length = ord(file.read(1))
- if length == 0:
- data = ''
- else:
- data = file.read(length)
- if length & 1 == 0:
- dummy = file.read(1)
- return data
-
- _HUGE_VAL = 1.79769313486231e+308 # See <limits.h>
-
- def _read_float(f): # 10 bytes
- import math
- expon = _read_short(f) # 2 bytes
- sign = 1
- if expon < 0:
- sign = -1
- expon = expon + 0x8000
- himant = _read_ulong(f) # 4 bytes
- lomant = _read_ulong(f) # 4 bytes
- if expon == himant == lomant == 0:
- f = 0.0
- elif expon == 0x7FFF:
- f = _HUGE_VAL
- else:
- expon = expon - 16383
- f = (himant * 0x100000000L + lomant) * pow(2.0, expon - 63)
- return sign * f
-
- def _write_short(f, x):
- f.write(struct.pack('>h', x))
-
- def _write_long(f, x):
- f.write(struct.pack('>L', x))
-
- def _write_string(f, s):
- f.write(chr(len(s)))
- f.write(s)
- if len(s) & 1 == 0:
- f.write(chr(0))
-
- def _write_float(f, x):
- import math
- if x < 0:
- sign = 0x8000
- x = x * -1
- else:
- sign = 0
- if x == 0:
- expon = 0
- himant = 0
- lomant = 0
- else:
- fmant, expon = math.frexp(x)
- if expon > 16384 or fmant >= 1: # Infinity or NaN
- expon = sign|0x7FFF
- himant = 0
- lomant = 0
- else: # Finite
- expon = expon + 16382
- if expon < 0: # denormalized
- fmant = math.ldexp(fmant, expon)
- expon = 0
- expon = expon | sign
- fmant = math.ldexp(fmant, 32)
- fsmant = math.floor(fmant)
- himant = long(fsmant)
- fmant = math.ldexp(fmant - fsmant, 32)
- fsmant = math.floor(fmant)
- lomant = long(fsmant)
- _write_short(f, expon)
- _write_long(f, himant)
- _write_long(f, lomant)
-
- class Chunk:
- def __init__(self, file):
- self.file = file
- self.chunkname = self.file.read(4)
- if len(self.chunkname) < 4:
- raise EOFError
- self.chunksize = _read_long(self.file)
- self.size_read = 0
- self.offset = self.file.tell()
-
- def rewind(self):
- self.file.seek(self.offset, 0)
- self.size_read = 0
-
- def setpos(self, pos):
- if pos < 0 or pos > self.chunksize:
- raise RuntimeError
- self.file.seek(self.offset + pos, 0)
- self.size_read = pos
-
- def read(self, length):
- if self.size_read >= self.chunksize:
- return ''
- if length > self.chunksize - self.size_read:
- length = self.chunksize - self.size_read
- data = self.file.read(length)
- self.size_read = self.size_read + len(data)
- return data
-
- def skip(self):
- try:
- self.file.seek(self.chunksize - self.size_read, 1)
- except RuntimeError:
- while self.size_read < self.chunksize:
- dummy = self.read(8192)
- if not dummy:
- raise EOFError
- if self.chunksize & 1:
- dummy = self.read(1)
-
- class Aifc_read:
- # Variables used in this class:
- #
- # These variables are available to the user though appropriate
- # methods of this class:
- # _file -- the open file with methods read(), close(), and seek()
- # set through the __init__() method
- # _nchannels -- the number of audio channels
- # available through the getnchannels() method
- # _nframes -- the number of audio frames
- # available through the getnframes() method
- # _sampwidth -- the number of bytes per audio sample
- # available through the getsampwidth() method
- # _framerate -- the sampling frequency
- # available through the getframerate() method
- # _comptype -- the AIFF-C compression type ('NONE' if AIFF)
- # available through the getcomptype() method
- # _compname -- the human-readable AIFF-C compression type
- # available through the getcomptype() method
- # _markers -- the marks in the audio file
- # available through the getmarkers() and getmark()
- # methods
- # _soundpos -- the position in the audio stream
- # available through the tell() method, set through the
- # setpos() method
- #
- # These variables are used internally only:
- # _version -- the AIFF-C version number
- # _decomp -- the decompressor from builtin module cl
- # _comm_chunk_read -- 1 iff the COMM chunk has been read
- # _aifc -- 1 iff reading an AIFF-C file
- # _ssnd_seek_needed -- 1 iff positioned correctly in audio
- # file for readframes()
- # _ssnd_chunk -- instantiation of a chunk class for the SSND chunk
- # _framesize -- size of one frame in the file
-
- ## if 0: access _file, _nchannels, _nframes, _sampwidth, _framerate, \
