Runtime Registry Entry

When Windows Media Player encounters a custom file name extension, it looks for a registry subkey that matches the extension. The subkey is described in File Name Extension Registry Settings. One of the registry entries that can appear under the extension's subkey is the Runtime entry.

The Runtime entry specifies the underlying technology that Windows Media Player can use to play or convert digital media files that have the custom extension. The Runtime entry has the following form.

Name Type Value
Runtime REG_DWORD A positive integer that identifies the underlying technology.


The value of the Runtime entry must be one the following.

Value (decimal) Description
6 Render using the Windows Media Format SDK.
7 Render using Microsoft DirectShow.
13 Convert the file using the specified conversion plug-in. Requires Windows Media Player 11.


The Runtime registry entry values 6 and 7 are supported by Windows Media Player 9 Series and later. The value 13 is supported by Windows Media Player 11.

ConvertPluginCLSID Subkey

File Name Extension Registry Settings