I tested too Lazarus&FPC svn. Latebinding doesn't work here.
There is also other problem. Parameter is URL, not filename.
EarlyBinding worked here with this change. (Otherwise it didn't play the file)
procedure TForm1.Button1Click(Sender: TObject);
var fn: widestring;
begin
fn := UTF8Decode('file:///'+StringReplace(FileNameEdit1.FileName, '\', '/', [rfReplaceAll]));
VLC.playlist.add(fn,'',vararrayof([':aspect-ratio=16:9']));
VLC.playlist.play;
end;