======================== unified (from filesystem) ========================
                                         'bitrate'  '128.0'
                                        'duration'  '135'
                                          'artist'  'The Belle of Chicago March'
                                     'text_people'  ''
                                         'release'  ''
                                           'title'  ''
                                           'quals'  ("['Q-HAP-3', 'Q-JZFKS-1', 'Q-LOCALNESS-1', 'Q-UNU-1', 'Q-HHRNBTT-1', "
 "'Q-OLDST-1', 'q-syn-1', 'q-bass-1', 'q-busy-2', 'q-grit-1', 'q-play-2', "
 "'q-chart-2', 'q-drums-3', 'q-other-4', 'q-piano-1', 'q-vocals-1', "
 "'q-mixbeat-1']")
                             'musicbrainz_albumid'  ''
                       'musicbrainz_albumartistid'  ''
                            'musicbrainz_artistid'  ''
                             'musicbrainz_trackid'  ''
                                     'tracknumber'  ''
                                      'tracktotal'  ''
                                            'date'  '1892'
                                        'comments'  ''
                                           'genre'  'prerock-unsorted'
                                             'bpm'  '123.3'
                                             'key'  '5B'
                                        'acoustid'  ''
rest: ''

======================== rawer (from filesystem) ========================

'TBPM' (BPM (beats per minute))                     '123.3'
'TCON' (Content type, a.k.a. Genre)                 'prerock-unsorted'
'TDRC' (Recording time)                             '1892'
'TKEY' (Initial key)                                '5B'
'TPE1' (Lead performer(s)/Soloist(s))               'The Belle of Chicago March'
'TXXX:Mp3gain_minmax'                               '099,208'
'TXXX:Mp3gain_undo'                                 '+002,+002,N'
'TXXX:Q-HAP'                                        '3'
'TXXX:Q-HHRNBTT'                                    '1'
'TXXX:Q-JZFKS'                                      '1'
'TXXX:Q-LOCALNESS'                                  '1'
'TXXX:Q-OLDST'                                      '1'
'TXXX:Q-UNU'                                        '1'
'TXXX:q-bass'                                       '1'
'TXXX:q-busy'                                       '2'
'TXXX:q-chart'                                      '2'
'TXXX:q-drums'                                      '3'
'TXXX:q-grit'                                       '1'
'TXXX:q-mixbeat'                                    '1'
'TXXX:q-other'                                      '4'
'TXXX:q-piano'                                      '1'
'TXXX:q-play'                                       '2'
'TXXX:q-syn'                                        '1'
'TXXX:q-vocals'                                     '1'
'TXXX:replaygain_track_gain'                        '+0.80 dB'
'TXXX:replaygain_track_peak'                        '0.724872'

========================== row from database ==========================
                                              'id'  513135
                                            'path'  /data/Music/Bulk/00exnnpjpsprgttidm/Wax Cylinder／very old recordings： 1878-1920 [wma／32k]/1892 - The Belle of Chicago March.mp3
                                         'working'  None
                                         'bitrate'  128
                                    'duration_sec'  135
                                           'genre'  prerock-unsorted
                                        'filesize'  2162678
                                           'mtime'  1621698444
                                   'redo_metaread'  0
                                        'rest_str'   00exnnpjpsprgttidm Wax Cylinder／very old recordings： 1878 1920 [wma／32k] 1892 prerock unsorted
                                      'tag_artist'  The Belle of Chicago March
                                     'tag_release'  None
                                       'tag_title'  None
                                             'bpm'  123.3
                                    'search_title'  None
                                   'search_artist'  'belle':2 'chicago':4 'march':5 'of':3 'the':1
                                  'search_release'  
                                     'search_rest'  '1878':11 '1892':20 '1920':12 '32k':14,16,18 'cylinder':2,4 'cylindervery':6 'old':7 'prerock':21 'recordings':8,9,10 'unsorted':22 'very':3,5 'wax':1 'wma':13,15,17 'wma32k':19
                                    'search_combo'  '1878':16 '1892':25 '1920':17 '32k':19,21,23 'belle':2B 'chicago':4B 'cylinder':7,9 'cylindervery':11 'march':5B 'of':3B 'old':12 'prerock':26 'recordings':13,14,15 'the':1B 'unsorted':27 'very':8,10 'wax':6 'wma':18,20,22 'wma32k':24
                                    'tag_tracknum'  None
                                      'num_images'  0
                                             'key'  5B
                                           'quals'  ['Q-HHRNBTT-1', 'q-vocals-1', 'Q-LOCALNESS-1', 'q-mixbeat-1', 'q-play-2', 'Q-OLDST-1', 'Q-UNU-1', 'Q-JZFKS-1', 'q-busy-2', 'q-drums-3', 'q-piano-1', 'q-syn-1', 'q-chart-2', 'q-other-4', 'Q-HAP-3', 'q-bass-1', 'q-grit-1']
                                      'lastfmtags'  []
                                        'tag_date'  1892
                                     'discogstags'  []

============================== file details ==============================
                                           'mtime'  1621698444.2336695  (2021-05-22 17:47:24)
                             'size'  2162678