Real World Scenario Using NetShow Presenter

The following instructions briefly explain one way to use NetShow Presenter to set up and show the presentation from the CEO in one location to employees in another. Viewers watch the streaming video of the CEO talking and images of the PowerPoint slides on a Web page. The ASF stream and the PowerPoint presentation described in the example are not provided; however, the Web pages that viewers will use to stuff the browser's cache and to view the ASF stream and the slide presentation have been provided in the \Program Files\Microsoft NetShow\Samples directory. To make these Web pages work, you will need to edit the paths and IP addresses in the scripting to reflect the locations of your images and servers.

This example is an overview of how to set up and use NetShow Presenter to send PowerPoint slides as part of an ASF stream. To set up this example, you will need a Real-Time Encoder, a NetShow Server (for unicasting and multicasting), a PowerPoint station, an IIS server (for back-up unicasting of URLs), and a client. The example uses a separate computer for each component, although this doesn't have to be the case in all situations. It is possible to double up NetShow components on computers, although if you do this, be sure that the CPU on the computer that you use as the ASF Real-Time Encoder isn't overwhelmed. Encoding video and audio into an ASF stream is extremely CPU intensive and forcing that computer to encode audio and video, and do other tasks may cause the Real-Time Encoder to lock up.

Before the presentation begins, the presenter should announce the lobby Web page URL and when to go to that URL. When a viewer opens the Web page, a control within the page begins streaming images of the PowerPoint Slides to the viewer's browser. These images are placed into the browser's cache. By pre-loading the images into the browser's cache, you eliminate the time it would take the browser to download the images from the IIS server. When it is time for the presentation to begin, the lobby Web page automatically flips over to the main Web page that contains NetShow Player and begins rendering the video. Part of the ASF stream is script commands that send URL flips to the browser. These script commands are sent by the CEO, who triggers the URL flips by switching slides in PowerPoint. Because these URLs point to images that are already in the browser's cache, the browser can instantly display the image.

On the PowerPoint station, create and save a PowerPoint presentation.
On the PowerPoint Station, on the Tools menu, point to NetShow Presenter and click Export Slides. In the Export Slides dialog box, specify the directory on the IIS or HTTP server where you want to export the images. NetShow Presenter can copy the image files to a local directory or can use FTP to export the images to a remote directory. Make sure that both the FTP and HTTP servers have a copy of the image file in their root directory. In the Image Properties area, set the properties to reflect the dimension, quality, and format of the images that you want to export. If you are unsure of how you would like the images to look, use the default values and click OK.
NetShow Presenter connects to the specified computer and exports the PowerPoint slides as images.
To prepare for the employees who want to watch the presentation over the network, create a "lobby" Web page and a main viewing Web page.
Examples of these Web pages are in the \Program Files\Microsoft NetShow\Samples\Presenter directory. To make these Web pages work, you will need to edit the paths and IP addresses in the scripting to reflect the locations of your images and servers. The lobby Web page contains a hidden file transfer control which is used to stuff the viewer's computer cache with the images of the presentation slides. Stuffing the viewer's cache means that the viewer won't have to wait while their computer downloads the image because the image will already be available. The main viewing page contains a frame for watching the video stream, a frame for viewing the presentation slides, and a hidden file transfer control that continues to stuff the computer's cache with images of the presentation slides. The main viewing page contains a file transfer control so that, if the viewer didn't get all the images at the lobby page, hopefully the remaining images will be transferred into the cache before the image is called by the script command in the ASF stream. If the main web page were to receive a script command that called for an image that wasn't in the computer's cache, the browser would download the image from an HTTP server that contained copies of the presentation images.
On NetShow Server, define three programs and streams. You need to define a program and stream for a File Transfer Stream (FTS) that will pre-load the browser's cache while the viewer waits at the "lobby" Web page, another FTS that will continue to load the browser's cache while the viewer is watching the presentation Web page, and the ASF stream that will carry the audio and video. The ASF stream will also carry the URL script commands that flip the slides in the adjacent frame. See the NetShow System Administration Guide for information on setting up file transfer controls and embedding NetShow Player in a Web page to view video.
On the Real-Time Encoder, configure the encoder and save the configuration as an .asd file. The encoder must be set to use script commands. If script commands are not enabled, the script commands that PowerPoint sends when you switch presentation slides won't be included as part of the ASF stream which means that images of the presentation slides won't appear on the viewer's computer. See the Real-Time Encoder online Help file for information on creating .asd files.
Before you are ready to give the presentation, give viewers the URL for the lobby Web page and encourage them to go to the URL a few minutes before the presentation starts.
When viewers open the lobby Web page, the file transfer channel opens and begins transferring the presenation images to the computer's cache. At the time when you are going to start the presentation, the lobby Web page should automatically flip to the main Web page. The code to cause the lobby web page to flip to the main Web page is already in the lobby Web page. All you need to do is enter the correct time when the Web page should flip and the URL of the main Web page.
On the Real-Time Encoder computer, ready the video camera and microphone that will be used to record the CEO. The video camera should deliver a signal to the video card on the Real-Time Encoder and the microphone should deliver a signal to the sound card. Before the CEO is ready to begin the presentation, open the .asd file you created in step 5 and start the Real-Time Encoder.
The Real-Time Encoder will start delivering the video to NetShow Server, but NetShow Server won't stream the video to viewers until the Programs have been started. This step comes later.
On the PowerPoint station, in the Tools menu, point to NetShow Presenter and click Real-Time Encoder Settings.
The Real-Time Encoder Settings dialog box appears.
In the Real-Time Encoder Settings dialog box, for the Encoder, specify the Real-Time Encoder that will encode the ASF stream. In the BaseURL dialog box, type the URL to the directory that you created in step 1.
The BaseURL is important because when you move from slide to slide in the presentation, Presenter appends the name of each image to the URL and then sends this URL as a script command to the client. On the Image Format menu, select JPEG. Check the Use Real-Time Encoder (RTE) during slide show check box. Select Connect to running Real-Time Encoder. In the ASD File box, type the path to the .asd file you created in step 3. Click OK.
Before the presentation is scheduled to begin, on NetShow Server, start the three programs that you set up: the two FTS programs and the ASF stream program.
When you start the programs, NetShow Server begins delivering information. Any viewer who goes to the lobby will begin receiving the file transfer of the presentation images.
On the PowerPoint station, on the Slide Show menu, click View Show.
The PowerPoint presentation starts and connects to the Real-Time Encoder. The Real-Time Encoder starts streaming the video and audio. When the CEO switches slides, PowerPoint sends a URL script command to the ASF Real-Time Encoder, which then includes the command as part of the ASF stream multicast. When NetShow Player receives the URL script command, it sends the URL to the browser, which checks its cache before it downloads the URL from the network. The URL should already be in the cache and the image that pertains to the URL should be displayed in the browser frame. However, if the URL isn't in the cache, then the browser downloads the URL from the IIS server.