找个第三方的软件在视频上传后分析视频文件,将某帧截取出来.

http://www.codeplex.com/site/search?query=video&sortBy=Relevance&tagName=,video,&licenses=|&refinedSearch=true

/// <summary>
    /// 生成缩略图
    /// </summary>
    /// <param name="fileName">原文件</param>
    /// <param name="width">宽度</param>
    /// <param name="height">高度</param>
    private void CreateThumbnailImage(string fileName, string smallPath, int width, int height)
    {
        //版权信息
        string strAdd = "www.wander.com";
        //生成的缩略图的名字=年月日+文件大小(防止文件名相同)
        string newFileName = smallPath;

        System.Drawing.Image image, newImage;
        //载入原图像
        image = System.Drawing.Image.FromFile(Server.MapPath(fileName));
        //回调
        System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(callBack);
        //生成缩略图
        newImage = image.GetThumbnailImage(width, height, callb, new System.IntPtr());

        AddInfo(newImage, strAdd, newFileName, 16);

        image.Dispose();
        newImage.Dispose();

        Image1.ImageUrl = newFileName;
    }

    /// <summary>
    /// 添加版权信息
    /// </summary>
    /// <param name="image"></param>
    /// <param name="strAdd"></param>
    /// <param name="newFileName"></param>
    /// <param name="fontSize"></param>
    private void AddInfo(System.Drawing.Image image, string strAdd, string newFileName, int fontSize)
    {
        Response.Clear();
        Bitmap b = new Bitmap(image);
        Graphics g = Graphics.FromImage(b);
        g.DrawString(strAdd, new Font("宋体", fontSize), new SolidBrush(Color.Red), image.Width / 2 - 80, image.Height - 30);
        b.Save(Server.MapPath(newFileName), System.Drawing.Imaging.ImageFormat.Gif);
    }

    private bool callBack()
    {
        return true;
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        if (loadFile.PostedFile != null)
        {
            //判断是不是图像文件
            if (loadFile.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
            {
                //文件类型错误
            }
            else
            {
                string ext = loadFile.PostedFile.FileName.Substring(loadFile.PostedFile.FileName.LastIndexOf("."));
                //生成新的原文件名 年月日+文件大小+扩展名
                string path = "Uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + ext;
                //加上版权信息的文件
                string newPath = "Uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + "new" + ext;
                //缩略图文件名
                string newFileName = "uploads\\" + System.DateTime.Now.Date.ToShortDateString() + loadFile.PostedFile.ContentLength.ToString() + "small.gif";
                //上传原图
                loadFile.PostedFile.SaveAs(Server.MapPath(path));
                //生成缩略图
                CreateThumbnailImage(path, newFileName, 200, 300);

                //给原图加上版权信息
                System.Drawing.Image image = System.Drawing.Image.FromFile(Server.MapPath(path));
                AddInfo(image, "www.wander.com", newPath, 20);
                image.Dispose();
            }
        }

    }

看看这个写得还可以哈

转自：http://www.cnblogs.com/gengaixue/archive/2008/10/15/1311963.html