//初始化AK，SK
            string sACCESS_KEY = "七牛账号对应的AK";
            string sSECRET_KEY = "七牛账号对应的SK";

            string namekey = DateTime.Now.ToString("HHmmss")+".mp4";
            byte[] b = System.Text.Encoding.Default.GetBytes("watermark:" + namekey);//将水印视频放入 watermark存储空间
            String saveasURL = Convert.ToBase64String(b);  //保存到-目标空间下的文件

            string fops = "avthumb/mp4/wmText/Ymlhbw==/wmFontColor/cmVk/wmFontSize/30/wmGravityText/SouthEast|saveas/" + saveasURL; //执行命令，部分是字符base64
            string pipeline = "watermark_line";
            string notifyUrl = "http://www.test.com/demo/ui/ResultNotifyQiniuWM.aspx";//成功回调的URL
            string bucket = "znmlr"; //目标空间
            string key = "hello.mp4"; //文件名
            Mac mac = new Mac(sACCESS_KEY, sSECRET_KEY);
            Pfop px = new Pfop(mac);
            PfopResult result = px.pfop(bucket, key, fops, pipeline, notifyUrl, true);
            if (result.PersistentId == null) {
                string ss = result.Response;
            }

            Console.WriteLine(JsonConvert.SerializeObject(result));
            Console.ReadLine();