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| """Stuff to parse WAVE files. | |
| Usage. | |
| Reading WAVE files: | |
| f = wave.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(). | |
| When the setpos() and rewind() methods are 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 linear samples) | |
| getcompname() -- returns human-readable version of | |
| compression type ('not compressed' linear samples) | |
| getparams() -- returns a namedtuple consisting of all of the | |
| above in the above order | |
| getmarkers() -- returns None (for compatibility with the | |
| aifc module) | |
| getmark(id) -- raises an error since the mark does not | |
| exist (for compatibility with the aifc module) | |
| 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() and the position given to setpos() | |
| are 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 WAVE files: | |
| f = wave.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: | |
| 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 | |
| tell() -- return current position in output file | |
| writeframesraw(data) | |
| -- write audio frames without patching 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(b'') or | |
| close() to patch up the sizes in the header. | |
| The close() method is called automatically when the class instance | |
| is destroyed. | |
| """ | |
| from chunk import Chunk | |
| from collections import namedtuple | |
| import audioop | |
| import builtins | |
| import struct | |
| import sys | |
| __all__ = ["open", "Error", "Wave_read", "Wave_write"] | |
| class Error(Exception): | |
| pass | |
| WAVE_FORMAT_PCM = 0x0001 | |
| _array_fmts = None, 'b', 'h', None, 'i' | |
| _wave_params = namedtuple('_wave_params', | |
| 'nchannels sampwidth framerate nframes comptype compname') | |
| class Wave_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 | |
| _soundpos -- the position in the audio stream | |
| available through the tell() method, set through the | |
| setpos() method | |
| These variables are used internally only: | |
| _fmt_chunk_read -- 1 iff the FMT chunk has been read | |
| _data_seek_needed -- 1 iff positioned correctly in audio | |
| file for readframes() | |
| _data_chunk -- instantiation of a chunk class for the DATA chunk | |
| _framesize -- size of one frame in the file | |
| """ | |
| def initfp(self, file): | |
| self._convert = None | |
| self._soundpos = 0 | |
| self._file = Chunk(file, bigendian = 0) | |
| if self._file.getname() != b'RIFF': | |
| raise Error('file does not start with RIFF id') | |
| if self._file.read(4) != b'WAVE': | |
| raise Error('not a WAVE file') | |
| self._fmt_chunk_read = 0 | |
| self._data_chunk = None | |
| while 1: | |
| self._data_seek_needed = 1 | |
| try: | |
| chunk = Chunk(self._file, bigendian = 0) | |
| except EOFError: | |
| break | |
| chunkname = chunk.getname() | |
| if chunkname == b'fmt ': | |
| self._read_fmt_chunk(chunk) | |
| self._fmt_chunk_read = 1 | |
| elif chunkname == b'data': | |
| if not self._fmt_chunk_read: | |
| raise Error('data chunk before fmt chunk') | |
| self._data_chunk = chunk | |
| self._nframes = chunk.chunksize // self._framesize | |
| self._data_seek_needed = 0 | |
| break | |
| chunk.skip() | |
| if not self._fmt_chunk_read or not self._data_chunk: | |
| raise Error('fmt chunk and/or data chunk missing') | |
| def __init__(self, f): | |
| self._i_opened_the_file = None | |
| if isinstance(f, str): | |
| f = builtins.open(f, 'rb') | |
| self._i_opened_the_file = f | |
| # else, assume it is an open file object already | |
| try: | |
| self.initfp(f) | |
| except: | |
| if self._i_opened_the_file: | |
| f.close() | |
| raise | |
| def __del__(self): | |
| self.close() | |
| def __enter__(self): | |
| return self | |
| def __exit__(self, *args): | |
| self.close() | |
| # | |
| # User visible methods. | |
| # | |
| def getfp(self): | |
| return self._file | |
| def rewind(self): | |
| self._data_seek_needed = 1 | |
| self._soundpos = 0 | |
| def close(self): | |
| self._file = None | |
| file = self._i_opened_the_file | |
| if file: | |
| self._i_opened_the_file = None | |
| 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 getparams(self): | |
| return _wave_params(self.getnchannels(), self.getsampwidth(), | |
| self.getframerate(), self.getnframes(), | |
| self.getcomptype(), self.getcompname()) | |
| def getmarkers(self): | |
| return None | |
| def getmark(self, id): | |
| raise Error('no marks') | |
| def setpos(self, pos): | |
| if pos < 0 or pos > self._nframes: | |
| raise Error('position not in range') | |
| self._soundpos = pos | |
| self._data_seek_needed = 1 | |
| def readframes(self, nframes): | |
| if self._data_seek_needed: | |
| self._data_chunk.seek(0, 0) | |
| pos = self._soundpos * self._framesize | |
| if pos: | |
| self._data_chunk.seek(pos, 0) | |
| self._data_seek_needed = 0 | |
| if nframes == 0: | |
| return b'' | |
| data = self._data_chunk.read(nframes * self._framesize) | |
| if self._sampwidth != 1 and sys.byteorder == 'big': | |
| data = audioop.byteswap(data, self._sampwidth) | |
| if self._convert and data: | |
| data = self._convert(data) | |
| self._soundpos = self._soundpos + len(data) // (self._nchannels * self._sampwidth) | |
| return data | |
| # | |
| # Internal methods. | |
| # | |
| def _read_fmt_chunk(self, chunk): | |
| try: | |
| wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign = struct.unpack_from('<HHLLH', chunk.read(14)) | |
| except struct.error: | |
| raise EOFError from None | |
| if wFormatTag == WAVE_FORMAT_PCM: | |
| try: | |
| sampwidth = struct.unpack_from('<H', chunk.read(2))[0] | |
| except struct.error: | |
| raise EOFError from None | |
