| # 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 postion 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(nchannels, sampwidth, framerate, nframes, comptype, compname) |
| #-- set all parameters at once |
| #setmark(id, pos, name) |
| #-- add specified mark to the list of marks |
| #tell()-- return current position in output file (useful |
| # in combination with setmark()) |
| #writeframesraw(data) |
| #-- write audio frames without pathing up the |
| # file header |
| #writeframes(data) |
| #-- write audio frames and patch up the file header |
| #close()-- patch up the file header and close the |
| # output file |
| # You should set the parameters before the first writeframesraw or |
| # writeframes. The total number of frames does not need to be set, |
| # but when it is set to the correct value, the header does not have to |
| # be patched up. |
| # It is best to first set all parameters, perhaps possibly the |
| # compression type, and 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 __builtin__ |
| try: |
| import CL |
| exceptImportError: |
| pass |
| |
| Error='aifc.Error' |
| |
| _AIFC_version=0xA2805140# Version 1 of AIFF-C |
| |
| _skiplist='COMT','INST','MIDI','AESD', \ |
| 'APPL','NAME','AUTH','(c) ','ANNO' |
| |
| def _read_long(file): |
| x=0L |
| for iin range(4): |
| byte= file.read(1) |
| if byte=='': |
| raiseEOFError |
| x= x*256+ ord(byte) |
| if x>=0x80000000L: |
| x= x-0x100000000L |
| return int(x) |
| |
| def _read_ulong(file): |
| x=0L |
| for iin range(4): |
| byte= file.read(1) |
| if byte=='': |
| raiseEOFError |
| x= x*256+ ord(byte) |
| return x |
| |
| def _read_short(file): |
| x=0 |
| for iin range(2): |
| byte= file.read(1) |
| if byte=='': |
| raiseEOFError |
| x= x*256+ ord(byte) |
| if x>=0x8000: |
| x= x-0x10000 |
| return x |
| |
| def _read_string(file): |
| length= ord(file.read(1)) |
| data= file.read(length) |
| if length&1==0: |
| dummy= file.read(1) |
| return data |
| |
| _HUGE_VAL=1.79769313486231e+308# See <limits.h> |
| |
| def _read_float(f):# 10 bytes |
| import math |
| expon= _read_short(f)# 2 bytes |
| sign=1 |
| if expon<0: |
| sign=-1 |
| expon= expon+0x8000 |
| himant= _read_ulong(f)# 4 bytes |
| lomant= _read_ulong(f)# 4 bytes |
| if expon== himant== lomant==0: |
| f=0.0 |
| elif expon==0x7FFF: |
| f= _HUGE_VAL |
| else: |
| expon= expon-16383 |
| f=(himant*0x100000000L+ lomant)* pow(2.0, expon-63) |
| return sign* f |
| |
| def _write_short(f, x): |
| d, m= divmod(x,256) |
| f.write(chr(d)) |
| f.write(chr(m)) |
| |
| def _write_long(f, x): |
| if x<0: |
| x= x+0x100000000L |
| data=[] |
| for iin range(4): |
| d, m= divmod(x,256) |
| data.insert(0, m) |
| x= d |
| for iin range(4): |
| f.write(chr(int(data[i]))) |
| |
| def _write_string(f, s): |
| f.write(chr(len(s))) |
| f.write(s) |
| if len(s)&1==0: |
| f.write(chr(0)) |
| |
| def _write_float(f, x): |
| import math |
| if x<0: |
| sign=0x8000 |
| x= x*-1 |
| else: |
| sign=0 |
| if x==0: |
| expon=0 |
| himant=0 |
| lomant=0 |
| else: |
| fmant, expon= math.frexp(x) |
| if expon>16384or 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) |
| |
| classChunk: |
| def __init__(self, file): |
| self.file= file |
| self.chunkname= self.file.read(4) |
| if len(self.chunkname)<4: |
| raiseEOFError |
| self.chunksize= _read_long(self.file) |
| self.size_read=0 |
| self.offset= self.file.tell() |
| |
| def rewind(self): |
| self.file.seek(self.offset,0) |
| self.size_read=0 |
| |
| def setpos(self, pos): |
| if pos<0or pos> self.chunksize: |
| raiseRuntimeError |
| self.file.seek(self.offset+ pos,0) |
| self.size_read= pos |
| |
| def read(self, length): |
| if self.size_read>= self.chunksize: |
| return'' |
| if length> self.chunksize- self.size_read: |
| length= self.chunksize- self.size_read |
| data= self.file.read(length) |
| self.size_read= self.size_read+ len(data) |
| return data |
| |
| def skip(self): |
| try: |
| self.file.seek(self.chunksize- self.size_read,1) |
| exceptRuntimeError: |
| while self.size_read< self.chunksize: |
| dummy= self.read(8192) |
| ifnot dummy: |
| raiseEOFError |
| if self.chunksize&1: |
| dummy= self.read(1) |
| |
| classAifc_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 |
| |
| access _file, _nchannels, _nframes, _sampwidth, _framerate, \ |
| _comptype, _compname, _markers, _soundpos, _version, \ |
| _decomp, _comm_chunk_read, __aifc, _ssnd_seek_needed, \ |
| _ssnd_chunk, _framesize: private |
| |
| def initfp(self, file): |
| self._file= file |
| self._version=0 |
| self._decomp=None |
| self._convert=None |
| self._markers=[] |
| self._soundpos=0 |
| form= self._file.read(4) |
| if form!='FORM': |
| raiseError,'file does not start with FORM id' |
| formlength= _read_long(self._file) |
