monark, Because Blu-ray discs are encoded near the very top layer of the disc with limited protection, the data is literally at higher risk to damage. Conversely, HD DVD maintains physical protection similar to standard DVD. Also concerns developed regarding Blu-ray's ability to manufacturer the discs at the capacity originally intended. In fact, with the Blu-ray launch in Japan, the discs are being created at single-layer 25 Gigabyte capacity, which is half of the originally intended 50 gigabytes.