In some embodiments, an electronic apparatus comprises at least one memory module, and a universal serial bus host controller coupled to the memory, wherein the USB host controller implements hardware assisted idleness endpoint detection. In an embodiment, a method for masking includes performing a prediction for at least one multimedia data block based on a prediction mode of a plurality of prediction modes. This structure allows quadrupole lenses to be formed as auxiliary lenses having strong focusing action horizontally and divergent action vertically, and thus an HV differential can be increased.