If data, which is irrelevant to recording data, is stored in a lower address of head word data of the run length compressed recording data stored in a receiving buffer unit, the irrelevant byte data of the lower address of the word data including the head byte data is nullified by masking to be developed by a decode circuit. The transition layer includes at least one of AlxGa1-xN layers provided on the initial buffer layer and an inserted buffer layer provided at least one of between the AlxGa1-xN layers, at a lower end portion of the transition layer, or at an upper end portion of the transition layer. The priorities can be assigned based at least upon prioritization rules that identify packets andor sub-packets most likely to successfully decode.