Some of the sites I've seen with information on the HD5 refer to its various file types (e.g. ATRAC) support at varying bitrates but, as far as mp3 goes, only list 128kbps. Excuse my potential ignorance here, but what does this mean - that it only plays mp3 at 128kbps? All my mp3s are encoded at 160kbps - would these work on the HD5..? Thanks for any answers.