Wireless streaming

Wireless streaming scenarios apply primarily to three kinds of devices that are or very soon will be capable of rendering streaming media content: portable computers, personal digital assistants, and Internet-capable phones. If your target audience includes these devices, consider the following:

• Enable forward error correction on your publishing points. Forward error correction (FEC) is a common method of preserving the integrity of data transmitted over unreliable or slow network connections. When forward error correction is used, the server broadcasts extra packets on the assumption that some of the packets will be lost before they reach the client. This process enables the client to reconstruct the original transmission even if a significant portion of the packets are missing.
• PDAs typically have a much smaller viewing area than desktop computers or even portable computers. When encoding video for a PDA, you must accommodate not only the PDA's small screen size, but also its modest computing power. For example, the screen size of a Pocket PC is 320 pixels by 240 pixels, but the best compromise of picture quality, frame rate, and bit rate suggests a frame size of 208 pixels by 160 pixels and a frame rate of 20 frames per second. In order to render streaming video at full screen size, the frame rate must be reduced, which often makes movement on the screen excessively jerky. Additional encoding profiles for encoding content for mobile devices are available from the Windows Media Encoder page at the Microsoft Web site
• Cellular data transfer technology has not advanced to the point of permitting broadband access to streaming media. Devices that use Cellular Digital Packet Data (CDPD) or other cellular modem technology are generally restricted to a bit rate of 9.6 kilobits per second (Kbps or less). Bit rates in this range cannot support streaming video.

Note

• Forward error correction is available only if Windows Media Services 9 Series is running on the following editions of the operating system: Windows Server 2003, Enterprise Edition and Windows Server 2003, Datacenter Edition. If you are running Windows Server 2003, Standard Edition, this feature is not supported.

Related topics

• Streaming programming to subscribers
• To configure the Enable forward error correction property