- ## _comptype, _compname, _markers, _soundpos, _version, \
- ## _decomp, _comm_chunk_read, __aifc, _ssnd_seek_needed, \
- ## _ssnd_chunk, _framesize: private
-
- def initfp(self, file):
- self._file = file
- self._version = 0
- self._decomp = None
- self._convert = None
- self._markers = []
- self._soundpos = 0
- form = self._file.read(4)
- if form != 'FORM':
- raise Error, 'file does not start with FORM id'
- formlength = _read_long(self._file)
- if formlength <= 0:
- raise Error, 'invalid FORM chunk data size'
- formdata = self._file.read(4)
- formlength = formlength - 4
- if formdata == 'AIFF':
- self._aifc = 0
- elif formdata == 'AIFC':
- self._aifc = 1
- else:
- raise Error, 'not an AIFF or AIFF-C file'
- self._comm_chunk_read = 0
- while formlength > 0:
- self._ssnd_seek_needed = 1
- #DEBUG: SGI's soundfiler has a bug. There should
- # be no need to check for EOF here.
- try:
- chunk = Chunk(self._file)
- except EOFError:
- if formlength == 8:
- print 'Warning: FORM chunk size too large'
- formlength = 0
- break
- raise EOFError # different error, raise exception
- if chunk.chunkname == 'COMM':
- self._read_comm_chunk(chunk)
- self._comm_chunk_read = 1
- elif chunk.chunkname == 'SSND':
- self._ssnd_chunk = chunk
- dummy = chunk.read(8)
- self._ssnd_seek_needed = 0
- elif chunk.chunkname == 'FVER':
- self._version = _read_long(chunk)
- elif chunk.chunkname == 'MARK':
- self._readmark(chunk)
- elif chunk.chunkname in _skiplist:
- pass
- else:
- raise Error, 'unrecognized chunk type '+chunk.chunkname
- formlength = formlength - 8 - chunk.chunksize
- if chunk.chunksize & 1:
- formlength = formlength - 1
- if formlength > 0:
- chunk.skip()
- if not self._comm_chunk_read or not self._ssnd_chunk:
- raise Error, 'COMM chunk and/or SSND chunk missing'
- if self._aifc and self._decomp:
- import cl
- params = [cl.ORIGINAL_FORMAT, 0,
- cl.BITS_PER_COMPONENT, self._sampwidth * 8,
- cl.FRAME_RATE, self._framerate]
- if self._nchannels == 1:
- params[1] = cl.MONO
- elif self._nchannels == 2:
- params[1] = cl.STEREO_INTERLEAVED
- else:
- raise Error, 'cannot compress more than 2 channels'
- self._decomp.SetParams(params)
-
- def __init__(self, f):
- if type(f) == type(''):
- f = __builtin__.open(f, 'rb')
- # else, assume it is an open file object already
- self.initfp(f)
-
- def __del__(self):
- if self._file:
- self.close()
-
- #
- # User visible methods.
- #
- def getfp(self):
- return self._file
-
- def rewind(self):
- self._ssnd_seek_needed = 1
- self._soundpos = 0
-
- def close(self):
- if self._decomp:
- self._decomp.CloseDecompressor()
- self._decomp = None
- self._file = None
-
- def tell(self):
- return self._soundpos
-
- def getnchannels(self):
- return self._nchannels
-
- def getnframes(self):
- return self._nframes
-
- def getsampwidth(self):
- return self._sampwidth
-
- def getframerate(self):
- return self._framerate
-
- def getcomptype(self):
- return self._comptype
-
- def getcompname(self):
- return self._compname
-
- ## def getversion(self):
- ## return self._version
-
- def getparams(self):
- return self.getnchannels(), self.getsampwidth(), \
- self.getframerate(), self.getnframes(), \
- self.getcomptype(), self.getcompname()
-
- def getmarkers(self):
- if len(self._markers) == 0:
- return None
- return self._markers
-
- def getmark(self, id):
- for marker in self._markers:
- if id == marker[0]:
- return marker
- raise Error, 'marker ' + `id` + ' does not exist'
-
- def setpos(self, pos):
- if pos < 0 or pos > self._nframes:
- raise Error, 'position not in range'
- self._soundpos = pos
- self._ssnd_seek_needed = 1
-
- def readframes(self, nframes):
- if self._ssnd_seek_needed:
- self._ssnd_chunk.rewind()
- dummy = self._ssnd_chunk.read(8)
- pos = self._soundpos * self._framesize
- if pos:
- self._ssnd_chunk.setpos(pos + 8)
- self._ssnd_seek_needed = 0
- if nframes == 0:
- return ''
- data = self._ssnd_chunk.read(nframes * self._framesize)
- if self._convert and data:
- data = self._convert(data)
- self._soundpos = self._soundpos + len(data) / (self._nchannels * self._sampwidth)
- return data
-
- #
- # Internal methods.
