As a general matter of practice I have always limited my authoring of DVDs to 2 hours of sound and video. It seemed to satisfy quality expectations of my clients as well as following the traditional 2 hour limit that VHS made us all believe was a standard length. So now I am being asked to create Blu-ray discs from fully HD sources as well as mixed sources. Are there any standards similar to the DVD perameters described above for Blu-ray programs? Time wise and bit rate wise etc.?