def pause(self, pause=0):
        """Insert a `pause`, in seconds."""
        fr = self.frames[-1]
        n = int(self.fps * pause)
        for i in range(n):
            fr2 = "/tmp/vpvid/" + str(len(self.frames)) + ".png"
            self.frames.append(fr2)
            os.system("cp -f %s %s" % (fr, fr2))
Insert a `pause`, in seconds.