PM> Install-Package Spire.Presentation

using Spire.Presentation;
using Spire.Presentation.Drawing;
using System.Drawing;

namespace InsertVideoInPPT
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"Input.pptx");

            //Get the first slide
            ISlide slide = presentation.Slides[0];

            //Add description text
            RectangleF rec_title = new RectangleF(50, 280, 160, 50);
            IAutoShape shape_title = slide.Shapes.AppendShape(ShapeType.Rectangle, rec_title);
            shape_title.ShapeStyle.LineColor.Color = Color.Transparent;
            shape_title.Fill.FillType = FillFormatType.None;
            TextParagraph para_title = new TextParagraph();
            para_title.Text = "Video:";
            para_title.Alignment = TextAlignmentType.Center;
            para_title.TextRanges[0].LatinFont = new TextFont("Myriad Pro Light");
            para_title.TextRanges[0].FontHeight = 32;
            para_title.TextRanges[0].IsBold = TriState.True;
            para_title.TextRanges[0].Fill.FillType = FillFormatType.Solid;
            para_title.TextRanges[0].Fill.SolidColor.Color = Color.FromArgb(68, 68, 68);
            shape_title.TextFrame.Paragraphs.Append(para_title);
            
            //Add a video to the first slide
            RectangleF videoRect = new RectangleF(presentation.SlideSize.Size.Width / 2 - 125, 240, 240, 130);
            IVideo video = slide.Shapes.AppendVideoMedia("Video.mp4", videoRect);
            //Set a thumbnail image for the video
            video.PictureFill.Picture.Url = @"Picture.png";   

            //Save the result document
            presentation.SaveToFile("InsertVideo.pptx", FileFormat.Pptx2010);
        }
    }
}

Imports Spire.Presentation
Imports Spire.Presentation.Drawing
Imports System.Drawing

Namespace InsertVideoInPPT
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("Input.pptx")

            'Get the first slide
            Dim slide As ISlide = presentation.Slides(0)

            'Add description text
            Dim rec_title As RectangleF = New RectangleF(50, 280, 160, 50)
            Dim shape_title As IAutoShape = slide.Shapes.AppendShape(ShapeType.Rectangle, rec_title)
            shape_title.ShapeStyle.LineColor.Color = Color.Transparent
            shape_title.Fill.FillType = FillFormatType.None
            Dim para_title As TextParagraph = New TextParagraph()
            para_title.Text = "Video:"
            para_title.Alignment = TextAlignmentType.Center
            para_title.TextRanges(0).LatinFont = New TextFont("Myriad Pro Light")
            para_title.TextRanges(0).FontHeight = 32
            para_title.TextRanges(0).IsBold = TriState.[True]
            para_title.TextRanges(0).Fill.FillType = FillFormatType.Solid
            para_title.TextRanges(0).Fill.SolidColor.Color = Color.FromArgb(68, 68, 68)
            shape_title.TextFrame.Paragraphs.Append(para_title)

            'Add a video to the first slide
            Dim videoRect As RectangleF = New RectangleF(presentation.SlideSize.Size.Width / 2 - 125, 240, 240, 130)
            Dim video As IVideo = slide.Shapes.AppendVideoMedia("Video.mp4", videoRect)
            'Set a thumbnail image for the video
            video.PictureFill.Picture.Url = "Picture.png"

            'Save the result document
            presentation.SaveToFile("InsertVideo.pptx", FileFormat.Pptx2010)
        End Sub
    End Class
End Namespace

using Spire.Presentation;
using System.IO;

namespace ReplaceVideoInPPT
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation ppt = new Presentation();
            //Load a PowerPoint document
            ppt.LoadFromFile("InsertVideo.pptx");

            //Get the first slide
            ISlide slide = ppt.Slides[0];

            //Load a video into a byte array
            byte[] bts = File.ReadAllBytes(@"NewVideo.mp4");
            //Add the loaded video to the video collection of the document
            VideoData videoData = ppt.Videos.Append(bts);

            //Loop through all shapes on the first slide
            foreach (Shape shape in slide.Shapes)
            {
                //Check if the shape is of IVideo type
                if (shape is IVideo)
                {
                    //Typecast the shape as IVideo
                    IVideo video = shape as IVideo;                   
                    //Replace the original video with the loaded video
                    video.EmbeddedVideoData = videoData;
                    //Change the thumbnail image of the video
                    video.PictureFill.Picture.Url = @"Picture1.png";
                }
            }

            //Save the result document
            ppt.SaveToFile("ReplaceVideo.pptx", FileFormat.Pptx2010);
        }
    }
}

Imports Spire.Presentation
Imports System.IO

Namespace ReplaceVideoInPPT
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim ppt As Presentation = New Presentation()
            'Load a PowerPoint document
            ppt.LoadFromFile("InsertVideo.pptx")

            'Get the first slide
            Dim slide As ISlide = ppt.Slides(0)

            'Load a video into a byte array
            Dim bts = File.ReadAllBytes("NewVideo.mp4")
            'Add the loaded video to the video collection of the document
            Dim videoData As VideoData = ppt.Videos.Append(bts)

            'Loop through all shapes on the first slide
            For Each shape As Shape In slide.Shapes
                'Check if the shape is of IVideo type
                If TypeOf shape Is IVideo Then
                    'Typecast the shape as IVideo
                    Dim video As IVideo = TryCast(shape, IVideo)
                    'Replace the original video with the loaded video
                    video.EmbeddedVideoData = videoData
                    'Change the thumbnail image of the video
                    video.PictureFill.Picture.Url = "Picture1.png"
                End If
            Next

            'Save the result document
            ppt.SaveToFile("ReplaceVideo.pptx", FileFormat.Pptx2010)
        End Sub
    End Class
End Namespace

using Spire.Presentation;

namespace ExtractVideosInPPT
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"ReplaceVideo.pptx");

            int i = 0;
            //Specify the output file path
            string result = string.Format(@"Videos\Video{0}.mp4", i);
                
            //Loop through all slides in the document
            foreach (ISlide slide in presentation.Slides)
            {
                //Loop through all shapes on each slide
                foreach (IShape shape in slide.Shapes)
                {
                    //Check if the shape is of IVideo type
                    if (shape is IVideo)
                    {
                        //Save the video to the specified path
                        (shape as IVideo).EmbeddedVideoData.SaveToFile(result);
                        i++;
                    }
                }
            }
        }
    }
}

Imports Spire.Presentation

Namespace ExtractVideosInPPT
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("ReplaceVideo.pptx")

            Dim i = 0
           'Specify the output file path
           Dim result = String.Format("Videos\Video{0}.mp4", i)

            'Loop through all slides in the document
            For Each slide As ISlide In presentation.Slides
                'Loop through all shapes on each slide
                For Each shape As IShape In slide.Shapes
                    'Check if the shape is of IVideo type
                    If TypeOf shape Is IVideo Then
                        'Save the video to the specified path
                        TryCast(shape, IVideo).EmbeddedVideoData.SaveToFile(result)
                        i += 1
                    End If
                Next
            Next
        End Sub
    End Class
End Namespace