New module aifc to read and write AIFF-C and AIFF files. See
(extensive) comments in the file for usage.
diff --git a/Lib/aifc.py b/Lib/aifc.py
new file mode 100644
index 0000000..72c1b23
--- /dev/null
+++ b/Lib/aifc.py
@@ -0,0 +1,912 @@
+# 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)
+# if 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')
+# or
+# f = aifc.openfp(filep, 'r')
+# where file is the name of a file and filep is 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
+# 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.
+#
+# Writing AIFF files:
+# f = aifc.open(file, 'w')
+# or
+# f = aifc.openfp(filep, 'w')
+# where file is the name of a file and filep is 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(nchannels, sampwidth, framerate, nframes, comptype, compname)
+# -- 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 the 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.
+#
+# 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 builtin
+import AL
+try:
+ import CL
+except ImportError:
+ pass
+
+Error = 'aifc.Error'
+
+_AIFC_version = 0xA2805140 # Version 1 of AIFF-C
+
+_skiplist = 'COMT', 'INST', 'MIDI', 'AESD', \
+ 'APPL', 'NAME', 'AUTH', '(c) ', 'ANNO'
+
+_nchannelslist = [(1, AL.MONO), (2, AL.STEREO)]
+_sampwidthlist = [(8, AL.SAMPLE_8), (16, AL.SAMPLE_16), (24, AL.SAMPLE_24)]
+_frameratelist = [(48000, AL.RATE_48000), \
+ (44100, AL.RATE_44100), \
+ (32000, AL.RATE_32000), \
+ (22050, AL.RATE_22050), \
+ (16000, AL.RATE_16000), \
+ (11025, AL.RATE_11025), \
+ ( 8000, AL.RATE_8000)]
+
+def _convert1(value, list):
+ for t in list:
+ if value == t[0]:
+ return t[1]
+ raise Error, 'unknown parameter value'
+
+def _convert2(value, list):
+ for t in list:
+ if value == t[1]:
+ return t[0]
+ raise Error, 'unknown parameter value'
+
+def _read_long(file):
+ x = 0L
+ for i in range(4):
+ byte = file.read(1)
+ if byte == '':
+ raise EOFError
+ x = x*256 + ord(byte)
+ if x >= 0x80000000L:
+ x = x - 0x100000000L
+ return int(x)
+
+def _read_ulong(file):
+ x = 0L
+ for i in range(4):
+ byte = file.read(1)
+ if byte == '':
+ raise EOFError
+ x = x*256 + ord(byte)
+ return x
+
+def _read_short(file):
+ x = 0
+ for i in range(2):
+ byte = file.read(1)
+ if byte == '':
+ raise EOFError
+ x = x*256 + ord(byte)
+ if x >= 0x8000:
+ x = x - 0x10000
+ return x
+
+def _read_string(file):
+ length = ord(file.read(1))
+ 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):
+ d, m = divmod(x, 256)
+ f.write(chr(d))
+ f.write(chr(m))
+
+def _write_long(f, x):
+ if x < 0:
+ x = x + 0x100000000L
+ data = []
+ for i in range(4):
+ d, m = divmod(x, 256)
+ data.insert(0, m)
+ x = d
+ for i in range(4):
+ f.write(chr(int(data[i])))
+
+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()
+ return self
+
+ 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() ir initfp() 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
+ # tell() 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
+ def initfp(self, file):
+ self._file = file
+ self._version = 0
+ self._decomp = 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 1:
+ self._ssnd_seek_needed = 1
+ try:
+ chunk = Chunk().init(self._file)
+ except EOFError:
+ raise Error, 'COMM chunk and/or SSND chunk missing'
+ formlength = formlength - 8 - chunk.chunksize
+ if chunk.chunksize & 1:
+ formlength = formlength - 1
+ 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
+ if formlength <= 0:
+ if not self._comm_chunk_read:
+ raise Error, 'COMM chunk missing'
+ break
+ 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
+ chunk.skip()
+ if self._aifc and self._decomp:
+ params = [CL.ORIGINAL_FORMAT, 0, \
+ CL.BITS_PER_COMPONENT, 0, \
+ CL.FRAME_RATE, self._framerate]
+ if self._nchannels == AL.MONO:
+ params[1] = CL.MONO
+ else:
+ params[1] = CL.STEREO_INTERLEAVED
+ if self._sampwidth == AL.SAMPLE_8:
+ params[3] = 8
+ elif self._sampwidth == AL.SAMPLE_16:
+ params[3] = 16
+ else:
+ params[3] = 24
+ self._decomp.SetParams(params)
+ return self
+
+ def init(self, filename):
+ return self.initfp(builtin.open(filename, 'r'))
+
+ #
+ # 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.close()
+ 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._nchannels, self._sampwidth, self._framerate, \
+ self._nframes, self._comptype, self._compname
+
+ 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._nchannels * self._sampwidth
+ if self._decomp:
+ if self._comptype in ('ULAW', 'ALAW'):
+ pos = pos / 2
+ if pos:
+ self._ssnd_chunk.setpos(pos + 8)
+ self._ssnd_seek_needed = 0
+ size = nframes * self._nchannels * self._sampwidth
+ if self._decomp:
+ if self._comptype in ('ULAW', 'ALAW'):
+ size = size / 2
+ data = self._ssnd_chunk.read(size)
+ if self._decomp and data:
+ params = [CL.FRAME_BUFFER_SIZE, len(data) * 2]
+ self._decomp.SetParams(params)
+ data = self._decomp.Decompress(len(data) / self._nchannels, data)
+ self._soundpos = self._soundpos + len(data) / (self._nchannels * self._sampwidth)
+ return data
+
+ #
+ # Internal methods.
