replaygain: Failure using audiotools backend with Python Audio Tools 3.1.1

[samuelnilsson]

Problem

Running this command in verbose (-vv) mode:

$ beet -vv replaygain --force

Led to this problem:

Sending event: library_opened
replaygain: analyzing Pink Floyd - The Wall - In the Flesh?
Traceback (most recent call last):
  File "/usr/bin/beet", line 11, in <module>
    load_entry_point('beets==1.5.0', 'console_scripts', 'beet')()
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beets/ui/__init__.py", line 1267, in main
    _raw_main(args)
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beets/ui/__init__.py", line 1254, in _raw_main
    subcommand.func(lib, suboptions, subargs)
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 1052, in func
    self.handle_track(item, write, force)
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 1003, in handle_track
    track_gains = backend_instance.compute_track_gain([item])
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 752, in compute_track_gain
    return [self._compute_track_gain(item) for item in items]
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 752, in <listcomp>
    return [self._compute_track_gain(item) for item in items]
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 781, in _compute_track_gain
    rg_track_gain, rg_track_peak = self._title_gain(rg, audiofile)
  File "/usr/lib/python3.7/site-packages/beets-1.5.0-py3.7.egg/beetsplug/replaygain.py", line 764, in _title_gain
    return rg.title_gain(audiofile.to_pcm())
  File "/usr/lib/python3.7/site-packages/audiotools/mp3.py", line 217, in to_pcm
    return MP3Decoder(self.filename)
TypeError: argument 1 must be str, not bytes

Setup

• OS: Arch Linux 5.1.2-arch1-1-ARCH
• Python version: 3.7.3
• beets version: 1.5.0 (master)
• Turning off plugins made problem go away (yes/no): no (this is a plugin related issue)

My configuration (output of beet config) is:

plugins: replaygain
replaygain:
    backend: audiotools
    overwrite: no
    auto: yes
    targetlevel: 89
    r128: [Opus]

[samuelnilsson]

Output from audiotools-config:

Default verbosity level : normal

extraction arguments
  Format Readable Writable Default Quality
  ────── ──────── ──────── ───────────────
    aiff      yes      yes
    alac      yes      yes
      au      yes      yes
    flac      yes      yes               8
     m4a      yes      yes             100
     mp2      yes      yes             192
     mp3      yes      yes               2
     ogg      yes      yes               3
    opus      yes      yes              10
     tta      yes      yes
     wav      yes      yes
      wv      yes      yes        standard

  Format : %(track_number)2.2d - %(track_name)s.%(suffix)s
  Default simultaneous jobs : 1
  Add ReplayGain by default : no

ID3 arguments
    ID3v2 tag version : ID3v2.3
  ID3v2 digit padding : not padded ("1", "2", …)
    ID3v1 tag version : ID3v1.1

CD lookup arguments
     Use MusicBrainz service : no
  Default MusicBrainz server : musicbrainz.org
    Default MusicBrainz port : 80

          Use FreeDB service : no
       Default FreeDB server : us.freedb.org
         Default FreeDB port : 80

system arguments
       Default CD-ROM device : /dev/cdrom
   CD-ROM sample read offset : 0
  CD-ROM sample write offset : 0
    Filesystem text encoding : utf-8
                Audio output : PulseAudio, ALSA, NULL

[sampsyo]

Thanks! Looks like another old library that (incorrectly, IMO) rejects bytestring paths. This is the situation for which we invented the py3_path function. I'll add that!