Bandwidth Simulator

When you create a streaming media presentation that targets audiences at different connection speeds, it's important to test your presentation at each target speed. Using the RealOne Player bandwidth simulator, you can use a single RealOne Player to evaluate how your presentation works at streaming speeds.

For More Information: See "Reaching Multiple Audiences" for background on targeting different audience bandwidths.

Streaming Your Presentations

The bandwidth simulator works only with clips that are streamed. It does not function when you play clips from your local computer. Although you can use a Web server, using Helix Universal Server (or an earlier version of RealSystem Server) is recommended for testing if you plan to stream to your audience over RTSP. If you do not have access to a Helix Universal Server used to stream actual content, you can download and install the free version of Helix Universal Server Basic on your desktop computer from this Web address:

http://www.realnetworks.com/products/server/index.html

Tip: By using Helix Universal Server on your local computer, you can test a presentation at any bandwidth, even at speeds higher than your computer's actual network speed.

Installing the Bandwidth Simulator

Installing Helix Producer Plus adds the bandwidth simulator to RealOne Player automatically. You should therefore download and install the latest version of RealOne Player from http://www.real.com. Helix Producer Plus is available for purchase and download at this Web page:

http://www.realnetworks.com/products/producer/index.html

Note: The bandwidth simulator is not included with the free version of Helix Producer.

Tip: If you install RealOne Player after you install Helix Producer Plus, you can install the bandwidth simulator by running the Bandwidth_Simulator_Setup.exe program in the Helix Producer Plus installation directory.

Running the Bandwidth Simulator

Once you have installed the bandwidth simulator and have a Helix Universal Server with content to stream, you can use the bandwidth simulator in RealOne Player.

To use the bandwidth simulator:

  1. Start RealOne Player and request your presentation from Helix Universal Server's content directory with File>Open. If you installed a copy of Helix Universal Server on your desktop machine, you typically can use the local host address to request the presentation, as shown in this example:
  2. rtsp://127.0.0.1/my_presentation.smil
    

  3. Give the RealOne Player command Tools>Bandwidth Simulator to display the bandwidth simulator.
  4. Tip: This command appears in the menu only after you've requested streaming content.

  5. Click and drag the bandwidth slider to the bit rate at which you want to test your presentation. The figure below shows the simulator set to an average streaming speed of 64 Kbps.
  6. Note: Choosing another bandwidth automatically restarts the presentation as long as Restart on Bandwidth Change is checked.

  7. Optionally, you can simulate one, five, or ten percent packet loss if you want to test how the presentation runs on a network, such as the Internet, where IP packets may be lost. A good Internet connection will lose no packets, or only a small percentage. The top range of 10 percent loss represents a severely bad connection.
  8. Monitor the presentation playback to ensure that it works properly for your chosen audience target.

Using the SMIL Test File

You can use the file bandwidth_simulation_test.smil in the samples/simulator directory of this online manual to test the bandwidth simulator. The file uses a <switch> group with inline text clips that report the approximate bandwidth of the simulated connection. Copy this SMIL file (it has no externally linked clips), to the content directory of your Helix Universal Server and request it through RealOne Player using an RTSP URL like one of the following:

rtsp://helixserver.example.com/bandwidth_simulation_test.smil
rtsp://127.0.0.1/bandwidth_simulation_test.smil

For More Information: The section "How to Download This Guide to Your Computer" explains how to get copies of sample files. For more on bandwidth switching, see "Switching Between Bandwidth Choices".


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