目的：实现在winfrom中，用代码实现截屏mp4视频，生成以时间为后缀的图片。

界面图如下：

界面图

截屏成功后，提示图

在代码操作前，先如下图操作：

操作图

1、将ffmpeg.exe这个控件放到根目录下，一般为WindowsFormsApplication名字\bin\Debug\ 下

2、此为截屏后生成的照片，暂不管（也可以代码自己修改保存路径）

3、此为需要被截屏的视频存放位置（也可以代码自己修改，视频读取路径）

下面为代码实现的操作：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.IO;

namespace WindowsFormsApplication9
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            readPic();
        }

        string cutTime = "";
        string PicPath0 = string.Format("{0}jietu.jpg", AppDomain.CurrentDomain.BaseDirectory);

        private void button1_Click(object sender, EventArgs e)
        {
            string name = string.Format("{0}测试.mp4", AppDomain.CurrentDomain.BaseDirectory);
       
            double time = axWindowsMediaPlayer1.Ctlcontrols.currentPosition;
            cutTime = time.ToString();
            if (time < 100 && time >= 10)
            {
                cutTime = string.Format("0{0}",time);
            }
            else if (time < 10)
            {
                cutTime = string.Format("00{0}", time);
            }

            string cutImagePath = GetPicFromVideo(name, cutTime);       
            if (File.Exists(cutImagePath))
            {
                MessageBox.Show(@"图片截取成功！");
            }
            else 
            {
                MessageBox.Show(@"图片截取失败！");
            }
        }

        private void readPic() 
        {
            string a = string.Format("{0}测试.mp4", AppDomain.CurrentDomain.BaseDirectory);
            axWindowsMediaPlayer1.URL = a;
            axWindowsMediaPlayer1.uiMode = "Full";
            int playState = (int)axWindowsMediaPlayer1.playState;
        }

        public string videoPath = string.Format("{0}测试.mp4", AppDomain.CurrentDomain.BaseDirectory);


        public string GetPicFromVideo(string VideoName, string CutTimeFrame)          
        {
            videoPath = get_uft8(videoPath);
            //string ffmpeg = "F:\ffmpeg.exe";
            string ffmpeg = string.Format("{0}ffmpeg.exe", AppDomain.CurrentDomain.BaseDirectory);
            string saveImgPath = System.IO.Path.ChangeExtension(PicPath0, "-" + cutTime.Replace(":", "：") + ".jpg");
            saveImgPath = get_uft8(saveImgPath);
            string saveImgSize = "852x480";
            //string saveImgSize = "3000x980";
            ProcessStartInfo startInfo = new ProcessStartInfo(ffmpeg);
            startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
            startInfo.Arguments = string.Format(" -i \"{0}\" -y -f image2 -ss {1} -t 0.001 -s \"{2}\" \"{3}\"", videoPath, cutTime, saveImgSize, saveImgPath);// string.Format(" -i \"{0}\" -y -f image2 -t 0.001 -s \"{1}\" \"{2}\"", vedioPath, saveImgSize, saveImgPath);
            //startInfo.Arguments = string.Format(" -ss {1} -i \"{0}\" -y -f image2 -t 0.001 \"{2}\"", videoPath, cutTime, saveImgPath);
            startInfo.CreateNoWindow = true;               

            startInfo.UseShellExecute = false;

            System.Diagnostics.Process p = new Process();
            p.StartInfo = startInfo;
            //p.StartInfo.FileName =ffmpeg;
            p.Start();
            p.WaitForExit();

            return saveImgPath;
            
        }

        public string get_uft8(string unicodeString)
        {
            UTF8Encoding utf8 = new UTF8Encoding();
            Byte[] encodedBytes = utf8.GetBytes(unicodeString);
            String decodedString = utf8.GetString(encodedBytes);
            return decodedString;
        }


    }
}

编译后，点击button就行了。