| """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_ushort(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_ushort(f, x): |
| f.write(struct.pack('>H', x)) |
| |
| def _write_long(f, x): |
| f.write(struct.pack('>l', x)) |
| |
| def _write_ulong(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(struct.pack('B', 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 or fmant != fmant: # 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_ushort(f, expon) |
| _write_ulong(f, himant) |
| _write_ulong(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): |
| if self._file is None: |
| return |
| try: |
| 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 |
| finally: |
| # Prevent ref cycles |
| self._convert = None |
| f = self._file |
| self._file = None |
| f.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_ulong(self._file, 4) |
| _write_ulong(self._file, self._version) |
| else: |
| self._file.write('AIFF') |
| self._file.write('COMM') |
| _write_ulong(self._file, commlength) |
| _write_short(self._file, self._nchannels) |
| self._nframes_pos = self._file.tell() |
| _write_ulong(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_ulong(self._file, self._datalength + 8) |
| _write_ulong(self._file, 0) |
| _write_ulong(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_ulong(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_ulong(self._file, self._nframeswritten) |
| self._file.seek(self._ssnd_length_pos, 0) |
| _write_ulong(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_ulong(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_ulong(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." |
