mutagen/wavpack.py

   1 # A WavPack reader/tagger
   2 #
   3 # Copyright 2006 Joe Wreschnig
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License version 2 as
   7 # published by the Free Software Foundation.
   8 #
   9 # $Id: wavpack.py 3997 2007-02-25 21:44:53Z piman $
  10
  11 """WavPack reading and writing.
  12
  13 WavPack is a lossless format that uses APEv2 tags. Read
  14 http://www.wavpack.com/ for more information.
  15 """
  16
  17 __all__ = ["WavPack", "Open", "delete"]
  18
  19 from mutagen.apev2 import APEv2File, error, delete
  20 from mutagen._util import cdata
  21
  22 class WavPackHeaderError(error): pass
  23
  24 RATES = [6000, 8000, 9600, 11025, 12000, 16000, 22050, 24000, 32000, 44100,
  25          48000, 64000, 88200, 96000, 192000]
  26
  27 class WavPackInfo(object):
  28     """WavPack stream information.
  29
  30     Attributes:
  31     channels - number of audio channels (1 or 2)
  32     length - file length in seconds, as a float
  33     sample_rate - audio sampling rate in Hz
  34     version - WavPack stream version
  35     """
  36
  37     def __init__(self, fileobj):
  38         header = fileobj.read(28)
  39         if len(header) != 28 or not header.startswith("wvpk"):
  40             raise WavPackHeaderError("not a WavPack file")
  41         samples = cdata.uint_le(header[12:16])
  42         flags = cdata.uint_le(header[24:28])
  43         self.version = cdata.short_le(header[8:10])
  44         self.channels = bool(flags & 4) or 2
  45         self.sample_rate = RATES[(flags >> 23) & 0xF]
  46         self.length = float(samples) / self.sample_rate
  47
  48     def pprint(self):
  49         return "WavPack, %.2f seconds, %d Hz" % (self.length, self.sample_rate)
  50
  51 class WavPack(APEv2File):
  52     _Info = WavPackInfo
  53     _mimes = ["audio/x-wavpack"]
  54
  55     def score(filename, fileobj, header):
  56         return header.startswith("wvpk") * 2
  57     score = staticmethod(score)