subprocess in pydub.AudioSegment.from_file

inside_audio_segment_from_file.py

# https://github.com/jiaaro/pydub/blob/master/pydub/audio_segment.py

if filename:
    conversion_command += ["-i", filename]
    stdin_parameter = None # <------------------------------------------- Look at this line !!
    stdin_data = None
else:
    if cls.converter == 'ffmpeg':
        conversion_command += ["-read_ahead_limit", str(read_ahead_limit),
                               "-i", "cache:pipe:0"]
    else:
        conversion_command += ["-i", "-"]
    stdin_parameter = subprocess.PIPE
    stdin_data = file.read()

...

p = subprocess.Popen(conversion_command, stdin=stdin_parameter, # <------- Yeah! stdin is None
                     stdout=subprocess.PIPE, stderr=subprocess.PIPE)
p_out, p_err = p.communicate(input=stdin_data)