Media Player Bandwidth Detection on "Hybrid" Internet Connection (253642)


The information in this article applies to:

  • Microsoft Windows Media Player 6.4
This article was previously published under Q253642
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you are playing streaming audio and video from the Internet in Windows Media Player by using a "hybrid" Internet connection (for example, an analog modem uplink and cable modem/DSL downlink), only the audio portion may be streamed, and the bit rate may show a much lower rate than is actually available.

CAUSE

This behavior occurs because the connection speed reported by the analog modem (TAPI) causes Windows Media Player to believe the bandwidth between the client and the server to be artificially low.

WORKAROUND

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To override the bandwidth detection logic (for Windows Media Player version 6.4.7.xxxx or later), create a DWORD registry value named ManualBandwidth in the following registry key:

HKEY_CURRENT_USER\Software\Microsoft\Netshow\Player\General

Set the data value, in bits per second, corresponding to the downlink bandwidth that is actually available.

MORE INFORMATION

Individual bandwidth measurements are stored in the registry (in bits per second) every time you open a streaming file from a new Microsoft Windows Media Services (WMS) server (version 4.1.0.3857 or later) by using the Microsoft Media Server (MMS)protocol. The measurements are stored in the following registry key:

HKEY_CURRENT_USER\Software\Microsoft\Netshow\Player\Remote\History

The values in this key are automatically flushed every time the client obtains a new IP address. If the client IP address has not changed recently and there are no readings in this key, the client is not communicating with a newer server. This is why the problem occurs on a hybrid network.

If the links to the files being streamed are HTTP links, Windows Media Player cannot empirically determine the bandwidth, so it must either rely on the history from MMS connections stored in the registry or use the speed the modem reports. This can be an issue for hybrid connections.

The new ManualBandwidth value overrides all detection logic, no matter what server the client is communicating with.
Modification Type:MajorLast Reviewed:8/6/2002
Keywords:kbenv kbprb KB253642
©2002 Microsoft Corporation. All rights reserved.