Как разделить запись видео в заданную продолжительность

Question

То, что я делаю, - это запись экрана с помощью этого кода, который я нашел на GitHub, он использует AForge и работает нормально, но я ищу, как разделить запись видео по заранее заданной продолжительности при записи видео. ясность представьте, что мы хотим Запись видео сохраняется каждые 20 секунд, а следующие 20 секунд начинается запись в следующем видеофайле и так далее. заранее спасибо. вот ссылка на проект https://github.com/Amine-Smahi/JetScreenRecorder

    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Linq;
    using System.Threading;
    using System.Windows.Forms;
    using AForge.Video.FFMPEG;
    using AForge.Video;
    using System.Diagnostics;


    namespace JetScreenRecorder
    {
        public partial class Form1 : Form
        {
        private bool _isRecording;
        private List<string> _screenNames;
        //private Rectangle _screenSize;
        private UInt32 _frameCount;
        private VideoFileWriter _writer;
        private int _width;
        private int _height;
        private ScreenCaptureStream _streamVideo;
        private Stopwatch _stopWatch;
        private Rectangle _screenArea;


        public Form1()
        {
            InitializeComponent();

            CheckForIllegalCrossThreadCalls = false;
            this._isRecording = false;
            //this._screenSize = Screen.PrimaryScreen.Bounds;
            this._frameCount = 0;
            this._width = SystemInformation.VirtualScreen.Width;
            this._height = SystemInformation.VirtualScreen.Height;
            this._stopWatch = new Stopwatch();
            this._screenArea = Rectangle.Empty;

            this.bt_Save.Enabled = false;
            this._writer = new VideoFileWriter();

            _screenNames = new List<string>();
            _screenNames.Add(@"Select ALL");
            foreach (var screen in Screen.AllScreens)
            {
                _screenNames.Add(screen.DeviceName);
            }
            this.cb_screenSelector.DropDownStyle = ComboBoxStyle.DropDownList;
            this.cb_screenSelector.DataSource = _screenNames;

            // Codec ComboBox
            this.cb_VideoCodec.DataSource = Enum.GetValues(typeof(VideoCodec));
            this.cb_VideoCodec.DropDownStyle = ComboBoxStyle.DropDownList;

            // BitRate 2000kbit/s 2000000 1000000
            this.cb_BitRate.DataSource = Enum.GetValues(typeof(BitRate));
            this.cb_BitRate.DropDownStyle = ComboBoxStyle.DropDownList;
            this.cb_BitRate.SelectedIndex = 3;
            panel1.Visible = false;

        }

        private void bt_start_Click(object sender, EventArgs e)
        {
            try
            {
                if (this.tb_SaveFolder.Text.Length < 1)
                {
                    FolderBrowserDialog fbd = new FolderBrowserDialog();
                    if (fbd.ShowDialog() == DialogResult.OK)
                    {
                        this.StartRec(fbd.SelectedPath);
                    }
                }
                else
                {
                    this.StartRec(this.tb_SaveFolder.Text);
                }
                if (tb_SaveFolder.Text.Length == 0)
                {
                    panel1.Visible = false;
                }
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.Message);
            }
        }

        private void StartRec(string path)
        {
            if (_isRecording == false)
            {
                panel1.Visible = true;
                this.SetScreenArea();

                this.SetVisible(true);

                this._frameCount = 0;

                this.tb_SaveFolder.Text = path;
                string fullName = string.Format(@"{0}\{1}_{2}.avi", path, Environment.UserName.ToUpper(), DateTime.Now.ToString("d_MMM_yyyy_HH_mm_ssff"));

                // Save File option
                _writer.Open(
                    fullName,
                    this._width,
                    this._height,
                    (int)nud_FPS.Value,
                    (VideoCodec)cb_VideoCodec.SelectedValue,
                    (int)(BitRate)this.cb_BitRate.SelectedValue);

                // Start main work
                this.StartRecord();
            }
        }


        private void SetScreenArea()
        {
            // get entire desktop area size
            string screenName = this.cb_screenSelector.SelectedValue.ToString();
            if (string.Compare(screenName, @"Select ALL", StringComparison.OrdinalIgnoreCase) == 0)
            {
                foreach (Screen screen in Screen.AllScreens)
                {
                    this._screenArea = Rectangle.Union(_screenArea, screen.Bounds);
                }
            }
            else
            {
                this._screenArea = Screen.AllScreens.First(scr => scr.DeviceName.Equals(screenName)).Bounds;
                this._width = this._screenArea.Width;
                this._height = this._screenArea.Height;
            }
        }

        private void StartRecord() //Object stateInfo
        {
            // create screen capture video source
            this._streamVideo = new ScreenCaptureStream(this._screenArea);

            // set NewFrame event handler
            this._streamVideo.NewFrame += new NewFrameEventHandler(this.video_NewFrame);

            // start the video source
            this._streamVideo.Start();

            // _stopWatch
            this._stopWatch.Start();
        }

        private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            if (this._isRecording)
            {
                this._frameCount++;
                this._writer.WriteVideoFrame(eventArgs.Frame);

                this.lb_1.Invoke(new Action(() =>
              {
                  lb_1.Text = string.Format(@"Frames: {0}", _frameCount);
              }));

                this.lb_stopWatch.Invoke(new Action(() =>
              {
                  this.lb_stopWatch.Text = _stopWatch.Elapsed.ToString();
              }));
            }
            else
            {
                _stopWatch.Reset();
                Thread.Sleep(500);
                _streamVideo.SignalToStop();
                Thread.Sleep(500);
                _writer.Close();
            }
        }

        private void bt_Save_Click(object sender, EventArgs e)
        {
            panel1.Visible = false;
            this.SetVisible(false);
            MessageBox.Show(@"File saved!");
        }

        private void SetVisible(bool visible)
        {
            this.bt_start.Enabled = !visible;
            this.bt_Save.Enabled = visible;
            this._isRecording = visible;
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            this._isRecording = false;
        }

        private void bunifuImageButton2_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }

        private void bunifuImageButton1_Click(object sender, EventArgs e)
        {
            Close();
        }

    }

    public enum BitRate
    {
        _50kbit = 5000,
        _100kbit = 10000,
        _500kbit = 50000,
        _700kbit = 700000,
        _1000kbit = 1000000,
        _2000kbit = 2000000,
        _3000kbit = 3000000
    } 
}