"""Stuff to parse AIFF-C and AIFF files. | |
Unless explicitly stated otherwise, the description below is true | |
both for AIFF-C files and AIFF files. | |
An AIFF-C file has the following structure. | |
+-----------------+ | |
| FORM | | |
+-----------------+ | |
| <size> | | |
+----+------------+ | |
| | AIFC | | |
| +------------+ | |
| | <chunks> | | |
| | . | | |
| | . | | |
| | . | | |
+----+------------+ | |
An AIFF file has the string "AIFF" instead of "AIFC". | |
A chunk consists of an identifier (4 bytes) followed by a size (4 bytes, | |
big endian order), followed by the data. The size field does not include | |
the size of the 8 byte header. | |
The following chunk types are recognized. | |
FVER | |
<version number of AIFF-C defining document> (AIFF-C only). | |
MARK | |
<# of markers> (2 bytes) | |
list of markers: | |
<marker ID> (2 bytes, must be > 0) | |
<position> (4 bytes) | |
<marker name> ("pstring") | |
COMM | |
<# of channels> (2 bytes) | |
<# of sound frames> (4 bytes) | |
<size of the samples> (2 bytes) | |
<sampling frequency> (10 bytes, IEEE 80-bit extended | |
floating point) | |
in AIFF-C files only: | |
<compression type> (4 bytes) | |
<human-readable version of compression type> ("pstring") | |
SSND | |
<offset> (4 bytes, not used by this program) | |
<blocksize> (4 bytes, not used by this program) | |
<sound data> | |
A pstring consists of 1 byte length, a string of characters, and 0 or 1 | |
byte pad to make the total length even. | |
Usage. | |
Reading AIFF files: | |
f = aifc.open(file, 'r') | |
where file is either the name of a file or an open file pointer. | |
The open file pointer must have methods read(), seek(), and close(). | |
In some types of audio files, if the setpos() method is not used, | |
the seek() method is not necessary. | |
This returns an instance of a class with the following public methods: | |
getnchannels() -- returns number of audio channels (1 for | |
mono, 2 for stereo) | |
getsampwidth() -- returns sample width in bytes | |
getframerate() -- returns sampling frequency | |
getnframes() -- returns number of audio frames | |
getcomptype() -- returns compression type ('NONE' for AIFF files) | |
getcompname() -- returns human-readable version of | |
compression type ('not compressed' for AIFF files) | |
getparams() -- returns a tuple consisting of all of the | |
above in the above order | |
getmarkers() -- get the list of marks in the audio file or None | |
if there are no marks | |
getmark(id) -- get mark with the specified id (raises an error | |
if the mark does not exist) | |
readframes(n) -- returns at most n frames of audio | |
rewind() -- rewind to the beginning of the audio stream | |
setpos(pos) -- seek to the specified position | |
tell() -- return the current position | |
close() -- close the instance (make it unusable) | |
The position returned by tell(), the position given to setpos() and | |
the position of marks are all compatible and have nothing to do with | |
the actual position in the file. | |
The close() method is called automatically when the class instance | |
is destroyed. | |
Writing AIFF files: | |
f = aifc.open(file, 'w') | |
where file is either the name of a file or an open file pointer. | |
The open file pointer must have methods write(), tell(), seek(), and | |
close(). | |
This returns an instance of a class with the following public methods: | |
aiff() -- create an AIFF file (AIFF-C default) | |
aifc() -- create an AIFF-C file | |
setnchannels(n) -- set the number of channels | |
setsampwidth(n) -- set the sample width | |
setframerate(n) -- set the frame rate | |
setnframes(n) -- set the number of frames | |
setcomptype(type, name) | |
-- set the compression type and the | |
human-readable compression type | |
setparams(tuple) | |
-- set all parameters at once | |
setmark(id, pos, name) | |
-- add specified mark to the list of marks | |
tell() -- return current position in output file (useful | |
in combination with setmark()) | |
writeframesraw(data) | |
-- write audio frames without pathing up the | |
file header | |
writeframes(data) | |
-- write audio frames and patch up the file header | |
close() -- patch up the file header and close the | |
output file | |
You should set the parameters before the first writeframesraw or | |
writeframes. The total number of frames does not need to be set, | |
but when it is set to the correct value, the header does not have to | |
be patched up. | |
It is best to first set all parameters, perhaps possibly the | |
compression type, and then write audio frames using writeframesraw. | |
When all frames have been written, either call writeframes('') or | |
close() to patch up the sizes in the header. | |
Marks can be added anytime. If there are any marks, ypu must call | |
close() after all frames have been written. | |
The close() method is called automatically when the class instance | |
is destroyed. | |
When a file is opened with the extension '.aiff', an AIFF file is | |
written, otherwise an AIFF-C file is written. This default can be | |
changed by calling aiff() or aifc() before the first writeframes or | |
writeframesraw. | |
""" | |
import struct | |
import __builtin__ | |
__all__ = ["Error","open","openfp"] | |
class Error(Exception): | |
pass | |
_AIFC_version = 0xA2805140L # Version 1 of AIFF-C | |
def _read_long(file): | |
try: | |
return struct.unpack('>l', file.read(4))[0] | |
except struct.error: | |
raise EOFError | |
def _read_ulong(file): | |
try: | |
return struct.unpack('>L', file.read(4))[0] | |
except struct.error: | |
raise EOFError | |
def _read_short(file): | |
try: | |
return struct.unpack('>h', file.read(2))[0] | |
except struct.error: | |
raise EOFError | |
def _read_string(file): | |
length = ord(file.read(1)) | |
if length == 0: | |
data = '' | |
else: | |
data = file.read(length) | |
if length & 1 == 0: | |
dummy = file.read(1) | |
return data | |
_HUGE_VAL = 1.79769313486231e+308 # See <limits.h> | |
def _read_float(f): # 10 bytes | |
expon = _read_short(f) # 2 bytes | |
sign = 1 | |
if expon < 0: | |
sign = -1 | |
expon = expon + 0x8000 | |
himant = _read_ulong(f) # 4 bytes | |
lomant = _read_ulong(f) # 4 bytes | |
if expon == himant == lomant == 0: | |
f = 0.0 | |
elif expon == 0x7FFF: | |
f = _HUGE_VAL | |
else: | |
expon = expon - 16383 | |
f = (himant * 0x100000000L + lomant) * pow(2.0, expon - 63) | |
return sign * f | |
def _write_short(f, x): | |
f.write(struct.pack('>h', x)) | |
def _write_long(f, x): | |
f.write(struct.pack('>L', x)) | |
def _write_string(f, s): | |
if len(s) > 255: | |
raise ValueError("string exceeds maximum pstring length") | |
f.write(chr(len(s))) | |
f.write(s) | |
if len(s) & 1 == 0: | |
f.write(chr(0)) | |
def _write_float(f, x): | |
import math | |
if x < 0: | |
sign = 0x8000 | |
x = x * -1 | |
else: | |
sign = 0 | |
if x == 0: | |
expon = 0 | |
himant = 0 | |
lomant = 0 | |
else: | |
fmant, expon = math.frexp(x) | |
if expon > 16384 or fmant >= 1: # Infinity or NaN | |
expon = sign|0x7FFF | |
himant = 0 | |
lomant = 0 | |
else: # Finite | |
expon = expon + 16382 | |
if expon < 0: # denormalized | |
fmant = math.ldexp(fmant, expon) | |
expon = 0 | |
expon = expon | sign | |
fmant = math.ldexp(fmant, 32) | |
fsmant = math.floor(fmant) | |
himant = long(fsmant) | |
fmant = math.ldexp(fmant - fsmant, 32) | |
fsmant = math.floor(fmant) | |
lomant = long(fsmant) | |
_write_short(f, expon) | |
_write_long(f, himant) | |
_write_long(f, lomant) | |
from chunk import Chunk | |
class Aifc_read: | |
