Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54702

Wrong plugins will be selected for WMV decoder
if we don't set format field.

Time length returned by ProcessOutput is equal to
the one passed to ProcessInput.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54724

Needed for mingw Firefox build.

This corrects what interface should be returned,  there isn't a hierarchy with
these IUISettings at all.  It should return IUISettings and the QI for
any others that it requires.