| if formlength<=0: |
| raiseError,'invalid FORM chunk data size' |
| formdata= self._file.read(4) |
| formlength= formlength-4 |
| if formdata=='AIFF': |
| self._aifc=0 |
| elif formdata=='AIFC': |
| self._aifc=1 |
| else: |
| raiseError,'not an AIFF or AIFF-C file' |
| self._comm_chunk_read=0 |
| while formlength>0: |
| self._ssnd_seek_needed=1 |
| #DEBUG: SGI's soundfiler has a bug. There should |
| # be no need to check for EOF here. |
| try: |
| chunk=Chunk(self._file) |
| exceptEOFError: |
| if formlength==8: |
| print'Warning: FORM chunk size too large' |
| formlength=0 |
| break |
| raiseEOFError# different error, raise exception |
| if chunk.chunkname=='COMM': |
| self._read_comm_chunk(chunk) |
| self._comm_chunk_read=1 |
| elif chunk.chunkname=='SSND': |
| self._ssnd_chunk= chunk |
| dummy= chunk.read(8) |
| self._ssnd_seek_needed=0 |
| elif chunk.chunkname=='FVER': |
| self._version= _read_long(chunk) |
| elif chunk.chunkname=='MARK': |
| self._readmark(chunk) |
| elif chunk.chunknamein _skiplist: |
| pass |
| else: |
| raiseError,'unrecognized chunk type '+chunk.chunkname |
| formlength= formlength-8- chunk.chunksize |
| if chunk.chunksize&1: |
| formlength= formlength-1 |
| if formlength>0: |
| chunk.skip() |
| ifnot self._comm_chunk_readornot self._ssnd_chunk: |
| raiseError,'COMM chunk and/or SSND chunk missing' |
| if self._aifcand self._decomp: |
| 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: |
| raiseError,'cannot compress more than 2 channels' |
| self._decomp.SetParams(params) |
| |
| def __init__(self, f): |
| if type(f)== type(''): |
| f= __builtin__.open(f,'r') |
| # else, assume it is an open file object already |
| self.initfp(f) |
| |
| def __del__(self): |
| if self._file: |
| self.close() |
| |
| # |
| # 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=None |
| |
| def tell(self): |
| return self._soundpos |
| |
| def getnchannels(self): |
| return self._nchannels |
| |
| def getnframes(self): |
| return self._nframes |
| |
| def getsampwidth(self): |
| return self._sampwidth |
| |
| def getframerate(self): |
| return self._framerate |
| |
| def getcomptype(self): |
| return self._comptype |
| |
| def getcompname(self): |
| return self._compname |
| |
| ##def getversion(self): |
| ##return self._version |
| |
| def getparams(self): |
| return self.getnchannels(), self.getsampwidth(), \ |
| self.getframerate(), self.getnframes(), \ |
| self.getcomptype(), self.getcompname() |
| |
| def getmarkers(self): |
| if len(self._markers)==0: |
| returnNone |
| return self._markers |
| |
| def getmark(self, id): |
| for markerin self._markers: |
| if id== marker[0]: |
| return marker |
| raiseError,'marker '+`id`+' does not exist' |
| |
| def setpos(self, pos): |
| if pos<0or pos> self._nframes: |
| raiseError,'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._framesize |
| if pos: |
| self._ssnd_chunk.setpos(pos+8) |
| self._ssnd_seek_needed=0 |
| if nframes==0: |
| return'' |
| data= self._ssnd_chunk.read(nframes* self._framesize) |
| if self._convertand data: |
| data= self._convert(data) |
| self._soundpos= self._soundpos+ len(data)/(self._nchannels* self._sampwidth) |
| return data |
| |
| # |
| # Internal methods. |
| # |
| access*: private |
| |
| def _decomp_data(self, data): |
| 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 _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': |
| try: |
| import cl, CL |
| exceptImportError: |
| if self._comptype=='ULAW': |
| try: |
| import audioop |
| self._convert= self._ulaw2lin |
| self._framesize= self._framesize/2 |
| return |
| exceptImportError: |
| pass |
| raiseError,'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: |
| raiseError,'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 iin range(nmarkers): |
| id= _read_short(chunk) |
| pos= _read_long(chunk) |
| name= _read_string(chunk) |
| self._markers.append((id, pos, name)) |
| exceptEOFError: |
| print'Warning: MARK chunk contains only', |
| print len(self._markers), |
| if len(self._markers)==1:print'marker', |
| else:print'markers', |
| print'instead of', nmarkers |
| |
| classAifc_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 |
| |
| access _file, _comptype, _compname, _nchannels, _sampwidth, \ |
| _framerate, _nframes, _aifc, _version, _comp, \ |
| _nframeswritten, _datalength, _datawritten: private |
| |
| def __init__(self, f): |
| if type(f)== type(''): |
| filename= f |
| f= __builtin__.open(f,'w') |
| 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: |
| raiseError,'cannot change parameters after starting to write' |
| self._aifc=0 |
| |
| def aifc(self): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| self._aifc=1 |
| |
| def setnchannels(self, nchannels): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| if nchannels<1: |
| raiseError,'bad # of channels' |
| self._nchannels= nchannels |
| |
| def getnchannels(self): |
| ifnot self._nchannels: |
| raiseError,'number of channels not set' |
| return self._nchannels |
| |
| def setsampwidth(self, sampwidth): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| if sampwidth<1or sampwidth>4: |
| raiseError,'bad sample width' |
| self._sampwidth= sampwidth |
| |
| def getsampwidth(self): |
| ifnot self._sampwidth: |
| raiseError,'sample width not set' |
| return self._sampwidth |
| |
| def setframerate(self, framerate): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| if framerate<=0: |
| raiseError,'bad frame rate' |
| self._framerate= framerate |
| |
| def getframerate(self): |
| ifnot self._framerate: |
| raiseError,'frame rate not set' |
| return self._framerate |
| |
| def setnframes(self, nframes): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| self._nframes= nframes |
| |
| def getnframes(self): |
| return self._nframeswritten |
| |
| def setcomptype(self, comptype, compname): |
| if self._nframeswritten: |
| raiseError,'cannot change parameters after starting to write' |
| if comptypenotin('NONE','ULAW','ALAW'): |
| raiseError,'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: |
| raiseError,'cannot change parameters after starting to write' |
| if comptypenotin('NONE','ULAW','ALAW'): |
| raiseError,'unsupported compression type' |
| self.setnchannels(nchannels) |
| self.setsampwidth(sampwidth) |
| self.setframerate(framerate) |
| self.setnframes(nframes) |
| self.setcomptype(comptype, compname) |
| |
| def getparams(self): |
| ifnot self._nchannelsornot self._sampwidthornot self._framerate: |
| raiseError,'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: |
| raiseError,'marker ID must be > 0' |
| if pos<0: |
| raiseError,'marker position must be >= 0' |
| if type(name)!= type(''): |
| raiseError,'marker name must be a string' |
| for iin 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 markerin self._markers: |
| if id== marker[0]: |
| return marker |
| raiseError,'marker '+`id`+' does not exist' |
| |
| def getmarkers(self): |
| if len(self._markers)==0: |
| returnNone |
| 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._nframesor \ |
| 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._nframesor \ |
| self._datalength!= self._datawrittenor \ |
| self._marklength: |
| self._patchheader() |
| if self._comp: |
| self._comp.CloseCompressor() |
| self._comp=None |
| self._file.flush() |
| self._file=None |
| |
| # |
| # Internal methods. |
| # |
| access*: private |
| |
| def _comp_data(self, data): |
| dum= self._comp.SetParam(CL.FRAME_BUFFER_SIZE, len(data)) |
| dum= self._comp.SetParam(CL.COMPRESSED_BUFFER_SIZE, len(data)) |
| return self._comp.Compress(nframes, data) |
| |
| def _lin2ulaw(self, data): |
| import audioop |
| return audioop.lin2ulaw(data,2) |
| |
| def _ensure_header_written(self, datasize): |
| ifnot self._nframeswritten: |
| if self._comptypein('ULAW','ALAW'): |
| ifnot self._sampwidth: |
| self._sampwidth=2 |
| if self._sampwidth!=2: |
| raiseError,'sample width must be 2 when compressing with ULAW or ALAW' |
| ifnot self._nchannels: |
| raiseError,'# channels not specified' |
| ifnot self._sampwidth: |
| raiseError,'sample width not specified' |
| ifnot self._framerate: |
| raiseError,'sampling rate not specified' |
| self._write_header(datasize) |
| |
| def _init_compression(self): |
| try: |
| import cl, CL |
| exceptImportError: |
| if self._comptype=='ULAW': |
| try: |
| import audioop |
| self._convert= self._lin2ulaw |
| return |
| exceptImportError: |
| pass |
| raiseError,'cannot write compressed AIFF-C files' |
| if self._comptype=='ULAW': |
| scheme= CL.G711_ULAW |
| elif self._comptype=='ALAW': |
| scheme= CL.G711_ALAW |
| else: |
| raiseError,'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: |
| raiseError,'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._aifcand self._comptype!='NONE': |
| self._init_compression() |
| self._file.write('FORM') |
| ifnot 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._aifcand self._comptypein('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, 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._datalengthand \ |
| self._nframes== self._nframeswrittenand \ |
| 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 markerin 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 markerin 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): |
| if mode=='r': |
| returnAifc_read(f) |
| elif mode=='w': |
| returnAifc_write(f) |
| else: |
| raiseError,"mode must be 'r' or 'w'" |
| |
| openfp= open# B/W compatibility |
