plugins/_mp3.py

   1 """
   2         Copyright 2005 Kenneth Hayber <ken@hayber.us>, All rights reserved.
   3
   4         This program is free software; you can redistribute it and/or modify
   5         it under the terms of the GNU General Public License as published by
   6         the Free Software Foundation; either version 2 of the License.
   7
   8         This program is distributed in the hope that it will be useful
   9         but WITHOUT ANY WARRANTY; without even the implied warranty of
  10         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11         GNU General Public License for more details.
  12
  13         You should have received a copy of the GNU General Public License
  14         along with this program; if not, write to the Free Software
  15         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16 """
  17
  18 try:
  19         import mad
  20         HAVE_MP3 = True
  21 except:
  22         HAVE_MP3 = False
  23         print 'No MP3 support!'
  24
  25 try:
  26         from pyid3lib import *
  27         HAVE_ID3V2 = True
  28 except:
  29         from ID3 import *
  30         HAVE_ID3V2 = False
  31         print 'No id3v2 support'
  32 import re
  33 import genres
  34 ID3V2_GENRE_RE = re.compile('\((?P<genre>\d+)\)')
  35
  36 def to_unicode(s, fallback_encoding='iso-8859-1'):
  37     try:
  38         return s.decode('utf-8')
  39     except UnicodeDecodeError:
  40         return s.decode(fallback_encoding, 'ignore')
  41
  42 def get_info(song):
  43         if HAVE_ID3V2:
  44                 tag_info = tag(song.filename)
  45         else: #ID3V1
  46                 try:
  47                         tag_info = ID3(song.filename)
  48                 except:
  49                         return
  50         val = None
  51         for key in ('title', 'track', 'album', 'artist', 'contenttype', 'genre'):
  52                 try:
  53                         if key == 'track':
  54                                 # it is a tuple (x of y)
  55                                 if HAVE_ID3V2:
  56                                         val = int(tag_info.track[0])
  57                                 else:
  58                                         val = tag_info.track
  59                         elif key == 'genre':
  60                                 val = tag_info.genre
  61                         else:
  62                                 val = to_unicode(getattr(tag_info, key))
  63                         if key == 'contenttype':
  64                                 key = 'genre'
  65                                 # ID3v2 genres are either a string/tuple index
  66                                 # e.g. '(17)' or the actual genre string.
  67                                 x = ID3V2_GENRE_RE.match(val)
  68                                 if x:
  69                                         val = int(x.group('genre'))
  70                         if key == 'genre' and isinstance(val, int):
  71                                 val = genres.genre_list[val]
  72                         if val != '':
  73                                 setattr(song, key, val)
  74                 except (AttributeError, IndexError):
  75                         pass
  76         # don't trust any length specs from a tag
  77         song.length = 0
  78
  79
  80 class MP3Decoder:
  81         def __init__(self, filename, buffersize):
  82                 """Initialize the decoder"""
  83                 self.buffersize = buffersize
  84                 self.filename = filename
  85
  86         def open(self):
  87                 """Open the file and prepare for decoding"""
  88                 self.mf = mad.MadFile(self.filename) #, self.buffersize)
  89
  90         def close(self):
  91                 """Close the file and do any needed cleanup"""
  92                 pass
  93
  94         def length(self):
  95                 """Return the length of the file in seconds as an integer"""
  96                 return self.mf.total_time()/1000
  97
  98         def samplerate(self):
  99                 """Return the sample rate of the file in samples per second"""
 100                 return self.mf.samplerate()
 101
 102         def channels(self):
 103                 """Return the number of channels in the file"""
 104                 if self.mf.mode() == mad.MODE_SINGLE_CHANNEL:
 105                         return 1
 106                 else:
 107                         return 2
 108
 109         def read(self):
 110                 """
 111                 Read data from the file and decode to PCM data. Return a buffer
 112                 of data and length, or (None, 0) at EOF
 113                 """
 114                 buff = self.mf.read()
 115                 if buff:
 116                         return (buff, len(buff))
 117                 else:
 118                         return (None, 0)
 119
 120         def tell(self):
 121                 """Return the current playback position in seconds"""
 122                 return self.mf.current_time() / 1000
 123
 124         def seek(self, pos):
 125                 """Jump to pos as a percentage of the total length of the file"""
 126                 self.mf.seek_time(long(self.length() * pos * 1000))
 127
 128         def info(self):
 129                 """Display some MP3 information"""
 130                 if self.mf.layer() == mad.LAYER_I:
 131                         print "MPEG Layer I"
 132                 elif self.mf.layer() == mad.LAYER_II:
 133                         print "MPEG Layer II"
 134                 elif self.mf.layer() == mad.LAYER_III:
 135                         print "MPEG Layer III"
 136                 else:
 137                         print "unexpected layer value"
 138
 139                 if self.mf.mode() == mad.MODE_SINGLE_CHANNEL:
 140                         print "single channel"
 141                 elif self.mf.mode() == mad.MODE_DUAL_CHANNEL:
 142                         print "dual channel"
 143                 elif self.mf.mode() == mad.MODE_JOINT_STEREO:
 144                         print "joint (MS/intensity) stereo"
 145                 elif self.mf.mode() == mad.MODE_STEREO:
 146                         print "normal L/R stereo"
 147                 else:
 148                         print "unexpected mode value"
 149
 150                 if self.mf.emphasis() == mad.EMPHASIS_NONE:
 151                         print "no emphasis"
 152                 elif self.mf.emphasis() == mad.EMPHASIS_50_15_US:
 153                         print "50/15us emphasis"
 154                 elif self.mf.emphasis() == mad.EMPHASIS_CCITT_J_17:
 155                         print "CCITT J.17 emphasis"
 156                 else:
 157                         print "unexpected emphasis value"
 158
 159                 print "bitrate %lu bps" % self.mf.bitrate()
 160                 print "samplerate %d Hz" % self.mf.samplerate()
 161                 millis = self.mf.total_time()
 162                 secs = millis / 1000
 163                 print "total time %d ms (%dm%2ds)" % (millis, secs / 60, secs % 60)
 164