修改probe文件  p = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, encoding='gbk')

当我用cmd调用ffprobe的时候完全没问题，

但是切换subprocess.Popen就一直报错

当把源码里面加入输出字符格式

然后打印，发现真正的报错是ffprobe不是一个可运行的程序，也就是环境变量识别失败

然后我去查看环境变量，发现并没有配置错误

然后我就思考会不会是subprocess.Popen本身存在问题，

果不其然，，，，当我用subprocess.Popen答应set命令，发现环境变量没有ffprobe的

然后我重启电脑后，再次使用subprocess.Popen，就好了，打印出来了

subprocess.Popen读取的上一次用户注销前的环境变量，，，，

话说这是windows，，总之重启之后就解决了

def probe(filename, cmd='ffprobe', **kwargs):
    """Run ffprobe on the specified file and return a JSON representation of the output.

    Raises:
        :class:`ffmpeg.Error`: if ffprobe returns a non-zero exit code,
            an :class:`Error` is returned with a generic error message.
            The stderr output can be retrieved by accessing the
            ``stderr`` property of the exception.
    """
    args = [cmd, '-show_format', '-show_streams', '-of', 'json']
    args += convert_kwargs_to_cmd_line_args(kwargs)
    args += [filename]

    p = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, encoding='gbk')
    print(args)
    out, err = p.communicate()
    print(out)
    print(p.returncode)
    if p.returncode != 0:
        raise Error(cmd, out, err)
    return json.loads(out.decode('utf-8'))