One of the typical tasks where Media Processor Add-on can be useful is creating video thumbnails. For example, if you want to create a collection of your video files, for each of them you can store a small preview image along with other descriptive data. Later these screenshots can be displayed while you browse the collection.

The function that will create thumbnails should perform the following operations:

  1. Create a reader and open the source file.
  2. Find a non-empty frame in the source file. The simplest way to do it is to read a frame from the middle of the video file using the IFormatReader.LoadFrame(Int32) method.
  3. Create an empty instance of the Bitmap object.
  4. Initialize the Bitmap object with the resized frame in one of the ways:
  5. Save the bitmap, for example, with the help of the Save method.
  6. Close the reader.

The following code snippets show how this can be done.

Visual Basic

Public Sub CreateVideoThumbnail(ByVal inputFilename As String, ByVal _
    outputBaseFilename As String)
    Try
        'Create the reader
        Dim reader As IFormatReader = MediaFormatManager.CreateFormatReader _
             (inputFilename)
        'Get the frame
        If reader.FrameCount < 1 Then
            Console.WriteLine("File contains no frames.")
            Return
        End If
        Dim index As Int32 = reader.FrameCount / 2
        Dim frame As IFrame = reader.LoadFrame(index)
        'Save the frame using GetThumbnail()
        Dim image1 As Aurigma.GraphicsMill.Bitmap = New _
            Aurigma.GraphicsMill.Bitmap
        frame.GetThumbnail(image1, 160, 120)
        image1.Save(outputBaseFilename + "1.gif")
        image1.Dispose()
        'Save the frame using GetBitmap() and Resize
        Dim image2 As Aurigma.GraphicsMill.Bitmap = New _
            Aurigma.GraphicsMill.Bitmap
        frame.GetBitmap(image2)
        Dim transformation As Resize = New Resize(160, 120)
        transformation.ApplyTransform(image2)
        image2.Save(outputBaseFilename + "2.gif")
        image2.Dispose()
        reader.Dispose()
    Catch ex As Exception
        Console.WriteLine(ex)
    End Try
End Sub

C#

public static void CreateVideoThumbnail(string inputFilename,
    string outputBaseFilename)
{
    try
    {
        //Create the reader
        IFormatReader reader = MediaFormatManager.CreateFormatReader(inputFilename);
        //Get the frame
        if (reader.FrameCount < 1)
        {
            Console.WriteLine("File contains no frames.");
            return;
        }
        Int32 index = reader.FrameCount / 2;
        IFrame frame = reader.LoadFrame(index);
        //Save the frame using GetThumbnail()
        Aurigma.GraphicsMill.Bitmap image1 = new Aurigma.GraphicsMill.Bitmap();
        frame.GetThumbnail(image1, 160, 120);
        image1.Save(outputBaseFilename + @"1.gif");
        image1.Dispose();
        //Save the frame using GetBitmap() and Resize
        Aurigma.GraphicsMill.Bitmap image2 = new Aurigma.GraphicsMill.Bitmap();
        frame.GetBitmap(image2);
        Resize transformation = new Resize(160, 120);
        transformation.ApplyTransform(image2);
        image2.Save(outputBaseFilename + @"2.gif");
        image2.Dispose();
        reader.Dispose();
    }
    catch (System.Exception ex)
    {
        Console.WriteLine(ex);
    }
}