- #
- ## if 0: access *: private
-
- def _decomp_data(self, data):
- import cl
- dummy = self._decomp.SetParam(cl.FRAME_BUFFER_SIZE,
- len(data) * 2)
- return self._decomp.Decompress(len(data) / self._nchannels,
- data)
-
- def _ulaw2lin(self, data):
- import audioop
- return audioop.ulaw2lin(data, 2)
-
- def _adpcm2lin(self, data):
- import audioop
- if not hasattr(self, '_adpcmstate'):
- # first time
- self._adpcmstate = None
- data, self._adpcmstate = audioop.adpcm2lin(data, 2,
- self._adpcmstate)
- return data
-
- def _read_comm_chunk(self, chunk):
- self._nchannels = _read_short(chunk)
- self._nframes = _read_long(chunk)
- self._sampwidth = (_read_short(chunk) + 7) / 8
- self._framerate = int(_read_float(chunk))
- self._framesize = self._nchannels * self._sampwidth
- if self._aifc:
- #DEBUG: SGI's soundeditor produces a bad size :-(
- kludge = 0
- if chunk.chunksize == 18:
- kludge = 1
- print 'Warning: bad COMM chunk size'
- chunk.chunksize = 23
- #DEBUG end
- self._comptype = chunk.read(4)
- #DEBUG start
- if kludge:
- length = ord(chunk.file.read(1))
- if length & 1 == 0:
- length = length + 1
- chunk.chunksize = chunk.chunksize + length
- chunk.file.seek(-1, 1)
- #DEBUG end
- self._compname = _read_string(chunk)
- if self._comptype != 'NONE':
- if self._comptype == 'G722':
- try:
- import audioop
- except ImportError:
- pass
- else:
- self._convert = self._adpcm2lin
- self._framesize = self._framesize / 4
- return
- # for ULAW and ALAW try Compression Library
- try:
- import cl
- except ImportError:
- if self._comptype == 'ULAW':
- try:
- import audioop
- self._convert = self._ulaw2lin
- self._framesize = self._framesize / 2
- return
- except ImportError:
- pass
- raise Error, 'cannot read compressed AIFF-C files'
- if self._comptype == 'ULAW':
- scheme = cl.G711_ULAW
- self._framesize = self._framesize / 2
- elif self._comptype == 'ALAW':
- scheme = cl.G711_ALAW
- self._framesize = self._framesize / 2
- else:
- raise Error, 'unsupported compression type'
- self._decomp = cl.OpenDecompressor(scheme)
- self._convert = self._decomp_data
- else:
- self._comptype = 'NONE'
- self._compname = 'not compressed'
-
- def _readmark(self, chunk):
- nmarkers = _read_short(chunk)
- # Some files appear to contain invalid counts.
- # Cope with this by testing for EOF.
