As part of the office Web Applications Installation, the powerpoint service supports online viewing and editing of powerpoint files. The service also provides the PowerPoint broadcast feature, which delivers a PowerPoint Presentation in a multicast mode.
The PowerPoint service application requests the presentation from the Broadcast site. The PowerPoint service application then instructs worker processes to convert the presentation into a series of images or XAML (if Silverlight is installed), and temporarily stores output locally on disk. The PowerPoint service application then creates an attendee URL and returns the URL and broadcast session information to PowerPointFrame.aspx. PowerPointFrame.aspx then returns the attendee URL to the presenter’s browser who then can send the URL in e-mail or post the link for attendees.
During the presentation session, PowerPointFrame.aspx determines the presenter's current location in the presentation, retrieves the current slide from the cache, and renders the updated slide in the browser. Attendee browsers poll PowerPoint.aspx once per second to check for updates in the slide show presentation.