diff options
Diffstat (limited to 'Lib/aifc.py')
| -rw-r--r-- | Lib/aifc.py | 145 |
1 files changed, 98 insertions, 47 deletions
diff --git a/Lib/aifc.py b/Lib/aifc.py index 2d897be..ee1f8f0 100644 --- a/Lib/aifc.py +++ b/Lib/aifc.py @@ -40,7 +40,7 @@ # <size of the samples> (2 bytes) # <sampling frequency> (10 bytes, IEEE 80-bit extended # floating point) -# if AIFF-C files only: +# in AIFF-C files only: # <compression type> (4 bytes) # <human-readable version of compression type> ("pstring") # SSND @@ -58,9 +58,9 @@ # or # f = aifc.openfp(filep, 'r') # where file is the name of a file and filep is 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. +# 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 @@ -85,6 +85,8 @@ # 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') @@ -122,11 +124,13 @@ # 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 the write audio frames using writeframesraw. +# 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 @@ -347,7 +351,7 @@ class Aifc_read: # methods # _soundpos -- the position in the audio stream # available through the tell() method, set through the - # tell() method + # setpos() method # # These variables are used internally only: # _version -- the AIFF-C version number @@ -362,6 +366,7 @@ class Aifc_read: self._file = file self._version = 0 self._decomp = None + self._convert = None self._markers = [] self._soundpos = 0 form = self._file.read(4) @@ -433,6 +438,10 @@ class Aifc_read: def init(self, filename): return self.initfp(builtin.open(filename, 'r')) + def __del__(self): + if self._file: + self.close() + # # User visible methods. # @@ -475,8 +484,9 @@ class Aifc_read: ## return self._version def getparams(self): - return self._nchannels, self._sampwidth, self._framerate, \ - self._nframes, self._comptype, self._compname + return self.getnchannels(), self.getsampwidth(), \ + self.getframerate(), self.getnframes(), \ + self.getcomptype(), self.getcompname() def getmarkers(self): if len(self._markers) == 0: @@ -506,16 +516,24 @@ class Aifc_read: if nframes == 0: return '' data = self._ssnd_chunk.read(nframes * self._framesize) - if self._decomp and data: - dummy = self._decomp.SetParam(CL.FRAME_BUFFER_SIZE, \ - len(data) * 2) - data = self._decomp.Decompress(len(data) / self._nchannels, data) + 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): + 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): nchannels = _read_short(chunk) self._nchannels = _convert1(nchannels, _nchannelslist) @@ -547,6 +565,14 @@ class Aifc_read: try: import cl, 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 @@ -557,6 +583,7 @@ class Aifc_read: else: raise Error, 'unsupported compression type' self._decomp = cl.OpenDecompressor(scheme) + self._convert = self._decomp_data else: self._comptype = 'NONE' self._compname = 'not compressed' @@ -622,6 +649,7 @@ class Aifc_write: self._comptype = 'NONE' self._compname = 'not compressed' self._comp = None + self._convert = None self._nchannels = 0 self._sampwidth = 0 self._framerate = 0 @@ -634,6 +662,10 @@ class Aifc_write: self._aifc = 1 # AIFF-C is default return self + def __del__(self): + if self._file: + self.close() + # # User visible methods. # @@ -752,15 +784,14 @@ class Aifc_write: 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._comp: - dummy = self._comp.SetParam(CL.FRAME_BUFFER_SIZE, \ - len(data)) - dummy = self._comp.SetParam(CL.COMPRESSED_BUFFER_SIZE,\ - len(data)) - data = self._comp.Compress(nframes, data) + if self._convert: + data = self._convert(data) self._file.write(data) self._nframeswritten = self._nframeswritten + nframes self._datawritten = self._datawritten + len(data) @@ -791,6 +822,15 @@ class Aifc_write: # # Internal methods. # + 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): if not self._nframeswritten: if self._comptype in ('ULAW', 'ALAW'): @@ -806,37 +846,48 @@ class Aifc_write: raise Error, 'sampling rate not specified' self._write_header(datasize) + def _init_compression(self): + try: + import cl, 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, 0, \ + CL.FRAME_RATE, self._framerate, \ + CL.FRAME_BUFFER_SIZE, 100, \ + CL.COMPRESSED_BUFFER_SIZE, 100] + 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) + # 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': - 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, \ - CL.FRAME_BUFFER_SIZE, 100, \ - CL.COMPRESSED_BUFFER_SIZE, 100] - 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) - # the compressor produces a header which we ignore - dummy = self._comp.Compress(0, '') + self._init_compression() self._file.write('FORM') if not self._nframes: self._nframes = initlength / (self._nchannels * self._sampwidth) |