- try:
- for i in range(nmarkers):
- id = _read_short(chunk)
- pos = _read_long(chunk)
- name = _read_string(chunk)
- if pos or name:
- # some files appear to have
- # dummy markers consisting of
- # a position 0 and name ''
- self._markers.append((id, pos, name))
- except EOFError:
- print 'Warning: MARK chunk contains only',
- print len(self._markers),
- if len(self._markers) == 1: print 'marker',
- else: print 'markers',
- print 'instead of', nmarkers
-
- class Aifc_write:
- # Variables used in this class:
- #
- # These variables are user settable through appropriate methods
- # of this class:
- # _file -- the open file with methods write(), close(), tell(), seek()
- # set through the __init__() method
- # _comptype -- the AIFF-C compression type ('NONE' in AIFF)
- # set through the setcomptype() or setparams() method
- # _compname -- the human-readable AIFF-C compression type
- # set through the setcomptype() or setparams() method
- # _nchannels -- the number of audio channels
- # set through the setnchannels() or setparams() method
- # _sampwidth -- the number of bytes per audio sample
- # set through the setsampwidth() or setparams() method
- # _framerate -- the sampling frequency
- # set through the setframerate() or setparams() method
- # _nframes -- the number of audio frames written to the header
- # set through the setnframes() or setparams() method
- # _aifc -- whether we're writing an AIFF-C file or an AIFF file
- # set through the aifc() method, reset through the
- # aiff() method
- #
- # These variables are used internally only:
- # _version -- the AIFF-C version number
- # _comp -- the compressor from builtin module cl
- # _nframeswritten -- the number of audio frames actually written
- # _datalength -- the size of the audio samples written to the header
- # _datawritten -- the size of the audio samples actually written
-
- ## if 0: access _file, _comptype, _compname, _nchannels, _sampwidth, \
- ## _framerate, _nframes, _aifc, _version, _comp, \
- ## _nframeswritten, _datalength, _datawritten: private
-
- def __init__(self, f):
- if type(f) == type(''):
- filename = f
- f = __builtin__.open(f, 'wb')
- else:
- # else, assume it is an open file object already
- filename = '???'
- self.initfp(f)
- if filename[-5:] == '.aiff':
- self._aifc = 0
- else:
- self._aifc = 1
-
- def initfp(self, file):
- self._file = file
- self._version = _AIFC_version
- self._comptype = 'NONE'
- self._compname = 'not compressed'
- self._comp = None
- self._convert = None
- self._nchannels = 0
- self._sampwidth = 0
- self._framerate = 0
- self._nframes = 0
- self._nframeswritten = 0
- self._datawritten = 0
- self._datalength = 0
- self._markers = []
- self._marklength = 0
- self._aifc = 1 # AIFF-C is default
-
- def __del__(self):
- if self._file:
- self.close()
-
- #
- # User visible methods.
- #
- def aiff(self):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- self._aifc = 0
-
- def aifc(self):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- self._aifc = 1
-
- def setnchannels(self, nchannels):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- if nchannels < 1:
- raise Error, 'bad # of channels'
- self._nchannels = nchannels
-
- def getnchannels(self):
- if not self._nchannels:
- raise Error, 'number of channels not set'
- return self._nchannels
-
- def setsampwidth(self, sampwidth):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- if sampwidth < 1 or sampwidth > 4:
- raise Error, 'bad sample width'
- self._sampwidth = sampwidth
-
- def getsampwidth(self):
- if not self._sampwidth:
- raise Error, 'sample width not set'
- return self._sampwidth
-
- def setframerate(self, framerate):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- if framerate <= 0:
- raise Error, 'bad frame rate'
- self._framerate = framerate
-
- def getframerate(self):
- if not self._framerate:
- raise Error, 'frame rate not set'
- return self._framerate
-
- def setnframes(self, nframes):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- self._nframes = nframes
-
- def getnframes(self):
- return self._nframeswritten
-
- def setcomptype(self, comptype, compname):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- if comptype not in ('NONE', 'ULAW', 'ALAW', 'G722'):
- raise Error, 'unsupported compression type'
- self._comptype = comptype