+ #
+ def _read_comm_chunk(self, chunk):
+ nchannels = _read_short(chunk)
+ self._nchannels = _convert1(nchannels, _nchannelslist)
+ self._nframes = _read_long(chunk)
+ sampwidth = _read_short(chunk)
+ self._sampwidth = _convert1(sampwidth, _sampwidthlist)
+ framerate = _read_float(chunk)
+ self._framerate = _convert1(framerate, _frameratelist)
+ 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':
+ try:
+ import cl, CL
+ except ImportError:
+ raise Error, 'cannot read 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._decomp = cl.OpenDecompressor(scheme)
+ else:
+ self._comptype = 'NONE'
+ self._compname = 'not compressed'
+
+ def _readmark(self, chunk):
+ nmarkers = _read_short(chunk)
+ for i in range(nmarkers):
+ id = _read_short(chunk)
+ pos = _read_long(chunk)
+ name = _read_string(chunk)
+ self._markers.append((id, pos, name))
+
+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() or initfp() 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
+
+ def init(self, filename):
+ self = self.initfp(builtin.open(filename, 'w'))
+ if filename[-5:] == '.aiff':
+ self._aifc = 0
+ else:
+ self._aifc = 1
+ return self
+
+ def initfp(self, file):
+ self._file = file
+ self._version = _AIFC_version
+ self._comptype = 'NONE'
+ self._compname = 'not compressed'
+ self._comp = None
+ self._nchannels = 0
+ self._sampwidth = 0
+ self._framerate = 0
+ self._nframes = 0
+ self._nframeswritten = 0
+ self._datawritten = 0
+ self._markers = []
+ self._marklength = 0
+ self._aifc = 1 # AIFF-C is default
+ return self
+
+ #
+ # 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'
+ 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'
+ 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'
+ 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'):
+ 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'):
+ raise Error, 'unsupported compression type'
+ self._nchannels = nchannels
+ self._sampwidth = sampwidth
+ self._framerate = framerate
+ self._nframes = nframes
+ self._comptype = comptype
+ self._compname = 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 writeframesraw(self, data):
+ if not self._nframeswritten:
+ if self._comptype in ('ULAW', 'ALAW'):
+ if not self._sampwidth:
+ self._sampwidth = AL.SAMPLE_16
+ if self._sampwidth != AL.SAMPLE_16:
+ raise Error, 'sample width must be 2 when compressing with ULAW or ALAW'
+ 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(len(data))
+ nframes = len(data) / (self._sampwidth * self._nchannels)
+ if self._comp:
+ params = [CL.FRAME_BUFFER_SIZE, len(data), \
+ CL.COMPRESSED_BUFFER_SIZE, len(data)]
+ self._comp.SetParams(params)
+ data = self._comp.Compress(nframes, 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):
+ 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.close()
+ self._file = None
+
+ #
+ # Internal methods.
+ #
+ def _write_header(self, initlength):
+ if self._aifc and self._comptype != 'NONE':
+ try:
+ import cl, CL
+ except ImportError:
+ 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, 0, \
+ CL.FRAME_RATE, self._framerate]
+ if self._nchannels == AL.MONO:
+ params[1] = CL.MONO
+ else:
+ params[1] = CL.STEREO_INTERLEAVED
+ if self._sampwidth == AL.SAMPLE_8:
+ params[3] = 8
+ elif self._sampwidth == AL.SAMPLE_16:
+ params[3] = 16
+ else:
+ params[3] = 24
+ self._comp.SetParams(params)
+ 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 and self._comptype in ('ULAW', 'ALAW'):
+ self._datalength = self._datalength / 2
+ 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, _convert2(self._sampwidth, _sampwidthlist))
+ _write_float(self._file, _convert2(self._framerate, _frameratelist))
+ 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:
+ 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(len(self._file, 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(filename, mode):
+ if mode == 'r':
+ return Aifc_read().init(filename)
+ elif mode == 'w':
+ return Aifc_write().init(filename)
+ else:
+ raise Error, 'mode must be \'r\' or \'w\''
+
+def openfp(filep, mode):
+ if mode == 'r':
+ return Aifc_read().initfp(filep)
+ elif mode == 'w':
+ return Aifc_write().initfp(filep)
+ else:
+ raise Error, 'mode must be \'r\' or \'w\''