Question

我有以下代码无效。如果我加载到Firefox并从我的摄像头流式传输，我的camUrl链接可以正常工作，但在运行时我的图片框中没有显示任何内容。有什么想法吗？

        public Thread _camThread;
        private string camUrl = "http://my-domain-ip:2080/videostream.cgi?user=admin&pwd=password";
        public HttpWebRequest webReq;
        public WebResponse webRes;
        public Stream sr;

        private void btnStart_Click(object sender, EventArgs e)
        {
            if (_camThread == null) _camThread = new Thread(new ThreadStart(RunCam));
            _camThread.Start();
        }

        private void RunCam()
        {
            try
            {
                webReq = (HttpWebRequest)WebRequest.Create(camUrl);
                webReq.AllowWriteStreamBuffering = true;
                webReq.Timeout = 20000;
                using (webRes = webReq.GetResponse())
                {
                    while ((sr = webRes.GetResponseStream()) != null)
                    {
                        image.Image = Image.FromStream(sr);
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            if (_camThread.IsAlive)
            {
                _camThread.Abort();
                _camThread = null;
            }
        }

Answer 1

看起来您从响应流中读取的循环不正确。您只能从响应中获取一个流，并且它上面会有多个图像。

您可能无法直接将响应流传递给Image.FromStream - 图像可能以多部分响应进行编码，该响应将图像与文本分隔符分开。您可以在RFC2046了解有关多部分回复格式的更多信息。

using (webRes = webReq.GetResponse())
{
    using (sr = webRes.GetResponseStream())
    {
        // continuously read images from the response stream until error
        while (true)
        {
            try
            {
                // note: the line below probably won't work, you may need to parse
                // the next image from the multi-part response stream manually
                image.Image = Image.FromStream(sr);


                // if the above doesn't work, then do something like this:
                // var imageBytes = ParseNextImage(sr);
                // var memoryStream = new MemoryStream(imageBytes);
                // image.Image = Image.FromStream(memoryStream);
            }
            catch(Exception e)
            {
                Console.WriteLine("Aborting read from response stream due to error {0}", e);
                break;
            }
        }
    }
}

Answer 2

camUrl是否会返回图片？

尝试调试sr = webRes.GetResponseStream()，如果它不为空，请尝试image.Invalidate()或image.Update()

More information about invalidate, update and refresh

来自IP cam C＃的流

2 个答案: