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