def embed_album_art(cover_filepath, path):
  """ Embed album art into audio files. """
  with open(cover_filepath, "rb") as f:
    cover_data = f.read()

  for filename in os.listdir(path):
    try:
      ext = os.path.splitext(filename)[1][1:].lower()
    except IndexError:
      continue

    if ext in AUDIO_EXTENSIONS:
      filepath = os.path.join(path, filename)
      mf = mutagen.File(filepath)
      if (isinstance(mf.tags, mutagen._vorbis.VComment) or
              isinstance(mf, mutagen.ogg.OggFileType)):
        picture = mutagen.flac.Picture()
        picture.data = cover_data
        picture.type = mutagen.id3.PictureType.COVER_FRONT
        picture.mime = "image/jpeg"
        encoded_data = base64.b64encode(picture.write())
        mf["metadata_block_picture"] = encoded_data.decode("ascii")
      elif (isinstance(mf.tags, mutagen.id3.ID3) or
            isinstance(mf, mutagen.id3.ID3FileType)):
        mf.tags.add(mutagen.id3.APIC(mime="image/jpeg",
                                     type=mutagen.id3.PictureType.COVER_FRONT,
                                     data=cover_data))
      elif (isinstance(mf.tags, mutagen.mp4.MP4Tags) or
            isinstance(mf, mutagen.mp4.MP4)):
        mf["covr"] = [mutagen.mp4.MP4Cover(cover_data,
                                           imageformat=mutagen.mp4.AtomDataType.JPEG)]
      mf.save()
Embed album art into audio files.