python-soundfile: Can't open FLAC file with read on macOS (get unimplemented format error)

Hi!

I got an issue when trying to open a FLAC file using the following simple code:

>>> import soundfile as sf
>>> data, sr = sf.read('test.flac')

That results in the following traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/anaconda3/envs/mqa/lib/python3.6/site-packages/soundfile.py", line 373, in read
    subtype, endian, format, closefd) as f:
  File "/usr/local/anaconda3/envs/mqa/lib/python3.6/site-packages/soundfile.py", line 740, in __init__
    self._file = self._open(file, mode_int, closefd)
  File "/usr/local/anaconda3/envs/mqa/lib/python3.6/site-packages/soundfile.py", line 1265, in _open
    "Error opening {0!r}: ".format(self.name))
  File "/usr/local/anaconda3/envs/mqa/lib/python3.6/site-packages/soundfile.py", line 1455, in _error_check
    raise RuntimeError(prefix + _ffi.string(err_str).decode('utf-8', 'replace'))
RuntimeError: Error opening '/Users/afuhrmann/Desktop/test.flac': File contains data in an unimplemented format.

The available formats don’t show FLAC:

>>> sf.available_formats()
{'AIFF': 'AIFF (Apple/SGI)', 'AU': 'AU (Sun/NeXT)', 'AVR': 'AVR (Audio Visual Research)', 'CAF': 'CAF (Apple Core Audio File)', 'HTK': 'HTK (HMM Tool Kit)', 'SVX': 'IFF (Amiga IFF/SVX8/SV16)', 'MAT4': 'MAT4 (GNU Octave 2.0 / Matlab 4.2)', 'MAT5': 'MAT5 (GNU Octave 2.1 / Matlab 5.0)', 'MPC2K': 'MPC (Akai MPC 2k)', 'PAF': 'PAF (Ensoniq PARIS)', 'PVF': 'PVF (Portable Voice Format)', 'RAW': 'RAW (header-less)', 'RF64': 'RF64 (RIFF 64)', 'SD2': 'SD2 (Sound Designer II)', 'SDS': 'SDS (Midi Sample Dump Standard)', 'IRCAM': 'SF (Berkeley/IRCAM/CARL)', 'VOC': 'VOC (Creative Labs)', 'W64': 'W64 (SoundFoundry WAVE 64)', 'WAV': 'WAV (Microsoft)', 'NIST': 'WAV (NIST Sphere)', 'WAVEX': 'WAVEX (Microsoft)', 'WVE': 'WVE (Psion Series 3)', 'XI': 'XI (FastTracker 2)'}

but the subformats with format flac does:

>>> sf.available_subtypes(format='FLAC')
{'PCM_S8': 'Signed 8 bit PCM', 'PCM_16': 'Signed 16 bit PCM', 'PCM_24': 'Signed 24 bit PCM'}

Also FLAC is in the supported formats in both soundfile.py and sndfile.h

    SF_FORMAT_FLAC          = 0x170000,     /* FLAC lossless file format */

Also, FLAC files can be played in macOS.

Does anyone know how to resolve that issue?

Thanks in advance