With the increased support for HTML5 in many of the browsers today, there is now the built in ability to support 3 different kinds of video playback natively in the browser. The HTML5 standard supports H264 MPEG video, WEBM video, and OGG video formats. These files do not require a browser plugin for playback.
To add an HTML 5 video file, select the "Add" button and in the create slide window select the "Browse" button to navigate to the video file that you want to playback. A file dialog will open. Select the file you want. If you choose a file that is not in the 3 formats listed above, you will be prompted to retry.
Enter a width and height for the video embed, any background color, and schedule the slide if you wish. Click on "Save" to save the settings.