New module aifc to read and write AIFF-C and AIFF files. See
(extensive) comments in the file for usage.
This commit is contained in:
Sjoerd Mullender
parent
0b0db8e3a0
commit
eeabe7eb35
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# Stuff to parse AIFF-C and AIFF files.
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#
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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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#
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# An AIFF-C file has the following structure.
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#
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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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#
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# An AIFF file has the string "AIFF" instead of "AIFC".
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#
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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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#
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# The following chunk types are recognized.
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#
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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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# if 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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#
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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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#
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# Usage.
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#
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# Reading AIFF files:
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# f = aifc.open(file, 'r')
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# or
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# f = aifc.openfp(filep, 'r')
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# where file is the name of a file and filep is an open file pointer.
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# The open file pointer must have methods read(), seek(), and
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# close(). In some types of audio files, if the setpos() method is
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# not used, the seek() method is not necessary.
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#
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# This returns an instance of a class with the following public methods:
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# getnchannels() -- returns number of audio channels (1 for
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# mono, 2 for stereo)
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# getsampwidth() -- returns sample width in bytes
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# getframerate() -- returns sampling frequency
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# getnframes() -- returns number of audio frames
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# getcomptype() -- returns compression type ('NONE' for 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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# 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 postion in the file.
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#
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# Writing AIFF files:
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# f = aifc.open(file, 'w')
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# or
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# f = aifc.openfp(filep, 'w')
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# where file is the name of a file and filep is an open file pointer.
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# The open file pointer must have methods write(), tell(), seek(), and
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# close().
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#
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# This returns an instance of a class with the following public methods:
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# 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(nchannels, sampwidth, framerate, nframes, comptype, compname)
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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 the 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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#
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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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import builtin
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import AL
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try:
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import CL
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except ImportError:
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pass
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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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_nchannelslist = [(1, AL.MONO), (2, AL.STEREO)]
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_sampwidthlist = [(8, AL.SAMPLE_8), (16, AL.SAMPLE_16), (24, AL.SAMPLE_24)]
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_frameratelist = [(48000, AL.RATE_48000), \
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(44100, AL.RATE_44100), \
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(32000, AL.RATE_32000), \
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(22050, AL.RATE_22050), \
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(16000, AL.RATE_16000), \
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(11025, AL.RATE_11025), \
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( 8000, AL.RATE_8000)]
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def _convert1(value, list):
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for t in list:
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if value == t[0]:
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return t[1]
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raise Error, 'unknown parameter value'
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def _convert2(value, list):
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for t in list:
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if value == t[1]:
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return t[0]
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raise Error, 'unknown parameter value'
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def _read_long(file):
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x = 0L
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for i in range(4):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x*256 + ord(byte)
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if x >= 0x80000000L:
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x = x - 0x100000000L
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return int(x)
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def _read_ulong(file):
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x = 0L
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for i in range(4):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x*256 + ord(byte)
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return x
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def _read_short(file):
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x = 0
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for i in range(2):
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byte = file.read(1)
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if byte == '':
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raise EOFError
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x = x*256 + ord(byte)
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if x >= 0x8000:
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x = x - 0x10000
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return x
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def _read_string(file):
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length = ord(file.read(1))
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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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d, m = divmod(x, 256)
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f.write(chr(d))
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f.write(chr(m))
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def _write_long(f, x):
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if x < 0:
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x = x + 0x100000000L
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data = []
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for i in range(4):
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d, m = divmod(x, 256)
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data.insert(0, m)
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x = d
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for i in range(4):
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f.write(chr(int(data[i])))
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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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class Chunk():
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def init(self, file):
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self.file = file
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self.chunkname = self.file.read(4)
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if len(self.chunkname) < 4:
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raise EOFError
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self.chunksize = _read_long(self.file)
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self.size_read = 0
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self.offset = self.file.tell()
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return self
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def rewind(self):
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self.file.seek(self.offset, 0)
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self.size_read = 0
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def setpos(self, pos):
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if pos < 0 or pos > self.chunksize:
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raise RuntimeError
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self.file.seek(self.offset + pos, 0)
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self.size_read = pos
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def read(self, length):
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if self.size_read >= self.chunksize:
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return ''
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if length > self.chunksize - self.size_read:
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length = self.chunksize - self.size_read
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data = self.file.read(length)
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self.size_read = self.size_read + len(data)
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return data
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def skip(self):
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try:
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self.file.seek(self.chunksize - self.size_read, 1)
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except RuntimeError:
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while self.size_read < self.chunksize:
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dummy = self.read(8192)
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if not dummy:
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raise EOFError
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if self.chunksize & 1:
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dummy = self.read(1)
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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() ir initfp() 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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# tell() 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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def initfp(self, file):
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self._file = file
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self._version = 0
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self._decomp = None
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self._markers = []
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self._soundpos = 0
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form = self._file.read(4)
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if form != 'FORM':
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raise Error, 'file does not start with FORM id'
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formlength = _read_long(self._file)
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if formlength <= 0:
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raise Error, 'invalid FORM chunk data size'
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formdata = self._file.read(4)
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formlength = formlength - 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().init(self._file)
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except EOFError:
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raise Error, 'COMM chunk and/or SSND chunk missing'
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formlength = formlength - 8 - chunk.chunksize
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if chunk.chunksize & 1:
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formlength = formlength - 1
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if chunk.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 chunk.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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if formlength <= 0:
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if not self._comm_chunk_read:
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raise Error, 'COMM chunk missing'
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break
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elif chunk.chunkname == 'FVER':
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self._version = _read_long(chunk)
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elif chunk.chunkname == 'MARK':
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self._readmark(chunk)
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elif chunk.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 self._aifc and self._decomp:
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params = [CL.ORIGINAL_FORMAT, 0, \
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CL.BITS_PER_COMPONENT, 0, \
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CL.FRAME_RATE, self._framerate]
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if self._nchannels == AL.MONO:
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params[1] = CL.MONO
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else:
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params[1] = CL.STEREO_INTERLEAVED
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if self._sampwidth == AL.SAMPLE_8:
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params[3] = 8
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elif self._sampwidth == AL.SAMPLE_16:
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params[3] = 16
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else:
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params[3] = 24
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self._decomp.SetParams(params)
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return self
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def init(self, filename):
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return self.initfp(builtin.open(filename, 'r'))
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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.close()
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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._nchannels, self._sampwidth, self._framerate, \
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self._nframes, self._comptype, self._compname
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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):
|
||||
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\''
|
||||
Loading…
Reference in New Issue