- self._compname = compname
-
- def getcomptype(self):
- return self._comptype
-
- def getcompname(self):
- return self._compname
-
- ## def setversion(self, version):
- ## if self._nframeswritten:
- ## raise Error, 'cannot change parameters after starting to write'
- ## self._version = version
-
- def setparams(self, (nchannels, sampwidth, framerate, nframes, comptype, compname)):
- if self._nframeswritten:
- raise Error, 'cannot change parameters after starting to write'
- if comptype not in ('NONE', 'ULAW', 'ALAW', 'G722'):
- raise Error, 'unsupported compression type'
- self.setnchannels(nchannels)
- self.setsampwidth(sampwidth)
- self.setframerate(framerate)
- self.setnframes(nframes)
- self.setcomptype(comptype, compname)
-
- def getparams(self):
- if not self._nchannels or not self._sampwidth or not self._framerate:
- raise Error, 'not all parameters set'
- return self._nchannels, self._sampwidth, self._framerate, \
- self._nframes, self._comptype, self._compname
-
- def setmark(self, id, pos, name):
- if id <= 0:
- raise Error, 'marker ID must be > 0'
- if pos < 0:
- raise Error, 'marker position must be >= 0'
- if type(name) != type(''):
- raise Error, 'marker name must be a string'
- for i in range(len(self._markers)):
- if id == self._markers[i][0]:
- self._markers[i] = id, pos, name
- return
- self._markers.append((id, pos, name))
-
- def getmark(self, id):
- for marker in self._markers:
- if id == marker[0]:
- return marker
- raise Error, 'marker ' + `id` + ' does not exist'
-
- def getmarkers(self):
- if len(self._markers) == 0:
- return None
- return self._markers
-
- def tell(self):
- return self._nframeswritten
-
- def writeframesraw(self, data):
- self._ensure_header_written(len(data))
- nframes = len(data) / (self._sampwidth * self._nchannels)
- if self._convert:
- data = self._convert(data)
- self._file.write(data)
- self._nframeswritten = self._nframeswritten + nframes
- self._datawritten = self._datawritten + len(data)
-
- def writeframes(self, data):
- self.writeframesraw(data)
- if self._nframeswritten != self._nframes or \
- self._datalength != self._datawritten:
- self._patchheader()
-
- def close(self):
- self._ensure_header_written(0)
- if self._datawritten & 1:
- # quick pad to even size
- self._file.write(chr(0))
- self._datawritten = self._datawritten + 1
- self._writemarkers()
- if self._nframeswritten != self._nframes or \
- self._datalength != self._datawritten or \
- self._marklength:
- self._patchheader()
- if self._comp:
- self._comp.CloseCompressor()
- self._comp = None
- self._file.flush()
- self._file = None
-
- #
- # Internal methods.
- #
- ## if 0: access *: private
-
- def _comp_data(self, data):
- import cl
- dum = self._comp.SetParam(cl.FRAME_BUFFER_SIZE, len(data))
- dum = self._comp.SetParam(cl.COMPRESSED_BUFFER_SIZE, len(data))
- return self._comp.Compress(nframes, data)
-
- def _lin2ulaw(self, data):
- import audioop
- return audioop.lin2ulaw(data, 2)
-
- def _lin2adpcm(self, data):
- import audioop
- if not hasattr(self, '_adpcmstate'):
- self._adpcmstate = None
- data, self._adpcmstate = audioop.lin2adpcm(data, 2,
- self._adpcmstate)
- return data
-
- def _ensure_header_written(self, datasize):
- if not self._nframeswritten:
- if self._comptype in ('ULAW', 'ALAW'):
- if not self._sampwidth:
- self._sampwidth = 2
- if self._sampwidth != 2:
- raise Error, 'sample width must be 2 when compressing with ULAW or ALAW'
- if self._comptype == 'G722':
- if not self._sampwidth:
- self._sampwidth = 2
- if self._sampwidth != 2:
- raise Error, 'sample width must be 2 when compressing with G7.22 (ADPCM)'
- 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 _init_compression(self):
- if self._comptype == 'G722':
- import audioop
- self._convert = self._lin2adpcm
- return
- try:
- import cl
- except ImportError:
- if self._comptype == 'ULAW':
- try:
- import audioop
- self._convert = self._lin2ulaw
- return
- except ImportError:
- pass
- raise Error, 'cannot write compressed AIFF-C files'
- if self._comptype == 'ULAW':
- scheme = cl.G711_ULAW
- elif self._comptype == 'ALAW':
- scheme = cl.G711_ALAW
- else:
- raise Error, 'unsupported compression type'
- self._comp = cl.OpenCompressor(scheme)
- params = [cl.ORIGINAL_FORMAT, 0,
- cl.BITS_PER_COMPONENT, self._sampwidth * 8,
- cl.FRAME_RATE, self._framerate,
