add new audio properties to library/DB

$samplerate now expands to "##kHz" in path formats.

beets/library.py

@@ -68,6 +68,9 @@ ITEM_FIELDS = [
     ('length',      'real', False, True),
     ('bitrate',     'int',  False, True),
     ('format',      'text', False, True),
+    ('samplerate',  'int',  False, True),
+    ('bitdepth',    'int',  False, True),
+    ('channels',    'int',  False, True),
     ('mtime',       'int',  False, False),
 ]
 ITEM_KEYS_WRITABLE = [f[0] for f in ITEM_FIELDS if f[3] and f[2]]

beets/util/__init__.py

@@ -328,7 +328,10 @@ def sanitize_for_path(value, pathmod, key=None):
         value = u'%02i' % value
     elif key == 'bitrate':
         # Bitrate gets formatted as kbps.
-        value = u'%ikbps' % (value / 1000)
+        value = u'%ikbps' % ((value or 0) / 1000)
+    elif key == 'samplerate':
+        # Sample rate formatted as kHz.
+        value = u'%ikHz' % ((value or 0) / 1000)
     else:
         value = unicode(value)
     return value

docs/changelog.rst

@@ -6,6 +6,9 @@ Changelog
 
 * The :doc:`/plugins/lyrics`, originally by `Peter Brunner`_, is revamped and
   included with beets, making it easy to fetch **song lyrics**.
+* Items now expose their audio sample rate, number of channels, and bits per
+  sample (bitdepth). See :doc:`/reference/pathformat` for a list of all
+  available audio properties. Thanks to Andrew Dunn.
 * The autotagger now tolerates tracks on multi-disc albums that are numbered
   per-disc. For example, if track 24 on a release is the first track on the
   second disc, then it is not penalized for having its track number set to 1

docs/reference/pathformat.rst

@@ -139,9 +139,12 @@ Ordinary metadata:
 
 Audio information:
 
-* length
-* bitrate
-* format
+* length (in seconds)
+* bitrate (in kilobits per second, with units: e.g., "192kbps")
+* format (e.g., "MP3" or "FLAC")
+* channels
+* bitdepth (only available for some formats)
+* samplerate (in kilohertz, with units: e.g., "48kHz")
 
 MusicBrainz IDs:
 

test/test_db.py

@@ -348,6 +348,10 @@ class DestinationTest(unittest.TestCase):
         val = util.sanitize_for_path(12345, posixpath, 'bitrate')
         self.assertEqual(val, u'12kbps')
 
+    def test_component_sanitize_uses_khz_samplerate(self):
+        val = util.sanitize_for_path(12345, posixpath, 'samplerate')
+        self.assertEqual(val, u'12kHz')
+
     def test_artist_falls_back_to_albumartist(self):
         self.i.artist = ''
         self.i.albumartist = 'something'