Permissions 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 Permissions entry.
The Permissions entry specifies the actions that Windows Media Player is allowed to perform on files that have the custom extension. The Permissions entry has the following form.
|Permissions||REG_DWORD||A set of flags, each of which grants permission for a specific action.|
The value of the Permissions entry is a bitwise OR of one or more of the following flags.
|Flag (decimal value)||Description|
|1||Permission for playback. Files having the registered file name extension can be played.|
|2||Permission for folder drop. Files having the registered file name extension will be included in the playlist created when the user drags a folder containing the files and drops it on the user interface of the Player.|
|4||Permission for media CD. Files having the registered file name extension will be included in the playlist created when a CD containing the files is inserted into the CD-ROM drive.|
|8||Permission for the library. Files having the registered file name extension can be added to the library. Required for conversion plug-ins.|
|16||Permission for HTML streaming. Files having the registered file name extension will be inserted into the Internet Explorer cache when delivered from a Web stream.|
|128||Permission for transcoding. Files having the registered file name extension can be transcoded to Windows Media Format under certain conditions. See IWMPTranscodePolicy::allowTranscode. Requires Windows Media Player 10 or later.|
When the user attempts to play a media file that has a custom file name extension, Windows Media Player looks for a registry subkey that matches the extension. If no match is found, the Player presents the user with a warning dialog box that prompts the user for permission to attempt to play the file. If you create digital media files with custom file name extensions, you can prevent this warning from appearing on the user's computer by registering the file name extension and providing a Permissions entry.
The Permissions entry (except for the flag value 128) is supported by Windows Media Player 9 Series and later. The flag value 128 is supported by Windows Media Player 10 and later.