# Variables used in this class: | |
# | |
# These variables are available to the user though appropriate | |
# methods of this class: | |
# _file -- the open file with methods read(), close(), and seek() | |
# set through the __init__() method | |
# _nchannels -- the number of audio channels | |
# available through the getnchannels() method | |
# _nframes -- the number of audio frames | |
# available through the getnframes() method | |
# _sampwidth -- the number of bytes per audio sample | |
# available through the getsampwidth() method | |
# _framerate -- the sampling frequency | |
# available through the getframerate() method | |
# _comptype -- the AIFF-C compression type ('NONE' if AIFF) | |
# available through the getcomptype() method | |
# _compname -- the human-readable AIFF-C compression type | |
# available through the getcomptype() method | |
# _markers -- the marks in the audio file | |
# available through the getmarkers() and getmark() | |
# methods | |
# _soundpos -- the position in the audio stream | |
# available through the tell() method, set through the | |
# setpos() method | |
# | |
# These variables are used internally only: | |
# _version -- the AIFF-C version number | |
# _decomp -- the decompressor from builtin module cl | |
# _comm_chunk_read -- 1 iff the COMM chunk has been read | |
# _aifc -- 1 iff reading an AIFF-C file | |
# _ssnd_seek_needed -- 1 iff positioned correctly in audio | |
# file for readframes() | |
# _ssnd_chunk -- instantiation of a chunk class for the SSND chunk | |
# _framesize -- size of one frame in the file | |
def initfp(self, file): | |
self._version = 0 | |
self._decomp = None | |
self._convert = None | |
self._markers = [] | |
self._soundpos = 0 | |
self._file = file | |
chunk = Chunk(file) | |
if chunk.getname() != 'FORM': | |
raise Error, 'file does not start with FORM id' | |
formdata = chunk.read(4) | |
if formdata == 'AIFF': | |
self._aifc = 0 | |
elif formdata == 'AIFC': | |
self._aifc = 1 | |
else: | |
raise Error, 'not an AIFF or AIFF-C file' | |
self._comm_chunk_read = 0 | |
while 1: | |
self._ssnd_seek_needed = 1 | |
try: | |
chunk = Chunk(self._file) | |
except EOFError: | |
break | |
chunkname = chunk.getname() | |
if chunkname == 'COMM': | |
self._read_comm_chunk(chunk) | |
self._comm_chunk_read = 1 | |
elif chunkname == 'SSND': | |
self._ssnd_chunk = chunk | |
dummy = chunk.read(8) | |
self._ssnd_seek_needed = 0 | |
elif chunkname == 'FVER': | |
self._version = _read_ulong(chunk) | |
elif chunkname == 'MARK': | |
self._readmark(chunk) | |
chunk.skip() | |
if not self._comm_chunk_read or not self._ssnd_chunk: | |
raise Error, 'COMM chunk and/or SSND chunk missing' | |
if self._aifc and self._decomp: | |
import cl | |
params = [cl.ORIGINAL_FORMAT, 0, | |
cl.BITS_PER_COMPONENT, self._sampwidth * 8, | |
cl.FRAME_RATE, self._framerate] | |
if self._nchannels == 1: | |
params[1] = cl.MONO | |
elif self._nchannels == 2: | |
params[1] = cl.STEREO_INTERLEAVED | |
else: | |
raise Error, 'cannot compress more than 2 channels' | |
self._decomp.SetParams(params) | |
def __init__(self, f): | |
if type(f) == type(''): | |
f = __builtin__.open(f, 'rb') | |
# else, assume it is an open file object already | |
self.initfp(f) | |
# | |
# User visible methods. | |
# | |
def getfp(self): | |
return self._file | |
def rewind(self): | |
self._ssnd_seek_needed = 1 | |
self._soundpos = 0 | |
def close(self): | |
if self._decomp: | |
self._decomp.CloseDecompressor() | |
self._decomp = None | |
self._file.close() | |
def tell(self): | |
return self._soundpos | |
def getnchannels(self): | |
return self._nchannels | |
def getnframes(self): | |
return self._nframes | |
def getsampwidth(self): | |
return self._sampwidth | |
def getframerate(self): | |
return self._framerate | |
def getcomptype(self): | |
return self._comptype | |
def getcompname(self): | |
return self._compname | |
## def getversion(self): | |
## return self._version | |
def getparams(self): | |
return self.getnchannels(), self.getsampwidth(), \ | |
self.getframerate(), self.getnframes(), \ | |
self.getcomptype(), self.getcompname() | |
def getmarkers(self): | |
if len(self._markers) == 0: | |
return None | |
return self._markers | |
def getmark(self, id): | |
for marker in self._markers: | |
if id == marker[0]: | |
return marker | |
raise Error, 'marker %r does not exist' % (id,) | |
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.seek(0) | |
dummy = self._ssnd_chunk.read(8) | |
pos = self._soundpos * self._framesize | |
if pos: | |
