Image Degradation on Conference Server Client Computers (282867)

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 using Exchange 2000 Conference Server with high-resolution cameras may notice image degradation, such as image blurring or flaring. The image degradation occurs after focusing on a stationary object for four seconds or longer.

CAUSE

The Telephony API (TAPI) 3.0 video-receive payload handler allocates only 8 buffers to reconstruct a video frame. When it is transmitting high-resolution video, the key frame can be split into as many as 17 packets. The payload handler delivers partial frames to the decoder because it does not have enough buffer space to reconstruct the whole frame, which can result in image degradation.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

The English version of this fix should have the following file attributes or later:

      Date        Time      Version      Size       File name
   ------------------------------------------------------------------
   2/27/2001   11:18a   5.0.2195.3310    265,488    Dxmrtp.dll
   2/27/2001   11:18a   5.0.2195.3310    277,264    H261_32.ax
   2/27/2001   11:18a   5.0.2195.3310    306,960    H263_32.ax

MORE INFORMATION

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.

This fix increases the default number of buffers to 20. If you need more than 20 buffers, you can modify the registry to configure the maximum video receive packets:

Start Registry Editor (Regedt32.exe).
Locate and click the following key in the registry:
HKEY_CURRENT_USER\RPH_PPM
On the Edit menu, click Add Value, and then add the following registry value:
Value name: MaxVideoPackets
Data type: DWORD
Radix: Decimal
Value data: 20
Quit Registry Editor.

For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:

249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes