But if you want the user to be able to stream the file directly, without being presented that message box, then you must perform some more steps. Create a new virtual directory on your SharePoint site inside the IIS (in the inetpub folder, wss, virtual directores, and then the sites folder), I named mine to “Webcasts”. Upload the wmv file to that Webcasts directory. Edit the directory security on the Virtual directory to Anonymous so that the user doesn’t get a login prompt.
Then create a new file inside the Webcasts-directory with the extension .wvx. This will trigger the wmv file and stream it directly inside Windows Media Player.
Open a text editor, such as Notepad. Type the following metafile script, but replace the URL with that of your file. Reference the audio or video file just as you would any other Web file:
add a href tag with only the filename: yourfile.wmv
Save the text file using the name of your digital media file followed by the .wvx extension if the metafile points to a file with a .wmv extension, or .wax if the metafile points to a file with a .wma extension, such as YourFile.wvx. You can also use the .asx file name extension for either audio or video.
Now, when you add the link to this wvx file by typing http://yoursharepointsite/webcasts/yourfile.wvx then the media file will stream in Media Player.