| self._sampwidth = (sampwidth + 7) // 8 | |
| if not self._sampwidth: | |
| raise Error('bad sample width') | |
| else: | |
| raise Error('unknown format: %r' % (wFormatTag,)) | |
| if not self._nchannels: | |
| raise Error('bad # of channels') | |
| self._framesize = self._nchannels * self._sampwidth | |
| self._comptype = 'NONE' | |
| self._compname = 'not compressed' | |
| class Wave_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 | |
| These variables are used internally only: | |
| _datalength -- the size of the audio samples written to the header | |
| _nframeswritten -- the number of frames actually written | |
| _datawritten -- the size of the audio samples actually written | |
| """ | |
| def __init__(self, f): | |
| self._i_opened_the_file = None | |
| if isinstance(f, str): | |
| f = builtins.open(f, 'wb') | |
| self._i_opened_the_file = f | |
| try: | |
| self.initfp(f) | |
| except: | |
| if self._i_opened_the_file: | |
| f.close() | |
| raise | |
| def initfp(self, file): | |
| self._file = file | |
| 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._headerwritten = False | |
| def __del__(self): | |
| self.close() | |
| def __enter__(self): | |
| return self | |
| def __exit__(self, *args): | |
| self.close() | |
| # | |
| # User visible methods. | |
| # | |
| def setnchannels(self, nchannels): | |
| if self._datawritten: | |
| 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._datawritten: | |
| 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._datawritten: | |
| raise Error('cannot change parameters after starting to write') | |
| if framerate <= 0: | |
| raise Error('bad frame rate') | |
| self._framerate = int(round(framerate)) | |
| def getframerate(self): | |
| if not self._framerate: | |
| raise Error('frame rate not set') | |
| return self._framerate | |
| def setnframes(self, nframes): | |
| if self._datawritten: | |
| 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._datawritten: | |
| raise Error('cannot change parameters after starting to write') | |
| if comptype not in ('NONE',): | |
| raise Error('unsupported compression type') | |
| self._comptype = comptype | |
| self._compname = compname | |
| def getcomptype(self): | |
| return self._comptype | |
| def getcompname(self): | |
| return self._compname | |
| def setparams(self, params): | |
| nchannels, sampwidth, framerate, nframes, comptype, compname = params | |
| if self._datawritten: | |
| raise Error('cannot change parameters after starting to write') | |
| 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 _wave_params(self._nchannels, self._sampwidth, self._framerate, | |
| self._nframes, self._comptype, self._compname) | |
| def setmark(self, id, pos, name): | |
| raise Error('setmark() not supported') | |
| def getmark(self, id): | |
| raise Error('no marks') | |
| def getmarkers(self): | |
| return None | |
| def tell(self): | |
| return self._nframeswritten | |
| def writeframesraw(self, data): | |
| if not isinstance(data, (bytes, bytearray)): | |
| data = memoryview(data).cast('B') | |
| self._ensure_header_written(len(data)) | |
| nframes = len(data) // (self._sampwidth * self._nchannels) | |
| if self._convert: | |
| data = self._convert(data) | |
| if self._sampwidth != 1 and sys.byteorder == 'big': | |
| data = audioop.byteswap(data, self._sampwidth) | |
| self._file.write(data) | |
| self._datawritten += len(data) | |
| self._nframeswritten = self._nframeswritten + nframes | |
| def writeframes(self, data): | |
| self.writeframesraw(data) | |
| if self._datalength != self._datawritten: | |
| self._patchheader() | |
| def close(self): | |
| try: | |
| if self._file: | |
| self._ensure_header_written(0) | |
| if self._datalength != self._datawritten: | |
| self._patchheader() | |
| self._file.flush() | |
| finally: | |
| self._file = None | |
| file = self._i_opened_the_file | |
| if file: | |
| self._i_opened_the_file = None | |
| file.close() | |
| # | |
| # Internal methods. | |
| # | |
| def _ensure_header_written(self, datasize): | |
| if not self._headerwritten: | |
| 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 _write_header(self, initlength): | |
| assert not self._headerwritten | |
| self._file.write(b'RIFF') | |
| if not self._nframes: | |
| self._nframes = initlength // (self._nchannels * self._sampwidth) | |
| self._datalength = self._nframes * self._nchannels * self._sampwidth | |
| try: | |
| self._form_length_pos = self._file.tell() | |
| except (AttributeError, OSError): | |
| self._form_length_pos = None | |
| self._file.write(struct.pack('<L4s4sLHHLLHH4s', | |
| 36 + self._datalength, b'WAVE', b'fmt ', 16, | |
| WAVE_FORMAT_PCM, self._nchannels, self._framerate, | |
| self._nchannels * self._framerate * self._sampwidth, | |
| self._nchannels * self._sampwidth, | |
| self._sampwidth * 8, b'data')) | |
| if self._form_length_pos is not None: | |
| self._data_length_pos = self._file.tell() | |
| self._file.write(struct.pack('<L', self._datalength)) | |
| self._headerwritten = True | |
| def _patchheader(self): | |
| assert self._headerwritten | |
| if self._datawritten == self._datalength: | |
| return | |
| curpos = self._file.tell() | |
| self._file.seek(self._form_length_pos, 0) | |
| self._file.write(struct.pack('<L', 36 + self._datawritten)) | |
| self._file.seek(self._data_length_pos, 0) | |
| self._file.write(struct.pack('<L', self._datawritten)) | |
| self._file.seek(curpos, 0) | |
| self._datalength = self._datawritten | |
| 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 Wave_read(f) | |
| elif mode in ('w', 'wb'): | |
| return Wave_write(f) | |
| else: | |
| raise Error("mode must be 'r', 'rb', 'w', or 'wb'") |