function WMPOpenExt(Name: string; Exts: string; Desc: string): boolean;
var
  WMPExt: string;
begin
  Result := false;

  if (WMPCount + Length(Exts)) >= WMPOpenMaxChar then Exit;

  if Exts <> '' then
  begin
    if RegQueryStringValue(HKLM, PlayerExts + 'Types', Uppercase(Name), WMPExt) then
    begin
      Exts := WMPExt + ';' + Exts;
      WMPCount := WMPCount - Length(WMPExt) - 1;
    end;

    WMPCount := WMPCount + Length(Exts) + 1;
    RegWriteStringValue(HKLM, PlayerExts + 'Types', Uppercase(Name), Exts);
    RegWriteStringValue(HKLM, PlayerExts + 'Descriptions', Uppercase(Name), Desc + ' (' + Exts + ')');
    RegWriteStringValue(HKLM, PlayerExts + 'MUIDescriptions', Uppercase(Name), Desc);
  end;

  Result := true;
end;