Just to be clear I do consider 24/44.1 hi res. I meant if the master was 16 bit upcoverted to 24bit (which in hindsight is unlikely as the audio would have been 16bit otherwise) Also should have mentioned that the minimum sample rate blu ray can have is 48k so conversion is required for 44.1 sources.Hi-Res does not mean higher sample rates as that is not what resolution indicates, that is the 24-bits. Higher sample rates spread the quantisation noise inherent in any sampling process over a wider bandwidth, and allow for low pass filtering with slower roll-off
By the way while on this subject can 24bit audio benefit to audio quality or does it only really benefit audio engineering?