 Because Blu-ray cases are smaller than DVD cases, more Blu-rays than DVDs can fit on a shelf.The "Mini Blu-ray Disc" (also, "Mini-BD" and "Mini Blu-ray") is a compact 8-centimetre-diameter (~3 in) variant of the Blu-ray Disc that can store 7.8 GB of data in its single layer configuration, or 15.6 GB on a dual layer disc.It is similar in concept to the MiniDVD and MiniCD.