self._ssnd_chunk.seek(pos + 8) | |
self._ssnd_seek_needed = 0 | |
if nframes == 0: | |
return '' | |
data = self._ssnd_chunk.read(nframes * self._framesize) | |
if self._convert and data: | |
data = self._convert(data) | |
self._soundpos = self._soundpos + len(data) // (self._nchannels * self._sampwidth) | |
return data | |
# | |
# Internal methods. | |
# | |
def _decomp_data(self, data): | |
import cl | |
dummy = self._decomp.SetParam(cl.FRAME_BUFFER_SIZE, | |
len(data) * 2) | |
return self._decomp.Decompress(len(data) // self._nchannels, | |
data) | |
def _ulaw2lin(self, data): | |
import audioop | |
return audioop.ulaw2lin(data, 2) | |
def _adpcm2lin(self, data): | |
import audioop | |
if not hasattr(self, '_adpcmstate'): | |
# first time | |
self._adpcmstate = None | |
data, self._adpcmstate = audioop.adpcm2lin(data, 2, | |
self._adpcmstate) | |
return data | |
def _read_comm_chunk(self, chunk): | |
self._nchannels = _read_short(chunk) | |
self._nframes = _read_long(chunk) | |
self._sampwidth = (_read_short(chunk) + 7) // 8 | |
self._framerate = int(_read_float(chunk)) | |
self._framesize = self._nchannels * self._sampwidth | |
if self._aifc: | |
#DEBUG: SGI's soundeditor produces a bad size :-( | |
kludge = 0 | |
if chunk.chunksize == 18: | |
kludge = 1 | |
print 'Warning: bad COMM chunk size' | |
chunk.chunksize = 23 | |
#DEBUG end | |
self._comptype = chunk.read(4) | |
#DEBUG start | |
if kludge: | |
length = ord(chunk.file.read(1)) | |
if length & 1 == 0: | |
length = length + 1 | |
chunk.chunksize = chunk.chunksize + length | |
chunk.file.seek(-1, 1) | |
#DEBUG end | |
self._compname = _read_string(chunk) | |
if self._comptype != 'NONE': | |
if self._comptype == 'G722': | |
try: | |
import audioop | |
except ImportError: | |
pass | |
else: | |
self._convert = self._adpcm2lin | |
self._framesize = self._framesize // 4 | |
return | |
# for ULAW and ALAW try Compression Library | |
try: | |
import cl | |
except ImportError: | |
if self._comptype == 'ULAW': | |
try: | |
import audioop | |
self._convert = self._ulaw2lin | |
self._framesize = self._framesize // 2 | |
return | |
except ImportError: | |
pass | |
raise Error, 'cannot read compressed AIFF-C files' | |
if self._comptype == 'ULAW': | |
scheme = cl.G711_ULAW | |
self._framesize = self._framesize // 2 | |
elif self._comptype == 'ALAW': | |
scheme = cl.G711_ALAW | |
self._framesize = self._framesize // 2 | |
else: | |
raise Error, 'unsupported compression type' | |
self._decomp = cl.OpenDecompressor(scheme) | |
self._convert = self._decomp_data | |
else: | |
self._comptype = 'NONE' | |
self._compname = 'not compressed' | |
def _readmark(self, chunk): | |
nmarkers = _read_short(chunk) | |
# Some files appear to contain invalid counts. | |
# Cope with this by testing for EOF. | |
try: | |
for i in range(nmarkers): | |
id = _read_short(chunk) | |
pos = _read_long(chunk) | |
name = _read_string(chunk) | |
if pos or name: | |
# some files appear to have | |
# dummy markers consisting of | |
# a position 0 and name '' | |
self._markers.append((id, pos, name)) | |
except EOFError: | |
print 'Warning: MARK chunk contains only', | |
print len(self._markers), | |
if len(self._markers) == 1: print 'marker', | |
else: print 'markers', | |
print 'instead of', nmarkers | |
class Aifc_write: | |
# Variables used in this class: | |
# | |
# These variables are user settable through appropriate methods | |
# of this class: | |
# _file -- the open file with methods write(), close(), tell(), seek() | |
# set through the __init__() method | |
# _comptype -- the AIFF-C compression type ('NONE' in AIFF) | |
# set through the setcomptype() or setparams() method | |
# _compname -- the human-readable AIFF-C compression type | |
# set through the setcomptype() or setparams() method | |
# _nchannels -- the number of audio channels | |
# set through the setnchannels() or setparams() method | |
# _sampwidth -- the number of bytes per audio sample | |
# set through the setsampwidth() or setparams() method | |
# _framerate -- the sampling frequency | |
# set through the setframerate() or setparams() method | |
# _nframes -- the number of audio frames written to the header | |
# set through the setnframes() or setparams() method | |
# _aifc -- whether we're writing an AIFF-C file or an AIFF file | |
# set through the aifc() method, reset through the | |
# aiff() method | |
# | |
# These variables are used internally only: | |
# _version -- the AIFF-C version number | |
# _comp -- the compressor from builtin module cl | |
# _nframeswritten -- the number of audio frames actually written | |
# _datalength -- the size of the audio samples written to the header | |
# _datawritten -- the size of the audio samples actually written | |
def __init__(self, f): | |
if type(f) == type(''): | |
filename = f | |
f = __builtin__.open(f, 'wb') | |
else: | |
# else, assume it is an open file object already | |
filename = '???' | |
self.initfp(f) | |
if filename[-5:] == '.aiff': | |
self._aifc = 0 | |
else: | |
self._aifc = 1 | |
def initfp(self, file): | |
self._file = file | |
self._version = _AIFC_version | |
self._comptype = 'NONE' | |
self._compname = 'not compressed' | |
self._comp = None | |
self._convert = None | |
self._nchannels = 0 | |
self._sampwidth = 0 | |
self._framerate = 0 | |
self._nframes = 0 | |
self._nframeswritten = 0 | |
self._datawritten = 0 | |
self._datalength = 0 | |
self._markers = [] | |
self._marklength = 0 | |
self._aifc = 1 # AIFF-C is default | |
def __del__(self): | |
if self._file: | |
self.close() | |
# | |
# User visible methods. | |
# | |
def aiff(self): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
self._aifc = 0 | |
def aifc(self): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
self._aifc = 1 | |
def setnchannels(self, nchannels): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
if nchannels < 1: | |
raise Error, 'bad # of channels' | |
self._nchannels = nchannels | |
def getnchannels(self): | |
if not self._nchannels: | |
raise Error, 'number of channels not set' | |
return self._nchannels | |
def setsampwidth(self, sampwidth): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
if sampwidth < 1 or sampwidth > 4: | |
raise Error, 'bad sample width' | |
self._sampwidth = sampwidth | |
def getsampwidth(self): | |
if not self._sampwidth: | |
raise Error, 'sample width not set' | |
return self._sampwidth | |
def setframerate(self, framerate): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
if framerate <= 0: | |
raise Error, 'bad frame rate' | |
self._framerate = framerate | |
def getframerate(self): | |
if not self._framerate: | |
raise Error, 'frame rate not set' | |
return self._framerate | |
def setnframes(self, nframes): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
self._nframes = nframes | |
def getnframes(self): | |
return self._nframeswritten | |
def setcomptype(self, comptype, compname): | |
if self._nframeswritten: | |
raise Error, 'cannot change parameters after starting to write' | |
if comptype not in ('NONE', 'ULAW', 'ALAW', 'G722'): | |
raise Error, 'unsupported compression type' | |
self._comptype = comptype | |
self._compname = compname | |
def getcomptype(self): | |
return self._comptype | |
def getcompname(self): | |
return self._compname | |
## def setversion(self, version): | |
## if self._nframeswritten: | |
## raise Error, 'cannot change parameters after starting to write' | |
## self._version = version | |
def setparams(self, info): | |
nchannels, sampwidth, framerate, nframes, comptype, compname = info | |
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 %r does not exist' % (id,) | |
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 | |
# Prevent ref cycles | |
self._convert = None | |
self._file.close() | |
# | |
# Internal methods. | |
# | |
def _comp_data(self, data): | |
import cl | |
dummy = self._comp.SetParam(cl.FRAME_BUFFER_SIZE, len(data)) | |
dummy = 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': | |
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." |