'Check to see if a MovieWriter subclass is actually available by
running the commandline tool.'

@classmethod
def isAvailable(cls):

    bin_path = cls.bin_path()
    if (not bin_path):
        return False
    try:
        p = subprocess.Popen(bin_path, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE, creationflags=subprocess_creation_flags)
        return cls._handle_subprocess(p)
    except OSError:
        return False