- cl.FRAME_BUFFER_SIZE, 100,
- cl.COMPRESSED_BUFFER_SIZE, 100]
- if self._nchannels == 1:
- params[1] = cl.MONO
- elif self._nchannels == 2:
- params[1] = cl.STEREO_INTERLEAVED
- else:
- raise Error, 'cannot compress more than 2 channels'
- self._comp.SetParams(params)
- # the compressor produces a header which we ignore
- dummy = self._comp.Compress(0, '')
- self._convert = self._comp_data
-
- def _write_header(self, initlength):
- if self._aifc and self._comptype != 'NONE':
- self._init_compression()
- self._file.write('FORM')
- if not self._nframes:
- self._nframes = initlength / (self._nchannels * self._sampwidth)
- self._datalength = self._nframes * self._nchannels * self._sampwidth
- if self._datalength & 1:
- self._datalength = self._datalength + 1
- if self._aifc:
- if self._comptype in ('ULAW', 'ALAW'):
- self._datalength = self._datalength / 2
- if self._datalength & 1:
- self._datalength = self._datalength + 1
- elif self._comptype == 'G722':
- self._datalength = (self._datalength + 3) / 4
- if self._datalength & 1:
- self._datalength = self._datalength + 1
- self._form_length_pos = self._file.tell()
- commlength = self._write_form_length(self._datalength)
- if self._aifc:
- self._file.write('AIFC')
- self._file.write('FVER')
- _write_long(self._file, 4)
- _write_long(self._file, self._version)
- else:
- self._file.write('AIFF')
- self._file.write('COMM')
- _write_long(self._file, commlength)
- _write_short(self._file, self._nchannels)
- self._nframes_pos = self._file.tell()
- _write_long(self._file, self._nframes)
- _write_short(self._file, self._sampwidth * 8)
- _write_float(self._file, self._framerate)
- if self._aifc:
- self._file.write(self._comptype)
- _write_string(self._file, self._compname)
- self._file.write('SSND')
- self._ssnd_length_pos = self._file.tell()
- _write_long(self._file, self._datalength + 8)
- _write_long(self._file, 0)
- _write_long(self._file, 0)
-
- def _write_form_length(self, datalength):
- if self._aifc:
- commlength = 18 + 5 + len(self._compname)
- if commlength & 1:
- commlength = commlength + 1
- verslength = 12
- else:
- commlength = 18
- verslength = 0
- _write_long(self._file, 4 + verslength + self._marklength + \
- 8 + commlength + 16 + datalength)
- return commlength
-
- def _patchheader(self):
- curpos = self._file.tell()
- if self._datawritten & 1:
- datalength = self._datawritten + 1
- self._file.write(chr(0))
- else:
- datalength = self._datawritten
- if datalength == self._datalength and \
- self._nframes == self._nframeswritten and \
- self._marklength == 0:
- self._file.seek(curpos, 0)
- return
- self._file.seek(self._form_length_pos, 0)
- dummy = self._write_form_length(datalength)
- self._file.seek(self._nframes_pos, 0)
- _write_long(self._file, self._nframeswritten)
- self._file.seek(self._ssnd_length_pos, 0)
- _write_long(self._file, datalength + 8)
- self._file.seek(curpos, 0)
- self._nframes = self._nframeswritten
- self._datalength = datalength
-
- def _writemarkers(self):
- if len(self._markers) == 0:
- return
- self._file.write('MARK')
- length = 2
- for marker in self._markers:
- id, pos, name = marker
- length = length + len(name) + 1 + 6
- if len(name) & 1 == 0:
- length = length + 1
- _write_long(self._file, length)
- self._marklength = length + 8
- _write_short(self._file, len(self._markers))
- for marker in self._markers:
- id, pos, name = marker
- _write_short(self._file, id)
- _write_long(self._file, pos)
- _write_string(self._file, name)
-
- def open(f, mode):
- if mode == 'r':
- return Aifc_read(f)
- elif mode == 'w':
- return Aifc_write(f)
- else:
- raise Error, "mode must be 'r' or 'w'"
-
- openfp = open # B/W compatibility
-
- if __name__ == '__main__':
- import sys
- if not sys.argv[1:]:
- sys.argv.append('/usr/demos/data/audio/bach.aiff')
- fn = sys.argv[1]
- f = open(fn, 'r')
- print "Reading", fn
- print "nchannels =", f.getnchannels()
- print "nframes =", f.getnframes()
- print "sampwidth =", f.getsampwidth()
- print "framerate =", f.getframerate()
- print "comptype =", f.getcomptype()
- print "compname =", f.getcompname()
- if sys.argv[2:]:
- gn = sys.argv[2]
- print "Writing", gn
- g = open(gn, 'w')
- g.setparams(f.getparams())
- while 1:
- data = f.readframes(1024)
- if not data:
- break
- g.writeframes(data)
- g.close()
- f.close()
- print "Done."
-