Bitstream errors occur when you use the Windows Media Video 9 Advanced Profile codec in Windows Media Player 11

Consider the following scenario: You use the Windows Media Video 9 Advanced Profile codec that is included with Windows Media Player 11 on a computer that is running Microsoft Windows XP or Windows Vista. You configure the Motion Vector Coding Method registry setting with a value of 1, 2, or 3 to code the motion vector information in field pictures. Then, you configure the Video Type registry setting with a value that indicates interlaced encoding. Also, you leave the Motion Search Range registry setting at the default value.

In this scenario, the resulting Windows Media Video bitstream may be incompliant with the VC-1 video codec specification. Because of this problem, bitstream errors may occur.

This problem occurs because you can only use extended delta Motion Vector if extended Motion Vector mode is enabled.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

To resolve this problem, use the Motion Vector Coding Method registry setting with a value of 1, 2, or 3 when the Motion Search Range registry setting is set to a non-default value. A non-default value is a value that is not zero. For safe measure, avoid using the option when you are encoding interlaced video. Also, avoid using the option when the Video Type registry setting is not set to a value of 0.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the advanced settings of the Windows Media Video 9 Advanced Profile codec that are enabled through registry settings, visit the following Microsoft Web page: