Manage Video Frames in Presentations in .NET

Introduction

A well-placed video in a presentation can make your message more compelling and increase engagement levels with your audience.

PowerPoint allows you to add videos to a slide in a presentation in two ways:

  • Add or embed a local video (stored on your machine)
  • Add an online video (from a web source such as YouTube).

To allow you to add videos (video objects) to a presentation, Aspose.Slides provides the IVideo interface, IVideoFrame interface, and other relevant types.

Create an Embedded Video Frame

If the video file you want to add to your slide is stored locally, you can create a video frame to embed the video in your presentation.

  1. Create an instance of the Presentation class.
  2. Get a slide’s reference through its index.
  3. Add an IVideo object and pass the video file path to embed the video with the presentation.
  4. Add an IVideoFrame object to create a frame for the video.
  5. Save the modified presentation.

This C# code shows you how to add a video stored locally to a presentation:

// Instantiates the Presentation class
using (Presentation pres = new Presentation("pres.pptx"))
{
    // Loads the video
    using (FileStream fileStream = new FileStream("Wildlife.mp4", FileMode.Open, FileAccess.Read))
    {
        IVideo video = pres.Videos.AddVideo(fileStream, LoadingStreamBehavior.KeepLocked);
        
        // Gets the first slide and adds a videoframe
        pres.Slides[0].Shapes.AddVideoFrame(10, 10, 150, 250, video);
        
        // Saves the presentation to disk
        pres.Save("pres-with-video.pptx", SaveFormat.Pptx);
    }
}

Alternatively, you can add a video by passing its file path directly to the AddVideoFrame method:

using (Presentation pres = new Presentation())
{
    ISlide sld = pres.Slides[0];
    IVideoFrame vf = sld.Shapes.AddVideoFrame(50, 150, 300, 150, "video1.avi");
}

Create a Video Frame with Video from a Web Source

Microsoft PowerPoint 2013 and newer support YouTube videos in presentations. If the video you want to use is available online (e.g. on YouTube), you can add it to your presentation through its web link.

  1. Create an instance of Presentation class
  2. Get a slide’s reference through its index.
  3. Add an IVideo object and pass the link to the video.
  4. Set a thumbnail for the video frame.
  5. Save the presentation.

This C# code shows you how to add a video from the web to a slide in a PowerPoint presentation:

public static void Run()
{
    // Instantiates a Presentation object that represents a presentation file 
    using (Presentation pres = new Presentation())
    {
        AddVideoFromYouTube(pres, "Tj75Arhq5ho");
        pres.Save("AddVideoFrameFromWebSource_out.pptx", SaveFormat.Pptx);
    }
}

private static void AddVideoFromYouTube(Presentation pres, string videoId)
{
    // Adds a VideoFrame
    IVideoFrame videoFrame = pres.Slides[0].Shapes.AddVideoFrame(10, 10, 427, 240, "https://www.youtube.com/embed/" + videoId);
    videoFrame.PlayMode = VideoPlayModePreset.Auto;

    // Loads thumbnail
    using (WebClient client = new WebClient())
    {
        string thumbnailUri = "http://img.youtube.com/vi/" + videoId + "/hqdefault.jpg";
        videoFrame.PictureFormat.Picture.Image = pres.Images.AddImage(client.DownloadData(thumbnailUri));
    }
}

Manage Video Captions

Aspose.Slides allows you to manage closed captions for video frames in PowerPoint presentations. Captions are stored in WebVTT format and are exposed through the IVideoFrame.CaptionTracks property.

Add Captions to a Video Frame

To add captions to a video frame:

  1. Create an instance of the Presentation class.
  2. Add a video to the presentation.
  3. Add an IVideoFrame object to a slide.
  4. Use the CaptionTracks collection to add a WebVTT caption track.
  5. Save the modified presentation.

The following code shows you how to add captions to a video frame:

using (Presentation presentation = new Presentation())
{
    byte[] videoData = File.ReadAllBytes("video.mp4");
    IVideo video = presentation.Videos.AddVideo(videoData);

    ISlide slide = presentation.Slides[0];
    IVideoFrame videoFrame = slide.Shapes.AddVideoFrame(0, 0, 100, 100, video);

    // Adds a new captions track from a WebVTT file.
    videoFrame.CaptionTracks.Add("English", "track.vtt");

    presentation.Save("video_with_captions.pptx", SaveFormat.Pptx);
}

The ICaptionsCollection interface also provides an overload that lets you add captions from a stream.

Extract Captions from a Video Frame

To extract captions from a video frame:

  1. Load the presentation that contains the video.
  2. Find the target IVideoFrame object.
  3. Iterate through the CaptionTracks collection.
  4. Save each caption track to a .vtt file.

The following code shows you how to extract captions from a video frame:

using (Presentation presentation = new Presentation("video_with_captions.pptx"))
{
    ISlide slide = presentation.Slides[0];
    foreach (IShape shape in slide.Shapes)
    {
        if (shape is IVideoFrame videoFrame)
        {
            foreach (ICaptions captionTrack in videoFrame.CaptionTracks)
            {
                // Saves the captions track to a WebVTT file.
                string filePath = $"{captionTrack.CaptionId}.vtt";
                File.WriteAllBytes(filePath, captionTrack.BinaryData);
            }
        }
    }
}

Each ICaptions object exposes the caption identifier, label, binary data, and caption text as a UTF-8 string.

Remove Captions from a Video Frame

To remove captions from a video frame:

  1. Load the presentation that contains the video.
  2. Get the target IVideoFrame object.
  3. Remove caption tracks from the CaptionTracks collection.
  4. Save the modified presentation.

The following code shows you how to remove all captions from a video frame:

using (Presentation presentation = new Presentation("video_with_captions.pptx"))
{
    ISlide slide = presentation.Slides[0];
    IVideoFrame videoFrame = slide.Shapes[0] as IVideoFrame;

    // Removes all captions from the video frame.
    videoFrame.CaptionTracks.Clear();

    presentation.Save("video_without_captions.pptx", SaveFormat.Pptx);
}

If you need to remove only one caption track, use the Remove or RemoveAt methods instead of Clear.

Extract Video from a Slide

Besides adding videos to slides, Aspose.Slides allows you to extract videos embedded in presentations.

  1. Create an instance of the Presentation class to load the presentation containing the video.
  2. Iterate through all the ISlide objects.
  3. Iterate through all the IShape objects to find a VideoFrame.
  4. Save the video to disk.

This C# code shows you how to extract the video on a presentation slide:

// Instantiates a Presentation object that represents a presentation file 
Presentation presentation = new Presentation("Video.pptx");

// Iterates through slides
foreach (ISlide slide in presentation.Slides)
{
    // Iterates through shapes
    foreach (IShape shape in presentation.Slides[0].Shapes)
    {
        // Saves video to disk once VideoFrame containing video is found
        if (shape is VideoFrame)
        {
            IVideoFrame vf = shape as IVideoFrame;
            String type = vf.EmbeddedVideo.ContentType;
            int ss = type.LastIndexOf('/');
            type = type.Remove(0, type.LastIndexOf('/') + 1);
            Byte[] buffer = vf.EmbeddedVideo.BinaryData;
            using (FileStream stream = new FileStream("NewVideo_out." + type, FileMode.Create, FileAccess.Write, FileShare.Read))
            {                                                     
                stream.Write(buffer, 0, buffer.Length);
            }
        }
    }
}

FAQ

Which video playback parameters can be changed for a VideoFrame?

You can control the playback mode (auto or on click) and looping. These options are available via the VideoFrame object’s properties.

Does adding a video affect the PPTX file size?

Yes. When you embed a local video, the binary data is included in the document, so the presentation size grows in proportion to the file size. When you add an online video, a link and a thumbnail are embedded, so the size increase is smaller.

Can I replace the video in an existing VideoFrame without changing its position and size?

Yes. You can swap the video content within the frame while preserving the shape’s geometry; this is a common scenario for updating media in an existing layout.

Can the content type (MIME) of an embedded video be determined?

Yes. An embedded video has a content type that you can read and use, for example when saving it to disk.